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1
Cathers, Ian Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Stretch signal and muscle state dependence of the tonic stretch reflex". Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2000. http://handle.unsw.edu.au/1959.4/17807.
Testo completoAbstract (sommario):
When active skeletal muscle is stretched, it generally responds with a contraction which resists the stretch. This response is termed the muscle stretch reflex. The size (gain) and timing (phase) of the response has been found to depend on many factors including the characteristics of the applied stretch, the muscle contraction level and the subject's intention. Investigations of this stretch reflex have often involved stretches to muscle which contained frequencies either beyond the range of voluntary movement or else which could be consciously tracked. This study sought to characterise the frequency response of the stretch reflex, in terms of its gain and phase, under a variety of conditions while using stretches to the muscle which were relevant to voluntary movement, yet which were too irregular to be tracked. The types of stretch which satisfied these criteria had first to be determined by an investigation of tracking performance under different conditions of peripheral feedback. Having established the types of stretch which could be used to guarantee reflex rather than voluntary responses, the stretch reflex was investigated using stretches of different amplitude and bandwidth and spanning the full range of contraction level. Research was also undertaken to determine whether the gain and phase of the reflex response could be decoupled from the background contraction level of the muscle and to examine any associated effects on the mechanical properties of the limb. Explanatory models for some of these reflex responses were developed. An interaction between normal physiological tremor and the stretch reflex response was also investigated.
2
Bock, Przemek John. "Modulation of stretch reflex excitability in quiet human standing". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82471.
Testo completoAbstract (sommario):
Stretch reflex excitability was measured during quiet standing by using a bilateral electro-hydraulic actuator to apply perturbations of angular position to the ankle. Subjects were instructed to stand quietly while pulse displacements were applied at random times. Position, torque, gastrocnemius-soleus EMG, tibialis anterior EMG, heel position, tibia angle, femur angle, and sacrum angle were measured. Background torque and reflex excitability varied substantially from trial to trial---reflex torque decreased as the background torque level increased; while reflex EMG increased when background torque increased. This behavior is consistent with previous findings in prone subjects. Reflex torque for a given activation level was found to vary with the initial torque derivative---reflex excitation was greater for negative torque derivatives than their positive counterparts. These findings suggest that reflex excitability in quiet human standing is modulated to optimize balance.
3
Duncan, Audrey. "Reflex modulation in human movement and posture". Thesis, University of Birmingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367627.
Testo completoAbstract (sommario):
Human soleus H-reflex gain was measured in supine lying and in standing vertically while stabilised by a backboard. H-reflex amplitude was less in stabilised standing than in supine lying. The reduction was partly due to the effect of gravitational load. When the same load was applied (by compression of the body between shoulders and feet) while lying supine the corresponding reduction was 70%. The results are discussed in relation to possible gravitational load receptors. In a second series of experiments a collapsible landing platform was used to differentiate between reflex and programmed contributions to EMG activity in landing from a jump. Post-landing activity of the calf muscles was a short latency spinal reflex triggered by ankle rotation. In the rectus femoris muscle, activity was programmed for short falls and had a reflex component in longer falls. When the collapsible platform caused a landing to occur at a time later than anticipated, reflex gain was increased in the gastrocnemius, biceps femoris and rectus femoris muscles. Experimental results were consistent with the time that would be required for descending pathways to modulate the reflex gain and an appropriate model is proposed.
4
Arbat, i. Plana Ariadna. "Modulation of the stretch reflex arc to improve functional recovery after peripheral nerve injury". Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/394061.
Testo completoAbstract (sommario):
Després d’una lesió del sistema nerviós perifèric, aquest té la capacitat de regenerar però la seva recuperació funcional sol ser limitada, principalment degut a la inespecificitat de la reinnervació dels òrgans perifèrics i als canvis plàstics maladaptatius de la circuiteria espinal. En aquesta tesi hem volgut modular els canvis a la circuiteria espinal del reflex d’estirament per poder millorar la recuperació funcional després de lesions del nervi perifèric en un model animal.
En primer lloc, es va dur a terme una caracterització immunohistoquímica dels canvis que patien les motoneurones espinals després d'una lesió del nervi ciàtic; aquests canvis es van estudiar en animal postnatal i en l’adult. En els animals postnatals, també es va estudiar la composició sinàptica de l’arbre dendrític de les neurones, i es va observar una elevada pèrdua de sinapsis excitatòries que no s’arriben a recuperar després de 2 mesos. Pel que fa als canvis produïts en l’adult, vam observar que la màxima pèrdua de sinapsis glutamatèrgiques i de xarxes perineurals (PNN) es produïa dues setmanes després de la lesió, amb una progressiva recuperació a partir de la quarta setmana.
Per intentar atenuar aquesta pèrdua sinàptica i de PNN, vam estudiar l’efecte de l’estimulació elèctrica i de la capacitat de diferents factors tròfics (aplicats a la zona de lesió mitjançant una matriu de col·lagen en un tub de silicona). No es van obtenir diferències significatives en cap de les dues teràpies. També vam avaluar diferents protocols d'exercici físic, concretament l’exercici forçat, voluntari i passiu. Si es feia servir un protocol d’alta intensitat, la pèrdua sinàptica i de PNN que patien les motoneurones era menor que la pèrdua observada en les motoneurones d'animals que no havien estat sotmesos a exercici, mentre que en aquells que corrien menys no presentaven millores respecte als animals no exercitats A més, en els animals exercitats també vam observar un augment de l’astrogliosis al voltant de les motoneurones axotomitzades i una disminució de l’activació de la microglia, excepte en l’exercici voluntari i passiu a baixa intensitat, on vam observar un augment de l’activació de microglia.
Degut als efectes positius induïts per l’exercici físic sobre els canvis plàstics en el nostre model, vam valorar potencials mecanismes implicats en aquestes efectes. Tot i que se sap que l’exercici incrementa l’expressió de neurotrofines, es desconeix com l'exercici modula aquestes neurotrofines i quines són les seves accions específiques. Per valorar el paper del BDNF en els efectes de l'exercici observats en el nostre model, vam administrar sistèmicament un agonista i un antagonista del TrkB. Vam observar que el manteniment de les sinapsis mediat per l'exercici físic depenia parcialment de l’activació del TrkB, però l'activació farmacològica d'aquest receptor no mimetitzava els efectes de l'exercici.
Com que l'exercici físic provoca un augment de l'activitat neural, també vam valorar el paper de les projeccions descendents noradrenèrgiques del tronc de l'encèfal en els efectes moduladors de l'exercici sobre les motoneurones. Aquestes vies descendents modulen l'excitabilitat de les motoneurones espinals i s'activen en situació d’estrès, com l'exercici forçat. Mitjançant l’administració de DSP-4, que destrueix el locus coeruleus i per tan, provoca la pèrdua de les projeccions noradrenergiques descendents, vam veure una reducció de PNN i una marcada reactivitat de la microglia. En els animals sotmesos a exercici, la pèrdua d'aquestes projeccions impedia la preservació de sinapsis i de PNN al voltant de les motoneurones lesionades, si bé la reactivitat microglial es veia igualment disminuïda. Aquestes troballes suggereixen que la modulació dels canvis espinals induïts per l'exercici físic seria parcialment dependent de l'activació d'aquestes projeccions noradrenèrgiques, mentre que la modulació de la micròglia per l'exercici en seria independentAfter a peripheral nerve injury, axons are able to regenerate but functional recovery is usually limited, mainly due to unspecific reinnervation of target organs and also to maladaptive plastic changes in the spinal circuitry. In this thesis we wanted to modulate the stretch reflex arc to improve functional recovery after peripheral nerve lesions in animal model. Firstly, we carried out an immunohistochemical characterization of the changes surrounding spinal motoneurons after sciatic nerve injury; these changes were studied in postnatal and adult animals. In postnatal animals, we also studied VGlut1 contacts along dendrites, observing a high loss of excitatory synapses that were not recovered at 2 months. Regarding adult motoneurons, we found that the maximum loss of glutamatergic synapses and perineuronal nets (PNN) took place two weeks after injury, with a progressive recovery at 4 weeks. To try to ameliorate this loss of synapses and PNN, we studied the effect of electrical stimulation and different trophic factors (applied directly to the injury with a collagen matrix in a silicone tube). No significant differences were observed in none of them. We also evaluated different exercise protocols, specifically forced, voluntary and passive exercise. A high intensity protocol was able to partially prevent the synaptic and PNN loss that suffer axotomized motoneurons, whereas low intensity programs did not show significant differences compared to untrained ones. We also observed an increase of astrogliosis surrounding axotomized motoneurons and a decrease of microglia activation in exercised animals, except for those receiving low intensity voluntary and passive exercise, where there was a significant increase of microglia. Due to the positive effects induced by physical exercise on central plastic changes, we evaluate potential mechanisms involved in these effects. Although it is known that exercise increase neurotrophins, it is unknown how exercise modulates these neurotrophins and their specific actions. To evaluate the role of BDNF in the effects of exercise on axotomized motoneurons, we systemically administered a TrkB agonist and antagonist. We observed that the maintenance of synapses mediated by exercise was partially dependent of TrkB activation, but pharmacological activation of this receptor did not mimic exercise effects. As after physical exercise there was an increase of neural activity, we studied the role of noradrenergic descending projections from brainstem in spinal cord motoneurons after exercise. These descending pathways modulate excitability of the spinal motoneurons and are activated by stress situations, such as forced exercise. By DSP-4 administration, we provoked the desestructuration of the Locus Coeruleus and thus, loss of noradrenergic descending projections, observing a reduction of PNN and a marked reactivity of microglia. In animals submitted to exercise, the loss of these projections prevented the preservation of synapses and PNN around injured motoneurons, although microglial reactivity was also decreased. These findings suggest that modulation of spinal changes induced by physical exercise would be partially dependent on the activation of noradrenergic projections, whereas the modulation of microglia is independent of the exercise.
