Dissertations / Theses on the topic 'Cochlear Implants'
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Long, Christopher Joseph 1971. "Bilateral cochlear implants : basic psychophysics." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/29891.
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Thesis (Ph. D.)--Harvard--Massachusetts Institute of Technology Division of Health Sciences and Technology, 2000.Includes bibliographical references (leaves 167-175).
by Christopher Joseph Long.
Ph.D.
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Strydom, Trudie. "Acoustic models of cochlear implants." Thesis, University of Pretoria, 2010. http://hdl.handle.net/2263/30721.
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Acoustic models are useful tools to increase understanding of cochlear implant perception. Two particular issues in modelling cochlear implant perception were considered in the present study, which aimed at improving acoustic models. The first included an electricallayer in the model, while the second manipulated synthesis signal parameters. Two parts of the study explored the effects of current decay, compression function and simultaneous stimulation, by including the electrical layer. The SPREAD model, which incorporated this layer, yielded the asymptote in speech intelligibility at seven channels observed in CI listeners. It was shown that the intensity of border channels was deemphasized in relation to more central channels. This was caused by the one-sided effects of current spread from neighbouring channels for the border channels, as opposed to the two-sided effects for the more central channels. It was theorised that more compressive mapping functions would affect spectral cues and consequently speech intelligibility, but speech intelligibility experiments did not confirm this theory. A simultaneous analogue stimulation (SAS) model, which modelled simultaneous stimulation, yielded intelligibility results that were lower than those of the SPREAD model at 16 channels. The SAS model also appeared to introduce more temporal distortion than the SPREAD model. A third part of the study endeavoured to improve correspondence of acoustic model results with cochlear implant listener results by using nine different synthesis signals. The best synthesis signal was noise-band based. The widths of these increased linearly from 0.4 mm at the apical to 8 mm at the basal end. Good correspondence between speech recognition outcomes using this synthesis signal with those of CI listeners was found. AFRIKAANS : Akoesties modelle word algemeen gebruik om die persepsie van inplantingsgebruikers beter te verstaan. Twee benaderings tot die modellering van kogleêre inplantingsgebruikerpersepsies is voorgestel om akoestiese modelle te verbeter. In die eerste benadering is die generiese model verbeter deur die byvoeging van 'n elektriese laag en in die tweede benadering is sinteseseinparameters gemanipuleer om die ooreenkoms met inplantingsgebruikersuitkomste te verbeter. Twee dele van die studie het die effek van stroomverspreiding, samedrukkings-funksie en gelyktydige stimulasie ondersoek deur die insluiting van die elektriese laag. Die SPREAD-model het die asimptoot in spraakherkenning by sewe kanale getoon. Die intensiteit van grenskanale is onderbeklemtoon in verhouding met meer sentrale kanale. Dit is veroorsaak deur die eensydige effekte van stroomverspreiding vir die grenskanale, teenoor die tweesydige effekte wat meer sentrale kanale tipies beïnvloed. Die model het gesuggereer dat meer samedrukkende funksies spektrale inligting sou affekteer, maar spraakherkenningsdata het nie hierdie teorie bevestig nie. Die gelyktydige- analoogstimulasiemodel, wat gelyktydige stimulasie gemodelleer het, het soortgelyke tendense getoon, maar met meer temporale effekte as die SPREAD-model. Die gelyktydige- analoogstimulasiemodel-model se resultate was ook swakker by 16 kanale as die SPREAD-modelresultate. Die derde deel van die studie het gepoog om beter ooreenkoms tussen modeluitkomste en inplantingsgebruikeruitkomste te verkry deur nege verskillende sinteseseine te gebruik. Die beste sintesesein was die ruisband met veranderende wydte; hierdie wydte het verbreed vanaf 0.4 mm by die apeks tot by 8 mm by die basis. 'n Goeie ooreenkoms is verkry tussen modeluitkomste en inplantingsgebruikeruitkomste deur hierdie sintesesein te gebruik.Thesis (PhD)--University of Pretoria, 2011.
Electrical, Electronic and Computer Engineering
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Newbold, Carrie. "Electrode tissue interface : development and findings of an in vitro model /." Connect to thesis, 2006. http://repository.unimelb.edu.au/10187/1692.
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In the period immediately following the implantation of a cochlear implant electrode array within the cochlear environment, the power required to stimulate the auditory nerve at preset current levels increases. This rise is due to increases in electrode impedance which in turn is suggested to be a result of tissue growth around the electrode array. The foreign body response initiated by the immune system encapsulates the array in a matrix of fibrous tissue, separating the electrode array from the rest of the body. A second change in electrode impedance occurs with the onset of electrical stimulation. A transitory reduction in impedance has been recorded in animals and humans after stimulation of electrodes. Impedance returns to pre-stimulation levels following the cessation of stimulation. It was suggested that these changes in impedance with stimulation were also related to the tissue growth around the electrode array. A more thorough understanding of the interface was required to ascertain these concepts.
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Bell, Bonnie M. "The psychological/social impact of cochlear implants /." Link to online version, 2005. https://ritdml.rit.edu/dspace/handle/1850/1003.
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Boyle, Patrick Joseph. "Automatic gain control for cochlear implants." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648151.
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Dachasilaruk, Siriporn. "Wavelet filter banks for cochlear implants." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/388109/.
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Cochlear implant (CI) users regularly perform as well as normal-hearing (NH) listeners in quiet conditions. However, CI users have reduced speech perception in noise. CI users suffer more in terms of speech intelligibility than NH listeners in the same noisy environment. Speech coding strategies with noise reduction algorithms for CI devices play an important role, allowing CI users to benefit more from their implants. This thesis investigates a wavelet packet-based speech coding strategy with envelope-based noise reduction algorithms to enhance speech intelligibility in noisy conditions. The advantages of wavelet packet transforms (WPTs), in terms of time-frequency analysis, the sparseness property, and low computational complexity, might make WPT appropriate for speech coding and denoising in CI devices. In cases with an optimal set of parameters for a wavelet packet-based speech coding strategy, the 23- and 64-band WPTs with sym8 and frame length of 8 ms were found to be more suitable than other combinations for this strategy. These parameters can optimise speech intelligibility to benefit CI users. However, both the standard ACE strategy and the wavelet packet-based strategy provided almost the same results in either quiet or noisy conditions. Cases using envelope-based denoising techniques in a wavelet packet-based strategy, namely time-adaptive wavelet thresholding (TAWT) and time-frequency spectral subtraction (TFSS) were developed and evaluated by objective and subjective intelligibility measures and compared to ideal binary masking (IdBM) as a baseline for denoising performance. IdBM can restore intelligibility to nearly the same level as NH listeners in all noisy conditions. Both TAWT and TFSS showed slight intelligibility improvements in some noisy conditions. This may result from noise estimation in denoising techniques. Noise level may be under- or overestimated, and this results in distortion in enhanced speech and difficult in speech discrimination. Both objective and subjective intelligibility measures can predict the trend of the performance of different denoising techniques for CI users. However, NH listeners can achieve better intelligibility at higher SNR levels without noise reduction, since they are less sensitive to noise but more sensitive to speech distortion when compared to CI listeners. Therefore, denoising techniques may work well for CI users in further investigations.
