Thèses : « Anosognosia for spatial neglect »

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RONCHI, ROBERTA. « Behavioural monitoring disorders in unilateral spatial neglect : productive symptoms and impaired awareness of disease ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/19801.

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This doctoral thesis investigates the relationships between disorders of behavioural monitoring (including “productive” behaviours and unawareness of neuropsychological deficits) and unilateral spatial neglect in right-brain-damaged patients. One main monitoring disorder is recurrent perseveration, namely a “productive” motor symptom frequently found in target cancellation tasks: we demonstrate, in two specific tasks (Experiments 1 and 2), that the disposition of the stimuli and the type of target modulate its severity. Neglect patients showing perseveration in visuo-motor exploratory tests perseverate also in drawing tasks. No correlation between omission and perseveration errors is found, supporting the functional independence of the two deficits. In the context of a two-component hypothesis, perseveration (the first component) is a specific disorder that manifests in a variety of tasks, particularly those requiring serial graphic production; unilateral spatial neglect (the second component) may trigger and facilitate the production of perseveration errors. Moreover results indicate that patients with perseveration are not disproportionately impaired in tasks assessing executive, visuo-spatial short-term memory, and attentional functions, suggesting the specificity of the monitoring disorder associated with spatial neglect. Lesion analysis indicates damage to the right insula as a relevant neural correlate of perseverative behaviour. Experiment 3 shows that perseverating patients produce a majority of substitution errors during a word reading task, suggesting that also this type of paralexic neglect error can be considered a “productive” manifestation. The clinical, experimental and neural features of another monitoring deficit and “positive” manifestation referring to the personal space, “somatoparaphrenia”, are reviewed: somatoparaphrenia is a symptom usually associated with right-sided hemispheric lesions, most often characterized by a delusion of disownership of contralesional body parts. Possible pathological factors may include a deranged representation of the body concerned with ownership, mainly right-hemisphere-based, and deficits of multisensory integration. Finally, Experiment 4 investigates anosognosia for unilateral spatial neglect by a quantitative assessment. Results indicate that unawareness for spatial attentional and representational deficits is not a pervasive disorder, and that some tasks can evoke different degrees of awareness. In addition, the scores assigned by neglect patients to their performance in spatial tasks are not modulated by the different conditions of the estimation tasks. In conclusion, we demonstrate that: 1) “productive”, as “defective”, manifestations of unilateral spatial neglect are multifarious; 2) these “positive” phenomena are independent of general executive deficits and of the severity of the spatial neglect syndrome; 3) the neural bases of motor productive disorders included the right insula; 4) neglect patients are not globally anosognosic about their spatial defective performances.

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Campbell, Ransom Whitaker. « Dynamic Fluctuations in Emotion and Space Representation : A Functional Cerebral Systems Approach to Right Hemisphere Dysfunction ». Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100952.

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This study proposed an experimental test of theoretical models related to emotion and space representation in the brain. Previous research has established that emotion is represented, processed, expressed, and regulated largely by the right hemisphere. Furthermore, there is evidence from experimental paradigms and clinical case reports to suggest that the same hemisphere plays a dominant role in the processing of external space. A conceptual difficulty of clinical and neural network overlap arises when right hemisphere disorders of emotion are compared with those of spatial representation. The current experiment tested some of these hypotheses about emotion regulation and spatial representation in the right hemisphere using nonclinical subjects under a cortical stress paradigm designed to mimic the conditions of cortical duress. An additional goal was an extension of a previous study that examined emotional influence on spatial orientation. Results did not support our initial hypotheses. Subsequent analyses did provide some evidentiary support for some theories related to emotion and brain function. Additionally, patterns of subject performance were observed that support traditionally held theories of differential hemispheric function with regard to emotion and spatial behavior. These findings are discussed within the context of theories of emotion, spatial function, and disorders secondary to right hemisphere damage.
Doctor of Philosophy

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Gerafi, Joel. « A Unified Perspective of Unilateral Spatial Neglect ». Thesis, Högskolan i Skövde, Institutionen för kommunikation och information, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-6095.

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The aim of this review is to provide a unified perspective of unilateral spatial neglect (USN). USN is a neurological disorder frequently observed following damage or diseases to the brain. It is particularly associated with strokes to specific anatomical structures within the right hemisphere. Patients with USN fail to respond to or orient towards stimuli located in the hemispace contralateral to the lesion. They also show peculiar behavioral manifestations. There are several distinct subtypes of USN which can affect sensory or motor modalities, spatial representations, the range of space, or pure imagery. This disorder can appear in any sensory modality but the majority of studies have investigated the visual aspect of USN in these subtypes. Theoretical proposals are supported by empirical evidence deriving from neuroimaging which distinguish between these subtypes of USN. Thus, the heterogeneity of the disorder is evident and clinical assessment methods face great difficulties while prevalence rates vary. The neural pathways of spatial attention distinguish between the ventral and dorsal visual streams, both with distinct functional roles and anatomical bases. Prism adaptation (PA) is a common rehabilitation technique among many others and has shown positive effects on USN while having some limitations. A general discussion and concluding remarks are presented in the final section followed by future research suggestions.

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Walker, Robin. « Visual attention with implications for unilateral spatial neglect ». Thesis, Durham University, 1992. http://etheses.dur.ac.uk/5611/.

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Recent models of visual attention (eg. Rizzolatti et al., 1987) have suggested that a similar system orients visual attention as is used to produce a saccadic eye movement. This thesis provides further support for the link between the attentional and eye orienting systems and has incorporated ideas from recent models of saccade generation. The time taken by normal subjects to initiate a saccade ('latency'), is examined in Chapters two, three and four. Subjects were given attentional instructions and saccades made to either: unilateral single, or, bilateral double, targets. Latency to attended targets was not greatly enhanced, while latency to non-attended targets was greatly slowed. The results support both the premotor model of visual attention and models of visual attention that emphasise the inhibitory consequence of directed attention. Bilateral double targets produced an additional slowing on saccade latency, which could reflect a further automatic attentional inhibition produced in the contralateral field by the stimulus onset. Fixation point offset (in 'gap' situations) is known to reduce saccade latency, which has been attributed to prior attentional disengagement (Fischer, 1987). In Chapter two, the use of a gap situation produced a generalised speeding which was independent of the effects of directed visual attention. This suggests that active fixation affects a separate component to that involved in orienting visual attention to a spatial location. This idea is incorporated into a model which emphasises the inhibitory consequences of attentive fixation. Chapters six and seven report the findings from an experimental investigation of a patient (B.Q.) with a 'unilateral spatial neglect', a condition often attributed to a deficit of visual attention. The 'gap' paradigm was shown to be effective at reducing the severity of B.Q.'s contralateral neglect. In contrast to normal subjects, bilateral double targets did not have an inhibitory effect on her saccade latency. These findings are explained in terms of a model that neglect results in part from the loss of attentional inhibition for the ipsilesional side of space and in part an inability to switch off contralesional inhibition produced during active fixation. A functional model is proposed in Chapter eight to account for the findings. This supports the close link between the attentional orienting and saccade programming systems. An additional implication of the findings is that models of visual attention and saccade generation need to consider the inhibitory consequences of directing attention to a spatial location.

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FORTIS, PAOLA. « Prism adaptation : a rehabilitation technique for spatial neglect ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/28396.

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This doctoral thesis is divided in six chapters and presents the results of four experiments. It investigates the use of prism adaptation (PA) in the rehabilitation of spatial neglect, how PA may affect spatial cognition, and the specific mechanisms that are influenced by PA. Knowing more about the systems responsive to PA may help our understanding of which symptoms, and which patients, improve optimally after PA training. The Introduction explains concepts and backgrounds useful for the understanding of the experimental projects. First, the definition and characteristics of Unilateral Spatial Neglect are introduced, followed by a review of the distinction in the variety of spatial neglect that separates “perceptual” versus “premotor” neglect and the anatomical and functional dissociation between brain areas associated with these two subtypes of neglect. The Introduction summarizes paradigms that have been used to disentangle the perceptual and premotor components of spatial neglect and the patterns of perceptual and premotor biases reported in neglect patients. A description of different methods that have previously been used in the rehabilitation of spatial neglect is also provided. Among them, the PA technique is described in detail, including the background in which PA has been used, measures to assess the presence of adaptation and aftereffects following the adaptation procedure, processes that have been proposed to be involved in the sensori-motor transformation that occurs during PA, the beneficial effects reported after PA paradigms in neglect patients, and the effects of PA in healthy individuals. Finally, the Introduction gives an overview of the cerebral circuits that appear to be involved in PA based on data derived from brain imaging studies, studies with brain-damaged patients, and studies with primates. The next four chapters report the results of four experiments. These chapters are divided in two main parts. The first section focuses on the feasibility of using ecological visuo-motor activities, based on diverse and engaging visuo-motor tasks, during adaptation to prism. In Experiment 1, 10 neglect patients were submitted to both a standard pointing adaptation training (Frassinetti et al., 2002) and a training involving diverse ecological visuo-motor tasks (Ecological procedure). The effect of the two treatments was compared in a large assessment including a variety of neuropsychological tests as well as functional scales. In Experiment 2, the presence of adaptation and aftereffects was assessed during the ecological procedure, and these measures were compared with those obtained during the traditional pointing task. In Experiment 3, we used a modified version of the paradigm of Schwartz et al. (1997) and Na et al., (1998) to decouple perceptual-attention “where” and motor-intention “aiming” components in visuo-motor tasks (line bisection). The effects of PA on where and aiming components were tested in a large group of neurologically healthy individuals. In Experiment 4, the same effects were tested in a group of five neglect patients. Lastly, the General Discussion summarizes and integrates the results of the four experiments, highlighting the implications for the rehabilitation of spatial neglect. Results from these experiments show that PA training associated with varied visuomotor activities is an effective tool to ameliorate some aspects of spatial neglect as well as functional disabilities, being as effective as the more established pointing task. In the four experiments, measures of adaptation and aftereffects were obtained using three different adaptation procedures: pointing, ecological, and line bisection tasks. It is argued that these measures, especially the aftereffect measures, may be important for establishing the effectiveness of adaptation procedures in neglect rehabilitation. It appears that the three adaptation procedures (pointing, ecological, line bisection) can all induce error correction during the exposure phase. However, the ecological and the pointing procedure seem to create strong and prolonged aftereffects, with the ecological task even better in inducing aftereffects than the pointing task. By contrast, the line bisection task appears to induce weaker aftereffects, suggesting that its use may not be optimal in prism paradigms. Reasons for such differences are explored, focusing on the motivations for the increased aftereffects during the ecological procedure. Indeed, exposure to prism decreased the aiming bias after PA in both studies. In the group of healthy individuals, the initial left aiming bias was reduced after exposure to left-shifting prisms (Experiment 3). In a similar way, in the group of neglect patients the initial right aiming bias improved after exposure to right-shifting prisms (Experiment 4). In addition, in the healthy participants no changes in the aiming bias were found after exposure to right-shifting prisms and control goggles, indicating that the effect of left-shifting prisms was not due to increased familiarity with the task (Experiment 3). These results are interpreted and integrated in light of recent findings. Experiments 1 and 4 also showed the cortical areas associated with neglect in our patients and the responsiveness to the PA paradigm. Results confirmed that patients with right-sided brain lesions in the frontal-parietal cortical and subcortical areas are still able to adapt to the lateral shift induced by prism, and further suggested that adaption to prism and improvement in neglect symptoms can occur even in the presence of an occipital lesion. Finally, the Discussion addresses the question of how to differentiate the effect of the experimental manipulation from spontaneous recovery while testing the efficacy of new rehabilitation methods in brain-damaged individuals. Therefore, evidence for the specificity of our intervention is provided. It is argued that spontaneous recovery cannot fully account for the present findings of improvement in neglect symptoms after PA treatment (Experiment 1 and 4). It is also suggested that performing studies employing neurologically healthy subjects can help in providing evidence for the effect of a treatment on cognitive function. In particular, testing healthy subjects to better understand the functioning of PA in neglect patients is facilitated by the fact that healthy individuals show biases in spatial cognition that mirror the biases in neglect patients.

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Menon, Anita. « Assessment of unilateral spatial neglect post stroke in acute care hospitals : are we neglecting neglect ? » Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80332.

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Timely and accurate assessment of unilateral spatial neglect (USN) post stroke is a critical component of best practice, given that a recent Clinical Practice Guidelines for stroke has recommended the standardized assessment of USN within 48 hours of regaining consciousness following a stroke. This multi-centered, retrospective study using data from medical charts of a representative sample of individuals admitted to 10 Ontario acute care hospitals from July 15th to December 15th 2002, examined the prevalence, timing and frequency of use of standardized assessments to evaluate USN post stroke. Out of the 248 subjects who should have received a USN assessment, 37.5% received an assessment; only 13.31% with a standardized visual perception tool and of these, only 0.81% (n = 2) with a standardized tool specific to USN assessment. All clients receiving a standardized assessment were evaluated for USN in the near extrapersonal space, the hemispace within reaching distance of the patient: no patient received a standardized assessment for USN in the personal space or far extrapersonal space. Three standardized visual perception tools that include a USN component were used: the Clock Drawing Test (n = 22), the Ontario Society of Occupational Therapists (OSOT) Perceptual Evaluation (n = 8) and the Motor-Free Visual Perception Test (n = 1). Only 8 (3.23%) of the 248 clients were screened with a standardized tool within the 2-day critical period as recommended by Stroke Guidelines. Reassessment was rare, even in those with detected USN, such that only 1 subject was ever reassessed with a standardized tool.

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Fisher, Zoe. « The effects of prism adaptation on unilateral spatial neglect ». Thesis, Swansea University, 2009. https://cronfa.swan.ac.uk/Record/cronfa43074.