5
Tung, James 1975. "Task-dependent modulation of stretch reflex stiffness in the ankle". Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79266.
Testo completoAbstract (sommario):
The stretch reflex is an involuntary contraction produced in response to muscle stretch. Despite extensive research, its role in the control of movement and posture remains controversial. One reason for this is that the torque output produced by reflex activity has been studied in only a limited number of tasks and behaviours. The main thrust of this thesis is to examine whether the central nervous system (CNS) modifies stretch reflex properties to suit the task.An electro-hydraulic actuator applied perturbations to the ankles of five subjects while they performed position-matching (PM) and torque-matching (TM) tasks. Stretch reflex properties were determined using a new closed-loop, reflex identification algorithm that analytically separated the torques produced by stretch reflexes from the overall ankle torque. Stretch reflex gain was greater in the PM task than for the TM task, under matched conditions.
6
Calota, Andra. "Reliability of spasticity measurement based on tonic stretch reflex threshold". Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111947.
Testo completoAbstract (sommario):
Studies suggest that deficits in central regulation of stretch reflex thresholds (SRT) underlie both spasticity and other disorders of motor control. We investigated intra- and inter-evaluator reliability to quantify spasticity based on tonic SRT (TSRT) and the relationship between TSRT and Modified Ashworth Scale (MAS, clinical assessment of resistance to stretch). Spasticity was evaluated in 20 subjects with chronic stroke-related spasticity in two different days, by three evaluators. Twenty different velocity-dependent dynamic SRT (angle where biceps brachii EMG signal increased for a given velocity of stretch) were recorded. TSRT (excitability of motoneurons at 0°/sec) was then computed. Spasticity was also estimated with MAS. Reliability was moderately good for subjects with moderately high spasticity (intra--evaluator: 0.46 to 0.68, inter--evaluator: 0.53 to 0.68). There was no correlation between TSRT and MAS since they measure different phenomena. TSRT is a promising new measure of spasticity. Further improvements for its quantification are suggested.
7
Vedula, Siddharth. "Ankle stretch reflexes during anticipatory postural adjustments". Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:8881/R/?func=dbin-jump-full&object_id=32517.
Testo completo
8
Horstman, Gabrielle Marie. "Limitations of Functional Recovery of Stretch Reflex Circuitry After Peripheral Nerve Regeneration". Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347852976.
Testo completo
9
Salazar-Torres, Jose de Jesus. "Biomechanical analysis of stretch reflex responses : an approach to spasticity measurement". Thesis, University of Newcastle Upon Tyne, 2005. http://hdl.handle.net/10443/2038.
Testo completoAbstract (sommario):
Spasticity is a clinical condition that may develop in people with central nervous system injuries. It is believed that spasticity results from changes in the excitability of the stretch reflex pathways manifesting clinically as a velocity dependent increase in resistance to passive movement (RTPM) and exaggerated tendon jerks. Stretch reflex excitability is influenced by neural (e.g. feed-forward and feedback mechanisms) and biomechanical components (e.g. muscle length). The objective of this work was to quantify the stretch reflex parameters of the biceps brachii under different initial conditions (amplitude of applied torque, initial muscle length, initial voluntary activity, head position) in non-impaired (NI) volunteers and stroke patients (SP) with diagnosed upper limb spasticity and objectively evaluate their differences. A biomechanical device was designed to provide a 90 ms initially applied torque controlled stretch to the biceps brachii. The stretch reflex response was recorded using surface electromyography and angular displacement with a potentiometer. Stretch reflex characterisation was done on EMG data collected 150 ms before and to complete 450 ms after the perturbation. The outcome measures were the amplitude of the rectified reflex response and, the latency, rise time and duration reflex response. Lower amplitudes, shorter latencies and longer durations were observed in the poststroke populancn when compared to the non-impaired volunteers. Amplitude results were unexpected. However latencies and durations suggest increased stretch reflex excitability. Significant differences dependent on the initial conditions were found within the non-impaired volunteers. No differences were found in the post-stroke population. These latter results suggest lack of modulation of the stretch reflex excitability after stroke. More research is necessary to understand the relationship between the changes in the stretch reflex excitability and the clinical concept of spasticity and the importance of their quantification to improve the quality of life of people with neurological lesions.
10
Lederman, Eyal. "The effect of manual therapy techniques on the neuromuscular system". Thesis, King's College London (University of London), 1999. https://kclpure.kcl.ac.uk/portal/en/theses/the-effect-of-manual-therapy-techniques-on-the-neuromuscular-system(3764f2dc-c18b-4f37-a1aa-0bcc0abe64ec).html.
Testo completo
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Chitre, Rohit Dilip. "Modeling the reflex-mediated mechanical response to muscle stretch in normal subjects and spasticity patients /". Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
Testo completo
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Parameswaran, Luckshman. "The effects of passive joint movement on human ankle stretch reflex dynamics". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29621.pdf.
Testo completo
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Parameswaran, Luckshman. "The effects of passive joint movement on human ankle stretch reflex dynamics /". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27248.
Testo completoAbstract (sommario):
The role of the monosynaptic stretch reflex in the realm of human motor activity has been controversial for many years. A non-linear parallel-cascade system identification technique was recently developed to non-invasively elucidate the ankle reflex dynamics. Identification of these dynamics requires the application of stochastic signals to the ankle joint. The stretch reflex is known to be highly modulated and attenuated during on-going cyclical movements and passively applied perturbations. The aim of this study was to investigate these effects.The stretch reflex gain was found to decrease progressively as the average velocity of the applied movement increased. The velocity-mediated effects were a function of the amplitude distribution characteristics, rather than the spectral properties, of the applied motion. The experiments confirmed that although the stretch reflex response is large enough to be important its effects will depend on the functional context.
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El-Sakkary, Baher. "Modulation of stretch reflex excitability with postural sway in the frontal plane". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18291.
Testo completoAbstract (sommario):
The stretch reflex response helps control upright stance by countering the effects of gravity. It has been suggested that sway in the sagittal or anterior-posterior (AP) plane contributes to the modulation of the reflex response; this thesis sought to examine if a similar relationship could be discerned between sway in the frontal or medial-lateral (ML) plane and the reflex. The sway in the ML plane was characterized by changes in the center of pressure (COP) and in the vertical forces between the feet. Two experiments were carried out. The results of the first experiment, which observed the COP and the vertical force during quiet stance, suggested that sway is not bilaterally symmetric and that the vertical force does not vary significantly between the two feet. In the second experiment, the subjects were asked to hold a weight to increase the vertical force on their right leg while angular perturbations were applied at the ankle to elicit reflex responses. The COP was found to be uncorrelated with the reflex response while the vertical force was positively correlated with the background and the reflex EMG and negatively correlated with the reflex torque. These experimental results suggest that the reflex excitability in quiet stance is modulated in part by to the vertical forces on the feet.La réponse du réflexe d’étirement aide à régler la position droite en opposant les effets de la gravité. Il était suggéré que le balancement dans l'avion antérieur-postérieur contribue à la modulation de la réponse réflexe; cette thèse cherche à examiner si un rapport semblable pourrait être discerné entre l’équilibre dans l'avion médial-latéral et le réflexe. L’équilibre dans l'avion médial-latéral a été caractérisé par des changements au centre de la pression et des forces verticales entre les pieds. Deux expériences ont été effectuées. Les résultats de la première expérience, qui a observé le centre de la pression et la force verticale pendant la position tranquille, ont suggéré que l’équilibre n’est pas bilatéralement symétrique et que la force verticale ne change pas de manière significative entre les deux pieds. Dans la deuxième expérience, les sujets ont été invités à tenir un poids afin d’augmenter la force verticale sur leur pied droit tandis que des perturbations angulaires étaient appliquées à la cheville pour obtenir des réponses réflexes. Le centre de la pression est avéré non-corrélée avec la réponse réflexe tandis que la force verticale était corrélée avec le fond et le réflexe EMG et négativement corrélée avec le couple réflexe. Ces résultats expérimentaux suggèrent que l'excitabilité réflexe dans la position tranquille soit modulée en partie selon les forces verticales sur les pieds.
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Mohi, Amr. "Analysis of Stretch Reflex Responses in Mice Lacking Munc18-1 in Proprioceptors". Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright15160256865382.