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Aitkenhead, Lynne. "Reading skills in adolescents with cochlear implants." Thesis, Royal Holloway, University of London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.588519.
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Reading outcomes following cochlear implantation are extremely variable. Understanding the factors underlying this variability is of clinical importance, and research has concentrated on how children with cochlear implants encode and process information. Existing research has focussed on younger children; the present study investigated the relationship between short-term and working memory and reading outcomes in adolescents with cochlear implants. A cross-sectional comparative design was selected. 18 adolescents with cochlear implants were recruited from a cochlear implant programme in London. All participants completed neuropsycho- logical measures of reading, phonological and visual working memory and non-verbal IQ, and scores were compared with normative data for hearing children: Significantly more adolescents with cochlear implants had below average reading outcomes than would be expected. Reading Composite scores were positively correlated with performance on a phonological working memory task (WISe-IV Digit Span). This correlation was not significantly different from manual norms for normal-hearing children. These findings show that the difference in reading attainment between children with cochlear implants and their hearing peers continues into adolescence. In keeping with previous research, outcomes were highly variable. Reading scores in adolescents are significantly correlated with Digit Span scores, consistent with findings in younger children. The size of this correlation did not differ significantly from normative data for hearing children. The results of this study stress the importance of careful, individualized assessments of reading for children with cochlear implants, and indicate that monitoring should continue into adolescence. The effect of interventions designed to improve or compensate for limited working memory capacity on reading outcomes is an important area for future research.
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Christopher, Punita R. Finley Charles C. "Current flow patterns generated by cochlear implants." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1359.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Apr. 25, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biomedical Engineering, School of Medicine." Discipline: Biomedical Engineering; Department/School: Medicine.
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Germanovix, Walter. "Analogue techniques for micro-power cochlear implants." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313753.
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Kendall, Melanie J. "Speech perception with multi-channel cochlear implants." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267060.
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Webb, Cherith Mercedes. "Obstruent acoustic landmark enhancement for cochlear implants." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/386157/.
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Cochlear implant users are typically able to achieve high levels of speech recognition in quiet but struggle to follow speech even in moderate levels of background noise. It may be possible to improve cochlear implant users’ speech perception scores in noise, by making more efficient use of the limited bandwidth available for transmitting important speech information, rather than increasing the amount of information transmitted. Acoustic landmarks are locations in the speech signal which are rich in information and allow a listener to identify a particular speech sound as a vowel, sonorant consonant or obstruent consonant; it is around these regions that important speech cues tend to be concentrated. Obstruent consonants are signalled by sudden amplitude and spectral changes and the onset/offset of a period of noise. It has been shown that the auditory system is particularly responsive to rapid spectral changes, manifested as increased firing rates of auditory nerve fibres, particularly at onsets of signals. Cochlear implant users commonly confuse speech sounds with rapidly changing spectral patterns, possibly due to the poor transmission of obstruent landmark information. The aim of the present work was to develop an obstruent landmark enhancement strategy which could be integrated into current cochlear implant processing. The first stage of this process required the identification of obstruent landmarks from the noise-mixed speech stimuli. An existing automatic landmark detection algorithm did not achieve the high levels of accuracy required for use in the present study and so a set of hand-generated labels were created, and used to guide the proposed obstruent landmark enhancement strategy. A series of cochlear implant simulation experiments were conducted to help evaluate the strategy and guide further developments. Results from the simulation studies suggest that the proposed method of obstruent landmark enhancement does not help to improve speech recognition in noise for normal hearing listeners listening to a cochlear implant simulation. It is likely that the strategy outlined in this thesis did not help to improve the saliency of obstruent landmark events as the enhancement was applied to the noise as well as the target speech signal, making it difficult for listeners to resolve the boosted landmark information. However, the results also highlight the limitations of using cochlear implant simulations to evaluate the strategy and so the findings are not necessarily a predictor of actual cochlear implant user performance.
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Elangovan, Saravanan. "Pediatric Cochlear Implants: "Putting it All Togther"." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/1573.
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Edin, Fredrik. "Strategies in Cochlear Nerve Regeneration, Guidance and Protection : Prospects for Future Cochlear Implants." Doctoral thesis, Uppsala universitet, Öron-, näs- och halssjukdomar, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-276336.
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Today, it is possible to restore hearing in congenitally deaf children and severely hearing-impaired adults through cochlear implants (CIs). A CI consists of an external sound processor that provides acoustically induced signals to an internal receiver. The receiver feeds information to an electrode array inserted into the fluid-filled cochlea, where it provides direct electrical stimulation to the auditory nerve. Despite its great success, there is still room for improvement, so as to provide the patient with better frequency resolution, pitch information for music and speech perception and overall improved quality of sound. A better stimulation mode for the auditory nerves by increasing the number of stimulation points is believed to be a part of the solution. Current technology depends on strong electrical pulses to overcome the anatomical gap between neurons and the CI. The spreading of currents limits the number of stimulation points due to signal overlap and crosstalk. Closing the anatomical gap between spiral ganglion neurons and the CI could lower the stimulation thresholds, reduce current spread, and generate a more discrete stimulation of individual neurons. This strategy may depend on the regenerative capacity of auditory neurons, and the ability to attract and guide them to the electrode and bridge the gap. Here, we investigated the potential of cultured human and murine neurons from primary inner ear tissue and human neural progenitor cells to traverse this gap through an extracellular matrix gel. Furthermore, nanoparticles were used as reservoirs for neural attractants and applied to CI electrode surfaces. The nanoparticles retained growth factors, and inner ear neurons showed affinity for the reservoirs in vitro. The potential to obtain a more ordered neural growth on a patterned, electrically conducting nanocrystalline diamond surface was also examined. Successful growth of auditory neurons that attached and grew on the patterned substrate was observed. By combining the patterned diamond surfaces with nanoparticle-based reservoirs and nerve-stimulating gels, a novel, high resolution CI may be created. This strategy could potentially enable the use of hundreds of stimulation points compared to the 12 – 22 used today. This could greatly improve the hearing sensation for many CI recipients.
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Withey, Daniel J. (Daniel James) Carleton University Dissertation Engineering Electrical. "A cochlear implant stimulation strategy and system." Ottawa, 1992.
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Wood, Caura L. "(Dis)abling paradigms, cochlear implants and contested identities." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28689.pdf.
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Webb, Alexander. "The mathematical skills of children with cochlear implants." Thesis, Royal Holloway, University of London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521774.
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Wass, Malin. "Children with Cochlear Implants : Cognition and Reading Ability." Doctoral thesis, Linköpings universitet, Institutet för handikappvetenskap (IHV), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51735.