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This thesis concerns the syndrome of visual unilateral spatial neglect (USN). Pisella and Mattingley (2004) argue that two of the core deficits associated with USN, the ipsilesional reaction time (RT) bias (thought to reflect the ipsilesional attention bias) and the ipsilesional detection bias, may have distinct neural substrates and thus may dissociate. In the research reported in this thesis, the 'dissociation hypothesis' was explored in a single patient (JH). JH was impaired at detecting contralesional targets on the visual search task in near space but her far space contralesional target detection was comparable with a healthy control group. However, despite showing 'normal' target detection in far space her far space RTs were significantly slower to detect contralesional targets relative to ipsilesional targets. In fact her RT data was comparable with the far space RT data of 6 patients with USN and was significantly different that that of 10 healthy control participants. This data suggests that the ipsilesional RT and the ipsilesional detection bias can dissociate and may be underpinned by distinct neural processes. The patient was then given PA training. Overall, the analysis showed that the ipsilesional detection bias was ameliorated after PA but the ipsilesional RT gradient remained unchanged. A group study was carried out to explore whether PA ameliorated both the ipsilesional detection bias and the ipsilesional RT bias, (due to the limitations of the case study approach). As research has already shown that PA improves contralesional target detection (Rossetti et al., 1998; Frassinetti et al., 2002) the experiments asked whether increased target detection after PA is accompanied by a normalisation of the ipsilesional RT bias on a visual search task, as would be predicted if PA ameliorated USN by facilitating a redistribution of spatial attention (Rode, 2003; and Pisella, 1999). The findings showed that increased contralesional target detection was not accompanied by a normalisation of the ipsilesional RT gradient. This suggests that a) the ipsilesional detection and the ipsilesional RT bias are not intrinsically related and b) that PA does not facilitate a redistribution of spatial attention. It was argued that PA improves target detection by ameliorating the remapping deficit associated with PA (Pisella and Mattingley, 2004) without ameliorating the ipsilesional attentional bias. It was argued in the rationale section of this thesis that the conventional PA procedure described by Rossetti (1998) is a far space based procedure as patients adapt to the prismatic shift by pointing to objects in far space (beyond arm's reach). However, die patients in Rossetti's (1998) study, and subsequent studies by others, were asked to perform tasks that evaluated the effects of PA only in near space. The findings of Rossetti (1998) and others showed that 'far PA training' ameliorated left USN performance in near space, thereby suggesting that a common underlying mechanism involved in both near and far space processing is ameliorated by PA. A candidate for this mechanism may be the oculomotor system since research has shown that it may be involved in die detection of objects in both far and near space (Previc, 1995). Further, the oculomotor system has been implicated as being involved in the amelioration of USN after PA training (Serino et al., 2007). If it is the case that a mechanism common to processing of both near and far space is ameliorated by PA training, then near space training should also ameliorate USN of far space. On the other hand, there are indications in the literature that the oculomotor system is involved in processing of near and far space to different degrees, being more directly involved in processing of far than near space (Berti and Rizzolatti, 2002) There is also evidence that near and far space are processed by different neural circuits (Rizzolatti et al., 1987, 1985 and 2002). It is conceivable, therefore, that a PA training method based on processing of near space information would have a greater effect on neglect for near space than for far space. A 'near space' training procedure was therefore devised to explore this issue. Specifically, the experiments reported in Chapter 7 asked whether a 'near PA' procedure, which attempted to activate near/reaching circuits (in addition to the oculomotor system), would ameliorate USN in near and far space but to a greater degree in near space. The findings showed that 'near PA' significantly increased contralesional target detection in both near and far space with no enhanced benefit in near space. It was evident when carrying out die group study described above that not all patients benefited from PA training. The group data was re-analysed at a single case level and the findings showed that of the 9 patients who were given PA training only 6 showed a subsequent reduction in symptoms of USN. All of the patients who responded to PA showed error reduction and after effect. Of the patients who did not respond to PA, none showed error reduction and two showed an after effect It was concluded that error reduction and not after effect is the critical predictor of amelioration of USN symptoms after PA. A final longitudinal study explored how long the effects of PA lasted in three patients with USN who responded to PA training. The findings showed that the beneficial effects of PA were maintained for at least two years in one patient but two patients who initially benefited initially from PA lost their training gains over time.

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Malhotra, Paresh Arjun. « Spatial Working Memory and Sustained Attention in the Neglect Syndrome ». Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487565.

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Spatial neglect is most prominently associated with damage to the right cerebral hemisphere, especially parietal and frontal regions. Although many studies of the neglect syndrome have tended to focus on spatial pathological mechanisms, an increasing body ofdata points to right hemisphere involvement in spatial and nonspatial domains, including spatial working memory (SWM) and sustained attention. The experiments described here critically examine the roles ofSWM, sustained attention and their interaction in the neglect syndrome. By employing a vertical variant of the traditional Corsi blocks it was possible to demonstrate impaired SWM in neglect. A deficit was also found using a second 'purer' task, which required no manual response or memory for sequence order. Impairment on this task correlated with neglect severity, providing evidence for a contributory role for impaired SWM in neglect. Sustained attention was examined by assessing the ability to maintain attention to centrally-displayed visual stimuli. Patients with neglect were impaired, although there was no worsening ofperformance over time, or vigilance decrement. A subsequent study revealed that neglect patients have worsening performance over time only when maintaining attention towards spatial targets... suggesting a previously undescribed interaction between spatial impairment and sustained attention in neglect. Damage to white matter underlying parietal cortex was associated with both impaired SWM and sustained attention, consistent with evidence suggesting involvement for right fronto-parietal networks in both these domains. As impaired SWM and sustained attention appear to contribute to neglect, modulation of one or both of these might lead to improvement. A proof-of-principle trial using guanfacine, anoradrenergic agent previously shown to affect SWM and vigilance, demonstrated that, in selected patients, noradrenergic stimulation leads to improved search. Together, these studies detail the roles of impaired SWM and sustained attention in neglect, in addition to exploring a possible role' for targeted pharmacological treatment.

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Sullivan, Carol-Anne Maria. « The effects of lateralized stimulation on unilateral visuo-spatial neglect ». Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341860.

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Murphy, Peter. « A study of hemispatial neglect in man and monkey ». Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290408.

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Liang, Yiqing. « A Modelling Approach to Computer-Based Assessment of Visuo-Spatial Neglect ». Thesis, University of Kent, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499681.

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Sarri, Margarita. « Spatial neglect and extinction : modulations by task, stimulus and prism therapy ». Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1445044/.

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Spatial neglect is a multi-component neurological syndrome, with the deficits including losses in awareness, attention and exploration towards the contralesional side of space, most commonly after right-hemisphere stroke. Neglect does not invariably affect just a fixed portion of space, but instead can be modulated by stimulation and task demands, including attentional factors. This thesis examines how aspects of neglect may be modulated by top-down task manipulations or bottom-up stimulus factors or by interventions, such as prism adaptation, that may have potential therapeutic benefit. The experiments show that varying top-down task-demands can substantially modulate neglect as revealed on cancellation measures similar to those commonly used in diagnosis. Specifically I show here that awareness for items towards the left space in cancellation tasks can be significantly modulated by just changing the task goal, and thus by directing the patients top-down attention to different aspects of the same stimulus displays. Prism interventions are found to improve awareness in neglect patients for certain tasks and stimulus types, but not others. Moreover, prism after-effects in neglect patients are found to be much larger when measured by subjective straight-ahead rather than open-loop pointing indices, which may be of importance for future studies of therapeutic impact from prism adapatation. Exploratory anatomical analyses indicate that this impact may also depend on the brain areas lesioned. Finally, using the phenomenon of extinction (a related sign to neglect) as a paradigm case of cross-modal modulation of awareness, the neural correlates of awareness or of unconscious processing were investigated by means of fMRI, in a patient with cross-modal extinction of left touch by right vision that affected perceptual sensitivity itself. This revealed that extinction and awareness do not correlate solely with activation within particular brain regions, but also relate to functional coupling between brain regions. These studies demonstrate various aspects of awareness that can be compromised following brain injury in neglect patients, and some of the factors that can modulate their awareness.

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Sosa, Machado Yamaya. « Studies of Visuospatial Attention ». Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26486.

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Pseudoneglect (PN) reveals a contralateral bias in the deployment of visuospatial attention by the dominant (right) hemisphere. The magnitude of PN is phasically modulated by transient exogenous visual cues which automatically recruit attention to cued locations. Optimal cue-line onset asynchrony (SOA), cue-contrast of this cueing effect and the relative effectiveness of cue locations relative to line endpoints are unknown. Similarly, the direction of line scanning modulates the tonic bias, although the origin of this modulation is unknown. The present experiments aim at informing theories about visuospatial attention as well as some neurological conditions such as hemispatial neglect. Four experiments were conducted where observers performed a tachistoscopic visual line bisection task. In experiments 1-3, pretransected lines were preceded by peripheral cues delivered to the left and right line ends at a variety of (1) stimulus onset asynchronies (SOAs), (2) contrasts and (3) horizontal positions relative to the line endpoints. Experiment 4 used a tachistoscopic line bisection protocol to manipulate the type (saccadic, smooth pursuit) and direction (leftward, rightward) of attentional scanning, executed with or without eye movements (overt, covert) while performing eye-tracking. Experiment 1 demonstrated early attentional capture with optimal cue-line SOA of 60 ms. Experiment 2 demonstrated that cue contrasts below 12% were ineffective in modulating perceived midpoint and the maximal effect occurred for cues of 100% contrast. Experiment 3 demonstrated modulation of the spatial error resulting from cues at all locations except the one lying completely beyond the line endpoints. Experiment 4 showed that leftward scanning resulted in leftward error and rightward scanning resulted in rightward error. Smooth pursuit scanning was more potent than saccadic scanning. Overt scanning was more potent than covert scanning and overall the strongest effects were found in leftward overt smooth pursuit scanning. Results from the cueing experiments suggest that the mechanisms subserving exogenous attentional capture in line bisection are fast, predominantly parvocellular-mediated and exert their effects at least partially in an object-referenced coordinate system. Experiment 4 suggests attentional magnification of the left line halve where visuospatial attention is deployed asymmetrically ahead of a scanned target.

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Raghavan, Charumati. « Hemispatial neglect : an evaluation of novel assessment methods and rehabilitation ». Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:793e3bae-afab-436e-9ca1-4c991d8ea99a.

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Hemispatial neglect, is a major cause of post-stroke disability and poor functional recovery. Hence, identifying sensitive methods to assess and rehabilitate neglect is important. Chapters 3 and 4 focused on development of novel assessment techniques for representational neglect. The 'Shopping Mall' and 'Clock Cueing' tasks improved upon previous tests and were useful in identifying dissociations in representational neglect based on type of stimuli (topological, non-topological) and time of assessment (pre-stroke, post-stroke) in chronic stroke patients. Chapters 5 and 6 investigated the efficacy of offline inhibitory repetitive Transcranial Magnetic Stimulation (rTMS) in producing short (<1 month) and long term (>6 months) changes in visual neglect behaviour. Overall, the findings from these chapters were limited due to lack of sufficient power. After controlling for the effect of baseline performance, the Intervention group's Activities of Daily Living scores significantly improved in the short-term post rTMS, as compared to the Control group. The fMRI task attempted to recruit attention-based top down modulation of sensory activity. It revealed relative hypoactivation of the right occipital lobe in the four left neglect patients tested, both pre and post rTMS, when compared to elderly controls. Chapter 7 explored cognitive predictors of spatial and object neglect in the sub-acute stage after controlling for demographic and stroke related factors, using multivariate blocked logistic regressions. Cognitive performance indicative of spatial attention and selective attention to local features predicted both spatial and object neglect. In addition, coding of spatial relations between features also predicted spatial neglect. Suggestions for combining neglect rehabilitation techniques to target these cognitive processes are discussed. Overall, this thesis provides novel methods to improve representational neglect assessment and highlights the importance of ancillary cognitive domains in contributing to both representational and visual neglect. The rTMS research provides study design-related insights to incorporate in future studies with larger patient samples.

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Bareham, Corinne Anne. « Investigation of alertness as a modulator of spatial bias : rehabilitation of neglect ». Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648676.

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Petzold, Anita. « Increasing knowledge of best practices in occupational therapists treating post-stroke unilateral spatial neglect ». Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=96950.