Testo completo
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Loew, Emily. "Comparison of Flexor Carpi Ulnaris Hoffmann Reflex at Different Levels of Elbow Stretch". University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1556792929213981.
Testo completo
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Horslen, Brian Christopher. "Postural threat-induced modulation of stretch reflex pathways in static and dynamic postural control". Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/28643.
Testo completoAbstract (sommario):
There are clear changes to human static and dynamic postural control in situations of elevated postural threat (e.g. standing at the edge of an elevated platform). One possible explanation for these changes is that the amount of afferent information from muscle spindles in the ankle musculature is altered by postural threat. Two experiments have been conducted to explore postural threat-induced changes to soleus spinal stretch reflex function during static control of posture (Study 1), and in response to dynamic postural disturbances (Study 2). In Study 1, soleus Hoffmann (H-) and tendon stretch (T-) reflexes were used to explore changes in reflex amplitude while subjects stood quietly in conditions of low (ground level) and high (3.2m above ground) postural threat. Height-induced postural threat was associated with larger T-reflexes and higher arousal, these effects occurred without systematic changes in H-reflex amplitudes or background muscle activation. We interpret these findings as indirect evidence for arousal-mediated changes in muscle spindle sensitivity. In Study 2, emotionally-charged pictures were used to explore the effects of arousal on H- and T-reflexes, as well as whole body postural perturbations. The pictures failed to elicit significant changes in physiological arousal, H- or T-reflexes, or perturbation response parameters. However, the threat of postural perturbation caused parallel increases in T-reflexes, physiological arousal, and perceived anxiety. Therefore, we conclude that arousal-induced changes in stretch reflexes are not context specific, but rather a generalized response to postural threat. Furthermore, these results together provide substantial evidence in support of independent modulation of muscle spindle sensitivity in humans.
18
Ruffner, Kayla L. "THE EFFECTS OF ESTROGEN PEAKS ON THE STRETCH REFLEX RESPONSE DURING THE MENSTRUAL CYCLE". Cleveland State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=csu1579519542553163.
Testo completo
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Rumsey, John. "Tissue Engineered Myelination and the Stretch Reflex Arc Sensory Circuit: Defined Medium Formulation, Interface Design and Microfabrication". Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3904.
Testo completoAbstract (sommario):
The overall focus of this research project was to develop an in vitro tissue-engineered system that accurately reproduced the physiology of the sensory elements of the stretch reflex arc as well as engineer the myelination of neurons in the systems. In order to achieve this goal we hypothesized that myelinating culture systems, intrafusal muscle fibers and the sensory circuit of the stretch reflex arc could be bioengineered using serum-free medium formulations, growth substrate interface design and microfabrication technology. The monosynaptic stretch reflex arc is formed by a direct synapse between motoneurons and sensory neurons and is one of the fundamental circuits involved in motor control. The circuit serves as a proprioceptive feedback system, relaying information about muscle length and stretch to the central nervous system (CNS). It is composed of four elements, which are split into two circuits. The efferent or motor circuit is composed of an [alpha]-motoneuron and the extrafusal skeletal muscle fibers it innervates, while the afferent or sensory circuit is composed of a Ia sensory neuron and a muscle spindle. Structurally, the two muscular units are aligned in parallel, which plays a critical role modulating the system's performance. Functionally, the circuit acts to maintain appropriate muscle length during activities as diverse as eye movement, respiration, locomotion, fine motor control and posture maintenance. Myelination of the axons of the neuronal system is a vertebrate adaptation that enables rapid conduction of action potentials without a commensurate increase in axon diameter. In vitro neuronal systems that reproduce these effects would provide a unique modality to study factors influencing sensory neuronal deficits, neuropathic pain, myelination and diseases associated with myelination. In this dissertation, results for defined in vitro culture conditions resulting in myelination of motoneurons by Schwann cells, pattern controlled myelination of sensory neurons, intrafusal fiber formation, patterned assembly of the mechanosensory complex and integration of the complex on bio-MEMS cantilever devices. Using these systems the stretch sensitive sodium channel BNaC1 and the structural protein PICK1 localized at the sensory neuron terminals associated with the intrafusal fibers was identified as well as the Ca2+ waves associated with sensory neuron electrical activity upon intrafusal fiber stretch on MEMS cantilevers. The knowledge gained through these multi-disciplinary approaches could lead to insights for spasticity inducing diseases like Parkinson's, demyelinating diseases and spinal cord injury repair. These engineered systems also have application in high-throughput drug discovery. Furthermore, the use of biomechanical systems could lead to improved fine motor control for tissue-engineered prosthetic devices.Ph.D.
Department of Biomolecular Science
Sciences
Biomedical Sciences PhD
20
O'Sullivan, Maeve C. "The development of the phasic stretch reflex in man and its pathophysiology in central motor disorders". Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287173.
Testo completo
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Rollins, Korynne Sierra. "Bradykinin does not acutely sensitize the reflex pressor response during hindlimb skeletal muscle stretch in decerebrate rats". Thesis, Kansas State University, 2018. http://hdl.handle.net/2097/38617.
Testo completoAbstract (sommario):
Master of ScienceDepartment of Kinesiology
Steven Copp
Hindlimb skeletal muscle stretch (i.e., selective activation of the muscle mechanoreflex) in decerebrate rats evokes reflex increases in blood pressure and sympathetic nerve activity. Bradykinin has been found to sensitize mechano-gated channels through a bradykinin B2 receptor-dependent mechanism. Moreover, bradykinin B2 receptor expression on sensory neurons is increased following chronic femoral artery ligation in the rat (a model of simulated peripheral artery disease). We tested the hypothesis that, in decerebrate, unanesthetized rats, the injection of bradykinin into the arterial supply of a hindlimb would acutely augment (i.e., sensitize) the increase in blood pressure and renal sympathetic nerve activity (RSNA) during hindlimb muscle stretch to a greater extent in rats with a ligated femoral artery than in rats with freely perfused femoral arteries. The pressor response during static hindlimb muscle stretch was compared before and after the hindlimb arterial injection of 0.5 µg of bradykinin. The injection of bradykinin itself increased blood pressure to a greater extent in “ligated” rats (n=10) than in “freely perfused” rats (n=10). The increase in blood pressure during hindlimb muscle stretch, however, was not different before compared to after bradykinin injection in either freely perfused (control: 14±2, post-bradykinin: 15±2 mmHg, p=0.62) or ligated (control: 15±3, post-bradykinin: 14±2 mmHg, p=0.80) rats. Likewise, the increase in RSNA during stretch was not different before compared to after bradykinin injection in either group of rats. We conclude that bradykinin did not acutely sensitize the pressor response during hindlimb skeletal muscle stretch in either freely perfused or ligated decerebrate rats.
22
Louder, Talin. "Establishing a Kinetic Assessment of Reactive Strength". DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6004.
Testo completoAbstract (sommario):
The reactive strength index (RSI) is the current “gold standard” assessment of reactive strength. Traditional measures of reactive strength, including the RSI, are not strength-based and are founded using untested theoretical assumptions. The purpose of this study was to develop two versions of a kinetic-based paradigm of reactive strength (New and AdjNew) and compare them against the Coefficient of Reactivity (CoR) and the RSI. Twenty one NCAA Division I basketball players and 59 young adults from the general population performed two reactive strength protocols: Progressive drop jumping and repetitive countermovement jumping. For every jump, the CoR, RSI, New, and AdjNew were computed. Measure agreeability was assessed using the Bland-Altman approach and linear regressions. Analyses of variance (ANOVA) assessed the effect of sport participation, age, and sex on the four measures of reactive strength. Lastly, effects of self-reported physical activity levels were assessed using stepwise linear regressions. The strongest association was observed between AdjNew and the RSI (R2= 0.636). All NCAA > young adults). The RSI, New, and AdjNew were sensitive to effects of sex and sport participation in repetitive countermovement jumping (males > females; NCAA > young adults). There are theoretical issues with the computation and implementation of the CoR and RSI. For example, the CoR and RSI are non-strength based measures that attempt to measure a strength construct. Further, the CoR, RSI, and New make the theoretical assumption that no biological variability exists in human movement. The AdjNew paradigm addresses and solves the theoretical issues with the CoR, RSI, and New. Therefore it may be argued that the AdjNew paradigm improves the theoretical validity of reactive strength assessment and is preferred over the RSI. The AdjNew is kinetic based, comprised of only measured component variables, and is not founded in assumptions of theory. This dissertation provides objective theoretical evidence to suggest that the AdjNew paradigm is an improvement over the RSI as a model of reactive strength.
23
Titus, Haley E. "Reorganization of Ia afferent synapses on motoneurons after peripheral nerve injuries". Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1245378110.
Testo completo
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Das, Mainak. "TISSUE ENGINEERING THE MOTONEURON TO MUSCLE SEGMENT OF THE STRETCH REFLEX ARC CIRCUIT UTILIZING MICRO-FABRICATION, INTERFACE DESIGN AND DEFINED MEDIUM FORMULATION". Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4491.