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The present thesis investigated cognitive ability in children with severe to profound hearing impairment who have received cochlear implants (CIs). The auditory stimulation from a cochlear implant early in life influences most cognitive functions as a consequence of the plasticity of the brain in the young child. It is important to understand the cognitive consequences of auditory stimulation from CIs in order to provide adequate support to these children. This thesis examined three specific aspects of cognitive ability (working memory, phonological skill and lexical access), and reading ability in children with CIs, as compared to children with normal hearing in the same age. The relations between cognitive abilities and reading skills were also investigated, as well as the associations between demographic variables (e.g., age at implantation and communication mode), cognitive abilities and reading skills. The children with CI generally had lower performance levels than the normal hearing children in tasks of phonological and general working memory, phonological skills and lexical access. They had specific problems in tasks with high demands on phonological working memory, whereas their performance levels in tasks of visuospatial working memory were on par with the hearing children. A majority of the children with CI demonstrated reading skills within the normal range for hearing children, both for decoding and reading comprehension. The relations between demographic factors and cognitive skills varied somewhat between the studies. The patterns of result are discussed with reference to contemporary theories of working memory, phonological skills, and lexical access.Avhandlingens övergripande syfte var att studera kognitiva förmågor hos barn med grav hörselskada eller dövhet som fått cochleaimplantat (CI). Auditiv stimulering från CI i tidig ålder påverkar de flesta kognitiva funktioner som en följd av hjärnans plasticitet hos små barn. Det är viktigt att förstå de kognitiva konsekvenserna av auditiv stimulering från CI för att kunna ge dessa barn bästa möjliga stöd. Avhandlingen undersökte tre specifika aspekter av kognitiv förmåga (arbetsminne, fonologiska förmågor och lexikal aktivering), samt läsförmåga hos barn med CI, i jämförelse med barn med normal hörsel i samma åldrar. Relationerna mellan kognitiva förmågor och läsförmåga studerades också, liksom sambanden mellan demografiska faktorer (t ex implantationsålder och kommunikationssätt) och kognitiva förmågor samt läsfärdigheter. Barnen med CI hade generellt lägre prestationsnivå än barnen med normal hörsel i uppgifter som mäter fonologiskt och generellt arbetsminne, fonologiska förmågor och lexikal aktivering. De hade specifika problem i uppgifter som i hög grad belastar fonologiskt arbetsminne, medan deras visuospatiala arbetsminneskapacitet var jämförbar med den hos barnen med normal hörsel. Majoriteten av barnen med CI hade läsfärdigheter i nivå med normalhörande barn, för både avkodning och läsförståelse. Sambanden mellan demografiska faktorer och kognitiva förmågor och läsförmåga varierade mellan studierna. Resultatmönstren diskuteras utifrån teorier om arbetsminne, fonologiska färdigheter och lexikal aktivering.
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Kuo, Y.-ching. "Cochlear implants in a tone language, Mandarin Chinese." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1445193/.
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Cochlear implantation, as a means of restoring hearing to profoundly and totally deaf people, has now become a routine clinical procedure. Implant users can perform remarkably well in many aspects of speech perception. However, current implant devices do not provide all speech information equally well. One major limitation is in providing voice fundamental frequency (fO), known to be problematic even for non-tonal languages in which intonation plays an important role in speech communication. This causes even more difficulty in tonal languages, such as Mandarin Chinese or Thai, in which pitch variations are used to convey lexical meanings. This thesis is mainly concerned with how implant users perceive and use tonal information. Studies were first conducted in normal-hearing listeners to investigate the nature of tone and the importance of voice fO in understanding running speech. Three acoustic cues (fO, amplitude envelope, and duration) were examined for their contributions to tonal perception in syllables. The results clearly demonstrated voice fO to be the dominant cue. To determine the effect of explicit fO in sentence recognition, vocoded stimuli with various degrees of spectral information were presented to four age groups of listeners (aged 6, 9, 12, and 20). Information about natural fO variations enhanced sentence recognition significantly even when spectral information was severely degraded, and the effect was strong across all ages. The investigation in implanted children first examined tone recognition performance and the acoustic cues used for recognising tonal contrasts, especially the use of amplitude envelope. These implanted children appeared to make some use of amplitude changes in recognising tonal contrasts, though the overall effect was rather small. They also showed some evidence for the use of duration and temporal pitch information. For the effect of fO in sentences, no significant difference was found in performance on sentences with their original fO contours and those with uninformative fO contours. This indicates that the voice pitch information provided by current implant devices is too limited to allow listeners to take advantage of the presence of natural fO. In the light of the significance of fO both in signalling tonal identity in syllables and in perceiving sentences, it is likely that implant users will further benefit with a better representation of voice pitch.
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Watson, Victoria Kathryn. "Exploring the experiences of teenagers with cochlear implants." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/386314/.
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Whilst much research has focused on the general health needs of adolescents, little is known about the specific needs of teenagers who wear cochlear implants. Thus it is important to widen the knowledge base regarding the experiences of this population, and to assist professionals to support this age group more effectively. This qualitative study investigated teenage cochlear implant users’ perceptions of deafness, surgery, fitting of the device and life as a cochlear implant wearer in order to gain a more comprehensive understanding of teenagers’ experiences of living with a cochlear implant by putting their perspectives at the heart of the research. This was achieved by working with the teenagers collaboratively throughout the research. Phase one of the study involved engaging with a small group of teenagers with cochlear implants to develop a website that would allow them to share their experiences. In phase two, ten semi-structured interviews were undertaken and nine were analysed using template analysis. Some teenagers experienced great preoperative anxiety and significant post-operative pain. Anxiety and pain are physiologically linked so strategies for reducing their anxiety are discussed. There was also a mismatch between their expectations and the disappointing reality of adjusting to the device. Disconfirmation-expectancy theory suggests that expectations counselling may narrow this gap. However, over time they experienced significant functional and psychosocial benefits as a result of their lives being easier. Almost all described complex, flexible identities where they felt connections with both the hearing and deaf world. Theoretical models of deaf identity support this ‘bicultural’ state. However, the hearing world sometimes posed difficulties for them when the listening environment was challenging. By giving prominence to the teenagers’ voices this study has added new knowledge concerning their experience of surgery. The findings also more fully revealed the challenges of adjusting to the device and the impact of having a cochlear implant on the teenagers’ identities.
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Walker, Elizabeth Ann. "Word learning processes in children with cochlear implants." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/616.
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Children with cochlear implants (CIs) typically have smaller lexicons in relation to their same-age hearing peers. There is also evidence that children with CIs show slower rates of vocabulary growth compared to hearing children. To understand why children with CIs have smaller vocabularies, we proposed to investigate their word learning process and determine how it compares to children with normal hearing. The present study explores multiple aspects of word learning - acquisition, extension, and retention - to better inform us about the real-world process of lexical acquisition in children with CIs.
We evaluated 24 children with cochlear implants, 24 children with normal hearing matched by chronological age, and 23 children with normal hearing who were matched by vocabulary size. Participants were trained and tested on a word learning task that incorporated fast mapping, word extension, and word retention over two days. We also administered a battery of tests that included measures of receptive vocabulary and speech perception skills to determine which variables might be significant predictors of fast mapping and word retention.
Children with CIs performed more poorly on word learning measures compared to their age-mates, but similarly to their vocabulary-mates. These findings indicate that children with CIs experience a reduced ability to initially form word-referent pairs, as well as extend and retain these pairs over time, in relation to their same-age hearing peers. Additionally, hearing age-mates and vocabulary-mates showed enhancement in their production of novel words over time, while the CI group maintained performance. Thus, children with CIs may not take the same route in learning new words as typically-developing children. These results could help explain, in part, why this population consistently demonstrates slower rates of vocabulary learning over time. Furthermore, we expected that speech perception and vocabulary size would relate to variations in fast mapping, as well as word retention. Neither of these variables proved to be significant predictors of fast mapping, but they were highly significant for word retention. Based on these findings, we may conclude that the factors that account for acquiring that first link between a word and its referent are not the same as those that are important for storing in a word in long-term memory.
