1
|
Tulimieri DT, Semrau JA. Impaired proprioception and magnified scaling of proprioceptive error responses in chronic stroke. J Neuroeng Rehabil 2024; 21:51. [PMID: 38594762 PMCID: PMC11003069 DOI: 10.1186/s12984-024-01350-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 03/29/2024] [Indexed: 04/11/2024] Open
Abstract
BACKGROUND Previous work has shown that ~ 50-60% of individuals have impaired proprioception after stroke. Typically, these studies have identified proprioceptive impairments using a narrow range of reference movements. While this has been important for identifying the prevalence of proprioceptive impairments, it is unknown whether these error responses are consistent for a broad range of reference movements. The objective of this study was to characterize proprioceptive accuracy as function of movement speed and distance in stroke. METHODS Stroke (N = 25) and controls (N = 21) completed a robotic proprioception test that varied movement speed and distance. Participants mirror-matched various reference movement speeds (0.1-0.4 m/s) and distances (7.5-17.5 cm). Spatial and temporal parameters known to quantify proprioception were used to determine group differences in proprioceptive accuracy, and whether patterns of proprioceptive error were consistent across testing conditions within and across groups. RESULTS Overall, we found that stroke participants had impaired proprioception compared to controls. Proprioceptive errors related to tested reference movement scaled similarly to controls, but some errors showed amplified scaling (e.g., significantly overshooting or undershooting reference speed). Further, interaction effects were present for speed and distance reference combinations at the extremes of the testing distribution. CONCLUSIONS We found that stroke participants have impaired proprioception and that some proprioceptive errors were dependent on characteristics of the movement (e.g., speed) and that reference movements at the extremes of the testing distribution resulted in significantly larger proprioceptive errors for the stroke group. Understanding how sensory information is utilized across a broad spectrum of movements after stroke may aid design of rehabilitation programs.
Collapse
Affiliation(s)
- Duncan Thibodeau Tulimieri
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, USA
- Program in Biomechanics and Movement Science (BIOMS), University of Delaware, 100 Discovery Blvd, Tower at STAR, Rm 234, Newark, DE, 19713, USA
| | - Jennifer A Semrau
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, USA.
- Program in Biomechanics and Movement Science (BIOMS), University of Delaware, 100 Discovery Blvd, Tower at STAR, Rm 234, Newark, DE, 19713, USA.
- Department of Biomedical Engineering, University of Delaware, Newark, USA.
| |
Collapse
|
2
|
Bakalkin G. The left-right side-specific endocrine signaling in the effects of brain lesions: questioning of the neurological dogma. Cell Mol Life Sci 2022; 79:545. [PMID: 36219330 PMCID: PMC9553812 DOI: 10.1007/s00018-022-04576-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/25/2022]
Abstract
Each cerebral hemisphere is functionally connected to the contralateral side of the body through the decussating neural tracts. The crossed neural pathways set a basis for contralateral effects of brain injury such hemiparesis and hemiplegia as it has been already noted by Hippocrates. Recent studies demonstrated that, in addition to neural mechanisms, the contralateral effects of brain lesions are mediated through the humoral pathway by neurohormones that produce either the left or right side-specific effects. The side-specific humoral signaling defines whether the left or right limbs are affected after a unilateral brain injury. The hormonal signals are released by the pituitary gland and may operate through their receptors that are lateralized in the spinal cord and involved in the side-specific control of symmetric neurocircuits innervating the left and right limbs. Identification of features and a proportion of neurological deficits transmitted by neurohormonal signals vs. those mediated by neural pathways is essential for better understanding of mechanisms of brain trauma and stroke and development of new therapies. In a biological context, the left–right side-specific neuroendocrine signaling may be fundamental for the control of the left- and right-sided processes in bilaterally symmetric animals.
Collapse
Affiliation(s)
- Georgy Bakalkin
- Department of Pharmaceutical Biosciences, Uppsala University, Box 591, SE-751 24, Uppsala, Sweden.
| |
Collapse
|
3
|
Pradines M, Ghédira M, Bignami B, Vielotte J, Bayle N, Marciniak C, Burke D, Hutin E, Gracies JM. Do Muscle Changes Contribute to the Neurological Disorder in Spastic Paresis? Front Neurol 2022; 13:817229. [PMID: 35370894 PMCID: PMC8964436 DOI: 10.3389/fneur.2022.817229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/01/2022] [Indexed: 11/13/2022] Open
Abstract
Background At the onset of stroke-induced hemiparesis, muscle tissue is normal and motoneurones are not overactive. Muscle contracture and motoneuronal overactivity then develop. Motor command impairments are classically attributed to the neurological lesion, but the role played by muscle changes has not been investigated. Methods Interaction between muscle and command disorders was explored using quantified clinical methodology-the Five Step Assessment. Six key muscles of each of the lower and upper limbs in adults with chronic poststroke hemiparesis were examined by a single investigator, measuring the angle of arrest with slow muscle stretch (XV1) and the maximal active range of motion against the resistance of the tested muscle (XA). The coefficient of shortening CSH = (XN-XV1)/XN (XN, normally expected amplitude) and of weakness CW = (XV1-XA)/XV1) were calculated to estimate the muscle and command disorders, respectively. Composite CSH (CCSH) and CW (CCW) were then derived for each limb by averaging the six corresponding coefficients. For the shortened muscles of each limb (mean CSH > 0.10), linear regressions explored the relationships between coefficients of shortening and weakness below and above their median coefficient of shortening. Results A total of 80 persons with chronic hemiparesis with complete lower limb assessments [27 women, mean age 47 (SD 17), time since lesion 8.8 (7.2) years], and 32 with upper limb assessments [18 women, age 32 (15), time since lesion 6.4 (9.3) years] were identified. The composite coefficient of shortening was greater in the lower than in the upper limb (0.12 ± 0.04 vs. 0.08 ± 0.04; p = 0.0002, while the composite coefficient of weakness was greater in the upper limb (0.28 ± 0.12 vs. 0.15 ± 0.06, lower limb; p < 0.0001). In the lower limb shortened muscles, the coefficient of weakness correlated with the composite coefficient of shortening above the 0.15 median CSH (R = 0.43, p = 0.004) but not below (R = 0.14, p = 0.40). Conclusion In chronic hemiparesis, muscle shortening affects the lower limb particularly, and, beyond a threshold of severity, may alter descending commands. The latter might occur through chronically increased intramuscular tension, and thereby increased muscle afferent firing and activity-dependent synaptic sensitization at the spinal level.
Collapse
Affiliation(s)
- Maud Pradines
- UR 7377 BIOTN, Laboratoire Analyse et Restauration du Mouvement, Université Paris Est Créteil (UPEC), Créteil, France.,AP-HP, Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France
| | - Mouna Ghédira
- UR 7377 BIOTN, Laboratoire Analyse et Restauration du Mouvement, Université Paris Est Créteil (UPEC), Créteil, France.,AP-HP, Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France
| | - Blaise Bignami
- AP-HP, Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France
| | - Jordan Vielotte
- AP-HP, Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France
| | - Nicolas Bayle
- UR 7377 BIOTN, Laboratoire Analyse et Restauration du Mouvement, Université Paris Est Créteil (UPEC), Créteil, France.,AP-HP, Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France
| | - Christina Marciniak
- Department of Physical Medicine and Rehabilitation, Northwestern University and the Shirley Ryan AbilityLab, Chicago, IL, United States.,Department of Neurology, Northwestern University and the Shirley Ryan AbilityLab, Chicago, IL, United States
| | - David Burke
- Department of Neurology, Royal Prince Alfred Hospital and the University of Sydney, Sydney, NSW, Australia
| | - Emilie Hutin
- UR 7377 BIOTN, Laboratoire Analyse et Restauration du Mouvement, Université Paris Est Créteil (UPEC), Créteil, France.,AP-HP, Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France
| | - Jean-Michel Gracies
- UR 7377 BIOTN, Laboratoire Analyse et Restauration du Mouvement, Université Paris Est Créteil (UPEC), Créteil, France.,AP-HP, Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France
| |
Collapse
|
4
|
Patterson JR, Dewald JPA, Drogos JM, Gurari N. Impact of Voluntary Muscle Activation on Stretch Reflex Excitability in Individuals With Hemiparetic Stroke. Front Neurol 2022; 13:764650. [PMID: 35359658 PMCID: PMC8964046 DOI: 10.3389/fneur.2022.764650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 02/07/2022] [Indexed: 11/21/2022] Open
Abstract
Objective To characterize how, following a stretch-induced attenuation, volitional muscle activation impacts stretch reflex activity in individuals with stroke. Methods A robotic device rotated the paretic elbow of individuals with hemiparetic stroke from 70° to 150°, and then back to 70° elbow flexion at an angular speed of 120°/s. This stretching sequence was repeated 20 times. Subsequently, participants volitionally activated their elbow musculature or rested. Finally, the stretching sequence was repeated another 20 times. The flexors' stretch reflex activity was quantified as the net torque measured at 135°. Results Data from 15 participants indicated that the stretching sequence attenuated the flexion torque (p < 0.001) and resting sustained the attenuation (p = 1.000). Contrastingly, based on data from 14 participants, voluntary muscle activation increased the flexion torque (p < 0.001) to an initial pre-stretch torque magnitude (p = 1.000). Conclusions Stretch reflex attenuation induced by repeated fast stretches may be nullified when individuals post-stroke volitionally activate their muscles. In contrast, resting may enable a sustained reflex attenuation if the individual remains relaxed. Significance Stretching is commonly implemented to reduce hyperactive stretch reflexes following a stroke. These findings suggest that stretch reflex accommodation arising from repeated fast stretching may be reversed once an individual volitionally moves their paretic arm.