Testo completoAbstract (sommario):
The stretch reflex circuit is one of the most primitive circuits of mammalian system and serves mainly to control the length of the muscle. It consists of four elements: the stretch sensor (muscle spindle/ intrafusal fiber lie parallel between extrafusal, contractile musculature), extrafusal muscle fiber, sensory neuron and motoneuron. The basic principle of the stretch reflex arc circuit is as follows: whenever there is a sudden stretch in a muscle, it needs to compensate back to its original length so as to prevent any kind of injury. It performs this compensation process using a simple negative feed back circuit called the stretch reflex arc. Any form of stretch in a muscle activates the stretch sensors (muscle spindle/ intrafusal fiber) lying deep in each muscle. After the stretch sensors get activated, it sends a train of signals to the spinal cord through the sensory neurons. The sensory neurons relay this information to the motoneuron. The motoneuron performs the necessary information processing and sends the message to the extrafusal fibers so as to compensate for the sudden stretch action. The motoneuron conveys this message to the extrafusal fibers by communicating through the special synaptic junctions called neuromuscular junctions. Based on this information, the extrafusal fibers act accordingly so as to counter the effect of sudden stretch. This is also called the monosynaptic stretch reflex that involves a single synapse between a sensory neuron and a motoneuron. To date studying these stretch reflex circuits is only feasible in animal models. Almost no effort has been made to tissue engineer such circuits for a better understanding of the complex development and repair processes of the stretch reflex circuit formation. The long-term goal of this research is to tissue engineer a cellular prototype of the entire stretch reflex circuit. The specific theme of this dissertation research was to tissue engineer the motoneuron to muscle segment of the stretch reflex arc circuit utilizing micro-fabrication, interface design and defined medium formulations. In order to address this central theme, the following hypothesis has been proposed. The first part of the hypothesis is that microfabrication technology, interface design and defined medium formulations can be effectively combined to tissue engineer the motoneuron to muscle segment of the stretch reflex arc. The second part of the hypothesis is that different growth factors, hormones, nanoparticles, neurotransmitters and synthetic substrate can be optimally utilized to regenerate the adult mammalian spinal cord neurons so as to replace the embryonic motoneurons in the stretch reflex tissue engineered construct with adult motoneurons. In this body of work, the different tissue engineering strategies and technologies have been addressed to enable the recreation of a in vitro cellular prototype of the stretch reflex circuit with special emphasis on building the motoneuron to muscle segment of the circuit. In order to recreate the motoneuron to muscle segment of the stretch reflex arc, a successful methodology to tissue engineer skeletal muscle and motoneuron was essential. Hence the recreation of the motoneuron to muscle segment of the stretch reflex circuit was achieved in two parts. In the part 1 (Chapters 2-5), the challenges in skeletal muscle tissue engineering were examined. In part 2 (Chapters 6-7), apart from tissue engineering the motoneuron to muscle segment, the real time synaptic activity between motoneuron and muscle segment were studied using extensive video recordings. In part 3 (Chapters 8-10), an innovative attempt had been made to tissue engineer the adult mammalian spinal cord neurons so that in future this technology could utilized to replace the embryonic neurons used in the stretch reflex circuit with adult neurons. The advantage of using adult neurons is that it provides a powerful tool to study older neurons since these neurons are more prone to age related changes, neurodegenerative disorders and injuries. This study has successfully demonstrated the recreation of the motoneuron to muscle segment of the stretch reflex arc and further demonstrated the successful tissue engineering strategies to grow adult mammalian spinal cord neurons. The different cell culture technologies developed in these studies could be used as powerful tools in nerve-muscle tissue engineering, neuro-prosthetic devices and in regenerative medicine.Ph.D.
Burnett School of Biomedical Sciences
Medicine
Biomedical Sciences
25
Lacey, Lauren Elizabeth. "Assessment of repetitive facilitation exercise with fMRI-compatible rehabilitation device for hemiparetic limbs". Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51879.
Testo completoAbstract (sommario):
In order for stroke subjects to gain functional recovery of their hemiparetic limbs, facilitation techniques such as the repetitive facilitation exercise, or RFE, have been developed. Currently, there is a lack of understanding of the neural mechanisms associated with these types of facilitation techniques. To better understand the neural mechanisms associated with the RFE a functional magnetic resonance imaging (fMRI) study should be conducted. This thesis presents experimental results testing the feasibility of implementing an fMRI-compatible actuator to facilitate a myotatic reflex in synchronization with the subject’s intention to move their hemiparetic limb. Preliminary data from a healthy individual demonstrated the feasibility of overlapping the long latency component of the afferent myotatic reflex, created by electrical stimulation, with descending nerve impulses, created using transcranial magnetic stimulation, in a time window of 15ms. In addition, a pneumatic actuation time delay due to long transmission line was evaluated. The pneumatic actuator met the timing precision requirement for the rehabilitation device for varying transmission line lengths. Therefore a pneumatic actuation system was chosen for the rehabilitation device. This thesis will also presents on the design of an fMRI-compatible pneumatic actuator device to excite a stretch reflex response. Initial, experimental results with the device demonstrated that the designed pneumatic device can control the timing of the muscle response with a fixed signal within the required 15ms window required for cortical facilitation, which was found in the previous feasibility study. However, the device was unable to create a long latency reflex observable at the muscle. Finally, this thesis presents on the capability of the device in creating subthreshold long latency response with precision to overlap with a subthreshold descending nerve impulse, created using transcranial magnetic stimulation. The overlap of the two responses was evaluated by comparing the amplitude of the muscle response with and without the stretch reflex, created by the fMRI-compatible pneumatic actuator device. Varying time delays were analyzed.
26
Zeren, Zekai Uygur. "Simulation Of A 1-d Muscle Model In Simulink". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609193/index.pdf.
Testo completoAbstract (sommario):
The most basic property of a muscle is its ability to contract and produce force when stimulated. A muscle is mainly composed of cells consisting of myofibrils with its basic unit called as a sarcomere. A sarcomere is composed of actin and myosin responsible for the muscle contraction. The Hill-type muscle model is the most commonly used model to simulate the behavior of a muscle. A muscle can produce its maximum force at isometric conditions. The level of force produced in the muscle is determined by the the frequency of the signals from the CNS. The force production is also a function of force-muscle current velocity and force-muscle current length relations. A muscle contains two types of sensorsi.e. muscle spindle and golgi tendon organ, which give rise to the feedback control of the muscle length and muscle contraction velocity. In this study a 1-D model of a muscle is formed step by step in Simulink. In the models the muscle mechanics has been investigated and the results are compared with the previous works.
27
Ross, Kyla Turpin. "Quantitative Analysis of Feedback During Locomotion". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14110.
Testo completoAbstract (sommario):
It is known that muscles possess both intrinsic and reflexive responses to stretch, both of which have been studied extensively. While much is known about heterogenic and autogenic reflexes during XER, these have not been well characterized during locomotion. In this study, we mapped the distribution of autogenic and heterogenic feedback in hindlimb extensor muscles using muscle stretch in the spontaneously locomoting premammillary decerebrate cat. We used natural stimulation and compared stretch-evoked force responses obtained during locomotion with those obtained during XER. The goal was to ascertain whether feedback was modulated between the two states. We found that heterogenic feedback pathways, particularly those emanating from MG, remained inhibitory during locomotion while autogenic feedback specifically in MG increases in gain. Furthermore, increases in MG gain were due to force-dependent mechanisms. This suggests that rather than an abrupt transition from inhibition to excitation with changes in motor tasks, these pathways coexist and contribute to maintaining interjoint coordination. Increases in autogenic gain provide a localized loading reflex to contribute to the completion of the movement. The results of these experiments are clinically significant, particularly for the rehabilitation of spinal cord injured patients. To effectively administer treatment and therapy for patients with compromised spinal reflexes, a complete understanding of the circuitry is required.
28
Dai, Yiyun. "The pattern of sensory axonal endings together with synaptic transmission influence the development of proprioceptive circuits in the spinal cord". Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1547921267000115.
Testo completo
29
Poliakov, Andrew Victor. "Stretch reflexes in human masseter /". Title page, table of contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09php766.pdf.
Testo completo
30
Nikitina, Tatiana. "An asymmetric bilateral model of stretch reflexes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/MQ44031.pdf.
Testo completo
31
Nikitina, Tatiana. "An asymmetric bilateral model of stretch reflexes /". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20512.
Testo completoAbstract (sommario):
A bilateral stretch reflex model was built based on asymmetric agonist---antagonist reflex connections at the ankle. The overall dynamics were analyzed using Mason's rule algebra. The model predicts the characteristic agonist and antagonist responses to stretch. Simulations with pulse displacements and random perturbations are in qualitative agreement with experimental data and suggest a mechanism whereby the mean absolute velocity of the perturbations could depress the stretch reflex at the spinal level. This implies that spinal neural circuits can calculate and carry out their own integrative functions and, in particular, modulate the stretch reflex gain.