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Gedge, Joseph L. "Living with cochlear implants, the perspective of hearing parents of three implanted children." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0033/MQ62363.pdf.
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Wolmarans, Hendrik Petrus. "Cochlear implant speech processing, based on the cochlear travelling wave." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-01242006-112642.
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Yuen, Wing-ka Charlotte. "Production of stop consonants by Cantonese-speaking cochlear implant users." Click to view the E-thesis via HKU Scholars Hub, 2007. http://lookup.lib.hku.hk/lookup/bib/B42006272.
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Thesis (B.Sc)--University of Hong Kong, 2007."A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2007." Includes bibliographical references (p. 27-30). Also available in print.
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Hoffman, Amber L. "Types of stress placed on parents of deaf children when deciding on cochlear implantation." Online version, 2002. http://www.uwstout.edu/lib/thesis/2002/2002hoffmana.pdf.
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Lineaweaver, Sean Kenneth Ridgway. "Dynamic spiral lumped element model of electrical field distribution and neural excitation in the implanted cochlea /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/6092.
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Schorr, Efrat Altshul. "Social and emotional functioning of children with cochlear implants." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2408.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Human Development. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Pieterse-Randall, Candice. "The speech processing skills of children with cochlear implants." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/2398.
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Thesis (MSL and HT (Interdisciplinary Health Sciences. Speech-Language and Hearing Therapy))--Stellenbosch University, 2008.This study aims to describe the speech processing skills of three children ages 6;0, 6;10 and 8; 10, with cochlear implants. A psycholinguistic framework was used to profile each child’s strengths and weaknesses, using a single case study approach. Each child’s speech processing skills are described based on detailed psycholinguistically-orientated assessments. In addition, retrospective data from 1-2 years post-implantation were examined in the light of the psycholinguistic framework in order to describe each child’s development over time and in relation to time of implantation. Results showed each child to have a unique profile of strengths and weaknesses, and widely varying outcomes in terms of speech processing even though all three children had the same initial difficulty (congenital bilateral hearing loss). Links between speech processing and other aspects of development as well as contextual factors are discussed in relation to outcomes for each child. The case studies contribute to knowledge of speech processing skills in children with cochlear implants, and have clinical implications for those who work with children with cochlear implants and their families.
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Bicknell, Ina Rea. "Detection of Frequency Modulation by Listeners with Cochlear Implants /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487933245539597.
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Swart, Tania. "The outcomes of bilateral cochlear implants in adult recipients." Diss., Pretoria : [s. n.], 2009. http://upetd.up.ac.za/thesis/available/etd-11302009-221632/.
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Gjerstad, Tara Ann. "Investigation of service provision for children with cochlear implants." Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/969.
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Objective. As a result of newborn hearing screenings, an increasing number of infants are being identified with a hearing loss at birth or within a few months of life. The literature supports that early identification in conjunction with early intervention services have led to drastic improvements in speech and language outcomes for children who have a received a cochlear implant (CI). The purpose of this study was to investigate the amount, type, and quality of services that young children with CI(s) are receiving.
Methods. Participants in this study included 22 teachers of the deaf/hard of hearing (TD/HH), 7 speech-language pathologists (SLP), and 4 early childhood interventionists (ECI). All of the service providers were serving at least one child with a CI(s) at the time of the study. Three on-line service provider surveys were modified from the National Early Intervention Longitudinal Study (NEILS) in order to specifically address the concerns and interests of service provision for children with CIs. The three surveys addressed the birth-3, preschool, and school-age populations.
Results. Results from the birth-3 and preschool populations with CIs were analyzed. The school-age population was not analyzed due to the low response rate from that age group. Findings from this study revealed that the TD/HH is the primary service provider for the birth-5 population with CIs. In addition, other service providers (i.e. SLP, ECI) reported that they do not feel completely comfortable working with the CI device (i.e. troubleshooting, utilizing the Ling Six Sound test). Another area of concern was the child's compliance in wearing the CI on a full-time, daily basis. Collaboration and education among professionals and the families of children with CIs must be stressed in order for early intervention services to effectively facilitate the child's speech, language, and educational development.
Conclusion. The results revealed characteristics specific to both the child (i.e. services the child has received in the past 6 months as part of his/her intervention program) and the service provider (i.e. amount of professional education concerning children with CIs). More research is needed to assess the relationship between the amount and quality of service provision and the child's speech and language performance to ensure that this population is receiving appropriate early intervention services.
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Greiner, Lea Ashley. "Measures of executive function in children with cochlear implants." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/506.
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This study aimed to answer whether current research addressing executive function abilities in cochlear implant users was accurately depicting their impairments. Secondly, this study aimed to identify differences in identification of executive function impairments when measured using parent report versus behavioral measures of executive function. Results suggest that children do have executive function impairments in areas of measure nonverbal planning, problem-solving, monitoring, and self-regulation abilities as well as attention to a visually presented array of pictures which has been documented in previous research. However, it is likely that these abilities are modulated by children with cochlear implants' poorer language ability as demonstrated on the PPVT, which seems not to be related to their age of implantation. The behavioral measures and parent report measures identified impairments in the subsets which required a greater language demand and subsequently subsets that were significantly more difficult for CI children.
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JAHNKE, MARGARET L. "QUALITATIVE ANALYSIS OF THE BENEFITS OF COCHLEAR IMPLANTS FOR CHILDREN WITH MULTIPLE HANDICAPS." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1084200167.
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Lim, Debbie K. Psychology Faculty of Science UNSW. "Cognitive style and adjustment in cochlear implant users." Awarded by:University of New South Wales. School of Psychology, 2005. http://handle.unsw.edu.au/1959.4/21897.