Collapse
Affiliation(s)
- Jacqueline R. Patterson
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, United States
- Northwestern University Interdepartmental Neuroscience, Northwestern University, Chicago, IL, United States
- Department of Physiology, Northwestern University, Chicago, IL, United States
| | - Julius P. A. Dewald
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, United States
- Northwestern University Interdepartmental Neuroscience, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Justin M. Drogos
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, United States
| | - Netta Gurari
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, United States
- Northwestern University Interdepartmental Neuroscience, Northwestern University, Chicago, IL, United States
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, United States
- *Correspondence: Netta Gurari
| |
Collapse
|
5
|
|
6
|
Parr T, Limanowski J, Rawji V, Friston K. The computational neurology of movement under active inference. Brain 2021; 144:1799-1818. [PMID: 33704439 PMCID: PMC8320263 DOI: 10.1093/brain/awab085] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 11/08/2020] [Accepted: 12/20/2020] [Indexed: 12/31/2022] Open
Abstract
We propose a computational neurology of movement based on the convergence of theoretical neurobiology and clinical neurology. A significant development in the former is the idea that we can frame brain function as a process of (active) inference, in which the nervous system makes predictions about its sensory data. These predictions depend upon an implicit predictive (generative) model used by the brain. This means neural dynamics can be framed as generating actions to ensure sensations are consistent with these predictions-and adjusting predictions when they are not. We illustrate the significance of this formulation for clinical neurology by simulating a clinical examination of the motor system using an upper limb coordination task. Specifically, we show how tendon reflexes emerge naturally under the right kind of generative model. Through simulated perturbations, pertaining to prior probabilities of this model's variables, we illustrate the emergence of hyperreflexia and pendular reflexes, reminiscent of neurological lesions in the corticospinal tract and cerebellum. We then turn to the computational lesions causing hypokinesia and deficits of coordination. This in silico lesion-deficit analysis provides an opportunity to revisit classic neurological dichotomies (e.g. pyramidal versus extrapyramidal systems) from the perspective of modern approaches to theoretical neurobiology-and our understanding of the neurocomputational architecture of movement control based on first principles.
Collapse
Affiliation(s)
- Thomas Parr
- Wellcome Centre for Human Neuroimaging, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Jakub Limanowski
- Faculty of Psychology and Center for Tactile Internet with Human-in-the-Loop, Technische Universität Dresden, Dresden, Germany
| | - Vishal Rawji
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Karl Friston
- Wellcome Centre for Human Neuroimaging, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| |
Collapse
|
7
|
Spasticity, spastic dystonia, and static stretch reflex in hypertonic muscles of patients with multiple sclerosis. Clin Neurophysiol Pract 2021; 6:194-202. [PMID: 34278056 PMCID: PMC8263531 DOI: 10.1016/j.cnp.2021.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 04/14/2021] [Accepted: 05/05/2021] [Indexed: 11/23/2022] Open
Abstract
Objective To investigate prevalence of EMG patterns underlying hypertonia in multiple sclerosis (MS) and whether these patterns indicate different levels of spinal excitability. Methods We investigated the EMG activity recorded from 108 hypertonic muscles of 59 consecutive MS patients. To investigate spastic dystonia (SD), we looked for the presence of EMG activity in muscles in a resting position. To investigate dynamic stretch reflex (DSR) and static stretch reflex (SSR), we looked for the presence of EMG activity in response to a manually performed passive stretch of the muscle. Results DSR was evoked in 104 muscles. In 51 muscles, DSR was the sole EMG activity. This pattern corresponds to the classical notion of spasticity, and was predominant in extensors. In contrast, SSR was detected in 48 muscles – predominantly in flexors. SD was observed in 28 muscles, showing even distribution in flexor and extensor muscles. Only in the flexors, SSR was associated with a larger DSR compared to spasticity. Conclusions These findings likely depend on the central effects of both flexor and extensor spindle afferents on the homonymous spinal motor neurons. Significance Improving our capacity to assess spinal excitability in MS patients.
Collapse
|
8
|
Ford TW, Kirkwood PA. Bulbospinal connections to intercostal motoneurones following a chronic lateral spinal cord lesion. Respir Physiol Neurobiol 2020; 284:103566. [PMID: 33129988 DOI: 10.1016/j.resp.2020.103566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/17/2020] [Accepted: 10/20/2020] [Indexed: 10/23/2022]
Abstract
Previous evidence from electrophysiological experiments in anaesthetized cats with a chronic lateral lesion of the lower thoracic spinal cord indicated an expansion of the functional projections of expiratory bulbospinal neurones (EBSNs) in the segment above the lesion, measured at 16 weeks post-lesion. Here we investigate connections made by the same EBSNs to motoneurones in that segment, using cross-correlations between their discharges. The connections to the internal intercostal nerve motoneurones were found to be no different from controls. However, a significant increase was found in the number of connections between EBSNs and γ motoneurones of the external intercostal nerve (8/24, compared to 1/16) with possibly additional connections to the α motoneurones of the same nerve. Increased connections to the γ motoneurones of the internal intercostal nerve could not be ruled out. The expanded functional projections are thus likely to include new connections to γ motoneurones. We suggest that γ motoneurones may be inherently more receptive to new inputs. If so, the previously discounted role of abnormal fusimotor discharges in motor disorders would be worth reconsideration.
Collapse
Affiliation(s)
- Timothy W Ford
- Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Peter A Kirkwood
- Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK.
| |
Collapse
|
9
|
Ledri LN, Pingel J, Hultborn H, Therkildsen ER, Wienecke J, Nielsen JB. Immobilization leads to reduced stretch reflexes but increased central reflex gain in the rat. J Neurophysiol 2020; 124:985-993. [PMID: 32783594 DOI: 10.1152/jn.00748.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Plastic adaptations are known to take place in muscles, tendons, joints, and the nervous system in response to changes in muscle activity. However, few studies have addressed how these plastic adaptations are related. Thus this study focuses on changes in the mechanical properties of the ankle plantarflexor muscle-tendon unit, stretch reflex activity, and spinal neuronal pathways in relation to cast immobilization. The left rat hindlimb from toes to hip was immobilized with a plaster cast for 1, 2, 4, or 8 wk followed by acute electrophysiological recordings to investigate muscle stiffness and stretch reflex torque. Moreover, additional acute experiments were performed after 4 wk of immobilization to investigate changes in the central gain of the stretch reflex. Monosynaptic reflexes (MSR) were recorded from the L4 and L5 ventral roots following stimulation of the corresponding dorsal roots. Rats developed reduced range of movement in the ankle joint 2 wk after immobilization. This was accompanied by significant increases in the stiffness of the muscle-tendon complex as well as an arthrosis at the ankle joint at 4 and 8 wk following immobilization. Stretch reflexes were significantly reduced at 4-8 wk following immobilization. This was associated with increased central gain of the stretch reflex. These data show that numerous interrelated plastic changes occur in muscles, connective tissue, and the central nervous system in response to changes in muscle use. The findings provide an understanding of coordinated adaptations in multiple tissues and have important implications for prevention and treatment of the negative consequences of immobilization following injuries of the nervous and musculoskeletal systems.NEW & NOTEWORTHY Immobilization leads to multiple simultaneous adaptive changes in muscle, connective tissue, and central nervous system.
Collapse
Affiliation(s)
| | - Jessica Pingel
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Hans Hultborn
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | | | - Jacob Wienecke
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bo Nielsen
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.,Elsass Foundation, Holmegårdsvej, Charlottenlund, Denmark
| |
Collapse
|
10
|
Zhang M, Watanabe H, Sarkisyan D, Andersen MS, Nosova O, Galatenko V, Carvalho L, Lukoyanov N, Thelin J, Schouenborg J, Bakalkin G. Hindlimb motor responses to unilateral brain injury: spinal cord encoding and left-right asymmetry. Brain Commun 2020; 2:fcaa055. [PMID: 32954305 PMCID: PMC7425521 DOI: 10.1093/braincomms/fcaa055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/02/2020] [Accepted: 04/07/2020] [Indexed: 12/26/2022] Open
Abstract
Mechanisms of motor deficits (e.g. hemiparesis and hemiplegia) secondary to stroke and traumatic brain injury remain poorly understood. In early animal studies, a unilateral lesion to the cerebellum produced postural asymmetry with ipsilateral hindlimb flexion that was retained after complete spinal cord transection. Here we demonstrate that hindlimb postural asymmetry in rats is induced by a unilateral injury of the hindlimb sensorimotor cortex, and characterize this phenomenon as a model of spinal neuroplasticity underlying asymmetric motor deficits. After cortical lesion, the asymmetry was developed due to the contralesional hindlimb flexion and persisted after decerebration and complete spinal cord transection. The asymmetry induced by the left-side brain injury was eliminated by bilateral lumbar dorsal rhizotomy, but surprisingly, the asymmetry after the right-side brain lesion was resistant to deafferentation. Pancuronium, a curare-mimetic muscle relaxant, abolished the asymmetry after the right-side lesion suggesting its dependence on the efferent drive. The contra- and ipsilesional hindlimbs displayed different musculo-articular resistance to stretch after the left but not right-side injury. The nociceptive withdrawal reflexes evoked by electrical stimulation and recorded with EMG technique were different between the left and right hindlimbs in the spinalized decerebrate rats. On this asymmetric background, a brain injury resulted in greater reflex activation on the contra- versus ipsilesional side; the difference between the limbs was higher after the right-side brain lesion. The unilateral brain injury modified expression of neuroplasticity genes analysed as readout of plastic changes, as well as robustly impaired coordination of their expression within and between the ipsi- and contralesional halves of lumbar spinal cord; the effects were more pronounced after the left side compared to the right-side injury. Our data suggest that changes in the hindlimb posture, resistance to stretch and nociceptive withdrawal reflexes are encoded by neuroplastic processes in lumbar spinal circuits induced by a unilateral brain injury. Two mechanisms, one dependent on and one independent of afferent input may mediate asymmetric hindlimb motor responses. The latter, deafferentation resistant mechanism may be based on sustained muscle contractions which often occur in patients with central lesions and which are not evoked by afferent stimulation. The unusual feature of these mechanisms is their lateralization in the spinal cord.