32
Castillo, Andrea Amaral. "Tônus muscular = uma contribuição para os estudos em imagem corporal". [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275086.
Testo completoAbstract (sommario):
Orientador: Maria da Consolação Gomes Cunha Fernandes TavaresDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física
Made available in DSpace on 2018-08-18T10:27:09Z (GMT). No. of bitstreams: 1 Castillo_AndreaAmaral_M.pdf: 1424495 bytes, checksum: 2e616dc1accf2266891ba1011fc14c1e (MD5) Previous issue date: 2011
Resumo: A Imagem Corporal foi conceituada por Paul Schilder (1999) como a representação mental do corpo. Neste conceito ele aponta para uma abordagem sistêmica dos aspectos fisiológicos, psíquicos, sociais e culturais no processo dinâmico da expressão singular da identidade corporal. Em seu livro "The Image and appearance of humam body", publicado em 1935, Schilder chama a atenção para a relação entre o Tônus Muscular e a Imagem Corporal num capítulo exclusivo sobre o tema. Ressaltou que a Imagem Corporal era tracionada em direção ao Tônus Muscular uma vez que a ação de um único segmento corporal é capaz de colocar o corpo como um todo em uma nova relação com o ambiente. No entanto esta relação não se encontra sistematizada e valorizada dentro das diversas áreas do saber e tem sido pouco abordada nas pesquisas em Imagem Corporal. O foco direcionado ora ao Tônus Muscular, ora à Imagem Corporal implica muitas vezes num entendimento fragmentado capaz de desconsiderar a singularidade do indivíduo e/ou o dinamismo neurofisiológico na sua relação com o meio e com o outro. Assim a proposta deste estudo é sistematizar e analisar o conhecimento sobre o Tônus Muscular nas perspectivas de Charles Scott Sherrington cujo foco se apóia na Ação Reflexa; de Henry Head, que apresenta o Modelo Postural como a base para as pesquisas em Imagem Corporal; e da Neurociência, que propõe análises do comportamento humano na relação com o ambiente. Dentre as inúmeras contribuições feitas por Charles Scott Sherrington, foi a perspectiva da Ação Integrativa do sistema nervoso que trouxe um novo entendimento ao meio científico da época. Ao considerar a ação reflexa como uma resposta adaptativa do organismo, Sherrington encontrou no Tônus Muscular o exemplo explícito de um processo integrativo cuja proposta é manter a postura do organismo contra a gravidade. Henry Head influenciado por esse novo olhar, e inquieto com suas observações clínicas tornou-se o próprio objeto experimental numa investigação sobre os tipos de sensibilidade. A partir dos resultados de suas pesquisas e apoiado nas idéias e conceitos de Sherrington, Head propõe a existência de um Modelo Postural como uma medida de referência sobre a qual o corpo se ajusta constantemente através das variações do Tônus Muscular. Estas medidas são então registradas dentro de um esquema plástico de representação mental da postura e do movimento. A neurociência intensifica suas investigações sobre o organismo dentro do contexto do ambiente onde um é capaz de influenciar o outro. Com isso abriu-se uma nova perspectiva acerca do Tônus Muscular e o comportamento humano. As descobertas sobre a participação do fuso neuromuscular na elaboração da Imagem Corporal, as alterações mecânicas que implicam em alterações sensoriais e a ação segmentar que se propaga ao longo de todo o corpo trazem contribuições importantes que reforçam a relação íntima entre o Tônus Muscular e a representação mental do corpo. A partir deste estudo espera-se trazer uma reflexão mais profunda sobre o papel do Tônus Muscular e contribuir para futuras pesquisas e estudos sobre a Imagem Corporal
Abstract: Paul Schilder (1999) defined Body Image as the mental representation of the body. In this concept, he points out to a systemic approach of physiological, psychological, social and cultural aspects in the dynamic process of the body image unique expression. In his book "The Image and appearance of human body", published in 1935, Schilder draws attention to the relationship between Muscle Tonus and Body Image, dedicating a whole chapter to this theme. He emphasized that Body Image was pulled towards Muscle Tonus, since the action of a single body segment can place the whole body in a new interaction with the environment. However, this relationship has not been schematized and given the proper value by different areas of knowledge and it has been little addressed in studies about Body Image. Changing the focus from Muscle Tonus to Body Image back and forth can frequently lead to a fragmented understanding which may disregard each individual particularity and/or the neurophysiological dynamics in the individual interaction with the environment and others. Hence, this study aims to systematize and discuss the knowledge about muscle tone, as seen by Charles Scott Sherrington who focus on Reflex Action; by Henry Head, who presents Postural Model as fundamental for Body Image researches; and by Neuroscience, which suggests the study of human behavior and its relation with the environment. One of the several contributions by Charles Scott Sherrington, the Integrative Action of the nervous system brought a new understanding to the scientific community at the time. By considering reflex action as an adjustable response of the body, Sherrington saw the Muscle Tonus as a clear example of an integrative process which aims to keep the body posture against gravity. Henry Head was influenced by this new approach, and, out of a strong urge towards his clinical observation, became his own experiment subject on his study about sensitivity types. Supported by the results of his own researches and backed by Sherrington's concepts and ideas, Head suggests that there is a Postural Model acting as a reference measure which the body constantly fits into according to Muscle Tonus variations. These measures are registered within a scheme of posture and movement representations. Neuroscience stresses the focus of studies about the body within a context where one causes an impact on the other, bringing out a new outlook for Muscle Tone and human behavior. Findings about neuromuscular fuse participation in Body Image building, mechanical changes which cause sensorial changes and the segmental action which spreads throughout the body play an important role and corroborate the close relationship between Muscle Tonus and body mental representation. This study is expected to bring up a more comprehensive discussion on the role of Muscle Tonus and to enhance future researches and studies on Body Image
Mestrado
Atividade Fisica Adaptada
Mestre em Educação Física
33
Goodwin, C. N. "Vibration- and strech-evoked reflexes in human flexor carpri radialis". Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383131.
Testo completo
34
Le, Bozec Serge. "aspects et bases de la synergie des muscles agonistes chez l'Homme". Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37599038x.
Testo completo
35
Vieira, Débora. "Influência do treinamento motor com biofeedback eletromiográfico na reabilitação da espasticidade após ave e a caracterização da atividade cortical correlata". Universidade Federal de Uberlândia, 2016. https://repositorio.ufu.br/handle/123456789/17968.
Testo completoAbstract (sommario):
Conselho Nacional de Desenvolvimento Científico e TecnológicoA espasticidade é observada na maioria dos pacientes após Acidente Vascular Encefálico (AVE), e exercem influência na presença de deficiências e incapacidades, comprometendo a função motora. As estratégias de neuroreabilitação, o biofeedback eletromiográfico (EMG), têm sido utilizado com aceitação na comunidade médica para reajustes nas habilidades sensório-motoras como retreinamento motor, redução da espasticidade e/ou treinamento de relaxamento. A intervenção ainda apresenta evidências delimitadas quanto a sua efetividade na reabilitação, principalmente, quanto a interferência sobre a atividade cortical e na redução dos sinais espásticos que oferece características negativas na execução do movimento. O objetivo dessa pesquisa foi analisar a possível interferência do treino com biofeedback eletromiográfico sobre a conscientização do controle motor no membro espástico e a caracterização da atividade das bandas de baixa frequência em diferentes regiões corticais orientada pela técnica de treinamento. Dezesseis voluntários acometidos por AVE isquêmicos foram selecionados e divididos em dois grupos (n=8). Grupo experimental (GE) submetidos ao treino com biofeedback associado a fisioterapia, e o grupo controle (GC) submetido apenas à fisioterapia convencional. Foi realizada a avaliação do grau de espasticidade pelo limiar de reflexo do estiramento tônico (LRET) e pela Escala Modificada de Ashworth (EMA) antes e três semanas após o término do treinamento com a técnica. Os sujeitos foram submetidos ao biofeedback durante 6 semanas, com 2 sessões semanalmente. O mesmo tempo para o tratamento fisioterápico foi padronizado para o GC. Os resultados mostram variação do percentual médio de melhora do grau de espasticidade, mensuradas pelo LRET, de 38,59% (dp=13,03%) no GE comparado com 18,58% (dp=11,90%) do GC. Essa variação apresentou diferença significativa (p=0,020; t=2,776; p<5%) entre os grupos (controle e experimental), e a diferença significativa do LRET antes e após do treinamento no GE (p=0,003; t=5,338; p<5%) quando comparado ao GC (p=0,015; t=3,657; p<5%). A medida semi-quantitativa da EMA antes e após o término das sessões mostraram variações apenas no GE. Com relação a atividade cortical, houve diferença de atividade das bandas (delta, teta, alfa e beta) quando a 3ª e 12ª sessão foram comparadas para cada sujeito do GE. Essa diferença foi encontrada, principalmente, em regiões frontal, central (vértex), parietal e occipital em ambos hemisférios (ipsilateral e contralateral a lesão) tanto na fase de planejamento cognitivo motor quanto na execução do movimento. Houve predominância da diferença de atividade para a banda delta, alfa e beta em diferentes sujeitos distribuída difusamente ao longo dos canais de registro de viii EEG. A atividade diferenciada das bandas foi devido ao aumento e/ou diminuição da energia espectral entre as sessões, notado apenas em alguns voluntários do GE. Observou ainda diferença de atividade em áreas motoras secundárias. As avaliações, principalmente do LRET mostram que o treino com biofeedback EMG foi efetivo na redução do grau de espasticidade. A diferença de atividade cortical das bandas de frequência entre as sessões sugere que o biofeedback modula a cognição por meio do esforço e atenção imposta pela tarefa na tentativa do movimento no membro acometido. Além de que a diferença de energia espectral entre as sessões é dependente do ajuste e complexidade da tarefa direcionado pelos sinais do biofeedback, auxiliando na aprendizagem motora.