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A significant gap exists between evidence-based practice (EBP) and actual occupational therapy (OT) practice in the management of a disabling post-stroke impairment - unilateral spatial neglect (USN). With improved patient outcomes linked to the use of best practices, it is crucial to modify OTs' actual practices in stroke care. To date, no research study has used knowledge translation (KT) to increase knowledge of EBP specific to OTs managing post-stroke USN. The first manuscript of this thesis explores how the "Knowledge to Action Process" model developed by Graham and colleagues, can be used as a step by step guide in creating an effective KT intervention for OTs working in acute stroke care. It describes how previous research has already addressed the "Knowledge Creation" domain of the model through the creation of synthesized materials and knowledge tools. It then goes on to describe how the first two steps of the "Action Cycle" domain have also been addressed; the main problem between EBP and actual practice has been identified and the evidence on best practice USN management has been adapted for acute care. The subsequent two steps that have not yet been addressed include assessing barriers to knowledge use and implementing an intervention. The Knowledge to Action Process model stresses that in order for a KT intervention to be effective in changing clinician practices, the facilitators and barriers faced by clinicians treating a specific clientele, in a specific type of setting, need to be identified.A few studies have assessed the barriers and facilitators to using EBP in rehabilitation; however none are specific to occupational therapists treating post-stroke USN. Thus, the objectives of the second manuscript were twofold: Phase 1) to identify the barriers and facilitators that affect EBP use by acute care OTs treating individuals with post-stroke USN; and Phase 2) to create, to pilot test, to evaluate the feasibility and to conduct preliminary analyses of effectiveness of a multi-modal KT intervention geared towards increasing EBP knowledge acquisition and self-efficacy for USN assessment and treatment. A sub-objective was to conduct preliminary analyses of the association between potential explanatory variables and change in knowledge acquisition and EBP self-efficacy.In the first phase, two focus groups (n=9) were held where acute care OTs treating patients with stroke discussed the barriers and facilitators to EBP use faced in practice. Key barriers included lack of time and basic EBP skills, and lack of personal motivation to change current practices and habits. Key identified facilitators included a multidisciplinary stroke team, recent graduation, and having access to learning material and several educational days annually. In the second phase, a multi-modal USN KT intervention was pilot tested on 20 OTs from Quebec and Ontario. Clinicians took part in an 8 week intervention beginning with a 7 hour in-person USN KT training session. This was followed by an 8 week reinforcement period where they continued their learning online. A pre, pre, post assessment of the main outcome - knowledge of best practices in USN management, was measured online via the Knowledge Questionnaire. The secondary outcome EBP self-efficacy, was assessed using the EBP Self-Efficacy Scale immediately prior to and following the in-person training session. All OTs improved in knowledge of EBP USN management and as a group, a statistically significant improvement was achieved. Similarly, significant improvement was found in clinicians' level of EBP self-efficacy. These results demonstrate that a multi-modal KT intervention based on the Knowledge to Action Process model and identified barriers and facilitators is feasible and effective based on preliminary analysis. However, further investigation of this KT intervention through a randomized control trial is necessary to validate the results on effectiveness obtained in this study.
Il existe un grand écart entre les données probantes et la pratique actuelle des ergothérapeutes traitant les patients qui ont subi un accident vasculaire cérébral (AVC) et qui sont atteints de la négligence spatiale unilatérale (NSU). Il est très important de modifier les pratiques actuelles de ces cliniciens vu l'amélioration remarquable des symptômes de NSU reliés à l'utilisation des données probantes. À date, il n'existe aucune étude de recherche utilisant l'application des connaissances (ADC) comme moyen d'augmenter les connaissances des données probantes spécifiquement pour ergothérapeutes traitant la NSU. Le premier manuscrit de cette thèse décrit comment un modèle d'ADC le « Knowledge to Action Process » conçu par Graham et collègues, peut guider le développement d'une ADC efficace ces ergothérapeutes. Il décrit la façon dont les études de recherches précédentes ont déjà adressés le domaine de la création des connaissances. Le manuscrit poursuit en décrivant comment les deux premières étapes du domaine du cycle d'actions ont aussi été adressées. Les deux étapes suivantes qui évaluent les obstacles à l'usage des données probantes et qui mettent en œuvre une intervention d'ADC n'ont pas été adressé à date. Le modèle souligne que l'intervention d'ADC ne pourra être efficace que si les obstacles et facilitateurs vécus par les cliniciens travaillant dans ce domaine sont identifiées. Il existe aucune étude à date qui identifie les obstacles et facilitateurs à l'utilisation des données probantes pour ergothérapeutes travaillant avec les patients avec AVC et la NSU. Les objectifs du deuxième manuscrit sont : Phase 1) d'identifier les obstacles et facilitateurs qui contribuent au manque d'utilisation des données probantes par les ergothérapeutes travaillant en soins aigues avec les patients atteints de la NSU suite à un AVC, et Phase 2) de créer, d'évaluer la plausibilité et d'exécuter des analyses préliminaires d'efficacité d'une intervention d'ADC ayant comme but d'augmenter les connaissances des données probantes et aussi d'auto-efficacité dans l'évaluation et le traitement de l'NSU parmi le même groupe de cliniciens.Dans la première phase, deux groupes de discussions (n=9) avec ergothérapeutes des soins aigues travaillant avec les individus atteints de NSU suite à un AVC ont eu lieu. Les obstacles les plus importants étaient le manque: de temps, d'habileté dans le domaine des données probantes, et de motivation personnelle à changer leur pratique actuelle. Les facilitateurs dominants étaient ayant: une équipe de AVC composée de différentes disciplines, terminée les études récemment et accès aux matériaux d'apprentissages et journées de formation annuellement. Dans la deuxième phase, une intervention d'ADC a été mise à l'essai sur 20 ergothérapeutes provenant des provinces de Québec et de l'Ontario. L'intervention a commencé avec une formation de sept heures suivie par huit semaines de renforcement où les cliniciens ont continué leur apprentissage sur l'internet. Deux évaluations préliminaires et une ultérieure des résultats principaux – les connaissances des données probantes pour la gestion de l'NSU ont été mesurées à travers le « Knowledge Questionnaire » répondu sur l'internet. Le deuxième résultat - d'auto-efficacité pour utiliser les données probantes a été évalué en utilisant le « EBP Self-Efficacy Scale». Les résultats ont démontré que tous les ergothérapeutes ont amélioré leurs connaissances de la gestion de la NSU et en tant que groupe, une amélioration significative a été atteinte. De même, une amélioration significative a été remarquée au niveau d'auto-efficacité pour l'utilisation des données probantes. Ces résultats démontrent qu'une intervention d'ADC basée sur le « Knowledge to Action Process » est réalisable et basée sur l'analyse préliminaire est aussi efficace. Cependant, un essai de contrôle randomisé est requis pour valider les résultats obtenus ici sur l'efficacité de l'intervention d'ADC.

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INVERNIZZI, PAOLA. « Productive symptoms in right brain damage : behavioural and anatomical observations ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/28151.

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This thesis describes behavioural observations and anatomical investigations concerning productive symptoms observable in right brain damaged patients with spatial neglect. A "productive" symptom is defined here as a behavioural manifestation that, contrary to what observed when performance is lacking or its failure is acknowledged by patients, is characterized by the active generation of acts or verbal reports reflecting a distorted mental representation of reality. A first classification of productive symptoms in neglect patients pertains the spatial frame of their manifestation, extrapersonal or personal. Following this classification, I examine these manifestations in separate sections of the thesis. Section 1 is dedicated to the peri/extrapersonal space, while, in Section 2, I focus on symptoms manifesting in the own bodily space. In chapter 2, I concentrate on graphic perseveration in cancellation tasks, the main productive symptom observable for the extrapersonal space in neglect patients. Together with omission of left-sided targets, a variety of irrelevant marks over already cancelled targets on the ipsilesional side can be observed. It is not clear whether these perseverative behaviours are functionally and anatomically connected, nor whether they correlate with the severity of spatial neglect. We retrospectively identified two well-distinct forms of perseveration on cancellation tasks ("additional marks" and "inkblot") in 33 neglect patients, and we investigated their relationship with neglect severity and their anatomical correlates. We show, on both a behavioural and anatomical level, that different kinds of perseverative behaviours are differently related with neglect. From chapter 3 onwards I concentrate on productive manifestations in personal space. One main such productive symptom is somatoparaphrenia, the delusional belief whereby a patient feels that a paralyzed limb does not belong to his body; the symptom is typically associated with unilateral neglect and most frequently with anosognosia for hemiplegia. In chapter 3, I describe the anatomical pattern associated with somatoparaphrenia in a wide sample of patients, and I propose that somatoparaphrenia occurs providing that a distributed cortical lesion pattern is present together with a subcortical lesion load that prevents most sensory input from being processed in neocortical structures. In chapter 4, I also show how somatoparaphrenia, that, so far, has been often considered simply the most severe and delusional manifestation along a continuum of body disorders also including anosognosia for hemiplegia, can be also observed in isolation from this symptom. I report anatomical observations on a small group of pure somatoparaphrenic patients and discuss the implications of this uncommon symptomatological dissociation. The experiments mentioned so far were based on classical anatomoclinical correlation inference. The study of productive/positive symptoms, however, would ideally need functional methods as well, in order to capture the neural correlates of the "active" component implied by the symptoms under investigation. I present an initial attempt along these lines. I considered the delusional behaviour of patients with anosognosia for hemiplegia (AHP): this has been often classified as a “negative” symptom as patients crucially “lack” the awareness of the motor deficit. However, beyond this defective aspect, AHP is usually characterized by an active delusional component that manifests in the patients’ firm assertion of having performed a movement with the paralyzed limb, in spite of any clear evidence that no movement has actually occurred. In this case, one has to postulate the presence of a residual, and maybe misinterpreted, motor brain activity to account for this delusional component. Here I illustrate, for the first time, the missing direct imaging evidence that the illusory movement of the left plegic hand is associated with brain activation of intact cortical motor regions implicated in motor control and intention (see chapter 5). It is suggested that motor delusions observed in AHP depend on a combination of well placed lesions and the presence of some motor intentionality represented by residual activity within the spared motor cortices. The diversity of the phenomena considered in this thesis makes it difficult to generalize anatomical considerations about productive manifestations associated with spatial neglect; yet, it is worth of notice the fact that all these disorders can be also conceptualized as self-monitoring disorders particularly related to motor/sensory control aspects in which the opercular part of the inferior frontal gyrus seems to play an important role. Indeed, we found it constantly involved in all the productive disorders considered, irrespective of whether defective monitoring was about the left plegic limb or the right intact one. In addition, we find it promising the adoption of functional methods to gather a more complete description of the neural underpinnings of symptoms of great complexity like the productive ones.

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Ogourtsova, Tatiana. « The involvement of the superior colliculi in post-stroke unilateral spatial neglect : a pilot study ». Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92279.

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The underlying mechanisms of the unilateral spatial neglect (USN), a highly prevalent and disabling consequence of stroke that responds poorly to existing interventions, remain unclear. Animal research suggests that post-stroke USN may be related in part to a disruption of visual attention mediated through the midbrain superior colliculi (SC). However, little attention has been placed on studying this mechanism in humans with post-stroke USN.
The first manuscript of this thesis presents a literature review on the implications of the SC in USN and reviews the rationale and potential for USN treatments aimed at involving the SC. Overall, 21 animal research studies and 24 human research studies were retrieved. Animal studies suggest a direct involvement of the SC in USN presentation and alleviation through a number of interconnections. It proposes that when the ipsilateral SC is deactivated, the animal presents with USN of the contralesional hemispace where the ipsilateral SC is found to be hypoactive, and the contralateral SC is hyperactive. This activity imbalance is restored after the contralateral SC is also deactivated, leading to USN alleviation. Nonetheless, given the paucity of human studies that were found, the contribution of the SC in USN, while plausible, remains to be confirmed. While intervention studies were retrieved where eye patching, with SC activity rationale, was used as a treatment for USN, several methodological issues were identified for future research in his area. Overall, it is suggested that further exploration of the mechanisms involved and their impact on USN in humans will help develop theoretically based intervention strategies tailored to USN type.
The implication of the collicular pathway has been studied using the spatial summation effect (SSE), where response to bilateral presentations is significantly faster that to unilateral presentations. It has never been directly analyzed in those with post-stroke USN. The objectives of the second manuscript, in which the thesis related study was conducted were twofold: 1. to determine the feasibility of investigating SC contribution using the SSE and, 2. to compare the SC contribution in three groups - individuals with left USN of the near extrapersonal space following right hemisphere stroke, those without USN following a right hemisphere stroke and healthy normal controls. This pilot study included individuals with (n=7) and without (n=10) right hemisphere post-stroke USN and individuals with no history of previous stroke and USN (n=10). All participants were tested on a computer reaction time test under two conditions: using both eyes and using a right monocular eye patch while responding to unilateral and bilateral achromatic stimuli presentations. An eye tracker device was used to control for fixation ability. It was found that the SSE was present in controls under binocular and monocular conditions. In individuals without post-stroke USN, SSE was found abnormal (under binocular and monocular conditions) where reaction times to bilateral stimuli were faster than to the unilateral left stimuli only and not to the unilateral right stimuli presentations. As for the participants with USN, we found that they had poor fixation ability by demonstrating either failure to fixate or several missed fixations (i.e. loosing fixation). Overall, the feasibility of using SSE to investigate the contribution of the SC in post-stroke USN is challenging with this population given poor fixation. Interestingly, the SC are connected to the frontal eye field in directing spatial attention and controlling voluntary and reflexive saccade eye movements that are involved in fixation. T
Les mécanismes neuronaux sous-jacents de la négligence spatiale unilatérale (NSU), une conséquence répandue et invalidante d'un accident vasculaire cérébral (AVC) qui répond pauvrement aux traitements, sont encore mal connus. Des travaux récents sur des animaux suggèrent que la NSU peut être liée en partie à une rupture du contrôle de l'attention visuelle médiée par les collicules supérieurs (CS) du mésencéphale. Toutefois, peu d'attention a été mise sur l'étude de ce mécanisme chez l'homme avec la NSU suite à un AVC. fr
Le premier manuscrit présente une revue de littérature sur les implications des CS dans la NSU et examine la justification et le potentiel, et vise à associer les CS à des traitements pour NSU. Au total, 21 études sur les animaux et 24 études sur l'homme étaient récupérées Les études chez l'animal suggèrent une implication directe des CS dans la présentation et l'allégement de la NSU. Principalement, lorsque la CS ipsilatérale est désactivé, l'animal présente la NSU de l'hémiespace contralésionnelle. Le CS ipsilatéral se trouve être hypoactif, et le CS contralatéral est hyperactif. Ce déséquilibre dans les activités des CS est rétabli suite à la désactivation du CS contralatéral mènant à l'allégement de la NSU. Néanmoins, étant donné la rareté des études sur l'homme qui ont été trouvées, la contribution des CS dans la NSU, tandis que plausible, reste à confirmer. Des études basées sur les connaissances des activités des CS chez l'homme ont été trouvées dans lesquelles la patche de l'il a été utilisée comme un traitement pour la NSU. Néanmoins, plusieurs questions doivent être abordées dans les futures études analysant l'effet de la patche de l'il sur la NSU. Dans l'ensemble, il est suggéré que l'exploration additionnelle et directe des mécanismes en jeu et leur impact sur la NSU chez l'homme contriburent au développement des stratégies d'intervention adaptées aux plusieurs types de NSU.
L'implication des parcours rétino-colliculaires a été étudiée en utilisant l'effet de la sommation spatiale (ESS), mais n'a jamais été directement analysé chez cieux avec de la NSU suite à un AVC. Les objectifs du deuxième manuscrit étaient de déterminer la faisabilité d'enquêter sur l'implication des CS en utilisant l'ESS et d'analyser la contribution des CS chez les individus présentant une NSU gauche de l'espace extrapersonnel près suite à un AVC de l'hémisphère droit (n=7), les personnes sans NSU suite à un AVC de l'hémisphère droit (n=10), et chez des individus sains (n=10). Les participants ont été testés sur une tâche de temps de réaction sur l'ordinateur en utilisant les deux yeux et en utilisant une patche monoculaire sur l'il droit tout en répondant à des présentations achromatique unilatérales et bilatérales. Un dispositif oculomètre a été utilisé pour measurer de la capacité de fixation. Par conséquent, l'ESS était présent chez les individus sains sous conditions binoculaire et monoculaire. Chez les personnes sans NSU, l'ESS était anormal (sous conditions binoculaire et monoculaire), dans lesquelles les temps de réaction aux présentations bilatérales étaient plus rapides qu'aux présentations unilatérales gauches, et pas droites. Les participants avec NSU ont démontré une capacité de fixation faible en démontrant soit une incapacité totale de fixer ou plusieurs pertes de fixation. En conclusion, la possibilité d'utiliser l'ESS pour enquêter sur la contribution des CS dans la NSU suite à un AVC est difficile étant donné une pauvre capacité de fixation. En effet les CS sont liés au domaine il frontal à diriger l'attention spatiale et le contrôle des mouvements oculaires volontaires et réflexes. Nous pouvons donc spéculer que l'incapacité à fixer indique une insuffisance des activités des CS chez des individus avec NSU suite à un AVC. D'autres recherches sur ce sujet sont nécessair

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VERONELLI, LAURA. « Spatial and linguistic encoding of orthographic material. Evidence from neglect patients in line bisection tasks ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/43292.