Collapse
Affiliation(s)
- Mengliang Zhang
- Department of Experimental Medical Science, Neuronano Research Center, Lund University, 221 00 Lund, Sweden
- Department of Molecular Medicine, University of Southern Denmark, DK-5000 Odense, Denmark
| | - Hiroyuki Watanabe
- Department of Pharmaceutical Biosciences, Uppsala University, 751 24 Uppsala, Sweden
| | - Daniil Sarkisyan
- Department of Pharmaceutical Biosciences, Uppsala University, 751 24 Uppsala, Sweden
| | - Marlene Storm Andersen
- Department of Molecular Medicine, University of Southern Denmark, DK-5000 Odense, Denmark
| | - Olga Nosova
- Department of Pharmaceutical Biosciences, Uppsala University, 751 24 Uppsala, Sweden
| | - Vladimir Galatenko
- Faculty of Mechanics and Mathematics, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Liliana Carvalho
- Departamento de Biomedicina da Faculdade de Medicina da Universidade do Porto, Instituto de Investigação e Inovação em Saúde, Instituto de Biologia Molecular e Celular, 4200-319 Porto, Portugal
| | - Nikolay Lukoyanov
- Departamento de Biomedicina da Faculdade de Medicina da Universidade do Porto, Instituto de Investigação e Inovação em Saúde, Instituto de Biologia Molecular e Celular, 4200-319 Porto, Portugal
| | - Jonas Thelin
- Department of Experimental Medical Science, Neuronano Research Center, Lund University, 221 00 Lund, Sweden
| | - Jens Schouenborg
- Department of Experimental Medical Science, Neuronano Research Center, Lund University, 221 00 Lund, Sweden
| | - Georgy Bakalkin
- Department of Pharmaceutical Biosciences, Uppsala University, 751 24 Uppsala, Sweden
| |
Collapse
|
11
|
Roche N, Bonnyaud C, Reynaud V, Bensmail D, Pradon D, Esquenazi A. Motion analysis for the evaluation of muscle overactivity: A point of view. Ann Phys Rehabil Med 2019; 62:442-452. [PMID: 31276837 DOI: 10.1016/j.rehab.2019.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 11/15/2022]
Abstract
Muscle overactivity is a general term for pathological increases in muscle activity such as spasticity. It is caused by damage to the central nervous system at the cortical, subcortical or spinal levels, leading to an upper motor neuron syndrome. In routine clinical practice, muscle overactivity, which induces abnormal muscle tone, is usually evaluated by using the Modified Ashworth Scale or the Tardieu Scale. However, both of these scales involve testing in passive conditions that do not always reflect muscle activity during dynamic tasks such as gait or reaching. To determine appropriate treatment strategies, muscle overactivity should be evaluated by using objective measures in dynamic conditions. Instrumental motion analysis systems that include 3-D motion analysis and electromyography are very useful for this purpose. The method can be used to identify patterns of abnormal muscle activity that can be related to abnormal kinematic patterns. It allows for objective and accurate assessment of the effects of treatments to reduce muscle overactivity on the movement to be improved. The aim of this point-of-view article is to describe the utility of instrumental motion analysis and to outline both its numerous advantages in evaluating muscle overactivity and to present the current limitations for its use (e.g., cost, the need for an engineer, errors relating to marker placement and cross talk between electromyography sensors).
Collapse
Affiliation(s)
- N Roche
- U1179, service de physiologie et d'explorations fonctionnelles, Assistance publique des Hôpitaux de Paris, Raymond Poincaré Hospital, Garches, France.
| | - C Bonnyaud
- U1179, service de physiologie et d'explorations fonctionnelles, Assistance publique des Hôpitaux de Paris, Raymond Poincaré Hospital, Garches, France
| | - V Reynaud
- U1179, service de physiologie et d'explorations fonctionnelles, Assistance publique des Hôpitaux de Paris, Raymond Poincaré Hospital, Garches, France
| | - D Bensmail
- U1179, service de physiologie et d'explorations fonctionnelles, Assistance publique des Hôpitaux de Paris, Raymond Poincaré Hospital, Garches, France
| | - D Pradon
- U1179, service de physiologie et d'explorations fonctionnelles, Assistance publique des Hôpitaux de Paris, Raymond Poincaré Hospital, Garches, France
| | - A Esquenazi
- Gait and Motion Analysis Laboratory, Department of Physical Medicine and Rehabilitation, MossRehab, Elkins Park, PA, USA
| |
Collapse
|
12
|
Milton JG, Insperger T, Cook W, Harris DM, Stepan G. Microchaos in human postural balance: Sensory dead zones and sampled time-delayed feedback. Phys Rev E 2018; 98:022223. [PMID: 30253531 DOI: 10.1103/physreve.98.022223] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Indexed: 06/08/2023]
Abstract
Models for the stabilization of an inverted pendulum figure prominently in studies of human balance control. Surprisingly, fluctuations in measures related to the vertical displacement angle for quietly standing adults with eyes closed exhibit chaos. Here we show that small-amplitude chaotic fluctuations ("microchaos") can be generated by the interplay between three essential components of human neural balance control, namely time-delayed feedback, a sensory dead zone, and frequency-dependent encoding of force. When the sampling frequency of the force encoding is decreased, the sensitivity of the balance control to changes in the initial conditions increases. The sampled, time-delayed nature of the balance control may provide insights into why falls are more common in the very young and the elderly.
Collapse
Affiliation(s)
- John G Milton
- W. M. Keck Science Center, The Claremont Colleges, Claremont, California 91711, USA
| | - Tamas Insperger
- Department of Applied Mechanics, Budapest University of Technology and Economics and MTA-BME Lendület Human Balancing Research Group, 1111 Budapest, Hungary
| | - Walter Cook
- W. M. Keck Science Center, The Claremont Colleges, Claremont, California 91711, USA
| | - David Money Harris
- Department of Engineering, Harvey Mudd College, Claremont, California 91711, USA
| | - Gabor Stepan
- Department of Applied Mechanics, Budapest University of Technology and Economics, 1111 Budapest, Hungary
| |
Collapse
|
13
|
Wang R, Gäverth J, Herman PA. Changes in the Neural and Non-neural Related Properties of the Spastic Wrist Flexors After Treatment With Botulinum Toxin A in Post-stroke Subjects: An Optimization Study. Front Bioeng Biotechnol 2018; 6:73. [PMID: 29963551 PMCID: PMC6013585 DOI: 10.3389/fbioe.2018.00073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 05/22/2018] [Indexed: 11/13/2022] Open
Abstract
Quantifying neural and non-neural contributions to the joint resistance in spasticity is essential for a better evaluation of different intervention strategies such as botulinum toxin A (BoTN-A). However, direct measurement of muscle mechanical properties and spasticity-related parameters in humans is extremely challenging. The aim of this study was to use a previously developed musculoskeletal model and optimization scheme to evaluate the changes of neural and non-neural related properties of the spastic wrist flexors during passive wrist extension after BoTN-A injection. Data of joint angle and resistant torque were collected from 21 chronic stroke patients before, and 4 and 12 weeks post BoTN-A injection using NeuroFlexor, which is a motorized force measurement device to passively stretch wrist flexors. The model was optimized by tuning the passive and stretch-related parameters to fit the measured torque in each participant. It was found that stroke survivors exhibited decreased neural components at 4 weeks post BoNT-A injection, which returned to baseline levels after 12 weeks. The decreased neural component was mainly due to the increased motoneuron pool threshold, which is interpreted as a net excitatory and inhibitory inputs to the motoneuron pool. Though the linear stiffness and viscosity properties of wrist flexors were similar before and after treatment, increased exponential stiffness was observed over time which may indicate a decreased range of motion of the wrist joint. Using a combination of modeling and experimental measurement, valuable insights into the treatment responses, i.e., transmission of motoneurons, are provided by investigating potential parameter changes along the stretch reflex pathway in persons with chronic stroke.