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This program of research investigated the role of cognitive factors in adjustment to cochlear implantation. A cochlear implant is a medical device for severe to profoundly deaf individuals that simulates sound in the cochlea by electrically stimulating the hearing nerve. The audiological benefits of implantation have shown to be highly variable and difficult to predict. This has led to the utilisation of psychological factors to predict adjustment. The aim of this thesis was to develop an understanding of the psychological factors influencing adjustment to implantation within a cognitive framework. Three studies were conducted that investigated the central hypothesis that individuals with a maladaptive cognitive style are more likely to experience poorer psychological adjustment following implantation. Study 1 was a cross-sectional survey that aimed to identify the main predictors of post-implant adjustment in a large representative sample of adult cochlear implant recipients. Participants completed measures of hearing-related cognitions, anxious and depressive symptomatology, emotional reaction to the implant, and hearing-related demographic characteristics. Psychological adjustment was assessed as stress and coping in relation to hearing impairment. The tendency to engage more frequently in negative hearing-related cognitions was found to be the strongest predictor of adjustment. This finding was consistent with the hypothesis that a maladaptive cognitive style plays a key role in determining psychological outcomes following implantation. Study 2 extended Study 1 by experimentally investigating the impact of a specific maladaptive cognitive process, rumination, on cochlear implant recipients' response to an auditory task. Based on the Study 1 finding that negative cognitions predicted poorer adjustment, participants engaged in either a positive or negative rumination task. During rumination, participants focussed on a series of either positive or negative self-statements. Following rumination, participants completed an auditory (story listening) task. Participants then rated their mood, extent of negative cognitions, and the perceived difficulty of the auditory task. Inconsistent with predictions, participants who engaged in negative rumination did not respond more negatively on any of the ratings than participants who engaged in positive rumination. A correlational analysis, however, showed that greater perceived task difficulty was associated with lower frequency of engagement in positive cognitions about hearing. Study 3 employed a thought suppression paradigm to investigate in cochlear implant recipients the effects of suppressing thoughts about hearing difficulty during an auditory task. It was predicted that participants instructed to suppress would experience an increased frequency of target thoughts and greater negative mood, both during and after suppression. During the first (baseline) experimental period, both suppression and non-suppression participants monitored their thoughts by pressing a button when they experienced a thought about hearing difficulty. In the second (suppression) period, suppression participants suppressed their thoughts about hearing difficulty. In the third (post-suppression) period, suppression participants were instructed to no longer suppress their thoughts. Participants who suppressed had an increased frequency of target thoughts subsequent to, but not during, suppression. There were no differences between suppression and non-suppression participants for mood, either during or after suppression. The finding of a delayed increase in target thoughts indicated that attempting to suppress thoughts about hearing difficulty may be a maladaptive cognitive strategy for managing unwanted negative cognitions about hearing in cochlear implant recipients. In concluding, the thesis proposes a cognitive model of adjustment to cochlear implantation that synthesises the findings of the studies conducted and takes into account the cognitive theories that informed the program of research. The major components of this model include the tendency to engage in negative hearing-related cognitions, the maladaptive cognitive processes employed to manage negative hearing-related cognitions, and cognitive load factors. While far from conclusive, the model presents an initial framework within which the current findings can be understood and further hypotheses generated. Methodologically, the model also provides an empirically informed framework for future investigations into the cognitive factors associated with adjustment in cochlear implant users.
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Zaidman-Zait, Anat. "Parenting children with cochlear implants : challenges, stress, coping, and processes." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31767.
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The central goal of the current dissertation was to expand the research on the experiences of parents of children with cochlear implants (CIs). To accomplish this goal, three studies were conducted: The first study explored everyday problems associated with parenting children who undergo cochlear implantation; to investigate parents' interpersonal relationships as a resource for collaborative problem solving; and to examine links between parents' everyday problems, stress, and life satisfaction. Thirty-one parents of children with CIs responded to open-ended questions regarding the types of everyday problems they encountered in parenting their child, and also rated their stress and life satisfaction. Problems were categorized into nine domains: implant drawbacks, communication difficulties, child's behavior, child's social competence, rehabilitation demands and parenting role, financial difficulties, services, educating others/advocacy, and academic concerns. Professionals, spouses, and other parents of deaf children were frequently nominated partners for collaborative problem solving and coping. Significant correlations emerged among parents' everyday problems, stress, and life satisfaction. The second study described and categorized the attributes that parents of young children with CIs consider as facilitating their parental coping experience. Fifteen hearing mothers and thirteen hearing fathers whose children had CIs were interviewed, using the critical incident technique. A total of 430 critical incidents were documented and sorted into 20 categories. Results indicated various sources of influence on parents' coping experience, associated with social contextual aspects, with the parent himself or herself, and with the child. The third study examined the complexity of parenting children who have received CIs as well as parents' involvement in the CI rehabilitation process. Action theory and its related qualitative action-project method were used in this study. Two cases were used to describe the individual and joint actions and projects, as related to the promotion of children's outcomes post-cochlear implantation that mothers engage in with their young children. Potentially illuminative implications were drawn for the 'current thinking' in relationship to parenting children with cochlear implants. Finally, four overarching themes emerging from the findings of the three studies were identified and described. These themes were discussed in terms of implications for practice and future research.Education, Faculty of
Educational and Counselling Psychology, and Special Education (ECPS), Department of
Graduate
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Machado, Gerson Augusto Salado. "Low-power analogue VLSI cochlear implants : approaches and design techniques." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266514.
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Poon, Becky Bikkei. "Sound localization and interaural time sensitivity with bilateral cochlear implants." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35548.
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Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2006.Includes bibliographical references.
Bilateral cochlear implantation is becoming more common as clinicians attempt to provide better sound-source localization and speech reception in noise for cochlear implant (CI) users. While some improvement over the abilities of monolateral implantees has been documented, bilateral performance for CI users is far from that achieved with normal hearing. Identifying factors that limit bilateral performance has been difficult because little is understood about CI listeners' localization abilities, their sensitivity to interaural cues, and the relationships between them. To better understand bilateral electric hearing, five bilateral CI users' abilities to locate sound sources and their sensitivities to interaural time difference (ITD) were studied in this thesis. Unlike past studies, monolateral and bilateral performance was recorded before and after exposure to daily, bilateral-CI listening using constant- and roving-level stimuli. For constant-level stimuli, increasing bilateral-listening experience improved all subjects' bilateral performance but degraded two subjects' monolateral performance. Using roving-level stimuli, increasing bilateral-listening experience also improved bilateral performance but did not alter monolateral performance.
(cont.) Our results show that depending on the method of evaluation, the benefit of bilateral CIs over monolateral CI could be overstated for some subjects. A simple decision model was used to predict subjects' localization performance based on their sensitivity to interaural time and level differences (TD and ILD) measured through their sound processors. The predicted performance indicated that the measured performance could be accounted for by subjects' ILD sensitivity but not by their ITD sensitivity alone. Poor ITD sensitivity may be one reason that bilateral CI users' localization performance is poor compared to that of normal-hearing (NH) listeners. To improve ITD sensitivity, a first step is to characterize ITD sensitivity on single, interaural electrode pairs because data in the literature is incomplete. In particular, the dependence of ITD sensitivity on the repetition rate and the number of pulses in the unmodulated pulse trains was studied. Just noticeable difference (JND) of ITD was measured with four subjects on their most ITD-sensitive, interaural electrode pair. At low rate (50 pps), ITD JND improved with increasing number of pulses, indicating integration of ongoing ITD cues. The best ITD JNDs were 85 - 354 pts. Using 800-pps trains, two subjects' ITD JND degraded with increasing number of pulses.
(cont.) Two subjects were insensitive to ITD up to 2 ms for 800-pps trains. To begin studying the impact of CI processing on ITD sensitivity, ITD JND was also measured using low-rate (50 pps) pulse trains delivered to the external input of the subjects' sound processors. ITD JND improved with increasing number of pulses. While subjects were insensitive to ongoing ITD in unmodulated, high-rate pulse trains delivered to single, interaural electrode pairs, they were sensitive to ongoing ITDs in the low-frequency modulator of high-rate pulse trains in the through-processor case. A next step toward greater understanding of bilateral electric hearing is to fully investigate the degree to which subjects are sensitive to ITD using modulated pulse trains. The results of this thesis show that there is significant localization benefit with bilateral CIs even though performance is not at the level of NL listeners. Further studies to improve ITD sensitivity may improve localization ability, which will further justify the risks and cost associated with bilateral implantation.
by Becky Bikkei Poon.
Ph.D.
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Hilton, K. M. "Exploring the psychosocial experiences of adolescents with sequential cochlear implants." Thesis, Canterbury Christ Church University, 2012. http://create.canterbury.ac.uk/10976/.