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In line bisection tasks, right-brain damaged patients with unilateral spatial neglect (USN) exhibit a rightward deviation with respect to the objective midpoint of the stimulus, while in neurologically unimpaired participants a reversed bias (“pseudoneglect”) has been consistently reported. In a study with healthy subjects, Arduino et al. (2010) suggested the existence of partially independent mechanisms involved in word and line bisection, not only linguistic but also visuo-perceptual. Furthermore, both lexical and syntactic factors are shown to modulate the reading performance in patients with neglect dyslexia (Rusconi et al., 2004; Cubelli & Beschin, 2005; Friedmann et al., 2011). A series of studies involving USN patients were conducted in order to investigate the spatial and linguistic encoding of orthographic material through a bisection task. In Study I, right-brain damaged patients with USN, right-brain damaged patients without USN, and matched controls were asked to manually bisect words (5-10-13 letters) and lines of comparable length (Exp. 1), and words with final sequences differing on the prediction made concerning how the word should have been read (stressed on the penultimate or antepenultimate syllable; Exp. 2). Study II required the bisection of words and lines of different lengths, radially oriented. In Study III, patients were asked to bisect affirmative and interrogative sentences varying on the syntactic structure, compared to letter strings and lines (Exp. 1), and sentences in which lexical and syntactic alterations were introduced (Exp.2). Data from Study I demonstrated that most USN patients show a rightward deviation similar for words and lines, with the bias increasing with stimulus length. However, in individual patients USN can affect the bisection of lines and orthographic material with various degrees of severity, demonstrating that at least partially independent mechanisms interact during bisection (Arduino et al., 2010). Furthermore, the ortho-phonological information contained in the final part of a word could act as a cue, modulating the bisection error in patients and healthy subjects. In Study II, radial words are re-oriented during bisection, reaching their canonical orientation. Finally, the linguistic nature of the stimulus induces facilitation in USN patients, who show a reduced error deviation in case of sentences with respect to letter strings and lines (Study III), even when lexical and syntactic alterations were introduced. In conclusion, visuo-perceptual and linguistic information (both lexical and possibly syntactic) modulates the allocation of attention in word and sentence bisection.

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Fordell, Helena. « Virtual Reality for Enriched Rehabilitation of Stroke Patients with Spatial Neglect : Diagnostics and the Rehabilitation Effect on Spatial Attention and Neuronal Activity ». Doctoral thesis, Umeå universitet, Institutionen för farmakologi och klinisk neurovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-141920.

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Background: Approximately a third of all stroke patients develop spatial neglect, a debilitating symptom associated with poor outcome. Spatial neglect is clinically defined as a deficit in processing and responding to stimuli presented on the contralesional side of the body, or the space surrounding that side of the body. The heterogenetic, multi-sensory nature of the symptoms renders it difficult to diagnose and treat; therefor effective methods for screening and intervention for neglect are needed. Virtual reality (VR) is a method of brain–computer interaction that involves realtime simulation of an environment, scenario or activity that allows for user interaction and targets multiple senses. We hypothesize that VR can facilitate identification of spatial neglect in stroke patients and that training with this interface will improve patient’s functional outcome, through stimulation to neuronal networks including those controlling attention. Objective: The objective was to construct and validate a computerized test battery for spatial neglect and to investigate its usability in stroke patients. Also to design and develop a VR rehabilitation method for spatial neglect and to evaluate its effects on spatial attention and on neuronal activity in the brain. Method: We designed, developed and evaluated a new concept for assessment (VR-DiSTRO®) and training (RehAtt®) of spatial attention, using VR technology. The hardware consisted of a PC, monitor, 3D-glasses and a force feedback device to control the tasks (i.e., a robotic pen). The software enabled targets to be moved, rotated and manipulated in the 3D environment using the robotic pen. RehAtt® made it possible to combine intense visual scanning training, multi-sensory stimulation (i.e., audio, visual, tactile) and sensory-motor activation of the contralesional arm. In a first study on 31 stroke patients we performed a construct validation of VR-DiSTRO® against Rivermead Behavioural Test Battery (BIT) and investigated the usability. In a second study, 15 subjects with chronic spatial neglect (symptoms >6 month) had self-training, 3 x 1 hour for 5 weeks using RehAtt®. Outcome were measured by changes in neglect tests and in Cathrine Bergego Scale (CBS). Training-related changes in neuronal activity of the brain was studied using fMRI during task and in resting state. Results: VR-DiSTRO® correctly identified all patients with neglect. The sensitivity was 100% and the specificity 82% for VR-DiSTRO® compared to BIT. Usability was high and no side-effects were noted. Using repeated measurement analysis, improvements due to the RehAtt® intervention were found for Baking tray task (p < 0.001), Star cancellation test (p = 0.006) and Extinction test (p = 0.05). Improvements were also seen in the Posner task as fewer missed targets (p = 0.024). Improvement in activities of daily living (CBS) was shown immediately after training (p < 0.01) and patients still reported improvement at 6 months follow-up. Trainingrelated changes in neuronal activity were seen as an increased task-evoked brain activity in prefrontal and temporal cortex, mainly outside the attention network but in related cortical areas. During resting state, changes in network connectivity were seen after intervention with RehAtt® in the Dorsal Attention Network (DAN) and interhemispheric connectivity. Conclusion: VR-DiSTRO® identified visuospatial neglect in stroke patients quickly and with a high accuracy. RehAtt® training improved in spatial attention in chronic neglect with transfer to functions in daily living. Increased neuronal brain activity was found in and between attention networks and related brain structures. This could represent a compensatory effect in addition to sign of a restorative effect from the RehAtt training. The results obtained in this study are promising, encourage further development of the methods and merit for further studies.

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Matthias, Ellen. « The influence of the level of alertness on spatial and non-spatial components of visual attention in healthy subjects and neglect patients ». Diss., kostenfrei, 2008. http://edoc.ub.uni-muenchen.de/8898/.

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Li, Dongyun [Verfasser], et Hans-Otto [Akademischer Betreuer] Karnath. « Trunk rotation affects temporal order judgments : evidence from spatial neglect / Dongyun Li ; Betreuer : Hans-Otto Karnath ». Tübingen : Universitätsbibliothek Tübingen, 2016. http://d-nb.info/1164168371/34.

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Guest, Richard M. « The diagnosis of visuo-spatial neglect through the computer-based analysis of hand-executed drawing tasks ». Thesis, University of Kent, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310163.

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Afifi, Linda Miriam. « The neural basis of behavioral recovery of chronic visuo-spatial neglect using repetitive transcranial magnetic stimulation ». Thesis, Boston University, 2012. https://hdl.handle.net/2144/12258.

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Thesis (Ph.D.)--Boston University
High frequency repetitive Transcranial Magnetic Stimulation (rTMS) has been used clinically on perilesional cortex to attenuate the neurological consequences of cerebral injuries. Presently the clinical benefits of rTMS remain controversial due to the high level of inter-individual variability in response to treatment. We explored the behavioral efficacy of multisession rTMS and studied the structural and metabolic characteristics underlying the recovery of visuo-spatial functions after unilateral parietal injury. A group of adult cats (n=12) underwent focal lesions in a region of the posterior parietal cortex (pMS, posterior middle suprasylvian area) leading to contralesional visuo-spatial deficits. Two and a half months post-injury, cats were treated with 7 consecutive rounds of 10 daily session of high frequency rTMS applied on an intact perilesional area (aMS, anterior middle suprasylvian area). We characterized two populations of animals: a group of 'Responders' (n=6) displaying significant visual detection improvements in contralesional hemispace and a group of 'Non-responders' (n=6) that did not show significant improvements and suffered unexpected decreases in ipsilesional performance. Detailed lesion analyses revealed no differences between the two groups neither in the amount of total spared cortex nor in the level of residual metabolic bactivity within areas of perilesional tissue. Additionally, we used 14C-2-deoxyglucose (2DG) to measure the metabolic impact of the aMS area on discrete nodes of the visuo-spatial network. When compared individually, none of the 60 regions proved to have significantly higher metabolic uptake in either group. Interestingly however, a cross-correlation analysis of metabolic activity throughout all sampled cortical and subcortical areas revealed that 'Responders' displayed a more metabolically cross-correlated visuo-spatial network than 'Nonresponders'. Furthermore, we found the aMS cortex in the 'Non-responders' group to hold no significant cross-correlations within the visuo-spatial network, indicating that the site of rTMS stimulation held no functional relationship with network regions. We conclude that multisession perilesional rTMS has the potential to induce behavioral ameliorations in chronic brain injury but the ability to consistently induce adaptive outcomes remains highly variable across animals. In addition, functional correlations indicate that rTMS-mediated recovery is dependent on the stimulated aMS cortex and its metabolic coupling with other nodes within visuo-spatial networks.

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Antoine, Sophie. « The spatial nature of ordinal information in verbal working memory ». Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/238833.

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At the beginning of this work, recent studies had evidenced a tight link between serial order in verbal working memory and space processing. In a first study, we investigated the nature of this link. By discarding the possibility that it results from conceptual associations, our results favoured the idea that the representation of serial order is intrinsically of a spatial nature. This led us to hypothesize that a deficit of space processing should be accompanied by a deficit of serial order. To test this hypothesis, we investigated verbal working memory abilities in a group of brain-damaged patients with hemispatial neglect, a syndrome characterized by a deficit of spatial attention. We showed that these patients have a specific deficit for serial order, as they showed difficulties when judging the ordinal relations between memorized items, whereas they were able to judge the identity of these items. This deficit of serial order was related to hemispatial neglect severity and to posterior parietal lesions. We formulated the hypothesis that the link between serial order and space results from the overlap of brain networks subtending these cognitive processes, at the level of the posterior parietal cortex. To test this hypothesis, we used transcranial magnetic stimulation (TMS) to temporarily disrupt this area in healthy participants, with the prediction that TMS would induce a similar bias when judging the position of a landmark on horizontal lines (spatial task), and when judging the position of an item in memorized sequences (ordinal task). In line with previous studies, TMS induced a bias in the spatial task. However, contrary to our prediction, TMS over the same area in the same participants did not induce a similar bias in the ordinal task.
Doctorat en Sciences psychologiques et de l'éducation
info:eu-repo/semantics/nonPublished

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MASSETTI, GEMMA. « A DIGITAL BATTERY FOR UNILATERAL SPATIAL NEGLECT : HOW NEW TECHNOLOGIES CAN MAKE THE NEUROPSYCHOLOGICAL EVALUATION MORE ACCURATE AND SENSITIVE ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/374741.

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La negligenza spaziale unilaterale (NSU) è un disturbo neuropsicologico dovuto a eventi cerebrovascolari (CVA), tumori cerebrali e lesioni cerebrali acquisite. I pazienti con NSU falliscono nell’orientarsi verso, rispondere e riportare eventi sensoriali che si verificano nel lato dello spazio e del corpo controlaterale al lato della lesione (tipicamente, il lato sinistro in pazienti con danno cerebrale destro), e nell’esplorare queste porzioni di spazio. La valutazione della NSU si basa soprattutto sulla valutazione delle prestazioni dei pazienti a test carta-e-matita. Tuttavia, sono ora disponibili evidenze emergenti che le tecnologie che si basano sui computer possano migliorare le procedure diagnostiche. I test computerizzati possono offrire più sensibilità e flessibilità, registrando molte più informazioni (ad es., l’accuratezza e i tempi di reazione simultaneamente). Queste caratteristiche riducono le possibilità di errore umano e permettono misurazioni quantitative e continue nei singoli pazienti, includendo un monitoraggio individuale e sensibile dei cambiamenti prestazionali lungo il corso di ripetute valutazioni. L’obiettivo principale della presente tesi di dottorato era quello di validare preliminarmente dei test digitali appositamente creati, comparandoli a test carta-e-matita tradizionalmente usati nella pratica clinica per la diagnosi di NSU. Tutti questi test sono stati creati in un ambiente digitale facile da usare e basato sull’utilizzo di uno schermo touch e di una penna digitale, così da simulare il tradizionale atto di scrittura. All’interno di tre studi, i partecipanti sani e i pazienti con danno cerebrale destro, con e senza NSU, sono stati sottoposti sia ai testi digitali che ai test carta-e-matita. Le analisi dei dati hanno mostrato risultati promettenti, suggerendo che i test digitali potrebbero condurre a una valutazione neuropsicologica più sensibile e precisa, smascherando inoltre casi di neglect residuale. Infine, i risultati presenti incoraggiano la raccolta di dati normativi per poter adottare i test digitali nella pratica clinica.
Unilateral Spatial Neglect (USN) is a neuropsychological disorder due to cerebrovascular accidents (CVA), cerebral tumours and brain injuries. USN patients fail to orient towards, respond to and report sensory events occurring in the side of space and the body contralateral to the side of the lesion (typically the left side in the right-brain-damaged patients), and to explore these portions of space. The assessment of USN has relied mainly on evaluating patients’ performances at paper-and-pencil tests. Nevertheless, emerging evidence that computer-based technologies may improve the assessment procedure is now available. More sensitivity and flexibility may indeed be offered by computerised tests, which typically record much more information (i.e., accuracy and reaction time measures simultaneously). These features reduce the chances of human error and allow for quantitative, continuous measures and even significance levels in single patients, including sensitive individual monitoring of performance changes through repeated assessments. The main aim of the present PhD thesis was to preliminarily validate purposely created digital tests, compared to similar classic paper-and-pencil tests traditionally used in the clinical setting for USN assessment. All these tasks were built up in a user-friendly digital environment based on touch screens and digital pens, simulating the act of filling in a paper-and-pencil set-up with the advantages of the touch system. Within three studies, healthy participants and right-brain-damaged patients with and without USN performed both the digital and the paper-and-pencil versions of tests. Data analyses showed promising results, suggesting that digital tests could lead to a more sensitive and precise neuropsychological evaluation, also unmasking cases of covert USN. Lastly, the present findings encourage the collection of normative data in order to adopt digital tests in clinical practice.