Collapse
Affiliation(s)
- Ruoli Wang
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Department of Mechanics, Royal Institute of Technology, Stockholm, Sweden.,KTH Biomex Center, Royal Institute of Technology, Stockholm, Sweden
| | - Johan Gäverth
- Functional Area Occupational Therapy & Physiotherapy, Karolinska University Hospital, Stockholm, Sweden
| | - Pawel A Herman
- Department of Computational Science and Technology, Royal Institute of Technology, Stockholm, Sweden
| |
Collapse
|
14
|
Miller DM, Rymer WZ. Sound-Evoked Biceps Myogenic Potentials Reflect Asymmetric Vestibular Drive to Spastic Muscles in Chronic Hemiparetic Stroke Survivors. Front Hum Neurosci 2017; 11:535. [PMID: 29176945 PMCID: PMC5686083 DOI: 10.3389/fnhum.2017.00535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 10/20/2017] [Indexed: 11/13/2022] Open
Abstract
Aberrant vestibular nuclear function is proposed to be a principle driver of limb muscle spasticity after stroke. We sought to determine whether altered cortical modulation of descending vestibulospinal pathways post-stroke could impact the excitability of biceps brachii motoneurons. Twelve chronic hemispheric stroke survivors aged 46–68 years were enrolled. Sound evoked biceps myogenic potentials (SEBMPs) were recorded from the spastic and contralateral biceps muscles using surface EMG electrodes. We assessed the impact of descending vestibulospinal pathways on biceps muscle activity and evaluated the relationship between vestibular function and the severity of spasticity. Spastic SEBMP responses were recorded in 11/12 subjects. Almost 60% of stroke subjects showed evoked responses solely on the spastic side. These data strongly support the idea that vestibular drive is asymmetrically distributed to biceps motoneuron pools in hemiparetic spastic stroke survivors. This abnormal vestibular drive is very likely to be a factor mediating the striking differences in motoneuron excitability between the clinically affected and clinically spared sides. This study extends our previous observations on vestibular nuclear changes following hemispheric stroke and potentially sheds light on the underlying mechanisms of post-stroke spasticity.
Collapse
Affiliation(s)
- Derek M Miller
- Single Motor Unit Laboratory, Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States.,Interdepartmental Neurosciences Program, Northwestern University, Evanston, IL, United States
| | - William Z Rymer
- Single Motor Unit Laboratory, Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States.,Interdepartmental Neurosciences Program, Northwestern University, Evanston, IL, United States
| |
Collapse
|
15
|
Turpin NA, Feldman AG, Levin MF. Stretch-reflex threshold modulation during active elbow movements in post-stroke survivors with spasticity. Clin Neurophysiol 2017; 128:1891-1897. [DOI: 10.1016/j.clinph.2017.07.411] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/24/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
|
16
|
Wang R, Herman P, Ekeberg Ö, Gäverth J, Fagergren A, Forssberg H. Neural and non-neural related properties in the spastic wrist flexors: An optimization study. Med Eng Phys 2017; 47:198-209. [PMID: 28694106 DOI: 10.1016/j.medengphy.2017.06.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 06/14/2017] [Accepted: 06/14/2017] [Indexed: 10/19/2022]
Abstract
Quantifying neural and non-neural contributions to increased joint resistance in spasticity is essential for a better understanding of its pathophysiological mechanisms and evaluating different intervention strategies. However, direct measurement of spasticity-related manifestations, e.g., motoneuron and biophysical properties in humans, is extremely challenging. In this vein, we developed a forward neuromusculoskeletal model that accounts for dynamics of muscle spindles, motoneuron pools, muscle activation and musculotendon of wrist flexors and relies on the joint angle and resistant torque as the only input measurement variables. By modeling the stretch reflex pathway, neural and non-neural related properties of the spastic wrist flexors were estimated during the wrist extension test. Joint angle and resistant torque were collected from 17 persons with chronic stroke and healthy controls using NeuroFlexor, a motorized force measurement device during the passive wrist extension test. The model was optimized by tuning the passive and stretch reflex-related parameters to fit the measured torque in each participant. We found that persons with moderate and severe spasticity had significantly higher stiffness than controls. Among subgroups of stroke survivors, the increased neural component was mainly due to a lower muscle spindle rate at 50% of the motoneuron recruitment. The motoneuron pool threshold was highly correlated to the motoneuron pool gain in all subgroups. The model can describe the overall resistant behavior of the wrist joint during the test. Compared to controls, increased resistance was predominantly due to higher elasticity and neural components. We concluded that in combination with the NeuroFlexor measurement, the proposed neuromusculoskeletal model and optimization scheme served as suitable tools for investigating potential parameter changes along the stretch-reflex pathway in persons with spasticity.
Collapse
Affiliation(s)
- R Wang
- Department of Mechanics, Royal Institute of Technology, Stockholm, Sweden; KTH Biomex Center, Royal Institute of Technology, Stockholm, Sweden; Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
| | - P Herman
- Dept. of Computational Science and Technology, Royal Institute of Technology, Stockholm, Sweden.
| | - Ö Ekeberg
- Dept. of Computational Science and Technology, Royal Institute of Technology, Stockholm, Sweden.
| | - J Gäverth
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
| | | | - H Forssberg
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
| |
Collapse
|
17
|
Li S, Shin H, Zhou P, Li X. Different Effects of Cold Stimulation on Reflex and Non-Reflex Components of Poststroke Spastic Hypertonia. Front Neurol 2017; 8:169. [PMID: 28503163 PMCID: PMC5408071 DOI: 10.3389/fneur.2017.00169] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/11/2017] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE To use an established biomechanical approach to quantify reflex and non-reflex responses from spastic-paretic elbow flexors in response to controlled cold and heat stimulation. METHODS Thirteen spastic-hemiplegic stroke subjects were tested in the experiment. The spastic elbow joint was stretched into extension for 50° at two speeds (5°/s and 100°/s) in a customized apparatus. Thermal stimulation (HEAT at heat pain threshold, COLD at 0°C, or BASELINE at room temperature) was applied to the thenar eminence of the contralateral hand immediately prior to stretching for at least 30 s. RESULTS Total torque was greater at 100°/s than at 5°/s. Total torque was significantly increased after COLD, but not HEAT as compared to BASELINE. When normalized to total torque at baseline, HEAT decreased total torque by 6.3%, while COLD increased total torque by 11.0%. There was no significant difference in the reflex torque among three thermal conditions. CONCLUSION The findings demonstrate differentiated effects of cold stimulation on the total resistance from spastic muscles. They provide objective evidence for anecdotal clinical observations of increased muscle spasticity by cold exposure.
Collapse
Affiliation(s)
- Sheng Li
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA
| | - Henry Shin
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA.,Guangdong Work Injury Rehabilitation Center, Guangzhou, China
| | - Xiaoyan Li
- Department of Physical Medicine and Rehabilitation, McGovern Medical School, University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA.,TIRR Memorial Hermann Research Center, TIRR Memorial Hermann Hospital, Houston, TX, USA
| |
Collapse
|
18
|
Ascending vestibular drive is asymmetrically distributed to the inferior oblique motoneuron pools in a subset of hemispheric stroke survivors. Clin Neurophysiol 2016; 127:2022-30. [PMID: 26971485 DOI: 10.1016/j.clinph.2016.01.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 01/25/2016] [Accepted: 01/26/2016] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Aberrant vestibular nuclear function is proposed to be a principle driver of limb muscle spasticity after stroke. Although spasticity does not manifest in ocular muscles, we sought to determine whether altered cortical modulation of ascending vestibuloocular pathways post-stroke could impact the excitability of ocular motoneurons. METHODS Nineteen chronic stroke survivors, aged 49-68 yrs. were enrolled. Vestibular evoked myogenic potentials (VEMPs) were recorded from the inferior oblique muscles of the eye using surface EMG electrodes. We assessed the impact of ascending otolith pathways on eye muscle activity and evaluated the relationship between otolith-ocular function and the severity of spasticity. RESULTS VEMP responses were recorded bilaterally in 14/19 subjects. Response magnitude on the affected side was significantly larger than on the spared side. In a subset of subjects, there was a strong relationship between affected response amplitude and the severity of limb spasticity, as estimated using a standard clinical scale. CONCLUSIONS This study suggests that alterations in ascending vestibular drive to ocular motoneurons contribute to post-stroke spasticity in a subset of spastic stroke subjects. We speculate this imbalance is a consequence of the unilateral disruption of inhibitory corticobulbar projections to the vestibular nuclei. SIGNIFICANCE This study potentially sheds light on the underlying mechanisms of post-stroke spasticity.
Collapse
|
19
|
Nam CW, Lee JH, Cho SH. The effect of non-elastic taping on balance and gait function in patients with stroke. J Phys Ther Sci 2015; 27:2857-60. [PMID: 26504310 PMCID: PMC4616111 DOI: 10.1589/jpts.27.2857] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 06/09/2015] [Indexed: 11/24/2022] Open
Abstract
[Purpose] This study investigated the influence of exercise on balance ability and gait
function in stroke patients after applying non-elastic tape, which can stabilize muscles
and joints, to the lower extremities of the affected side. [Subjects and Methods] The
subjects were 30 patients diagnosed with stroke. They were divided into an experimental
group (n = 15) and a control group (n = 15). The experimental group performed mat and
treadmill exercises three times a week for six weeks with non-elastic tape applied to the
lower extremities of the affected side. The control group performed the same exercises but
without taping. [Results] The intervention significantly improved Berg balance scale
scores and timed up and go (TUG) test scores as well as reduced stance duration and stride
duration in the experimental group. In the control group, statistically significant
improvements were observed in TUG test scores. [Conclusion] Although some differences did
not reach the level of statistical significance, the application of non-elastic tape
stabilized the joints of the lower extremities, thereby increasing balance and reducing
stance duration and one step duration, which resulted in a reduction of overall gait
duration.