Spasticity is observed in most patients after cerebrovascular accident (CVA), and exerts influence in the presence of disabilities, affecting motor function. For neurorehabilitation strategies, electromyographic biofeedback (EMG) has been used with acceptance in the medical community for adjustments in the sensory-motor skills as a motor retraining, reducing spasticity and/or relaxation training. The intervention still presents limited evidence regarding their effectiveness in rehabilitation, especially as the interference of cortical activity and the reduction of spastic signs that provides negative characteristics in movement execution. The aim of this study was to analyze the workout possible interference with EMG biofeedback on the motor control awareness in spastic member in the characterization of the activity of low-frequency bands in different cortical regions targeted by the training technique. Sixteen volunteers affected by ischemic stroke were selected and divided into two groups (n = 8). Experimental group (EG) underwent biofeedback training associated with physical therapy and control group (CG) only conventional physiotherapy. The assessment of the degree of spasticity by reflex threshold of the tonic stretch (TSRT) and Modified Ashworth Scale (MAS) was performed before and three weeks after the end of treatment with the technique. The subjects underwent biofeedback for 6 weeks, with two sessions weekly. The same time for physiotherapy treatment was standardized to the GC. The results show variation of the average percent improvement in the degree of spasticity measured at TRST, 38,59% (sd=13,03%) in GE compared to 18,58% (sd=11,90%) of GC. This variation showed a significant difference (p=0.020; t=2,776; p<5%) between groups (control and experimental), and the significant difference of TRST before and after training in EG (p = 0.003; t=5,338; p <5%) when compared to the CG (p=0.015; t=0,015; p<5%). The semi-quantitative measure of the MAS before and after the end of the sessions presented variations only in GE. Regarding the cortical activity, there were band activities differences when 3rd and 12th sessions were compared for each subject of GE. This difference was found primarily in the frontal, central (vertex), parietal and occipital lobe in both hemispheres (contralateral and ipsilateral to the lesion) in both the cognitive motor planning phase and in the movement execution. It was observed the predominance of activity difference for the delta band, alpha and beta in different subjects distributed diffusely over the EEG recording channels. The different activity of the bands was due to the increase and/or decrease the spectral energy between sessions, x noticed only in some GE volunteers. It was also pointed out distinct activity in secondary motor areas. Evaluations mainly from TSRT show that training with EMG biofeedback was effective in reducing the degree of spasticity. The difference in cortical activity of the frequency bands between sessions suggested that biofeedback modulates cognition through the effort and attention required by the task of movement attempt in the affected limb. Besides that, the spectral energy difference between the sessions depends on the tuning and task complexity driven by biofeedback signals, helping motor learning.
Tese (Doutorado)
36
Cathers, Ian. "Stretch signal and muscle state dependence of the tonic stretch reflex /". 2000. http://www.library.unsw.edu.au/~thesis/adt-NUN/public/adt-NUN20010831.131852/index.html.
Testo completo
37
Lai, Chun-Hui, e 賴俊輝. "Quantitative Analysis of Stretch Reflex in Hemiparetic Subjects". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/01795641530968582391.
Testo completoAbstract (sommario):
碩士國立成功大學
醫學工程學系
84
The existing clinical measures for spasticity, by determining the resistance to external imposed passive movement of a joint, are usually subjective and qualitative. The aim of this research is to improve a spasticity measurement system, developed in our pervious study, for the quantification of stretch reflex of the impaired limbs. The spasticity measurement system consists of real-time controlled servemotor, torque sensor, and EMG surface recording electrodes. For the execution of different experiments, a friendly graphic user interface is implemented in this study for on-line change of parameters and for monitoring the data quality. The quantification parameter is defined as averaged speed dependent reflex torque (ASRT) for quantifying the spasticity. Three subjects suffering from cerebrovascular accident (CVA) were recruited for time-course study. Generally, higher ASRT can be observed in involved elbow joint than the unaffected side. From the time-course studies, ASRT and velocity sensitivity increased with time in involved elbow joints. It can be concluded that our spasticity measurement system with ASRT parameter is suitable for quantitatation of muscle hypernotia.
38
Wang, Guan-Jhih, e 王冠智. "Effects of Muscle Vibration on Stretch Reflex of Fingers". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/00126696715884478349.
Testo completoAbstract (sommario):
碩士國立交通大學
機械工程系所
97
Previous studies have shown that muscle vibration, below the threshold of inducing illusory movement or tonic vibration reflex, could modulate motor-evoked potential (MEP) of pathways controlling hand muscles in intact and chronic stroke individuals. It is evident that this type of sub-threshold muscle vibration provides corticomotor modulations on the pathways controlling the vibrated and adjacent non-vibrated muscles. However, spinal-level contribution to the muscle vibration-induced changes in MEPs is not clear. The purpose of this study was to investigate the effects of muscle vibration on the excitability of the spinal neural pathway. Ten healthy male subjects (age, 24.1±1.5 years; body height, 178.1±5.4 cm; body weight, 76.3±14.3 kg) volunteered for this study. Muscle vibration (MV) was applied to the muscle belly of first dorsal interosseus (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM) by an electrodynamic shaker with a custom-made 7mm-diameter probe. Muscle activities were recorded using surface electromyography (EMG). The vibration frequency was set at 80Hz, and the amplitude was adjusted to be just below the threshold of inducing tonic vibration reflex or illusory movement. A custom-made finger stretching device driven by a servo motor was used to stretch the hand muscles to induce a rapid adduction/abduction. Custom-designed software written in LabVIEW was used to control the device. The onset of stretching finger was randomized from 1s to 3s after onset of vibration. The duration of vibration was extended to offset of stretching finger after 1s. Subjects were instructed to perform an isometric contraction in the target muscle at 20% MVC before stretching the finger and maintain the activity level until the trial ended. Our results indicate that the amplitude of M1 of the three finger muscles was depressed 17.8% during muscle vibration as compared to that with no vibration; however, there was no significant difference in the amplitude of M2 between with and without muscle vibration. In addition, muscle vibration did not affect the latency of either M1 or M2. These findings suggest that muscle vibration-induced MEP facilitation may not occur in the spinal-level pathway.
39
Huang, Ying-Zu, e 黃英儒. "Quantification of the Spasticity by Stretch Reflex and Reciprocal Inhibition". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/29246114414960081755.
Testo completoAbstract (sommario):
碩士國立成功大學
醫學工程研究所
87
Spasticity is a common sequela of an anatomic or physiologic anomaly of the central nervous system. It has been defined as a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks. In clinical evaluation, spasticity is usually assessed by subjectively determining the resistance of a joint to an externally imposed passive movement, and lacks a good quantification tool. In this study, an on-line spasticity measurement system was developed for quantifying the stretch reflex by stretching the elbow at ramp-and-hold mode of varied constant velocities. Subjects were tested at supine position with the upper limb stretched toward the ground, in contrast with the horizontally stretched movement used in other studies. So that the bias caused by the shoulder movement during horizontal stretch can be limited. The averaged speed-dependent reflex torque (ASRT), defined as the measured torque deviated from the baseline torque, is used for quantifying the spastic hypertonia. From electrophysiologic aspect, reciprocal inhibition is a kind of conditioned H-reflex study. Stimuli on the nerves innervating on an antagonist muscle and on an agonist muscle are performed simultaneously under different intervals. Then the change on the H-reflex induced by stimulating the nerve innervating on an agonist muscle will be recorded. Former studies had shown that the third inhibitory phase in reciprocal inhibition is thought to be related to the polysynaptic long latency stretch reflex pathway. Therefore, it is also chosen to measure the spasticity. On the other hand, the Hmax/Mmax ratio in patients with spasticity is also evaluated in our study. Patients with varying degrees of spasticity and control groups were recruited. The modified Ashworth scale (MAS), a clinical assessment of extremity tone, was evaluated first. Then the ASRT measurement, the reciprocal inhibition test and the Hmax/Mmax ratio test were performed in all subjects. The result shows good correlation between ASRT and MAS, and indicates that the ASRT is a good tool to quantify the spasticity. The result of reciprocal inhibition test discloses significant change between patients with spasticity and normal controls in the third inhibitory phase. That proves the relationship between the third inhibitory phase of reciprocal inhibition and the stretch reflex. However, the amount of change is unpredictable, so it is not suitable for quantifying the spasticity. As for the ratio of Hmax to Mmax, it shows disappointing results, and has no significant relationship with the severity of spasticity.