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Zhou, Yueqin. « Spatial Analysis of Substantiated Child Maltreatment in Metro Atlanta, Georgia ». Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/geosciences_theses/7.

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Identifying high-risk areas for child maltreatment to ultimately aid public health agencies for interventions is necessary for protecting children at high risk. Rates of substantiated neglect and physical/emotional abuse in 2000-2002 are computed for the census tracts in the urban area of five counties in Metro Atlanta, Georgia, and analyzed using spatial regression to determine their relationships with twelve risk variables computed from the Vital Records births and the 2000 Census data. After accounting for multicollinearity among risk variables and spatial autocorrelation among observations for neighboring locations, it is found that high percentages of (1) births to non-married mothers, (2) births to mothers who smoked or drank alcohol during pregnancy, (3) unemployed males and females, and (4) single-parent families with children under age six best predict the rates of substantiated neglect, and that high percentage of births to mothers who smoked or drank alcohol during pregnancy best predicts the rates of substantiated physical/emotional abuse.

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Volkening, Katharina [Verfasser], et Ingo [Akademischer Betreuer] Keller. « Processing of time and space in visuo-spatial neglect and the influence of galvanic vestibular stimulation / Katharina Volkening. Betreuer : Ingo Keller ». München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1101344156/34.

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Marques, Carlos Leonardo Sacomani. « Validação da escala de Catherine Bergego em pacientes com Negligência Espacial Unilateral após acidente vascular cerebral ». Botucatu, 2018. http://hdl.handle.net/11449/154396.

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Orientador: Rodrigo Bazan
Resumo: Introdução: A negligência espacial unilateral (NEU) é uma manifestação prevalente entre os pacientes com acidente vascular cerebral, porém seu diagnóstico é difícil e sua mensuração e repercussão na vida do paciente carecem de métodos de avaliação. A escala de Catherine Bergego tem por objetivo mensurar esse acometimento e o impacto no cotidiano do paciente. Não há validação desta escala na população brasileira. Objetivo: Avaliar a confiabilidade, compreensão e aceitação da versão em português da escala CBS em paciente com diagnóstico clínico de negligência espacial unilateral após Acidente Vascular Cerebral. Método: CBS foi traduzida, culturalmente adaptada e aplicada por dois investigadores independentes. O estudo foi transversal, em 22 pacientes após AVC confirmado por neuroimagem, tomografia de crânio e/ou ressonância de encéfalo. tomografia computadorizada. Além da CBS, foi aplicada a NHISS na entrada do paciente no hospital e no momento da avaliação da CBS, a BIT para diagnóstico da NEU e Barthel. A consistência e coerência foram analisados por meio de α-Cronbach, confiabilidade interobservador por meio do Kappa e a correlação entre as escalas de CBS, BIT mRS, NIHSS e Barthel por meio do coeficiente de Pearson. Resultados: Foram avaliados 22 pacientes sendo encontrado consistência e coerência de  = 0,913, obtendo excelente consistência. Em análise de reprodutibilidade interobservador através do Coeficiente de Kappa, a escala para os 10 itens, mostrou uma confiabilidade... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Introduction: spatial unilateral neglect (SUN) is a prevalent clinical manifestation in stroke patients, however its diagnosis is difficult, also mensuration and repercussion in patients’ life lacks evaluation methods. Catherine Bergego’s scale (CBS) has the objective of evaluate the impact in quotidian life. There is no validation fo r this scale in Brazilian population. Objective: evaluate confiability, comprehension and acceptation of the Portuguese version of CBS for patients with clinical diagnosis of SUN after stroke. Methods: CBS was translated, culturaly adapted and applied by two independent investigators. It’s a transversal study that evaluated 22 patients with stroke diagnosis confirmed by computed tomography, and a previous score in modified Rankin (mRs) scale of 0. Besides CBS there was application of the National Institute of Health Stroke Scale (NIHSS) at patients’ admission. Together with the CBS the Behaviour Innatention Test (BIT) was applied for NEU diagnosis, and Bartel scale for independency in daily life. Consistency and consistency were analyzed using α-Cronbach, inter-observer reliability using Kappa and the correlation between the CBS, BIT mRS, NIHSS and Barthel scales using the Pearson coefficient. Results: Twenty-two patients were evaluated and was observed consistency and coherence of  = 0.913. In the intra-observer reproducibility analysis using the Kappa Coefficient, the scale for the 10 items showed a reasonable and high reliability among the e... (Complete abstract click electronic access below)
Mestre

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CARELLI, Laura. « Modulation of visuo-spatial attention by means of emotional facial and bodily expressions : theoretical basis and empirical evidence ». Doctoral thesis, Università degli studi di Bergamo, 2011. http://hdl.handle.net/10446/858.

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Faces and bodies are both efficient in communicating emotions and attracting attention automatically. However, faces seem especially informative when seen in the near space, whereas bodies are particularly effective in the far space.
In the patient’s subgroup showing near-space neglect, a significant effect in reducing rightward bisection errors was found with both fearful and happy facial expressions presented in the near space, and with fearful and happy bodies presented in the far space. Conversely, in the patient’s subgroup showing far-space neglect, the most consistent reduction was observed for left-side fearful bodies shown in the far space. No significant effect was found with regard to healthy participants.
Fearful, happy and neutral facial or bodily expressions were used as lateral cues during a line bisection task. We studied 24 spatial neglect patients, 19 with a prevailing deficit in the near space and 5 with deficit in the far space. Besides, a 20 healthy participants group was recruited. Lines could be placed either near (60 cm) or far (150 cm) from the patients, who were asked to mask the midpoint regardless of the presence or nature of the lateral cues.
The present work bases on the available literature, showing that fearful and happy facial and bodily expressions may summon attention and overcome leftward bias in patients with hemispatial neglect. Here we tested the biologically-inspired hypothesis that faces are more effective than bodies in reducing neglect when presented in the near space, whereas bodily expressions are more effective when displayed in the far space.

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SPOSITO, AMBRA VALENTINA. « The spatial metric representation of body parts : behavioural and neuropsychological evidence ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/20101.

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The mental representation of the body is being a subject of intensive research from different perspectives starting from the 20th Century. Indeed, the body is a peculiar object for the brain, being at the same time a physical, space-occupying object and the critical mean for perception and action in the world around us. The present doctoral work focussed on the spatial representation of the body; in particular it was investigated whether the body holds a specific metric representation, which is supposed to be useful for action programming and interaction with the environment, as introduced in Chapter 1. To this aim Experimental Part 1 (Chapter 2 and 3) investigated the stable properties of the body metrics, while Experimental Part 2 (Chapter 4) focussed on its plastic and dynamic features. Chapter 2 discusses the differences between the spatial metric representation of body parts and non bodily three-dimensional objects. In particular, Experiment 1 investigated the possibility that Unilateral Spatial Neglect (USN) may affect to a different extent the spatial analysis of body parts relative to extrapersonal three-dimensional objects. Participants were required to bisect their left forearm and a length-matched cylinder with their right index finger. Both USN patients and neurologically unimpaired participants showed a significantly more accurate estimation of the subjective midpoint of the forearm, relative to the solid object. Besides the main pattern of an advantage in the forearm bisection, a further analysis suggested the possibility of a double dissociation, with two patients exhibiting the opposite advantage in the solid bisection. Experiment 2, asking unimpaired volunteers to perform the same bisection task in three different conditions (Forearm, Fake Forearm, Cylinder), showed a similar kind of spatial analysis for stimuli displaying bodily features, either real or fake, relative to non-corporeal objects. Thus, it can be suggested that the spatial processing of body parts critically depends upon their prototypical visuo-spatial shape and that the spatial metrics of body parts, relatively to noncorporeal objects, is also more resistant to the disruption of spatial processing and representation brought about by USN. Chapter 3, starting from recent evidence showing how the body can be used as an intrinsic metric system for the representation of near space, illustrates how the length of extrapersonal objects can be scaled using the metric representation of body parts, and to what extent a higher-order metric representation of the body relays upon the somatosensory system. Experiment 3 showed, by means of a bisection task, that the spatial encoding of an extracorporeal object (i.e., a cylinder) may be facilitated by the presence of the forearm in that space –i.e. when the forearm was placed inside the cylinder- as if participants can unconsciously rely on its well known metric representation in order to better estimate the length of the cylinder. In Experiment 4 the same task was administered to a group of right-brain damaged patients, with or without somatosensory and proprioceptive defict, and to a matched control group. The results showed that the spatial metric representation of body parts might be distorted, or even not available, when the somatosensory sensitivity is altered by a cerebral lesion. Data about the plasticity of the metric representation of body parts are presented in Chapter 4. In this last group of experiments, blindfolded participants were required to perform a radial proprioceptive bisection of their forearm before and after a training with a tool, which allowed an extension of the action space in the far space. The results of Experiment 5 supported the working hypothesis that the arm metric representation can be changed by tool-use. In this experiment participants performed a radial bisection of their arm and indicated the subjective midpoint of their arm more distally after the training, suggesting that the perceived length of their own arm was increased. Interestingly, no effect was obtained following a training with a shorter tool (i.e., 20 cm long). Experiment 6 further supported this interpretation by showing, through a proprioceptive control task, that the dynamic lengthening induced in the metric representation of the arm was not due to a mere illusory distal drift of the whole arm. Furthermore, it demonstrated that the spatial metric representations of the dominant and the non-dominant arms share similar plastic features, being both equally prone to be modified by tool use. In conclusion this doctoral work showed that body size holds a mental representation that is very stable (even more than that of extrapersonal objects), but also characterized by flexible functional plasticity.

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ALBONICO, ANDREA. « Dissociation between the focal and orientation component of spatial attention in detection, discrimination and reading tasks ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2016. http://hdl.handle.net/10281/100364.

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In our daily life, attention plays a fundamental role in governing our visual experience. Indeed, every visual experience consists in an overwhelming amount of visual information reaching our visual system. Selective attention allows us to select the relevant information, which is important for our goals, while ignoring the irrelevant information in our environment. However, selective attention is not a unitary notion, but a multi-faceted concept constituted by different components. Several models on how the attentional resources can be allocated in the space identify two distinct components: an orientation component, which moves the attentional resources to relevant locations for further processing, and a focal component, which allows us to converge our resource on a limited amount of space. The present dissertation inquires the classical view of these two components of selective attention, providing a characterization of both and their mutual relationship. Using a combination of behavioural and neuropsychological evidence, I investigated how these two components operate in different viewing conditions, with different temporal trends and different task demands. Finally, I examined how a deficit in the ability to adjust the attentional focus can condition the reading process in brain-damaged patients. By measuring the cue-size effect in healthy participants, the first set of studies characterizes how the focal component is deployed in the centre of the visual field. These studies show that, even if detectable in both exogenous and endogenous conditions, the facilitatory effect of the focal component is best revealed and more effective in exogenous conditions. Moreover, I elucidated the role played by the task demands and the stimuli used in evoking this facilitatory effect. The second set of studies, always on healthy participants, further extends these findings by showing that the focal and the orientation component are two independent components, which displayed their effects in different viewing conditions and with different temporal trends. The dissociation of these two components is evident not only in simple tasks, as single letter detection or discrimination, but also in a more reading-related task, consisting in discriminating a letter among others. At complement with evidence in healthy participants, the third set of studies investigates how a deficit in the control of the focal component could be responsible for the substitution errors that brain-damage patients affected by Neglect Dyslexia (ND) make in reading texts and single words. The substitution errors would depend on the difficulty to perceptually segregate the letters between each other, and a deficit in the control of the focal component would play a main role in increasing this phenomenon, by preventing the adjustment of the integration field necessary to identify and read the letter correctly. Overall, this set of experiments illustrates a dissociation between the focal and the orientation component of selective attention and suggests the existence of a causal link between the former one and the substitution errors in reading.

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Widengren, Mattias. « A HOPE FOR STROKE REHABILITATION : EXPLORING THE REHATT MIXED REALITY APPLICATION ». Thesis, Umeå universitet, Institutionen för psykologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185272.

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Unilateral spatial neglect (USN) is a common disorder after stroke. An application especially developed for stroke rehabilitation, the RehAtt Mixed Reality (MR) intends to train cognitive and motor functions that are affected by USN, by the means of interactive 3D games played in mixed reality, through smart glasses. The present study targets one specific cognitive function, namely spatial attention, and compares individual performances in one of the games (scenarios) to performances in a widely used test for detection of deficits in spatial attention – the Posner test. The hypothesis is that user reaction times in the RehAtt MR scenario correlates with user reaction times in the Posner test. Another test, including a questionnaire, to validate the usability of the RehAtt MR is also conducted. The sample for the usability test and questionnaire includes a total of 74 participants (47 women, 27 men, M = 39.6 years of age), of which 29 individuals (13 women, 16 men, M = 35 years of age) carried out the experimental part of the study. The results suggest that there is a significant correlation, r(27) = .411, p = .027, between reaction times in the Posner test and the scenario in the RehAtt MR, and that the product usability shows high quality. It is concluded that the results support that the scenario explored in the RehAtt MR trains spatial attention, although further research is needed for full validation.
Unilateraltspatialt neglekt (USN) är en vanlig funktionsnedsättning efter stroke. En applikation som utvecklats speciellt för strokerehabilitering - RehAtt Mixed Reality (MR) - har som mål att träna kognitiva och motoriska funktioner som är påverkade av USN, med hjälp av 3D-spel som spelas i mixed reality, genom smarta glasögon. Den aktuella studien siktar in sig på en specifik kognitiv funktion – spatial uppmärksamhet – och jämför individuella prestationer i ett av spelen i RehAtt MR med prestationer i ett vanligt, ofta använt test för att upptäcka nedsättningar i spatial uppmärksamhet – Posner-testet. Hypotesen är att användares reaktionstider i spelet i RehAtt MR korrelerar med användares reaktionstider i Posner-testet. Ett annat test, inklusive en enkät, görs också, för att validera användbarheten i RehAtt MR. 74 deltagare (47 kvinnor, 27 män, M = 39.6 år) finns med i användbarhetstestet och enkäten, av vilka 29 individer (13 kvinnor, 16 män, M = 35 år) medverkade i den experimentella delen av studien. Resultaten indikerar att det är en signifikant korrelation, r(27) = .411, p = .027, mellan reaktionstiderna i Posner-testet och spelet i RehAtt MR, och att användbarheten hos produktenvisar hög kvalitet. Slutsatsen är att vad som hittats i den aktuella studien stödjer idéen att spelet i RehAtt MR tränar spatial uppmärksamhet, även om vidare studier krävs för en full validering.