Collapse
Affiliation(s)
- Chan-Woo Nam
- Department of Physical Therapy, College of Rehabilitation Science, Daegu University, Republic of Korea
| | - Jung-Ho Lee
- Department of Physical Therapy, Kyungdong University, Republic of Korea
| | - Sung-Hyoun Cho
- Department of Physical Therapy, Nambu University, Republic of Korea
| |
Collapse
|
20
|
Hu X, Suresh NL, Chardon MK, Rymer WZ. Contributions of motoneuron hyperexcitability to clinical spasticity in hemispheric stroke survivors. Clin Neurophysiol 2014; 126:1599-606. [PMID: 25438885 DOI: 10.1016/j.clinph.2014.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 10/31/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Muscle spasticity is one of the major impairments that limits recovery in hemispheric stroke survivors. One potential contributing mechanism is hyperexcitability of motoneurons. Previously, the response latency of the surface electromyogram (EMG) record evoked by joint rotation has been used to characterize motoneuron excitability. Given the limitations of this method, the objective of the current study was to reexamine the excitability of motoneurons in chronic stroke survivors by estimating reflex latency using single motor unit discharge. METHODS We quantified the excitability of spastic motoneurons using the response latency of a single motor unit discharge elicited by a position controlled tap on the biceps brachii tendon. We applied tendon taps of different amplitudes on the biceps tendons of both arms of the stroke survivors. Unitary reflex responses were recorded using intramuscular EMG recordings. RESULTS Our results showed that the latency of unitary discharge was systematically shorter in the spastic muscle compared with the contralateral muscle, and this effect was consistent across multiple tap amplitudes. CONCLUSIONS This method allowed us to quantify latencies more accurately, potentially enabling a more rigorous analysis of contributing mechanisms. SIGNIFICANCE The findings provide evidence supporting a contribution of hyperexcitable motoneurons to muscle spasticity.
Collapse
Affiliation(s)
- Xiaogang Hu
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA.
| | - Nina L Suresh
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA
| | - Matthieu K Chardon
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA
| | - William Z Rymer
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| |
Collapse
|
21
|
Miller DM, Klein CS, Suresh NL, Rymer WZ. Asymmetries in vestibular evoked myogenic potentials in chronic stroke survivors with spastic hypertonia: evidence for a vestibulospinal role. Clin Neurophysiol 2014; 125:2070-8. [PMID: 24680197 DOI: 10.1016/j.clinph.2014.01.035] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/15/2014] [Accepted: 01/29/2014] [Indexed: 02/08/2023]
Abstract
OBJECTIVE Indirect evidence suggests that lateralized changes in motoneuron behavior post-stroke are potentially due to a depolarizing supraspinal drive to the motoneuron pool, but the pathways responsible are unknown. In this study, we assessed vestibular evoked myogenic potentials (VEMPs) in the neck muscles of hemispheric stroke survivors with contralesional spasticity to quantify the relative levels of vestibular drive to the spastic-paretic and contralateral motoneuron pools. METHODS VEMPs were recorded from each sternocleidomastoid muscle in chronic stroke survivors. Side-to-side differences in cVEMP amplitude were calculated and expressed as an asymmetry ratio, a proxy for the relative amount of vestibular drive to each side. RESULTS Spastic-paretic VEMPs were larger than contralateral VEMPs in 13/16 subjects. There was a strong positive relationship between the degree of asymmetry and the severity of spasticity in this subset of subjects. Remaining subjects had larger contralateral responses. CONCLUSION Vestibular drive to cervical motoneurons is asymmetric in spastic stroke survivors, supporting our hypothesis that there is an imbalance in descending vestibular drive to motoneuron pools post-stroke. We speculate this imbalance is a consequence of the unilateral disruption of inhibitory corticobulbar projections to the vestibular nuclei. SIGNIFICANCE This study sheds new light on the underlying mechanisms of post-stroke spasticity.
Collapse
Affiliation(s)
- Derek M Miller
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA; Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL 60611, USA.
| | - Cliff S Klein
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL 60611, USA
| | - Nina L Suresh
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL 60611, USA
| | - William Z Rymer
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA; Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL 60611, USA
| |
Collapse
|
22
|
Abstract
Antispastic medications that are directed to reduce clinical signs of spasticity, such as exaggerated reflexes and muscle tone, do not improve the movement disorder. Medication can even increase weakness which might interfere with functional movements, such as walking. In this chapter we address how spasticity affects mobility and how this should be taken into account in the treatment of spasticity. In clinical practice, signs of exaggerated tendon tap reflexes associated with muscle hypertonia are the consequence of spinal cord injury (SCI). They are generally thought to be responsible for spastic movement disorders. Most antispastic treatments are, therefore, directed at the reduction of reflex activity. In recent years, a discrepancy between spasticity as measured in the clinic and functional spastic movement disorder was noticed, which is primarily due to the different roles of reflexes in passive and active states, respectively. We now know that central motor lesions are associated with loss of supraspinal drive and defective use of afferent input with impaired behavior of short-latency and long-latency reflexes. These changes lead to paresis and maladaptation of the movement pattern. Secondary changes in mechanical muscle fiber, collagen tissue, and tendon properties (e.g., loss of sarcomeres, subclinical contractures) result in spastic muscle tone, which in part compensates for paresis and allows functional movements on a simpler level of organization. Antispastic drugs should primarily be applied in complete SCI. In mobile patients they can accentuate paresis and therefore should be applied with caution.
Collapse
Affiliation(s)
- Volker Dietz
- Balgrist University Hospital, Zurich, Switzerland.
| | | |
Collapse
|
23
|
Nielsen JB, Petersen NT, Crone C, Sinkjaer T. Stretch reflex regulation in healthy subjects and patients with spasticity. Neuromodulation 2013; 8:49-57. [PMID: 22151383 DOI: 10.1111/j.1094-7159.2005.05220.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In recent years, part of the muscle resistance in spastic patients has been explained by changes in the elastic properties of muscles. However, the adaptive spinal mechanisms responsible for the exaggeration of stretch reflex activity also contribute to muscle stiffness. The available data suggest that no single spinal mechanism is responsible for the development of spasticity but that failure of different spinal inhibitory mechanisms (reciprocal IA inhibition, presynaptic inhibition, IB inhibition, recurrent inhibition) are involved in different patients depending on the site of lesion and the etiology of the spastic symptoms. A recent finding also shows no sign of exaggerated stretch reflexes in muscles voluntarily activated by the spastic patient in general. This is easily explained by the control of stretch reflex activity in healthy subjects. In healthy subjects, the stretch reflex activity is increased during voluntary muscle contraction in part because of depression of the inhibitory mechanisms that are affected in spasticity. In spastic patients, these inhibitory mechanisms are already depressed at rest and cannot be depressed further in connection with a contraction. In relation to most normal movements, antagonist muscles should remain silent and maximally relaxed. This is ensured by increasing transmission in several spinal inhibitory pathways. In spastic patients, this control is inadequate, and therefore stretch reflexes in antagonist muscles are easily evoked at the beginning of voluntary movements or in the transition from flexor to extensor muscle activity. This problem is contradicted by the fact that antispastic therapy to improve voluntary movements should be directed.
Collapse
Affiliation(s)
- Jens Bo Nielsen
- Department of Medical Physiology, University of Copenhagen, Copenhagen; Department of Clinical Neurophysiology, Copenhagen University Hospital (Rigshospitalet), Copenhagen; Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark
| | | | | | | |
Collapse
|
24
|
Mullick AA, Musampa NK, Feldman AG, Levin MF. Stretch reflex spatial threshold measure discriminates between spasticity and rigidity. Clin Neurophysiol 2012; 124:740-51. [PMID: 23146713 DOI: 10.1016/j.clinph.2012.10.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 10/02/2012] [Accepted: 10/02/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Muscle spasticity following stroke has been shown to result from limitations in the range of regulation of the tonic reflex spatial threshold (ST), i.e., the joint angle at which the stretch reflex begins to act due to descending and segmental influences on motoneurons. The purpose of this study was to determine whether spasticity due to stroke and rigidity due to parkinsonism can be discriminated based on the ST measure. METHODS Elbow muscles were stretched at different velocities in healthy, stroke (spasticity) and parkinsonism (rigidity) subjects. The elbow angle at which muscle activation began for each stretch velocity (dynamic ST) and the velocity sensitivity of the ST were measured. Dynamic ST values extrapolated to zero velocity defined the tonic ST. RESULTS Compared to healthy subjects, spasticity and rigidity were associated with a decrease in the range of central regulation of tonic STs. STs were hypersensitive in spastic muscles and either hypo- or inversely sensitive to stretch velocity in rigid muscles. CONCLUSIONS ST characteristics discriminate between neurological deficits of muscle tone. SIGNIFICANCE Results suggest that spasticity and rigidity result from deficits in descending facilitatory control combined with deficits in dynamic fusimotor or/and presynaptic control of Ia inputs to motoneurons.
Collapse
Affiliation(s)
- Aditi A Mullick
- School of Physical and Occupational Therapy, McGill University, Canada
| | | | | | | |
Collapse
|
25
|
Abstract
The term "spasticity" describes the velocity-dependent increase in tonic stretch reflexes. The symptom is commonly seen in patients with injury to the central nervous system. It is rarely isolated but, instead, part of a set of symptoms that is sometimes confusing. However, the pathophysiology of the symptom has evolved over the past three decades, and it is now considered part of a global process that includes not only spinal reflex loop modifications, but also changes in the biomechanical properties of muscle fibers. Finally, recent studies of changes in the membrane properties of motor neurons and the occurrence of plateau potential have opened new perspectives. This review aims to describe these new pathophysiological models.