40
Lin, Po-Chieh, e 林柏伽. "Effect of Muscle Vibration on Stretch Reflex of Finger Post Stroke". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/70652937524228659438.
Testo completoAbstract (sommario):
碩士國立交通大學
機械工程學系
99
Previous studies have shown that muscle vibration (MV), below the threshold of inducing illusory movement or tonic vibration reflex, could modulate motor-evoked potentials (MEPs) of pathways controlling hand muscles in intact individuals. It is evident that this type of sub-threshold muscle vibration provides corticomotor modulations on the pathways controlling the vibrated and adjacent non-vibrated muscles. However, spinal-level contribution to the muscle vibration-induced changes in MEPs is not clear. We proposed a systematic approach for inducing and quantifying stretch reflex in strokes, and examined the effects of muscle vibration on the excitability of the spinal neural pathway. There muscles were examined: first dorsal interossei (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM). We tested four stroke subjects in our study. The results indicated that the amplitudes of short-latency stretch reflex (M1 Peak) of the three finger muscles were depressed during muscle vibration as compared to those with no vibration (MV: 71.53%MVC vs. No MV: 79.46%MVC). Muscle vibration did not affect the latency of either M1 or M2. These findings suggest that muscle vibration-induced MEPs facilitation may not occur in the spinal-level pathway. In addition, we also proposed a systematic approach for selecting stretch reflex with high correlation between trials.
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Palomino, Andres Felipe. "Rhythmic arm cycling differentially modulates stretch and H-reflex amplitudes in soleus muscle". Thesis, 2011. http://hdl.handle.net/1828/3401.
Testo completoAbstract (sommario):
During rhythmic arm cycling soleus H-reflex amplitudes are reduced by modulation of group Ia presynaptic inhibition (Frigon et al, 2004). This reflex suppression is graded with the frequency of arm cycling (Loadman & Zehr 2007; Hundza & Zehr 2009) and 0.8 Hz is the minimum frequency to significantly reduce the soleus H-reflex (Hundza & Zehr 2009). Despite the data on modulation of the soleus H-reflex amplitude induced by rhythmic arm cycling, comparatively little is known about the modulation of stretch reflexes due to remote limb movement. Therefore, the present study was intended to explore the effect of arm cycling on stretch and H-reflex amplitudes in the soleus muscle. In so doing, additional information on the mechanism of action during rhythmic arm cycling would be revealed. Although both reflexes share the same afferent pathway, we hypothesized that stretch reflex amplitudes would be less suppressed by arm cycling because they are less inhibited by presynaptic inhibition (Morita et al, 1998). Failure to reject this hypothesis would add additional strength to the argument that Ia presynaptic inhibition is the mechanism modulating soleus H-reflex amplitude during rhythmic arm cycling. Participants were seated in a customized chair with feet strapped to footplates. Three motor tasks were performed: static control trials and arm cycling at 1 and 2 Hz. Soleus H-reflexes were evoked using single 1 ms pulses of electrical stimulation delivered to the tibial nerve at the popliteal fossa. A constant M-wave and ~6% MVC activation of soleus was maintained across conditions. Stretch reflexes were evoked using a vibratory shaker (ET-126; Labworks Inc). The shaker was placed over the triceps surae tendon and controlled by a custom written LabView program (single sinusoidal pulse at 100Hz). Results demonstrated that rhythmic arm cycling that was effective for conditioning soleus H-reflexes did not show a suppressive effect on the amplitude of the soleus stretch reflex. We suggest this indicates that stretch reflexes are less sensitive to conditioning by rhythmic arm movement, as compared to H-reflexes, due to the relative insensitivity of Ia presynaptic inhibition.Graduate
42
Hayes, Bradley T. "The neuromuscular effects of a long-term static stretching program on the human soleus". 2006. http://www.oregonpdf.org.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Oregon State University, 2006.Blank pages 143 and 159 not microfilmed. Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.
43
PRUSZYNSKI, JEDRZEJ (ANDREW). "INVESTIGATING THE SOPHISTICATION OF LONG-LATENCY STRETCH RESPONSES DURING POSTURAL CONTROL OF THE UPPER LIMB". Thesis, 2011. http://hdl.handle.net/1974/6278.
Testo completoAbstract (sommario):
A recent theory of motor control, based on optimal feedback control, posits that voluntary motor behaviour involves the sophisticated manipulation of sensory feedback. Although this theory can explain how people move in the world, it does not specifically describe how this control process is implemented by the nervous system. In this thesis, we propose and explore one physiological implication of this theory. Specifically, we hypothesize that rapid feedback responses should possess the key functional attributes of voluntary control because these two systems share a common neural pathway through motor areas of cerebral cortex.
Our first four studies were designed to elaborate the functional attributes of the long-latency stretch reflex, a fast feedback response which occurs 50-100ms following the mechanical stretch of a muscle. Consistent with our hypothesis, we found that the
long-latency response possesses many attributes commonly reserved for voluntary
control: the long-latency response is continuously modulated by subject intent (Chapter 2), it compensates for the size-recruitment principle of the motoneuron pool (Chapter 3) and it accounts for the mechanical properties of the upper-limb (Chapter 5). Further investigation revealed that the long-latency response can be decomposed into two functionally-independent processes (Chapter 4), and that one of these components contributes all of the sophistication observed in Chapters 2 and 3.
The goal of our fifth study was to investigate the neural basis of the long-latency response (Chapter 6). Our results provide strong evidence from both single-neuron recordings in non-human primates and transcranial magnetic stimulation in humans that primary motor cortex, which is known to be a critical node for voluntary control, also contributes to the sophistication of the long-latency response.
Taken together, the studies presented in this thesis demonstrate that the long-
latency response possesses several functional attributes typically reserved for voluntary control and that this sophistication likely arises via a transcortical pathway through primary motor cortex.Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2011-01-18 09:19:24.579
44
Sanderson, Bailey. "GsMTx4 reduces the pressor response during dynamic hindlimb skeletal muscle stretch in decerebrate rats". Thesis, 2018. http://hdl.handle.net/2097/39112.
Testo completoAbstract (sommario):
Master of ScienceDepartment of Kinesiology
Steven W. Copp
Mechanical signals within contracting skeletal muscles contribute to the generation of the exercise pressor reflex; an important autonomic and cardiovascular control mechanism. In decerebrate rats, GsMTx4, a mechanically–activated channel inhibitor that is partially selective for piezo channels, was found recently to reduce the pressor response during static hindlimb muscle stretch; a maneuver used to investigate the mechanical component of the exercise pressor reflex (i.e., the mechanoreflex). However, the effect was found only during the very initial phase of the stretch when muscle length was changing which may have reflected the inhibition of rapidly-deactivating piezo 2 channels and the fact that different mechanically-activated channels with slower deactivation kinetics evoked the pressor response during the static phase of the maneuver. We tested the hypothesis that in decerebrate, unanesthetized rats, GsMTx4 would reduce the pressor response throughout the duration of a 30 second, 1 Hz dynamic hindlimb muscle stretch protocol. We found that the injection of 10 µg of GsMTx4 into the arterial supply of a hindlimb reduced the peak pressor response (control: 15±4, GsMTx4: 5±2 mmHg, p<0.05, n=8) and the pressor response at multiple time points throughout the duration of the stretch. GsMTx4, however, had no effect on the pressor response to the hindlimb arterial injection of lactic acid. Moreover, the injection of GsMTx4 into the jugular vein (a systemic control, n=5) or the injection of saline into the hindlimb arterial supply (a vehicle control, n=4) had no effect on the pressor response during dynamic stretch. We conclude that GsMTx4 reduced the pressor response throughout the duration of a 1 Hz dynamic stretch protocol which may have reflected the inhibition of piezo 2 channels throughout the dynamic stretch maneuver.
45
Sung-Lang e 陳順郎. "Acute Anal Stretch Inhibits NMDA-Dependent Pelvic-Urethra Reflex Potentiation via Spinal GABAergic Inhibition in Anesthetized Rats". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/15387256124449940399.
Testo completoAbstract (sommario):
博士中山醫學大學
醫學研究所
97
The impact of acute anal stretch on the pelvic-urethra reflex potentiation was examined in urethane-anesthetized rats by recording the external urethra sphincter electromyogram (EUSE) activity evoked by the pelvic afferent stimulation. Test stimulation (TS, 1 stimulation/30 sec) evoked a baseline reflex activity with a single action potential that was abolished by gallamine (5 mg/kg, i.v.). On the other hand, the repetitive stimulation (RS, 1 stimulation/1 sec) induced spinal reflex potentiation (SRP) that was attenuated by intrathecal CNQX (a glutamatergic AMPA receptor antagonist, 100 μM, 10 μl) and APV (a glutamatergic NMDA antagonist, 100 μM, 10 μl). Acute anal stretch using a mosquito clamp with a distance of 4 mm exhibited no effect, while with distances of 8 mm attenuated and of 12 mm abolished the repetitive stimulation-induced SRP. Intrathecal NMDA (100 μM, 10 μl) reversed the abolition on SRP caused by anal stretch. On the other hand, pretreated bicuculline (GABA A receptor antagonist, 100 μM, 10 μl) but not hydroxysaclofen (GABA B receptor antagonist) counteracted the abolition on the repetitive stimulation-induced SRP caused by the anal stretch. All the results suggested that anal stretch may be used as an adjunct to assist voiding dysfunction in patients with overactive urethra sphincter, and that GABAergic neurotransmission is important in the neural mechanisms underlying external urethra sphincter activity inhibited by anal stretch.