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Section A is a review of the literature on the psychological and social implications of cochlear implants (CIs) in deaf children and adolescents. The literature is critically evaluated in relation to health-related quality of life, quality of life, psychological and emotional well-being, social well-being and identity. Relevant theories are outlined and discussed. Methodological limitations and gaps in the literature are discussed, and the review concludes with recommendations for further research. Section B describes a study using Interpretative Phenomenological Analysis to explore adolescent experiences of receiving and living with sequential cochlear implants (SCIs). Semi-structured interviews were conducted with eleven adolescents. The master and sub-themes are presented and the results are discussed with consideration of previous research findings and theoretical, clinical and research implications. Most participants enjoyed improved confidence and social well-being following their SCI, and felt that two CIs were superior to one. The majority identified themselves as hearing and deaf, but not culturally Deaf, as they strived to live in the hearing world. However, this was not without challenges and many young people experienced feelings of difference in the hearing world. These findings have clinical implications in terms of the role of clinical psychologists in CI clinics, and in providing information to families making decisions about CIs. These findings add to the emergent deaf identity development literature in young people with CIs.
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Saleh, S. M. I. "The efficacy of fitting cochlear implants based on pitch perception." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1400212/.
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Cochlear implants (CI) provide useful hearing for many hearing-impaired individuals. The CI’s external sound processor has to be programmed to optimise performance. However, performance varies greatly amongst CI recipients. This thesis evaluated a pure-tone electrode-differentiation (PTED) pitch-ranking task for optimising programming. The PTED was evaluated for reliability, validity and clinical-suitability. PTED scores were a significant (p<0.05) predictor of speech-perception. The angular-depth-of-insertion for the CI array was estimated for 16 recipients, there was a significant correlation with speech-perception. Cone beam computed tomography (CBCT) increased accuracy for estimating scalar-placement of electrodes and no association was found with speech-perception. 25 unilaterally-implanted recipients received programs with indiscriminable electrodes deactivated based on PTED. Two programs were provided, one with the same rate-of-pulses-per-channel (RPC) as the clinical program and one with increased RPC. Programs were evaluated in a cross-over study. Speech-perception was evaluated using BKB (Bamford-Kowal-Bench) sentences in quiet and noise and the Coordinate Response Measure (CRM). Statistically significant improvements were found with at least one research program on all measures. A pure-tone intermediate frequency (PTIF) task was conducted to compare pitch perception in regions of good ED with regions of poor ED. Participants gaining benefit from electrode deactivation had fewer intermediate frequencies (IF) in poor ED regions compared to good ED regions and more IF in electrode deactivation regions following deactivation. This pattern was not observed in participants not gaining benefit from electrode deactivation. Six bilaterally-implanted participants underwent pitch matching between ears and new programs were created using only discriminable electrodes. Two matching approaches were used; direct stimulation via clinical equipment and pure-tone stimulation. Significant improvements were found in localisation and BKB in noise with at least one research program. The results of these experiments suggest potential for improving performance for CI users by programming based on PTED; a clinically viable task.
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Ostrowski, Mark G. "Cochlear Implants and Language Outcomes in Children with Symptomatic CMV." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1242951563.
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Clayton, Lynn E. "Intervention Settings for Children with Cochlear Implants and Developmental Disabilities." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1243189468.
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McGrath, Andrew J. "Beyond Plasticity: Cochlear Implants, Family Objects, and Quasi-Neuronal Lives." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504781636219078.
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De, Seta Daniele. "Quality of insertion in cochlear implants : a clinical and temporal bone study." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066174/document.
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L'implant cochléaire représente le dispositif de référence pour réhabiliter l'audition des patients atteints de surdités sévère à profonde. Les indications se sont récemment étendues vers les patients avec une audition résiduelle avec de bons résultats. Il persiste cependant une grande hétérogénéité des résultats auditifs. Plusieurs facteurs ont été identifiés comme influençant les performances auditives: durée de la surdité, intelligibilité préopératoire et stratégie de codage. Dans cette thèse, l'anatomie de la cochlée et la position postopératoire du porte-électrodes ont été étudiés afin d'identifier les facteurs de variabilité de la discrimination vocale inter- et intra-individuelle. Les résultats de cette thèse ont montré un lien entre la position de l'électrode et les performances auditives à court terme, alors que la plasticité neuronale pourrait jouer un rôle important dans l'adaptation de l'implant cochléaire aux structures neurales à long terme. De plus, la préservation des structures cochléaires est maintenant recommandée pour tous les candidats à l'implantation, quelle que soit leur audition préopératoire. Une étude radio-histologique sur rochers avec une insertion motorisée du porte-électrodes a été réalisée afin d'identifier les paramètres des forces d'insertion qui pourraient prédire le traumatisme de l'oreille interne lié à l'insertion. Une corrélation entre les valeurs de forces d'insertion et le traumatisme cochléaire a été trouvée dans les os temporaux. Ces valeurs, serviront au développement d'outils d'insertion " intelligents " pour réduire les lésions liées à l'insertion et ainsi conduire à des conditions de rééducation auditive optimaleThe cochlear implantation represents the standard technique to restore the hearing in totallydeafened persons, and the indications during the last years are widening also to patients withresidual hearing or presenting single sided deafness. Despite the overall good to very goodresults after cochlear implantation reported in literature a wide heterogeneity of the hearingoutcomes emerges in the single studies and poor results both in unilateral and bilateralcochlear implantation are still reported. Several patients’ specific factors have been identifiedas affecting postimplant speech perception score, including duration of deafness, residualpreoperative speech recognition, and different speech coding strategy. In this thesis theanatomy of the cochlea and the position of the electrode array in implanted patients have beenstudied with the attempt to identify the affecting factors that contribute to the variability of theinter- and intra-individual speech discrimination scores both in bilaterally and unilaterallyimplanted patients. Moreover, following the expanding indication for cochlear implantation,the preservation of inner ear structures is becoming recommended for all cochlear implantcandidates, regardless of their preoperative hearing. A radio-histological temporal bone studywith a motorized insertion of the array was performed in order to identify the insertion forcesparameters that could predict the possible traumatism involving the inner ear. The results ofthis thesis showed a relationship between the intracochlear electrode position and hearingperformance in the short term follow up, whereas the neural plasticity would play animportant role in the adaptation of the cochlear implant to the neural structures in the longterm. A correlation between insertion forces and inner ear traumatism was found in temporalbones. Two different force profiles for traumatic and atraumatic insertion were obtained; thesevalues, if confirmed by further studies, could be useful for the development of future forcefeedback automated cochlear implant insertion tool in order to reduce the risk of insertionrelated damage and provide the best chance for an optimal hearing rehabilitation in cochlearimplanted candidates
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Taft, Daniel Adam. "Cochlear implant sound coding with across-frequency delays." Connect to thesis, 2009. http://repository.unimelb.edu.au/10187/5783.