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Romeo, Zaira. « The cognitive demand of multitasking under visuo-spatial processing : Assessment, ERPs and electrophysiology of brain networks in chronic stroke patients ». Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3426801.

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This thesis investigates several aspects of visuo-spatial processing from a clinical, electrophysiological and neurofunctional perspective, with the aim of enriching our understanding of neurological syndromes that affect such fundamental perceptual-cognitive skill. A common thread is the use of cognitive load as a mean to study spatial awareness deficits following brain stroke. We show that increased task demands uncovers pathological spatial asymmetries both in right and left hemisphere damaged patients that performed at ceiling in standard paper-and-pencil tests. Although visuo-spatial deficits are commonly considered infrequent after left hemisphere lesions, the comparison between the two clinical populations showed that multitasking reveals patterns of neglect and extinction regardless of the affected hemisphere. A similar multitasking paradigm was then administered to young healthy participants in order to study the electrophysiological signatures of spatial monitoring, examining correct and erroneous processing of peripheral visual stimuli. Task difficulty was increased compared to the clinical version in order to obtain a consistent number of missed targets, thereby simulating patients’ performance. Our results support the hypothesis that processing of visual information under multitasking is regulated by a threshold criterion: the target is successfully detected only when the electrophysiological activity reaches a critical amplitude. Finally, we conducted a resting state electroencephalographic (EEG) study in order to correlate patterns of spontaneous brain activity with neuropsychological scores and multitasking costs indices. This investigation builds on the hypothesis that cognition is not only associated with the specialization of brain regions, but also with the large-scale organization of functionally connected networks. A state-of-art methodology was used to reconstruct 14 brain networks, previously detected in fMRI studies, from electrophysiological signals in chronic stroke patients. The integration of critical clusters within each network was then examined, exploring also its correlation with behavioural measures and the contribution of specific frequency bands. Overall, this empirical work provides an original contribution to the study of the mechanisms underlying brain organization after unilateral damage and the consequent implications for cognitive performance.
Questo lavoro di tesi indaga diversi aspetti relativi all’elaborazione visuo-spaziale da un punto di vista clinico, elettrofisiologico e neurofunzionale, al fine di contribuire allo studio dei disturbi neurologici che comportano deficit a livello percettivo. Il filo conduttore è stato l’utilizzo del carico cognitivo per studiare deficit di consapevolezza spaziale che possono emergere a seguito di un ictus cerebrale. Abbiamo mostrato come l’aumento della difficoltà di un compito sia in grado di rilevare asimmetrie spaziali patologiche in pazienti con lesioni cerebrali all’emisfero destro o sinistro che avevano una prestazione nella norma ai classici test neuropsicologici “carta e matita”. Sebbene i disturbi visuo-spaziali siano ritenuti infrequenti a seguito di lesioni emisferiche sinistre, sorprendentemente il confronto di queste due popolazioni cliniche mette in luce l’efficacia del multitasking nell’individuare pattern di negligenza ed estinzione indipendentemente dal lato della lesione. Una versione modificata del nostro paradigma di multitasking è stata inoltre somministrata ad un gruppo di giovani partecipanti sani al fine di studiare i correlati elettrofisiologici del monitoraggio spaziale, confrontando l’elaborazione corretta ed incorretta di stimoli apparsi nella periferia del campo visivo. La difficoltà del compito è stata aumentata rispetto alla versione clinica al fine di ottenere un consistente numero di stimoli non individuati e dunque di simulare la prestazione di pazienti neurologici. I nostri risultati supportano l’ipotesi che in condizione di multitasking l’elaborazione di informazioni visive sia regolata da un criterio di soglia. Nello specifico, la corretta percezione di uno stimolo è determinata dal raggiungimento di un’ampiezza critica dell’attività corticale. Infine, abbiamo condotto uno studio in resting state al fine di studiare la correlazione tra attività cerebrale spontanea e prestazione comportamentale, misurata attraverso classici indici neuropsicologici ed indici di costo al multitasking. Questo studio prende in considerazione l’ipotesi che la cognizione non sia associata soltanto alla specializzazione delle regioni cerebrali, ma anche all’organizzazione su larga scala di reti neuronali funzionalmente connesse. Attraverso l’utilizzo di un metodo di analisi allo stato dell’arte, 14 reti cerebrali, precedentemente studiate con tecniche di risonanza magnetica funzionale, sono state estratte dal segnale elettroencefalografico in un gruppo di pazienti con esiti di ictus in fase cronica. Inoltre, è stata analizzata l’integrazione di particolari cluster all’interno di ciascuna rete, indagando anche la relativa correlazione con indici comportamentali ed il contributo di specifiche bande di frequenza. In sintesi, questo lavoro empirico offre un contributo originale allo studio dei meccanismi sottostanti l’organizzazione cerebrale a seguito di ictus e delle relative ripercussioni sulla prestazione cognitiva.

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Patel, Vaidehi. « Effects of Early Life Neglect on Cocaine use during adolescence and subsequent effect on FGF-2 levels in adulthood ». Kent State University Honors College / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1588276506770239.

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Jacquin-Courtois, Sophie. « Plasticité sensorimotrice et cognition spatiale : généralisation des effets consécutifs de l’adaptation prismatique ». Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10209.

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L’adaptation des fonctions motrices permet l’optimisation des interactions avec l’environnement et ses modifications. Une des grandes questions posées à ce sujet concerne la spécificité des modifications implémentées. Dans la littérature traditionnelle sur l’adaptation visuo-manuelle au port de prismes, on retrouve une généralisation de l’adaptation à des positions spatiales non-apprises, mais un très faible transfert de l’adaptation aux autres effecteurs moteurs. Par contraste, les résultats thérapeutiques acquis chez le patient négligent depuis 12 ans suggèrent que l’adaptation visuo-manuelle peut produire des effets à tous les niveaux affectés par cette pathologie. Cette opposition apparente pose la question de la validité du modèle pathologique pour explorer l’adaptation sensori-motrice, et une façon d’y répondre est d’explorer les effets de l’adaptation sur les fonctions perturbées par la négligence chez le sujet normal. Ces trois volets de la littérature apportent des éclairages complémentaires sur la question de la généralisation des adaptations. Par la mise en évidence d’une généralisation des effets consécutifs de l’adaptation prismatique, notamment à un niveau transmodal, non impliqué dans la procédure d’adaptation per se, ce travail de thèse apporte des éléments pertinents en terme de niveau d’action et d’organisation des réseaux impliqués, laissant suggérer un effet de restructuration sur des représentations spatiales de haut niveau, permettant d’élargir l’orientation des stratégies de réhabilitation, par la mise en évidence d’une activation dynamique de fonctions et de réseaux liés à l’intégration multi-sensorielle, nécessaire aux représentations spatiales
Adaptation of motor functions allows optimization of interactions with environment and its alterations. One major question concerns specificity of implemented modifications. Classical data about visuo-manual adaptation to prisms reveal generalization of adaptation to non learned spatial locations, but a very poor transfer to others motor effectors. By contrast, therapeutic results obtained in neglect patients since 12 years suggest that visuo-manual adaptation could produce effects at various levels affected by neglect. This apparent opposition raises the question of validity of pathologic model to explore sensori-motor adaptation, and one way to answer is to explore effects of prism adaptation on disturbed functions by neglect in normal subject. These three sections of review bring out complementary lightings about question of adaptations generalization. By underlying generalization of after-effects of prism adaptation, in particular at a transmodal level, non implicated in adaptative procedure per se, these results bring some relevant arguments in terms of level of action and implicated networks organization, suggesting a restructuring effect on high level spatial representations, allowing to enlarge orientation of rehabilitative strategies. These results bring out a dynamic activation of functions and networks linked to multisensory integration, appropriate to spatial representations

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Braem, Bérenger. « Perception des orientations et intégration multisensorielle ». Thesis, Lille 3, 2014. http://www.theses.fr/2014LIL30010/document.

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La perception de la verticale repose sur l’intégration des informations vestibulaires, visuelles et somesthésiques. Elle est généralement étudiée dans la modalité visuelle (VVS) ou haptique (VHS) et plus rarement dans la modalité visuo-haptique (VVHS). Cette modalité pose la question de l’intégration des informations mises en jeu par ces deux modalités dans la perception multimodale et du modèle cognitif sous-jacent. Se pose également la question de l'effet des lésions cérébrales perturbant la perception spatiale (hémi-négligence) dans la perception de la verticale.Une comparaison des VVS, VHS et VVHS est réalisée dans les quatre premières études de cette thèse, chez des participants sains jeunes et plus âgés et chez des patients cérébro-lésés droits avecou sans troubles visuo-spatiaux. Les performances observées sont proches de la verticale gravitaire chez les participants sains pour les VVS et VVHS. La VHS (avec la main droite) est déviée, dans le sens horaire chez les jeunes participants et anti-horaire pour les participants plus âgés. La présence d’un cadre visuel perturbe les VVS et VVHS chez les participants dépendants à l'égard du champ.Les patients cérébro-lésés droits présentent une déviation anti-horaire des trois verticales, plus marquée pour la VHS. Les VVHS mesurées sont correctement prédites, dans toutes les conditions,par la somme des VVS et VHS pondérées par leurs précisions relatives. La variance de la VVHS est moindre que les variances des VVS et VHS. La VHS, systématiquement déviée dans ces quatre premières études, fait l’objet d’une évaluation détaillée dans les deux dernières études de cette thèse. Les résultats montrent que la VHS est déviée dans le sens horaire avec la main droite, dans le sens anti-horaire avec la main gauche chez les participants sains jeunes ; les déviations s’inversent avec l’âge. Par ailleurs, les performances sont systématiquement déviées dans le sens des positions initiales. Considérés ensemble, ces résultats montrent que la perception de la verticale implique les informations mises en jeu par les modalités visuelle et haptique mais avec une prépondérance de la première. Ce travail de thèse montre ainsi que la perception de la verticale subjective repose sur une intégration multimodale pondérée des informations sensorielles en accord avec le modèle statistique bayésien du maximum de vraisemblance. Ce mode d'intégration multi-sensorielle n'est pas altéré par l’âge ou la présence de lésions cérébrales affectant la perception visuo-spatiale. Plusieurs pistes restent à explorer, notamment, le poids de la contribution des informations vestibulaires dans la verticale subjective
The perception of the vertical direction is achieved through vestibular, visual and somatosensory information integration. It is studied in the visual (SVV), haptic (SHV) and less often in the visuo-haptic modality (SVHV). The latter raises the question of the integration of visual the information involved in the visual and haptic modalities and of the cognitive model underlying this integration. SVV, SHV and SVHV were compared in the first four studies of this thesis, inhealthy young and older subjects and in right-brain damaged patients with or without visuo-spatial disorders. Performances were closed to the gravity in healthy participants, for SVV as well as forSVHV. VHS, assessed with the right hand, was tilted clockwise in young participants and anticlockwise in older participants. The presence of a visual frame disrupted SVV and SVHV. The right-brain damaged patients had an anti-clockwise deviation of SVV and SVHV and the SHV was even more tilted. SVHV was well predicted from the sum of the SVV and SHV weighted by their relative variances in all conditions and the SVHV variances were lesser. SHV was evaluated in detail in the two last studies of this thesis because of the systematic tilt in the first four studies. The results show that the SHV is tilted clockwise with the right hand and anti-clockwise with the left hand in young healthy subjects. Moreover, deviations reversed in older group and performances are systematically tilted toward the initial positions in the two groups. Taken together, these results show that the way participants integrate visual and haptic information fits the maximum like lihoodmodel with a greater weighting of information available in visual modality and that ageing and right-brain lesions does not alter the multisensory integration. The weight of vestibular information in the subjective vertical, which has not been evaluated per se in this thesis, needs further investigations

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Blini, Elvio A. « Biases in Visuo-Spatial Attention : from Assessment to Experimental Induction ». Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424480.