Collapse
Affiliation(s)
- P Marque
- Unité 825 Inserm, Pavillon Baudot, CHU Purpan, 1 Place Baylac, 31059 Toulouse cedex 9, France.
| | | |
Collapse
|
26
|
Macefield VG. Discharge rates and discharge variability of muscle spindle afferents in human chronic spinal cord injury. Clin Neurophysiol 2012; 124:114-9. [PMID: 22727338 DOI: 10.1016/j.clinph.2012.05.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 05/21/2012] [Accepted: 05/21/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVES To test the hypothesis that the firing rates and discharge variability of human muscle spindles are not affected by spinal cord injury. METHODS Tungsten microelectrodes were inserted into muscle fascicles of the peroneal nerve in six individuals with complete paralysis of the lower limbs following spinal cord injury: 12 afferents were spontaneously active at rest and 7 were recruited during passive muscle stretch. For comparison, recordings were made from 17 spontaneously active and 9 stretch-recruited afferents in 12 intact subjects. RESULTS Firing rates for the spontaneously active muscle spindles were not significantly different between the spinal (9.8 ± 1.6 Hz) and intact (10.2 ± 1.3 Hz) subjects; the same was true for the stretch-recruited afferents - static firing rates, measured over the final 1s of a ramp-and-hold stretch, were not different between the spinal and intact groups (13.1 ± 3.1% vs 10.0 ± 2.5 Hz). There were also no differences in discharge variability between the spinal and intact subjects, either for the spontaneously active spindles (8.1 ± 2.0% vs 5.7 ± 0.9%) or for the stretch-activated spindles, calculated over the final 1s of static stretch (19.7 ± 5.6% vs 17.0 ± 1.9%). In addition, the responses to stretch imposed manually by the experimenter provided no evidence for an increase in the dynamic response to stretch in the patients. CONCLUSIONS The static stretch sensitivity of human muscle spindles is not affected by chronic spinal cord injury, suggesting that there is no difference in static (and possibly dynamic) fusimotor drive to paralyzed muscles in chronic spinal cord injury. SIGNIFICANCE This study provides no evidence for an increase in fusimotor drive as a mechanism for the spasticity associated with chronic spinal injury, though further studies using controlled stretch would be required before it can be concluded that dynamic fusimotor drive is "normal" in these patients.
Collapse
Affiliation(s)
- Vaughan G Macefield
- School of Medicine, University of Western Sydney, and Neuroscience Research Australia, Sydney, Australia.
| |
Collapse
|
27
|
Groenewegen JS, de Groot JH, Schouten AC, Maier AB, Arendzen JH, Meskers CGM. Spinal reflex properties in the long term after stroke. J Electromyogr Kinesiol 2011; 22:234-42. [PMID: 22196888 DOI: 10.1016/j.jelekin.2011.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 10/25/2011] [Accepted: 10/26/2011] [Indexed: 10/14/2022] Open
Abstract
In the long term after stroke, secondary functional deterioration may be observed while patients also get older. Possible underlying mechanisms are largely unknown. We aimed to assess neuromuscular degeneration represented by alterations in peripheral reflex loop characteristics as a function of follow-up time after stroke, controlled for age. Twenty-one stroke survivors within a small age range (62-67 years) but large variance in follow-up time after stroke (1-15 years) and both five age matched (59-62 years) and young subjects (28-36 years) participated. Short and long latency reflexes evoked by ramp and hold stretches were identified from EMG traces of the m. flexor carpi radialis. Short latency reflex onset time was not enhanced (mean difference 1.6ms compared to age matched controls) and did not relate to follow-up time after stroke (p=0.81). Young controls showed significantly lower reflex delay times (mean difference 7.2ms with respect to older subjects, p=0.009). No evidence was found for peripheral neuromuscular deterioration as a function of follow up time after stroke. Functional deterioration as a result of ageing of stroke patients that may interact with post stroke follow-up time is of further interest.
Collapse
Affiliation(s)
- Jan S Groenewegen
- Leiden University Medical Center, Department of Rehabilitation Medicine, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | | | | | | | | | | |
Collapse
|
28
|
Bernuz B, Genet F, Terrat P, Pradon D, Barbot F, Bussel B, Bensmail D. Botulinum Toxin Effect on Voluntary and Stretch Reflex–Related Torque Produced by the Quadriceps. Neurorehabil Neural Repair 2011; 26:542-7. [DOI: 10.1177/1545968311423668] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background. An understanding of the mechanical effects of botulinum toxin type A (BoNT A) on spastic and voluntary muscle contraction may help predict functional responders. Objective. To compare the effect of BoNT A on the voluntary and stretch reflex–related torques produced by activation of the rectus femoris (RF). Methods. This was a prospective open study where 15 incomplete spinal cord injury patients, impaired by a stiff-knee gait, with RF hyperactivity in mid-swing quantified by formal gait analysis (GA), were assessed before and after RF BoNT A injection (Botox, 200 UI). Main outcome measures included isokinetic peak torque (and angle at peak torque) at 0° (supine) and 90° (seated) during passive stretch (10 deg/s, 90 deg/s, and 150 deg/s), and voluntary contraction (60 deg/s) of the quadriceps. Secondary measures included impairment by Modified Tardieu Scale (MTS), peak knee flexion and spatial-temporal data by GA, activity (6-minute walking test, timed stair climbing), and discomfort (Verbal Rating Scale). Results. Voluntary torque decreased (−16%; P = .0004) but with only a trend toward a decrease in stretch reflex–related torque. The angle at spastic torque increased at 90 deg/s (+5°; P = .03), whereas MTS, peak knee flexion (+4°; P = .01), spatial-temporal data, timed stair climbing test (25%; P = .02), and discomfort were significantly improved. Conclusion. BoNT A appeared to delay the stretch-reflex angle at peak torque, whereas the voluntary torque decreased. After strict patient selection, BoNT A injection into the RF muscle led to improvements in impairment, activity, and discomfort.
Collapse
Affiliation(s)
- Benjamin Bernuz
- Versailles University, Garches, France
- Hôpital Leon Berard, Hyères, France
| | | | | | | | | | | | | |
Collapse
|
29
|
Serrao M, Ranavolo A, Andersen OK, Don R, Draicchio F, Conte C, Di Fabio R, Perrotta A, Bartolo M, Padua L, Santilli V, Sandrini G, Pierelli F. Reorganization of multi-muscle and joint withdrawal reflex during arm movements in post-stroke hemiparetic patients. Clin Neurophysiol 2011; 123:527-40. [PMID: 21824814 DOI: 10.1016/j.clinph.2011.07.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 06/29/2011] [Accepted: 07/11/2011] [Indexed: 01/12/2023]
Abstract
OBJECTIVES To investigate the behavior of the nociceptive withdrawal reflex (NWR) in the upper limb during reaching and grasping movements in post-stroke hemiparetic patients. METHODS Eight patients with chronic stroke and moderate motor deficits were included. An optoelectronic motion analysis system integrated with a surface EMG machine was used to record the kinematic and EMG data. The NWR was evoked through a painful electrical stimulation of the index finger during a movement which consisted of reaching out, picking up a cylinder, and returning it to the starting position. RESULTS We found that: (i) the NWR is extensively rearranged in hemiparetic patients, who were found to present different kinematic and EMG reflex patterns with respect to controls; (ii) patients partially lose the ability to modulate the reflex in the different movement phases; (iii) the impairment of the reflex modulation occurs at single-muscle, single-joint and multi-joint level. CONCLUSIONS Patients with chronic and mild-moderate post-stroke motor deficits lose the ability to modulate the NWR dynamically according to the movement variables at individual as well as at multi-muscle and joint levels. SIGNIFICANCE The central nervous system is unable to use the NWR substrate dynamically and flexibly in order to select the muscle synergies needed to govern the spatio-temporal interaction among joints.
Collapse
Affiliation(s)
- Mariano Serrao
- University of Rome La Sapienza, Polo Pontino, Latina, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Bensmail D, Robertson JVG, Fermanian C, Roby-Brami A. Botulinum Toxin to Treat Upper-Limb Spasticity in Hemiparetic Patients: Analysis of Function and Kinematics of Reaching Movements. Neurorehabil Neural Repair 2010; 24:273-81. [DOI: 10.1177/1545968309347682] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background. Poor control of reaching in spastic hemiparetic patients could be because of a combination of poor individuation of joints, weakness, spasticity, and/or sensory loss. Objective. To assess the effect of botulinum toxin injections (BTIs) on spasticity, upper-limb function, and kinematics of reaching movements in patients with spastic hemiparesis caused by brain injury. Methods. Fifteen patients with spastic hemiparesis and 9 healthy controls were included in this single-site, open-labeled study. The trajectories of reaching movements were recorded, and kinematic variables were computed. A clinical evaluation included the Motor Activity Log, the Action Research Arm Test (ARAT), and the Box and Block Test (BBT). Patients were assessed before (M0), 1 month after a first (M1), and 1 month after a second BTI (M4, at 4 months) in proximal and distal muscles. Results. Significant differences were found between hemiparetic patients and healthy participants for all kinematic parameters. All parameters tended to improve after BTI. This effect was significant for velocity and smoothness. Functional scores also tended to improve. Improvements were greater at M4 than at M1, although the differences were not significant. Conclusions. Kinematic parameters improved following BTI, without significant changes in clinical outcomes such as ARAT and BBT. The decrease in spasticity alone does not seem to explain the results, which may be a result of adaptation to the decrease in hypertonicity leading to increased use of the arm and possibly an increase in antagonist muscle strength.