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The experiments described in this thesis investigate the temporal relationship between frequency bands in a cochlear implant sound processor. Initial studies were of cochlea-based traveling wave delays for cochlear implant sound processing strategies. These were later broadened into studies of an ensemble of across-frequency delays.Before incorporating cochlear delays into a cochlear implant processor, a set of suitable delays was determined with a psychoacoustic calibration to pitch perception, since normal cochlear delays are a function of frequency. The first experiment assessed the perception of pitch evoked by electrical stimuli from cochlear implant electrodes. Six cochlear implant users with acoustic hearing in their non-implanted ears were recruited for this, since they were able to compare electric stimuli to acoustic tones. Traveling wave delays were then computed for each subject using the frequencies matched to their electrodes. These were similar across subjects, ranging over 0-6 milliseconds along the electrode array.
The next experiment applied the calibrated delays to the ACE strategy filter outputs before maxima selection. The effects upon speech perception in noise were assessed with cochlear implant users, and a small but significant improvement was observed. A subsequent sensitivity analysis indicated that accurate calibration of the delays might not be necessary after all; instead, a range of across-frequency delays might be similarly beneficial.
A computational investigation was performed next, where a corpus of recorded speech was passed through the ACE cochlear implant sound processing strategy in order to determine how across-frequency delays altered the patterns of stimulation. A range of delay vectors were used in combination with a number of processing parameter sets and noise levels. The results showed that additional stimuli from broadband sounds (such as the glottal pulses of vowels) are selected when frequency bands are desynchronized with across-frequency delays. Background noise contains fewer dominant impulses than a single talker and so is not enhanced in this way.
In the following experiment, speech perception with an ensemble of across-frequency delays was assessed with eight cochlear implant users. Reverse cochlear delays (high frequency delays) were equivalent to conventional cochlear delays. Benefit was diminished for larger delays. Speech recognition scores were at baseline with random delay assignments. An information transmission analysis of speech in quiet indicated that the discrimination of voiced cues was most improved with across-frequency delays. For some subjects, this was seen as improved vowel discrimination based on formant locations and improved transmission of the place of articulation of consonants.
A final study indicated that benefits to speech perception with across-frequency delays are diminished when the number of maxima selected per frame is increased above 8-out-of-22 frequency bands.
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Friesen, Lendra M. "Speech-evoked auditory potentials in cochlear implant listeners /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/8239.
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Smith, Kristen A. "The Receptive and Expressive Language Outcomes of Children who have Received Cochlear Implants and have an Autism Spectrum Disorder." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1212095057.
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Pinheiro, Maria Madalena Canina [UNIFESP]. "Processamento temporal e resposta auditiva de média latência em idosos candidatos e usuários de prótese auditiva." Universidade Federal de São Paulo (UNIFESP), 2011. http://repositorio.unifesp.br/handle/11600/9978.
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Previous issue date: 2011-02-22Introdução: O envelhecimento pode ocasionar alterações no processamento temporal e nas funções cognitivas. A avaliação eletrofisiológica tem sido recomendada para complementar a avaliação comportamental do processamento auditivo. Objetivo: Verificar e comparar as respostas auditivas comportamentais de processamento temporal e resposta de média latência com o processamento cognitivo em idosos, candidatos e novos usuários de próteses auditivas. Métodos: Participaram do estudo 60 idosos, sendo 20 sexo masculino e 40 sexo feminino, cuja faixa etária era 61 a 85 anos (média 71,7 anos), atendidos no Núcleo Integrado de Assistência, Pesquisa e Ensino da Audição (NIAPEA) da Escola Paulista de Medicina da Universidade Federal de São Paulo, todos novos usuários de prótese auditiva. Os indivíduos foram reunidos em dois grupos segundo o grau da perda auditiva, ao considerar as frequências de 500 a 4000 Hz do audiograma, denominados de Grupo I (GI) e Grupo II (GII). No GI os indivíduos apresentavam grau de perda auditiva inferior ou igual a 50 dB, e no GII, superior ou igual a 51 dB. Os aspectos cognitivos foram avaliados por meio do Potencial Evocado Auditivo de Longa Latência – P300, Mini-Exame do Estado Mental (MEEM) e Escala de Avaliação da Doença de Alzheimer (ADAS-COG). Os procedimentos selecionados para contemplar os objetivos foram o Potencial Evocado Auditivo de Média Latência (PEAML), no qual foi estudada a latência das ondas Na e Pa (milissegundos), amplitude do complexo Na-Pa (microvolts) e quando ocorreu a presença de efeito auditivo e/ou eletrodo o exame foi considerado alterado. Ainda, foram aplicados o Teste Padrão de Duração (TPD) e Teste de Detecção de Gap no Ruído (GIN) no qual foram analisadas as respostas de identificação correta, e o limar de acuidade temporal. Resultados: Os idosos usuários de prótese auditiva apresentaram menor limiar de acuidade temporal, maior reconhecimento de gaps e de discriminação do padrão de duração, menor latência e diminuição das alterações do PEAML em relação ao momento em que eram candidatos. Quando mostravam déficits no processamento da informação em área auditiva primária, apresentaram prejuízo na habilidade auditiva de resolução temporal, que piorava na presença de alteração cognitiva. Conclusão: Houve deterioração das habilidades de resolução e ordenação temporal, independente do grau da perda auditiva, mostrando o efeito- idade originado pelo envelhecimento. As respostas do Potencial Evocado de Média Latência também não foram influenciadas pelo grau da perda auditiva e ocorreu mudança significativa na reavaliação após a aclimatização. Assim, o efeito de estimulação acústica pelo uso de prótese auditiva melhorou a habilidade auditiva de ordenação temporal, resolução temporal e o processamento das informações do Sistema Nervoso Auditivo Central até o córtex temporal primário. O comportamento de ordenação temporal não se modificou nos idosos com alterações cognitivas, no entanto indivíduos sem alteração cognitiva têm menor déficit na integridade funcional das áreas auditivas primárias e melhora no comportamento de resolução temporal.
Introduction: Aging can cause alterations in temporal processing and cognitive functions. Electrophysiological evaluation has been widely recommended to complement the behavioral evaluation of auditory processing. Objective: Verify and compare the behavioral auditory responses of temporal processing and the auditory middle latency response with cognitive processing in elderly candidates for and users of hearing aids. Methods: Sixty elderly people participated in the study, 20 males and 40 females, ranging in age from 61 to 85 (avg. 71.7) who are attended at the Integrated Hearing Assistance, Research and Education Center (NIAPEA) of the Federal University at São Paulo, and who are all new users of hearing aids. The individuals were organized in two groups according to their degree of hearing loss, considering frequencies of 500- 4000 Hz on the audiogram, denominated Group I (GI) and Group II (GII). In GI, the individuals had a degree of hearing loss lower than 50 dB and in GII above 50 dB. The cognitive factors were evaluated by means of long-latency auditory evoked potential tests– P300, Mini mental state examination (MMSE) and the Alzheimer Disease Assessment Scale (ADAS-COG). The procedures selected to achieve the objectives were the Middle Latency Auditory Evoked Potentials (MLAEP) tests, which studied the latency of the Na and Pa waves in milliseconds, and the amplitude of Na-Pa (μv). When an auditory and or electrode effect was present, the exam was considered altered. The Duration Pattern Tests (TPD) and Gap in Noise (GIN) test were used to analyze the responses of correct identification, and the gap detection threshold. Results: Elderly people who use hearing aids display a lower gap detection threshold, greater recognition of gaps and of discrimination of the duration pattern, lower latency and decrease in MLAEP in relation to the time when they were candidates. When they displayed deficits in information processing in auditory cortex, they displayed losses in the temporal resolution ability, which became worse in the presence of cognitive alteration. Conclusion: The temporal ordering and temporal resolution abilities deteriorated independent of the degree of hearing loss, revealing the age effect. The responses to Middle Latency Auditory Evoked Potentials tests were not influenced by the degree of hearing loss and significant changes in reassessment occurred after acclimatization. Thus, the effect of acoustic stimulation by the use of a hearing aid improved the hearing ability of temporal ordering, temporal resolution and the processing of information from the Central Auditory Nervous System to the primary auditory cortex. The behavior of temporal ordering did not change in the elderly with cognitive alterations; however, individuals without cognitive alterations had lower deficits in the functional integrity of the primary hearing areas and improvement in the behavior of temporal resolution.