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In this work I present several studies, which might appear rather heterogeneous for both experimental questions and methodological approaches, and yet are linked by a common leitmotiv: spatial attention. I will address issues related to the assessment of attentional asymmetries, in the healthy individual as in patients with neurological disorders, their role in various aspects of human cognition, and their neural underpinning, driven by the deep belief that spatial attention plays an important role in various mental processes that are not necessarily confined to perception. What follows is organized into two distinct sections. In the first I will focus on the evaluation of visuospatial asymmetries, starting from the description of a new paradigm particularly suitable for this purpose. In the first chapter I will describe the effects of multitasking in a spatial monitoring test; the main result shows a striking decreasing in detection performance as a function of the introduced memory load. In the second chapter I will apply the same paradigm to a clinical population characterized by a brain lesion affecting the left hemisphere. Despite a standard neuropsychological battery failed to highlight any lateralized attentional deficit, I will show that exploiting concurrent demands might lead to enhanced sensitivity of diagnostic tests and consequently positive effects on patients’ diagnostic and therapeutic management. Finally, in the third chapter I will suggest, in light of preliminary data, that attentional asymmetries also occur along the sagittal axis; I will argue, in particular, that more attentional resources appear to be allocated around peripersonal space, the resulting benefits extending to various tasks (i.e., discrimination tasks). Then, in the second section, I will follow a complementary approach: I will seek to induce attentional shifts in order to evaluate their role in different cognitive tasks. In the fourth and fifth chapters this will be pursued exploiting sensory stimulations: visual optokinetic stimulation and galvanic vestibular stimulation, respectively. In the fourth chapter I will show that spatial attention is highly involved in numerical cognition, this relationship being bidirectional. Specifically, I will show that optokinetic stimulation modulates the occurrence of procedural errors during mental arithmetics, and that calculation itself affects oculomotor behaviour in turn. In the fifth chapter I will examine the effects of galvanic vestibular stimulation, a particularly promising technique for the rehabilitation of lateralized attention disorders, on spatial representations. I will discuss critically a recent account for unilateral spatial neglect, suggesting that vestibular stimulations or disorders might indeed affect the metric representation of space, but not necessarily resulting in spatial unawareness. Finally, in the sixth chapter I will describe an attentional capture phenomenon by intrinsically rewarding distracters. I will seek, in particular, to predict the degree of attentional capture from resting-state functional magnetic resonance imaging data and the related brain connectivity pattern; I will report preliminary data focused on the importance of the cingulate-opercular network, and discuss the results through a parallel with clinical populations characterized by behavioural addictions.
In questo lavoro presenterò una serie di ricerche che possono sembrare piuttosto eterogenee per quesiti sperimentali e approcci metodologici, ma sono tuttavia legate da un filo conduttore comune: i costrutti di ragionamento e attenzione spaziale. Affronterò in particolare aspetti legati alla valutazione delle asimmetrie attenzionali, nell'individuo sano come nel paziente con disturbi neurologici, il loro ruolo in vari aspetti della cognizione umana, e i loro substrati neurali, guidato dalla convinzione che l’attenzione spaziale giochi un ruolo importante in svariati processi mentali non necessariamente limitati alla percezione. Quanto segue è stato dunque organizzato in due sezioni distinte. Nella prima mi soffermerò sulla valutazione delle asimmetrie visuospaziali, iniziando dalla descrizione di un nuovo paradigma particolarmente adatto a questo scopo. Nel primo capitolo descriverò gli effetti del doppio compito e del carico attenzionale su un test di monitoraggio spaziale; il risultato principale mostra un netto peggioramento nella prestazione al compito di detezione spaziale in funzione del carico di memoria introdotto. Nel secondo capitolo applicherò lo stesso paradigma ad una popolazione clinica contraddistinta da lesione cerebrale dell’emisfero sinistro. Nonostante una valutazione neuropsicologica standard non evidenziasse alcun deficit lateralizzato dell’attenzione, mostrerò che sfruttare un compito accessorio può portare ad una spiccata maggiore sensibilità dei test diagnostici, con evidenti ricadute benefiche sull'iter clinico e terapeutico dei pazienti. Infine, nel terzo capitolo suggerirò, tramite dati preliminari, che asimmetrie attenzionali possono essere individuate, nell'individuo sano, anche lungo l’asse sagittale; argomenterò, in particolare, che attorno allo spazio peripersonale sembrano essere generalmente concentrate più risorse attentive, e che i benefici conseguenti si estendono a compiti di varia natura (ad esempio compiti di discriminazione). Passerò dunque alla seconda sezione, in cui, seguendo una logica inversa, indurrò degli spostamenti nel focus attentivo in modo da valutarne il ruolo in compiti di varia natura. Nei capitoli quarto e quinto sfrutterò delle stimolazioni sensoriali: la stimolazione visiva optocinetica e la stimolazione galvanico vestibolare, rispettivamente. Nel quarto capitolo mostrerò che l’attenzione spaziale è coinvolta nella cognizione numerica, con cui intrattiene rapporti bidirezionali. Nello specifico mostrerò da un lato che la stimolazione optocinetica può modulare l’occorrenza di errori procedurali nel calcolo mentale, dall'altro che il calcolo stesso ha degli effetti sull'attenzione spaziale e in particolare sul comportamento oculomotorio. Nel quinto capitolo esaminerò gli effetti della stimolazione galvanica vestibolare, una tecnica particolarmente promettente per la riabilitazione dei disturbi attentivi lateralizzati, sulle rappresentazioni mentali dello spazio. Discuterò in modo critico un recente modello della negligenza spaziale unilaterale, suggerendo che stimolazioni e disturbi vestibolari possano sì avere ripercussioni sulle rappresentazioni metriche dello spazio, ma senza comportare necessariamente inattenzione per lo spazio stesso. Infine, nel sesto capitolo descriverò gli effetti di cattura dell’attenzione visuospaziale che stimoli distrattori intrinsecamente motivanti possono esercitare nell'adulto sano. Cercherò, in particolare, di predire l’entità di questa cattura attenzionale partendo da immagini di risonanza magnetica funzionale a riposo: riporterò dati preliminari focalizzati sull'importanza del circuito cingolo-opercolare, effettuando un parallelismo con popolazioni cliniche caratterizzate da comportamenti di dipendenza.

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Guilbert, Alma. « Evaluation et prise en charge du syndrome de négligence spatiale unilatérale : apports de la modalité auditive et de la musique ». Thesis, Lille 3, 2016. http://www.theses.fr/2016LIL30033/document.

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L'objectif de cette thèse était d'étudier la modalité auditive dans le syndrome de négligence spatiale unilatérale (NSU) que ce soit dans l'évaluation ou dans la prise en charge. Notre première hypothèse défendue était que, bien que la NSU touche aussi la modalité auditive, des différences dues aux spécificités de chaque modalité existent entre les symptômes auditifs et visuels de ce syndrome neuropsychologique. En conséquence, notre seconde hypothèse était que les spécificités propres à la modalité auditive pourraient permettre de pallier les déficits attentionnels rencontrés en modalité visuelle et, donc, faire de cette modalité un support efficace pour la rééducation. Concernant l'évaluation des symptômes auditifs, les mécanismes d'orientation de l'attention en modalité auditive ainsi que la latéralisation de sons ont été explorés chez des patients atteints de NSU. Ces études ont souligné des difficultés dans les deux domaines dans la NSU. Concernant la réhabilitation, la place de l'audition, et plus particulièrement de la musique, dans les rééducations proposées aux patients atteints de NSU a été explorée. Enfin, un programme de rééducation basé sur la pratique musicale a été créé et testé auprès d'une patiente atteinte de NSU chronique. Celui-ci a montré des bénéfices à long-terme sur les signes visuels de la NSU mais également dans la vie quotidienne. Les résultats de ces études vont dans le sens des hypothèses et soulignent l'importance de prendre en compte la modalité auditive dans la pratique clinique que ce soit lors de l'évaluation du syndrome de NSU ou lors de sa réhabilitation
The aim of this thesis was to focus on hearing in the evaluation and the rehabilitation of unilateral spatial neglect (USN) syndrome. USN not only affects the visual, but also the auditory modality. The first hypothesis of this thesis was that, due to the specificities of each modality, differences exist between the auditory and visual symptoms of USN. Consequently, the second hypothesis was that the specificities of the auditory modality could permit to compensate the attentional deficits that occur in the visual modality and, thus, make this modality an efficient tool for the rehabilitation. Concerning the evaluation of the auditory symptoms, orienting attention mechanisms in the auditory modality as well as sound lateralisation were explored with patients with USN. These studies showed patients with USN to have difficulties in both. Concerning the rehabilitation, the place of hearing, and in particular of music, in the re-educations in patients with USN was explored. Finally, a program based on music practice was developed and tested with a patient with a chronic USN. This patient showed long-term benefits on USN visual signs and also on daily activities. The results of these studies are consistent with the hypotheses and underline the importance of considering hearing in clinical practice either for the USN evaluation or for its rehabilitation

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Lunven, Marine. « Les disconnexions de la substance blanche comme facteur prédictif de l’évolution de la négligence spatiale unilatérale ». Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10352.

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La négligence spatiale unilatérale (NSU) est une affection neurologique fréquemment observée après une lésion de l'hémisphère cérébral droit. Les patients ne vont plus être en mesure de prendre en compte les stimuli présentés dans l'hémi-espace gauche. La NSU participe à l'aggravation du handicap des patients, par la réduction des possibilités en rééducation motrice et cognitive à la phase aigue d'un accident vasculaire comme sur le long terme. L'identification des facteurs prédictifs de sa chronicité pourrait permettre une meilleure prise en charge clinique de ces patients. Nous avons étudié les altérations des connexions anatomiques observées en IRM de diffusion sous-tendant la persistance de la NSU. Nos résultats démontrent qu'en plus d'un dysfonctionnement fronto-pariétal hémisphérique droit, la persistance de ce syndrome serait associée à une déconnexion interhémisphérique. L'hémisphère gauche isolé ne serait pas en mesure de compenser les déficits des patients. La récupération devrait s'effectuer par une amélioration dans les capacités d'échange des informations entre les deux hémisphères, notamment dans les régions postérieures pariétales et occipitales. Nous nous sommes intéressés à tester cette hypothèse par le biais d'une méthode de rééducation, l'adaptation prismatique (AP). Il s'agit d'une thérapie dont les effets sur la sémiologie des patients sont remarquables. Nos résultats suggèrent que l'amélioration de la NSU pourrait s'observer par le recrutement du réseau fronto-ponto-cérébelleux. Les régions frontales gauches seraient un relais anatomique entre le cervelet droit et le réseau fronto-pariétal gauche
Unilateral spatial neglect is a frequent neurological condition after right hemisphere damage. Patients behave as if objects on their left did not exist anymore. The presence of neglect has negative prognostic value for functional recovery in the acute and chronic phases after a stroke. Finding predictors of persistent neglect would permit to adapt rehabilitation procedures. We used diffusion MRI to define the state of anatomical connections in neglect and their predictor value for neglect persistence. Our results revealed that, together with right intra-hemispheric fronto-parietal disconnections, persistence of neglect is associated with inter-hemispheric disconnection. We concluded that an isolated left hemisphere may fail to compensate neglect because it cannot take into account left-sided objects. Recovery of neglect would instead occur thanks to the sharing of visual information between the two hemispheres, notably in posterior parietal and occipital cortices. We tested this hypothesis by using prism adaptation (PA) therapy. PA is a non-invasive and convenient technique to rehabilitate neglect. We showed that patients with damaged fronto-ponto-cerebellar pathways did not benefit from PA. This finding strongly suggests that PA can ameliorate signs of neglect by improving inter-hemispheric communication through enhanced activity of these connections. Left frontal areas may constitute the anatomical link between the right cerebellum and the left fronto-parietal network. Thus, connectional anatomy can help predict both neglect recovery and the quality of its response to rehabilitation therapies

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Luvizutto, Gustavo José [UNESP]. « Investigação de negligência espacial unilateral após Acidente Vascular Cerebral ». Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/139529.

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Introdução: A negligência espacial unilateral (NEU) é caracterizada pela incapacidade de reportar ou responder pessoas ou objetos do lado contralateral à lesão cerebral, e ocorre principalmente após Acidente Vascular Cerebral (AVC) do lobo parietal direito, sendo associada à pior desfecho funcional à longo prazo. Objetivo: Os objetivos desta tese foram: normatizar os principais testes diagnósticos de NEU e verificar a relação com fatores sócio-demográficos na população brasileira; avaliar as variáveis bioquímicas que interferem na NEU na fase aguda do AVC; e revisar sistematicamente os principais tratamentos farmacológicos na NEU em pacientes após AVC. Método: Para o primeiro objetivo foi realizado estudo transversal em 150 indivíduos sem alterações neurológicas, sendo aplicados: teste face-mão (TFM), testes de cancelamento de linhas (TCL), cancelamento de estrelas (TCE) e bisseção de linhas (TBL). Os resultados dos testes foram relacionados com o perfil sócio demográfico da população, sendo estipulado pontos de cortes para a normalidade; para o objetivo 2 foi realizado estudo observacional em 40 indivíduos com diagnostico de NEU após AVC. Foram aplicados os TCL, TCE e TBL, sendo relacionado com o nível de hemoglobina na fase aguda do AVC corrigido para potenciais confundidores; para o objetivo 3 foi realizado revisão sistemática de literatura por meio de ensaios clínicos randomizados e quasi-randomizados para determinar o melhor tratamento farmacológico. Resultados: os resultados do objetivo 1 estão apresentados nos artigos 1 e 2; o objetivo 2 no artigo 3; e o objetivo 3 no artigo 4. Conclusão: Com base nos resultados obtidos dos artigos 1 e 2, o TFM apresenta taxa de normalidade entre 8 a 10 estímulos sensoriais, com prevalência de extinção associada com o grau de escolaridade e aumento da idade; no TCL o ponto de corte para considerar NEU é acima de 0 e no TCE acima de 2, ambos associados à idade. No TBL o ponto médio de corte para considerar NEU foi de 6,6 mm, associado com pior escolaridade. No artigo 3 foi observado que quanto menor o valor de hemoglobina na fase aguda do AVC, pior o desempenho nos testes de NEU; No artigo 4 foi observado que a efetividade e segurança dos tratamentos farmacológicos para NEU após AVC permanecem incertos, necessitando de ensaios clínicos randomizados adicionais para avaliar o efeito deste tratamento.
Background: Unilateral spatial neglect (USN) is characterized by the inability to report or respond to people or objects presented on the side contralateral to the lesioned side of the brain and has been associated with poor functional outcomes. Objective: The objectives of this thesis were: to standardize the USN tests and verify the relationship with socio-demographic data in the Brazilian population; evaluate the biochemical variables that influence in USN tests after acute stroke; and systematically review the pharmacological interventions to treat USN after stroke. Method: For the first aim, we performed a cross-sectional study of 150 individuals without neurological changes by applying: face-hand test (FHT), line cancellation test (LCT), star cancellation test (SCT) and line bisection test (LBT). The test results were related to the sociodemographic data, with cutoff points being stipulated to define USN; the second aim was achieved by conducting an observational study of 40 individuals with USN after acute stroke. The tests applied – LCT, SCT and LBT – were correlated with the hemoglobin level in the acute phase of stroke corrected by confounders; the third aim was analyzed by a systematic review of randomized controlled trials and quasi-randomized clinical trials to determine the efficacy of pharmacological intervention. Results: The first aim is presented in Articles 1 and 2, the second aim in Article 3 and the third in Article 4. Conclusion: Based on the results of Articles 1 and 2, the FHT shows normal rate between 8-10 sensory stimuli, with an extinction prevalence associated with the education level and increasing age; The LCT cutoff point to define is USN above 0 and SCT above 2, and both were associated with age. The LBT cutoff point to indicate NEU was 6.6 mm, associated with poorer education level. Article 3 reveals the relationship between a lower hemoglobin level in acute phase of stroke with worse performance on USN tests; Article 4 reports that the effectiveness and safety of pharmacological treatments for USN after stroke remain uncertain, requiring additional randomized clinical trials to evaluate the effect of treatment.

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Conti, Daniela. « Robotics and intellectual disabilities : models and treatment ». Doctoral thesis, Università di Catania, 2016. http://hdl.handle.net/10761/3818.