Collapse
Affiliation(s)
- Djamel Bensmail
- Hôpital R. Poincaré, AP-HP, Garches, France, Université Paris Descartes, Paris, France,
| | | | - Christophe Fermanian
- Hôpital R. Poincaré, AP-HP, Garches, France, Hôpital Ambroise Paré, Boulogne-Billancourt, France
| | - Agnès Roby-Brami
- Hôpital R. Poincaré, AP-HP, Garches, France, Université Paris Descartes, Paris, France
| |
Collapse
|
31
|
Lewis GN, McNair PJ. Heteronymous Ia-afferent connections in the upper limb following stroke. Muscle Nerve 2010; 41:71-7. [DOI: 10.1002/mus.21444] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
32
|
Doheny EP, Lowery MM, O'Malley MJ, Fitzpatrick DP. The effect of elbow joint centre displacement on force generation and neural excitation. Med Biol Eng Comput 2009; 47:589-98. [PMID: 19399543 DOI: 10.1007/s11517-009-0488-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 04/05/2009] [Indexed: 11/27/2022]
Abstract
Joint centre displacement may occur following total elbow replacement due to aseptic loosening or surgical misalignment, and has been linked to implant failure. In this study, the effects of joint centre displacement were examined using a neuromusculoskeletal model of the elbow joint. Isometric contractions were simulated at a range of joint angles during elbow flexion and extension. Displacement of the joint centre affected the force-generating capacity about the joint, due to changes in both muscle lengths and moment arms. The magnitude and direction of the maximum joint reaction force were also altered, potentially contributing to aseptic loosening and compromising joint stability. The relationship between force generated and the level of neural excitation to the elbow flexor and extensor muscles was also affected, suggesting that altered neural control patterns could be required following joint centre displacement.
Collapse
|
33
|
Holcombe AO, Seizova-Cajic T. Illusory motion reversals from unambiguous motion with visual, proprioceptive, and tactile stimuli. Vision Res 2008; 48:1743-57. [DOI: 10.1016/j.visres.2008.05.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 05/22/2008] [Accepted: 05/24/2008] [Indexed: 10/21/2022]
|
34
|
Doheny EP, Lowery MM, FitzPatrick DP, O'Malley MJ. A neuromusculoskeletal model of the elbow joint for pre-clinical testing of total elbow replacement. ACTA ACUST UNITED AC 2007; 2007:2400-3. [PMID: 18002477 DOI: 10.1109/iembs.2007.4352811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this study, the effect of changing the geometry of the elbow joint was examined using a neuromusculoskeletal model. The position of the center of the joint was altered in order to simulate aseptic loosing or misalignment of the humeral component of a total elbow replacement. The effect of this change on model parameters, including the muscle moment arm and maximum wrist force, was examined. An isometric contraction with increasing voluntary drive was then simulated for a range of joint center positions, and the resulting joint reaction forces, and the direction of the force vectors were monitored. A change in the maximum force, measured at the wrist (17% - elbow flexion, 28% - extension), and in joint reaction force (up to 145N) was observed when the position of the joint center was altered. In addition, slight changes (up to 4.45 degrees ) in the direction of the joint reaction force vector were also observed.
Collapse
Affiliation(s)
- Emer P Doheny
- School of Electrical, Electronic and Mechanical Engineering, University College Dublin.
| | | | | | | |
Collapse
|
35
|
Grey MJ, Klinge K, Crone C, Lorentzen J, Biering-Sørensen F, Ravnborg M, Nielsen JB. Post-activation depression of Soleus stretch reflexes in healthy and spastic humans. Exp Brain Res 2007; 185:189-97. [PMID: 17932663 DOI: 10.1007/s00221-007-1142-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Accepted: 09/14/2007] [Indexed: 11/26/2022]
Affiliation(s)
- Michael J Grey
- Department of Exercise and Sport Science & Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
| | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
In clinical practice, signs of exaggerated tendon tap reflexes associated with muscle hypertonia are generally thought to be responsible for spastic movement disorders. Most antispastic treatments are, therefore, directed at the reduction of reflex activity. In recent years, however, researchers have noticed a discrepancy between spasticity as measured in the clinic and functional spastic movement disorders, which is primarily due to the different roles of reflexes in passive and active states, respectively. We now know that central motor lesions are associated with loss of supraspinal drive and defective use of afferent input with impaired behaviour of short-latency and long-latency reflexes. These changes lead to paresis and maladaptation of the movement pattern. Secondary changes in mechanical muscle fibre, collagen tissue, and tendon properties (eg, loss of sarcomeres, subclinical contractures) result in spastic muscle tone, which in part compensates for paresis and allows functional movements on a simpler level of organisation. Antispastic drugs can accentuate paresis and therefore should be applied with caution in mobile patients.
Collapse
Affiliation(s)
- Volker Dietz
- Spinal Cord Injury Centre, University of Zurich, Switzerland.
| | | |
Collapse
|
37
|
Nielsen JB, Crone C, Hultborn H. The spinal pathophysiology of spasticity--from a basic science point of view. Acta Physiol (Oxf) 2007; 189:171-80. [PMID: 17250567 DOI: 10.1111/j.1748-1716.2006.01652.x] [Citation(s) in RCA: 258] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Spasticity is a term, which was introduced to describe the velocity-sensitive increased resistance of a limb to manipulation in subjects with lesions of descending motor pathways. This distinguishes spasticity from the changes in passive muscle properties, which are often seen in these patients, but are not velocity-sensitive. Increased excitability of the stretch reflex is thus a central component of the definition of spasticity. This review describes changes in cellular properties and transmission in a number of spinal reflex pathways, which may explain the increased stretch reflex excitability. The review focuses mainly on results derived from the use of non-invasive electrophysiological techniques, which have been developed during the past 20-30 years to investigate spinal neuronal networks in human subjects, but work from animal models is also considered. The reflex hyperexcitability develops over several months following the primary lesion and involves adaptation in the spinal neuronal circuitries caudal to the lesion. In animal models, changes in cellular properties (such as 'plateau potentials') have been reported, but the relevance of these changes to human spasticity has not been clarified. In humans, numerous studies have suggested that reduction of spinal inhibitory mechanisms (in particular that of disynaptic reciprocal inhibition) is involved. The inter-subject variability of these mechanisms and the lack of objective quantitative measures of spasticity have impeded disclosure of a clear causal relationship between the alterations in the inhibitory mechanisms and the stretch reflex hyperexcitability. Techniques which make such a quantitative measure possible as well as longitudinal studies where development of reflex excitability and changes in the inhibitory mechanisms are followed over time are in great demand.
Collapse
Affiliation(s)
- J B Nielsen
- Department of Exercise and Sport Science, University of Copenhagen, Copenhagen N, Denmark.
| | | | | |
Collapse
|
38
|
Huang CY, Wang CH, Hwang IS. Characterization of the mechanical and neural components of spastic hypertonia with modified H reflex. J Electromyogr Kinesiol 2006; 16:384-91. [PMID: 16253519 DOI: 10.1016/j.jelekin.2005.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 07/19/2005] [Accepted: 07/28/2005] [Indexed: 11/25/2022] Open
Abstract
As the H reflex remains unable to assess mechanical changes intrinsic to a muscle, the aim of this study was to modify the H reflex techniques and to characterize the neural and mechanical components of muscle spasticity, relating the two components to clinical observations. Thirty-four patients featuring either a spinal-cord lesion (n=15) or stroke (n=19) and 23 neurologically normal subjects were recruited. Soleus H reflex and maximal M response (M(max)) were measured with electromyography and mechanomyography (MMG). The motoneuronal excitability was represented with the adjusted ratio of the H reflex to the M(max) (H/M(max)) and the ratio of the paired H reflexes (H(2)/H(1)). Muscle mechanical properties were characterized by the amplitude and median frequency of maximal M response recorded with MMG (MMG(Mmax)). The results showed that spastic patients exhibited a larger H/M(max), H(2)/H(1) and amplitude of MMG(Mmax) than the control group. H/M(max) and amplitude of MMG(Mmax) accounted for 55.7% of the variance in the Modified Ashworth Scale, the clinical hypertonia assessment. The amplitude of MMG(Mmax) correlated with functional impairments, as assessed with the Barthel index and Fugl-Meyer motor-assessment scale. It was concluded that spastic hypertonia involved an atypical increase in motoneuronal excitability and muscle mechanical properties, while impairment of functional performance and daily activity was attributable primarily to altered mechanical properties of a spastic muscle.