TEDE
BV UNIFESP: Teses e dissertações
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Viik, Rickard. "Endeavors toward Novel Cochlear Implants from Stretchable Printed Circuit Board Technology." Thesis, Uppsala universitet, Mikrosystemteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-382489.
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Profound sensorineural hearing loss is at the present time a major worldwide health concern, affecting over 5% of the worlds' population. Through cochlear implants (CI), treatment of sensorineural hearing loss now offers the possibility to restore hearing function through electrical stimulation of auditory nerves. Treatment is based on the surgical implantation of a thin, flexible array of microelectrodes into the cochlea. Nevertheless, availability of the treatment is limited due to high costs, and surgical insertion is associated with a high risk of trauma to the fragile soft tissue of the cochlea. At the heart of this thesis lies the proposition that these two problems may be addressed by the development of a novel type of cochlear implant founded on batch-producible, stretchable printed circuit board (PCB) technology. As an alternative to conventional cochlear implant fabrication, this thesis presents a fabrication process based on batch-producible stretchable PCB, featuring liquid alloy microchannels in place of solid metallic wire conductors. A series of proof-of-concept prototypes were designed, fabricated and evaluated. According to results obtained from evaluation of the prototypes, certain steps in the fabrication process were later revisited and improved upon. Preliminary prototype fabrication yielded batches of thin flexible cone-shaped electrode arrays designed for in-vivo evaluation in guinea-pig cochleae. In-vitro evaluation in 3D-printed cochlea models revealed that the prototypes were sufficiently thin and compliant for insertion 23 mm deep into a human cochlea and 4-6 mm into a guinea-pig cochlea, comparable to commercially available counterparts. Characterization of prototype test devices by optical microscopy, optical interferometry and resistance measurements revealed a high inherent variability in the developed fabrication process. In order to ensure consistently adequate quality, further improvement must be done. In particular, results of this work suggest that the deposition of liquid alloy involved in stretchable PCB fabrication should be automated to minimize uncertainty in the deposited liquid alloy thickness and thus enable further miniaturization of the stretchable PCB. Future efforts to successfully produce and integrate electrodes from soft materials, e.g. conductive polymer, liquid alloy or conductive hydrogels are highly recommended to further reduce implant stiffness.
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Andersson, Jens. "Horizontal sound localization in adults with unilateral or bilateral cochlear implants." Thesis, Örebro universitet, Institutionen för medicinska vetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-48406.
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Na, Eunjung. "Cochlear Implants for Children with Residual Hearing: Supporting Family Decision-making." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/41994.
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Children with residual hearing have become eligible for consideration as CI candidates in some pediatric programs because of the positive clinical research outcomes of cochlear implant (CI). However, decision-making about CIs for children with residual hearing is difficult for parents because they experience uncertainty when their children show auditory benefits and are developing language through hearing aids (HAs). Clinicians may be uncomfortable recommending CI for these children due to variability in audiometric candidacy criteria in individual clinical practice. However, there is very limited information about the CI decision-making process and needs to assist the parents of these children and practitioners.
We conducted a comprehensive study to better understand and support the CI decision-making experiences of families and practitioners. The objectives of our study were to: 1) explore the clinical characteristics and outcomes of children with residual hearing who received CIs, 2) summarize the evidence about the benefits and risks of CIs compared to HAs in children with residual hearing, and 3) explore the decision-making process and needs for children with residual hearing from the perspective of parents and practitioners.
This research project combined quantitative and qualitative research designs. A retrospective chart review was conducted to address the first objective. Data on the clinical characteristics of children with residual hearing were extracted from medical charts from a tertiary care pediatric CI center in Ottawa, Canada. A systematic review was performed on the benefits and risks of CIs versus HAs for children with residual hearing to address the second objective. The third objective was addressed through two sub-studies. The first sub-study involved qualitative semi-structured interviews. A total of 12 parents participated in individual interviews. In the second sub-study, 17 practitioners at a pediatric CI center in Ottawa, Canada, and specialized teachers of the deaf and hard of hearing at local school boards were recruited, and four focus groups and one individual interview were conducted.
This study showed that a total of 100 of 389 (25.7%) children who received CIs from 1992 to 2018 at the Children's Hospital of Eastern Ontario (CHEO) had residual hearing, representing more than half the children who were implanted in the last two years covered by the study. As documented in our study, overall, children with residual hearing demonstrated benefits in auditory functioning following cochlear implantation. Approximately 70% of these children achieved open-set word perception scores of 80% or more post-CI.
In the systematic reviews, a total of 3265 citations were identified, of which eight studies met inclusion criteria. The articles consisted of four moderate and two weak quality pre-post cohort studies and two weak quality cross-sectional studies. The systematic review confirmed that children with CIs showed significantly better speech perception scores than those with HAs. Limited evidence of improvement in auditory performance and non-significant improvement in speech intelligibility was found. Two aspects of social-emotional functioning (hyperactivity/inattention and pro-social behaviour) showed significant improvement with CIs. Our finding also contributes new information about the loss of residual hearing and device use. Four studies provided data on risks following CIs; a total of 16 of 43 (37.2%) children showed loss of residual hearing and 14.0% (8/57) of children had discontinued or limited use of their CI or HA.
The qualitative interviews revealed that both parents and practitioners identified child’s everyday functioning as an important factor that influenced their decision-making. It was clear through the qualitative research with parents that they held a strong preference for child’s inclusion into hearing society. Spoken communication was a core value for the parents of these children and some parents expressed high expectations that their children’s hearing would become ‘normal’. We found that practitioners primarily supported parental decision-making by providing information on the practical aspects of the benefits and risks of CIs. Overall parents were satisfied with the decision-making process and decision support from practitioners. However, parents stressed the importance of receiving more personalized information that considered their specific concerns, values and preferences related to their child and family’s circumstances. Practitioners also noted that more research among children with residual hearing is needed to guide parental CI decision-making.
To our knowledge, the findings from this dissertation are the first to examine decision-making for children with residual hearing. Our study contributes new information about the characteristics of children receiving CIs, the potential benefits and risks for children with residual hearing, and decision-making needs from the perspectives of families and practitioners. In addition, our research is a useful first step in understanding what families need to make better decisions to assist in the CI decision-making process for this specific population.
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Mercadante, Jenna Nicole. "Growth Attenuation, Sterilization, and Cochlear Implants: Ethical, Legal and Social Themes." Wright State University Professional Psychology Program / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wsupsych1309537482.
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