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Public perception of an emerging scientific and technological product is important for the acceptance of such a product. Ethical studies based on public surveys toward using robots in eldercare and other applications, showed a high acceptance for pet-like therapeutic robot, the human-like care robot, and a surveillance care robot. However, it also reported a rejection in the case of a bathing robot because of the judgment that the robot-based action would be inferior to the human-based action and that it would take away jobs from human workers. Taking into account this scenario, chapter IV (4.1) focus on the acceptance by practitioners that work on a daily basis with children with intellectual disabilities, and on a group of university students from two classes concerned with social professions: education and psychology. Moreover, the purpose of the other study in the chapter IV (4.2) is to examine the acceptance and willingness to use robots among psychology students with Italian (ITA) and British (UK) background cultures in order to evaluate cultural differences in the acceptance of robotics by future psychology practitioners. Both studies were conducted using a platform for Socially Assistive Robotics and a questionnaire based on the Unified Theory of Acceptance and Use of Technology (UTAUT) model. In this case, the aim was to identify the capability of items in UTAUT questionnaire to reveal cultural differences, and, thus, the main factors that may influence each group in the use of robots in their future practice. This negative attitude is one of the biggest challenges that scientific research must address to be completely successful in giving actual benefits in the field of education and care. This rapid progress in technology, especially in the area of robotics, offers numerous possibilities for innovation in the education and care of individuals. Starting from these findings, in the chapter V my on-going research aims to identify effective modalities for treatment of Autism Spectrum Disorder (ASD) through interaction with a robot, and to integrate them into existing therapeutic protocols to improve their efficacy. I detail the methodology and give the results of a pilot clinical trial, focused on imitation skills, with three children affected by ASD and Intellectual Disability under treatment in a research centre specialized in the care of children with disabilities. Analysis of these initial results encourages the development of effective protocols in which the robot becomes a mediator between the child with ASD and humans and suggests some research avenues for focus in the future. However, the robotics is not only social. For this reason the aim of chapter VI, is artificial life where the models derived from the data , implement artificial organisms that replicate experimental observations. Specific skills or behaviours are not directly imitated or reproduced, as schematic photographs of a part of reality, but emerge as a result of adaptation processes put in place by the new reality built artificially. Traditionally, artificial life realizes models that simulate psychophysical activities. In fact, in the chapter VI, I will present the experimental results of a cognitive robotic approach for modelling the human cognitive deficit known as Unilateral Spatial Neglect (USN), where I replicated a previous experiment with human patients affected by the USN and iCub robotic platform. The numerical results show that the robot simulate the behaviours previously exhibited by humans and this last work of dissertation highlights some possible advantages of the use of robotic platforms to model and study cognitive dysfunctions of the human brain.

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Luvizutto, Gustavo José. « Investigação de negligência espacial unilateral após Acidente Vascular Cerebral ». Botucatu, 2016. http://hdl.handle.net/11449/139529.

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Orientador: Luiz Antônio de Lima Resende
Resumo: Introdução: A negligência espacial unilateral (NEU) é caracterizada pela incapacidade de reportar ou responder pessoas ou objetos do lado contralateral à lesão cerebral, e ocorre principalmente após Acidente Vascular Cerebral (AVC) do lobo parietal direito, sendo associada à pior desfecho funcional à longo prazo. Objetivo: Os objetivos desta tese foram: normatizar os principais testes diagnósticos de NEU e verificar a relação com fatores sócio-demográficos na população brasileira; avaliar as variáveis bioquímicas que interferem na NEU na fase aguda do AVC; e revisar sistematicamente os principais tratamentos farmacológicos na NEU em pacientes após AVC. Método: Para o primeiro objetivo foi realizado estudo transversal em 150 indivíduos sem alterações neurológicas, sendo aplicados: teste face-mão (TFM), testes de cancelamento de linhas (TCL), cancelamento de estrelas (TCE) e bisseção de linhas (TBL). Os resultados dos testes foram relacionados com o perfil sócio demográfico da população, sendo estipulado pontos de cortes para a normalidade; para o objetivo 2 foi realizado estudo observacional em 40 indivíduos com diagnostico de NEU após AVC. Foram aplicados os TCL, TCE e TBL, sendo relacionado com o nível de hemoglobina na fase aguda do AVC corrigido para potenciais confundidores; para o objetivo 3 foi realizado revisão sistemática de literatura por meio de ensaios clínicos randomizados e quasi-randomizados para determinar o melhor tratamento farmacológico. Resultados: os resul... (Resumo completo, clicar acesso eletrônico abaixo)
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Schintu, Selene. « The action of prism adaptation on intact visuospatial cognition : when time matters to space ». Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10320/document.

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Nous sommes fonctionnellement et structurellement asymétriques. La symétrie parfaite que nous expérimentons subjectivement en observant l'espace qui nous entoure est, dans une certaine mesure, une illusion. La cognition visuospatiale, comme indiqué par les tâches de bissection de lignes, est généralement biaisée à gauche chez les sujets sains et à droite suite à des lésions de l'hémisphère droit causant la Négligence Spatiale Unilatérale (NSU). Ces biais peuvent être modulés et l'adaptation prismatique (AP) a démontré sa capacité à réduire les symptômes de la NSU et à induire des comportements similaires à la NSU chez les individus sains. La question de savoir comment ce type d'adaptation sensorimotrice module la cognition spatiale est encore débattue. L'objectif de cette thèse était d'utiliser des approches comportementales et physiologiques, pour examiner les mécanismes sous-jacents des effets de l'AP sur la cognition visuospatiale d'individus sains. Dans une 1ère étude comportementale, nous avons observé la présence d'une dynamique temporelle des effets survenant après l'AP. Suite à ce premier résultat, nous avons testé sur une période de temps plus longue les effets faisant suite à l'AP déviant la vision vers la droite ou la gauche, et nous avons dévoilé, dans une 2ème étude, des dynamiques temporelles différentes en fonction de la direction de l'AP. Dans une 3ème étude, nous avons utilisé la stimulation magnétique transcrânienne pour étudier la physiologie sous-tendant la modulation visuospatiale efficacement induite par l'AP. Les résultats de cette thèse appellent à un raffinement des modèles actuels de l'action de l'AP sur la cognition visuospatiale
We are functionally and structurally asymmetric. The perfect symmetry we subjectively experience through vision of the space around us is, to some extent, an illusion. Visuospatial cognition, as indexed by performance on line bisection tasks, is generally biased leftward in healthy individuals and pathologically rightward after right brain damage causing unilateral spatial neglect (USN). These biases can be modulated and prism adaptation (PA) is capable of both alleviating USN symptoms and inducing a rightward shift (the so-called “neglect-like behavior”) in healthy individuals. How this type of sensorimotor adaptation modulates spatial cognition is still debated. The goal of this thesis was to use both behavioral and physiological approaches to investigate the underlying mechanisms of PA’s effects on visuospatial cognition in healthy individuals. In a first behavioral study we found the presence of a temporal dynamic in PA after-effects. Based on this first finding we tested, over a longer period of time the PA after-effects following both right and leftward PA and unveiled, with the second study, different temporal dynamics depending on PA direction. In a third study we used transcranial magnetic stimulation to investigate the physiology underlying the effective visuospatial modulation induced by PA. The results of this thesis call for a refinement of the current models of PA action on visuospatial cognition

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SEDDA, GIULIA. « The interplay between movement and perception : how interaction can influence sensorimotor performance and neuromotor recovery ». Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1011732.

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Movement and perception interact continuously in daily activities. Motor output changes the outside world and affect perceptual representations. Similarly, perception has consequences on movement. Nevertheless, how movement and perception influence each other and share information is still an open question. Mappings from movement to perceptual outcome and vice versa change continuously throughout life. For example, a cerebrovascular accident (stroke) elicits in the nervous system a complex series of reorganization processes at various levels and with different temporal scales. Functional recovery after a stroke seems to be mediated by use-dependent reorganization of the preserved neural circuitry. The goal of this thesis is to discuss how interaction with the environment can influence the progress of both sensorimotor performance and neuromotor recovery. I investigate how individuals develop an implicit knowledge of the ways motor outputs regularly correlate with changes in sensory inputs, by interacting with the environment and experiencing the perceptual consequences of self-generated movements. Further, I applied this paradigm to model the exercise-based neurorehabilitation in stroke survivors, which aims at gradually improving both perceptual and motor performance through repeated exercise. The scientific findings of this thesis indicate that motor learning resolve visual perceptual uncertainty and contributes to persistent changes in visual and somatosensory perception. Moreover, computational neurorehabilitation may help to identify the underlying mechanisms of both motor and perceptual recovery, and may lead to more personalized therapies.

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Norton, Daniel. « Functional characterization of spatial neglect in Parkinson's disease ». Thesis, 2015. https://hdl.handle.net/2144/14053.

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Parkinson’s disease (PD) is associated with perceptual as well as motor disturbances. Unlike those with right-side onset (RPD), individuals whose motor symptoms begin on the left side of the body (LPD) may experience mild neglect of left hemispace. The functional cause of these perceptual abnormalities in LPD is unknown; possibilities include altered eye movements, changes in perceptual representation of left versus right hemispace, and attentional abnormalities. Three studies explored these possibilities in non-demented individuals with mild-moderate idiopathic PD (24-36 per experiment) and matched normal control adults (NC; 14-24 per experiment). Study 1 consisted of two psychophysical line-bisection experiments that used brief stimulus presentations to preclude exploratory eye movements. In both, participants judged whether a systematically adjusted hatchmark was left or rightward of a horizontal line’s midpoint. In the second, eye tracking was used to ensure that participants fixated during stimulus onset. The first experiment revealed neglect-like performance in LPD, but the second did not, suggesting that neglect may arise from biased eye gaze but not from abnormal saccades. Study 2 evaluated two hypotheses to explain spatial bias in LPD; one an active hypothesis in the literature that the representation of left hemispace is compressed, and the other a novel hypothesis that left hemispace is less salient than the right in LPD. Both hypotheses were assessed psychophysically, using spatial frequency and contrast discrimination paradigms, and neither was supported. Study 3 investigated whether endogenous visuospatial attentional abnormalities exist in PD, and particularly whether LPD show weaker attentional abilities in the left hemifield. A multiple-object tracking paradigm was used along with eye tracking to ensure that participants used only endogenous (not exogenous) attention. PD showed dilated temporal resolution of attention, and were less accurate in tracking multiple objects at once. LPD did not differ from RPD for either of these metrics. Overall the results suggest that there is no intrinsic difference in the representation of space in LPD relative to RPD or NC, but that visuospatial attention is altered in PD generally. The latter finding is particularly important for considering spatial navigation in individuals with PD even in early stages of the disease.

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Sung, Mei-yung, et 宋美雲. « The relationship between unilateral spatial neglect and postural stability in stroke patients ». Thesis, 1994. http://ndltd.ncl.edu.tw/handle/73011999215987090024.

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Hsing-Fen, Tu. « Performance on Spatial Attention Tests by Adults with and without Unilateral Stroke : Functional Implications of spatial neglect ». 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2507200622020300.

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Tu, Hsing-Fen, et 杜杏芬. « Performance on Spatial Attention Tests by Adults with and without Unilateral Stroke : Functional Implications of spatial neglect ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/15846909581488719265.

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碩士
國立臺灣大學
職能治療研究所
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Background: Previous studies on neglect have shown that there is significant influence to functional outcome to patients with stroke. Less evidence provided neglect subtypes, such as egocentric and allocentric neglect related to function. Purpose: (a) to investigate the performance on spatial attention tests of healthy adults to establish cut-off level; and (b) to investigate personal neglect and extra-personal neglect in patients groups related to function; (c) to exam the neglect subtypes predictive of anosognosia for functional deficits. The hypotheses of this study were (a) neglect subtypes would influence the functional performance in patients groups; (b) anosognosia for functional deficit related to neglect subtypes; (c) when further control age, motor, and sensory, the relationship between spatial attention and function would still remain. Methods: Four extrapersonal neglect tests and one personal neglect test were applied to assess neglect. Self-report and therapist-report Barthel Index (BIS and BIT) were used to measure functional performance. Cut-off level on extrapersonal neglect tests was determined by 81 healthy adults. And 58 patients with right brain damage (RBD) and 57 with left brain damage (LBD) were recruited from the hospital in north Taiwan. Results: The random shape cancellation test was the most sensitive to RBD (62%) and so was the Random Chinese Word Cancellation test to LBD (32%). Besides, neglect subtypes (extra-personal vs. personal neglect; egocentric vs. allocentric neglect) related to different functional status. Anosognosia showed predictive to function of RBD (p<0.001). And after controlling confounders, the correlation still remained. Conclusions: Sensitivity differed from tasks and brain lesion sites. And neglect subtypes influence function, as well as egocentric and allocentric neglect would influence functional performance significantly, especially to patients with RBD. And BIS could be differentiated functional performance of egocentric and allocentric neglect better than BIT. If further analyzed anosognosia score (BID), personal neglect showed the predictive for unawareness of functional deficit.

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Vasquez, Brandon Paul. « DIRECTION SPECIFIC COSTS TO SPATIAL WORKING MEMORY FROM SACCADIC AND SPATIAL REMAPPING ». Thesis, 2007. http://hdl.handle.net/10012/3290.

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Right parietal lesions often lead to neglect, in which patients fail to attend to leftward stimuli. Recent models of neglect suggest that, in addition to attentional impairments, patients demonstrate impairments of spatial remapping and/or spatial working memory (SWM). Although spatial remapping could be considered a kind of spatial memory process itself (i.e., updating remembered locations based on anticipated saccade outcomes), the two processes operate on very different time scales (milliseconds versus seconds). In the present study, the influence of saccadic and spatial remapping on SWM was examined in healthy individuals. An initial control condition, in which participants had to respond to a probe stimulus (i.e., “is the probe in the location previously occupied by the target?”) following a 1500 ms delay, was contrasted with conditions in which the fixation point moved (left, right, up, or down) at the onset of the delay. In a second version of the task, participants made covert shifts of attention at delay onset requiring covert spatial, rather than saccadic, remapping. In both tasks SWM performance was best when no remapping was required. Decrements in SWM were largest overall in the spatial remapping task, whereas for both saccadic and spatial remapping, a consistent cost was observed for remapping the target array into right visual space. Results are discussed in terms of hemispheric biases in attention and differences in performance for peripersonal versus extrapersonal space.

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