46
Hsin-Ta, Lee, e 李信德. "Relationship of reaction time in heel rising with related posture, stretch reflex, muscle fitness or range of motion". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/97652465968017064222.
Testo completoAbstract (sommario):
碩士臺北巿立體育學院
運動科學研究所
91
The purposes of this study were to examine the relationship of reaction time in heel rising with related posture, stretch reflex, muscle fitness or range of motion. Recruited were forty university students who did habitual exercise（19~23 years old, more than 3 days/week, more than 30 mins/day）. No disturbance existed before experiment, and sequences of measurement were randomized. Product-moment correlation of Carl Pearson were to used determine correlations between variables. The t-test and one-way ANOVA with a repeated design were used to test the reaction time of different conditions. Findings were as follows： （1）posture affects MRT（motor reaction time）more then PMRT（premotor reaction time）. All MRT, PMRT, and RT, of sitting were firstest, of readiness posture were slower, and of standing is the slowest. （2）the subjects whose muscle strength were stronger had a faster MRT of sitting, and a slower PMRT of readiness posture and standing than the others. This is significance. （3）the subjects who had better muscle endurance had a slower MRT of sitting, readiness posture, and standing than the others, but this is no significance. （4）there was no correlation between reaction time and stretch reflex. （5）the subjects whose dorsi-flexion angle were larger had a faster PMRT of sitting, and MRT of standing than the others. There was no correlation between reaction time and plant-flexion angle.
47
Mohammadzadeh, Forough. "Mechanical strain stimulates JNK-mediated expression of matrix metalloproteinase-2 in endothelium /". 2004.
Cerca il testo completoAbstract (sommario):
Thesis (M.Sc.)--York University, 2004. Graduate Programme in Biology.Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11866
48
Longo, Diego. "EFFECTS OF MUSCLE SHORTENING MANOEUVRE ON MOTOR CONTROL: A CLINICAL MODEL". Doctoral thesis, 2022. http://hdl.handle.net/2158/1275217.
Testo completoAbstract (sommario):
The Muscle Shortening Maneuver (MSM), a physiotherapy approach, was introduced by Grimaldi et al. in the eighties and is derived from Feldman’s λ model of motor control (Melchiorre, 2014). In the λ model the regulation of the stretch reflex threshold, that is the lower muscle length or joint angle at which motoneuronal recruitment occurs, plays a pivotal role (Feldman, 1995; Latash, 2010). The dynamic stretch reflex threshold (DSRT) is influenced by stretch speed. The tonic stretch reflex threshold (TSRT) represents the specific value of the DSRT at zero velocity. DSRTs and TSRTs are expressed in relation to the configuration of the joints, within a body frame of reference (FR) [4]. MSM is non-invasive and free of side effects, and is locally used in clinical practice (Ferrarello, 2021); it consists of two essential simultaneously applied elements: a muscle shortening and a solicitation in traction. A physiotherapist applies a series of fast accelerations to a skeletal segment (e.g., the foot) in the presence of forces acting in the opposite direction (added mass), thus producing a tensile stress. MSM provokes a dynamic lengthening associated with sudden shortening of the agonist and antagonist muscles. Tissue deformation stimulates the muscle spindles, with an enrolment of motor units and an attempt to produce muscle tension. However, the development of tension is prevented by the sudden shortening of the muscle due to the therapeutic maneuver. It is widely used in clinical practice but with little scientific evidence. The aim of the thesis is to investigate the neurophysiological mechanisms underlying it.
With these assumptions, an intervention study on patients with chronic stroke in which, through the use of a portable device, it has been possible to use the TSRTs as an objective outcome measure, has been designed. In order to test this protocol and before embarking on a real randomized clinical trial, a pilot study was performed. Despite the limitations of this type of study design do not allow to make assumptions on the real efficacy of the treatment, it was already possible to identify real physiological changes in patients. Moreover, the pilot study has been useful to detect the criticalities of the original research project and therefore to make changes to support a better execution of the future trial.
In the meanwhile a retrospective analysis which led to a re-elaboration of data obtained in the recent past was conducted. In particular, in a case series of 9 subjects with infantile cerebral palsy, the evaluation of objective outcomes (muscle strength, range of motion) is found for the first time in relation to functional outcomes measured by scales (Selective Motor Control Scale, Physician Rating Scale). Despite the many limitations that a series of cases with such a small sample can have, it was considered important to proceed with a more in-depth analysis of the data obtained in order to reflect on the possible presence of strong outcomes that would really change the physiological and functional characteristics of the subjects. This would have allowed to lay the foundations for future work to better investigate the effects of MSM on movement control in individuals with central nervous system injury.
The effects of the maneuver were also investigated in terms of pure electromyographic activity in a pediatric patient with post-surgical peroneal nerve resection. Also in this patient it was possible to find a clear modification of the outcomes in question with a strong reduction in clinical and functional findings and greater daily autonomy in the activities of life. Obviously, the limits of the observation of a single case are evident and the results cannot be considered as evidence of efficacy but it is considered important, even in this case, to detect the presence of hard outcomes of the therapeutic path.
Furthermore, the literature on MSM shows the possible effects of this type of treatment also on orthopedic injuries. In particular, two articles by Melchiorre et al. showed that this type of intervention seems effective on patients with Shoulder Impingement Syndrome (SIS) in terms of morpho-structural changes in the musculotendinous compartment of the joint, detectable by ultrasound, and of increased strength and pain relief. This protocol was selected for the design and execution of a study on subjects with SIS from a population that practices an overhead sport, water polo. In this randomized and controlled study, it was possible to observe objective and immediate changes in the musculotendinous components in correspondence with a significant decrease of pain. In conclusion, the results of these studies seem to highlight a real effect of MSM on motor control understood as modulation of TSRT, in the perspective of Feldman's threshold referent control theory.
49
高肇利. "Quantitative analysis of stretch reflexes in spastic subjects and spasticity measurement system setup". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/15945261794283001124.
Testo completoAbstract (sommario):
碩士國立成功大學
醫學工程研究所
83
Spasticity in stroke, traumatic brain injury, and spinal cord injury often interferes the patientk's limb functions, and often combined with other motor deficits such as rigidity, ataxia, and flexor and extensor synergies. The existing clinical measures, by determining the resistance to external imposed passive movement of a joint, are usually subjective and qualitative. An objective and quantitative evaluation of the spastic hypertonia is highly needed for improving the treatment and rehabilitation process of cerebral stroke patients. The aim of this research is to develop a computer-controlled spasticity measurement system for the quantification of stretch reflex of the impaired limbs. A real-time spasticity measurement system which produces constant velocity stretch to teh examined limb is developed in this study.The spasticity measurement system consists of real-time controlled servomotor system with torque sensor, accelerator, and EMG recording electrodes. A real-time controller with TMS320C40 digital signal processor was chosen for its flexibility and extensibility. The control system for a servomotor first was implemented in SIMULINK, a simulation software, and later was directly transferred for real-time application. Five different constant stretching velocities (20，40，60，80，100deg/sec) were used to elicit stretch reflex of elbow joint in spastic subjects. A torque sensor located in the rotation center of torque motor was used to measure the resistance of flexor muscles. Three muscle groups, including biceps, brachioradialis, and triceps were recorded for monitoring the EMG activity. From our studies, we have found that observation of the increase of measured torque might not be used directly for spasticity quantification. This is partly due to the influence of the inevitable misalignment of the elbow joint to the rotation center during stretch of examined elbow. To alleviate the misalignment of elbow joint, two parameters, magnitude of dynamic versus static reflex (Mrefl) and its stiffness ration (DT/ST stiffness ratio), which measure the relative increase of torque were chosen for quantifying the hypertonia of spastic subjects. From our observations, these parameters were well correlated with the EMG activity (p<0.05). Four subjects, including two CVA's, one multiple sclerosis, and one parkinson's disease, were tested to verify the applicabilities of this measurement system. For the intrinsic differences between subjects, we only compare the differences of parameters between two elbow joints of each individual. Higher Mrefl and stiffness ration as well as higher velocity sensitivity of both parameters can be observed in severely involved elbow joint than those in contralatral one In particular, the augmentation of velocity sensitivity of two parameters in severely involved elbow joint was observed in parkinsonian subject after the cessation of medical therapeutics. It can be concluded that our spasticity system with relative torque parameters and their velocity sevsitivity might be suitable for the quantitation of muscle hypertonia.