Collapse
Affiliation(s)
- Cheng-Ya Huang
- Institute of Allied Health Sciences, National Cheng Kung University, Tainan 701, Taiwan
| | | | | |
Collapse
|
39
|
Koo TKK, Mak AFT. A neuromusculoskeletal model to simulate the constant angular velocity elbow extension test of spasticity. Med Eng Phys 2006; 28:60-9. [PMID: 15908257 DOI: 10.1016/j.medengphy.2005.03.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 10/27/2004] [Accepted: 03/16/2005] [Indexed: 11/17/2022]
Abstract
We developed a neuromusculoskeletal model to simulate the stretch reflex torque induced during a constant angular velocity elbow extension by tuning a set of physiologically-based parameters. Our model extended past modeling efforts in the investigation of elbow spasticity by incorporating explicit musculotendon, muscle spindle, and motoneuron pool models in each prime elbow flexor. We analyzed the effects of changes in motoneuron pool and muscle spindle properties as well as muscle mechanical properties on the biomechanical behavior of the elbow joint observed during a constant angular velocity elbow extension. Results indicated that both motoneuron pool thresholds and gains could be substantially different among muscles. In addition, sensitivity analysis revealed that spindle static gain and motoneuron pool threshold were the most sensitive parameters that could affect the stretch reflex responses of the elbow flexors during a constant angular velocity elbow extension, followed by motoneuron pool gain, and spindle dynamic gain. It is hoped that the model will contribute to the understanding of the underlying mechanisms of spasticity after validation by more elaborate experiments, and will facilitate the future development of more specific treatment of spasticity.
Collapse
Affiliation(s)
- Terry K K Koo
- Jockey Club Rehabilitation Engineering Centre, The Hong Kong Polytechnic University, Hung Hom, Kwoloon, Hong Kong
| | | |
Collapse
|
40
|
Chen HY, Chen SC, Chen JJJ, Fu LL, Wang YL. Kinesiological and kinematical analysis for stroke subjects with asymmetrical cycling movement patterns. J Electromyogr Kinesiol 2005; 15:587-95. [PMID: 16051498 DOI: 10.1016/j.jelekin.2005.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This aim of this study is to provide quantitative analyses of asymmetrical movements between affected and unaffected limbs for hemiparetic subjects in a cycling ergometer. To acquire kinesiological and kinematical data, electromyography (EMG) of quadriceps muscles in the both legs as well as crank positions under three cycling workloads were recorded. The symmetry index (SI) was designed to measure the similarity between muscle activities recorded from affected and unaffected limbs. Using kinematical information of the crank position, the cycling unsmoothness (denoted as roughness index, RI) can be derived from the curvature of the instantaneous cycling speed. Thirteen hemiparetic subjects following a cerebrovascular accident (CVA) and eight able-bodied subjects participated in this study. With total symmetry at SI=1, the average SIs of hemiparetic subjects (0.66+/-0.18) were significantly lower (p<0.01) than those of normal subjects (0.91+/-0.08) but no significant difference found among three workloads. From the average RI, subjects with hemiparesis exhibited less smooth cycling movements compared to normal group (p<0.01). Non-parametric Friedman and Wilcoxon tests of RIs further indicated that the workload factors are significantly different only for hemiparetic group (p<0.01). No significant difference between lower workloads in RIs showed that the CVA subjects' sound side alone can execute most of the cycling load with minimal involvement of the affected side under lower workload condition. When cycling at a heavier load, however, it is essential to force the affected limb to assist in the pedaling, thus accomplishing an effective cycling exercise. By combining these two quantitative indices, we can observe the kinesiological measurement of the symmetry of EMG phasic activities from SI and the kinematical cycling smoothness in a coordinated movement from RI, which could provide a clinical guideline for cycling exercises for hemiparetic subjects.
Collapse
Affiliation(s)
- Hsin-Yung Chen
- Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan, ROC
| | | | | | | | | |
Collapse
|
41
|
Abstract
In the subacute and chronic stages of spastic paresis, stretch-sensitive (spastic) muscle overactivity emerges as a third fundamental mechanism of motor impairment, along with paresis and soft tissue contracture. Part II of this review primarily addresses the pathophysiology of the various forms of spastic overactivity. It is argued that muscle contracture is one of the factors that cause excessive responsiveness to stretch, which in turn aggravates contracture. Excessive responsiveness to stretch also impedes voluntary motor neuron recruitment, a concept termed stretch-sensitive paresis. None of the three mechanisms of impairment (paresis, contracture, and spastic overactivity) is symmetrically distributed between agonists and antagonists, which generates torque imbalance around joints and limb deformities. Thus, each may be best treated focally on an individual muscle-by-muscle basis. Intensive motor training of the less overactive muscles should disrupt the cycle of paresis-disuse-paresis, and concomitant use of aggressive stretch and focal weakening agents in their more overactive and shortened antagonists should break the cycle of overactivity-contracture-overactivity.
Collapse
Affiliation(s)
- Jean-Michel Gracies
- Department of Neurology, Mount Sinai Medical Center, One Gustave L Levy Place, Annenberg 2/Box 1052, New York, New York 10029-6574, USA.
| |
Collapse
|
42
|
Hidler JM, Schmit BD. Evidence for force-feedback inhibition in chronic stroke. IEEE Trans Neural Syst Rehabil Eng 2004; 12:166-76. [PMID: 15218931 DOI: 10.1109/tnsre.2004.828428] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The presence of force-feedback inhibition was explored during reflex responses in five subjects with known incidence of stroke. Using constant velocity stretches, it was previously found that after movement onset, active reflex force progressively increases with increasing joint angle, at a rate proportional to a fractional exponent of the speed of stretch. However, after the reflex force magnitude exceeds a particular level, it begins rolling off until maintaining a steady-state value. The magnitudes of these force plateaus are correlated with the speed of stretch, such that higher movement speeds result in higher steady-state forces. Based upon these previous studies, we hypothesized that force plateau behavior could be explained by a force-feedback inhibitory pathway. To help facilitate an understanding of this stretch reflex force roll off, a simple model representing the elbow reflex pathways was developed. This model contained two separate feedback pathways, one representing the monosynaptic stretch reflex originating from muscle spindle excitation, and another representing force-feedback inhibition arising from force sensitive receptors. It was found that force-feedback inhibition altered the stretch reflex response, resulting in a force response that followed a sigmoidal shape similar to that observed experimentally. Furthermore, simulated reflex responses were highly dependent on force-feedback gain, where predicted reflex force began plateauing at decreasing levels with increases in this force-feedback gain. The parameters from the model fits indicate that the force threshold for force-sensitive receptors is relatively high, suggesting that the inhibition may arise from muscle free nerve endings rather than Golgi tendon organs. The experimental results coupled with the simulations of elbow reflex responses suggest the possibility that after stroke, the effectiveness of force-feedback inhibition may increase to a level that has functional significance. Practical implications of these findings are discussed in relation to muscle weakness commonly associated with stroke.
Collapse
Affiliation(s)
- Joseph M Hidler
- Department of Biomedical Engineering, Catholic University, Washington, DC 20064, USA.
| | | |
Collapse
|
43
|
Hortobágyi T, Taylor JL, Petersen NT, Russell G, Gandevia SC. Changes in segmental and motor cortical output with contralateral muscle contractions and altered sensory inputs in humans. J Neurophysiol 2004; 90:2451-9. [PMID: 14534271 DOI: 10.1152/jn.01001.2002] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Motor or sensory activity in one arm can affect the other arm. We tested the hypothesis that a voluntary contraction can affect the motor pathway to the contralateral homologous muscle and investigated whether alterations in sensory input might mediate such effects. Responses to transcranial magnetic stimulation [motor-evoked potentials (MEPs)], stimulation of the descending tracts [cervicomedullary MEPs (CMEPs)], and peripheral nerve stimulation (H-reflex) were recorded from the relaxed right flexor carpi radialis (FCR), while the left arm underwent unilateral interventions (5 s duration) that included voluntary contraction, muscle contraction evoked through percutaneous stimulation, tendon vibration, and cutaneous and mixed nerve stimulation. During moderate to strong voluntary wrist flexion on the left, MEPs in the right FCR increased, CMEPs were unaffected, and the H-reflex was depressed. These results are consistent with an increase in excitability of the motor cortex, no effect on the motoneuron pool, and presynaptic inhibition of Ia afferents. In contrast, percutaneous muscle stimulation facilitated both MEPs and the H-reflex. However, muscle contraction produced by a combination of voluntary effort and electrical stimulation also reduced the contralateral H-reflex. After voluntary contractions, the H-reflex remained depressed for 35 s, but after stimulation-evoked contractions, it rapidly returned to baseline. Under both conditions, MEPs recovered rapidly. After voluntary contractions, CMEPs were also depressed for approximately 10 s despite their lack of change during contractions. Wrist tendon vibration (100 Hz) did not affect, and 20-Hz median nerve stimulation or forearm medial cutaneous nerve stimulation mildly facilitated, the H-reflex without affecting MEPs. Voluntary wrist extension, similarly to wrist flexion, increased MEPs and depressed H-reflexes. However, ankle dorsiflexion facilitated the H-reflex akin to the Jendrassik maneuver. These data suggest that a unilateral voluntary muscle contraction has contralateral effects at both cortical and segmental levels and that the segmental effects are not replicated by stimulated muscle contraction or by input from muscle spindles or non-nociceptive cutaneous afferents.
Collapse
Affiliation(s)
- Tibor Hortobágyi
- East Carolina University, Biomechanics Laboratory, Greenville, North Carolina 27858, USA
| | | | | | | | | |
Collapse
|
44
|
Pandyan AD, Cameron M, Powell J, Stott DJ, Granat MH. Contractures in the post-stroke wrist: a pilot study of its time course of development and its association with upper limb recovery. Clin Rehabil 2003; 17:88-95. [PMID: 12617383 DOI: 10.1191/0269215503cr587oa] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Contractures are common in a stroke population, yet there is little information on the time course of development. OBJECTIVES Investigate quantitatively changes associated with contracture formation in an acute stroke population. STUDY DESIGN Longitudinal study on 22 subjects who were 2-4 weeks post stroke. OUTCOME MEASURES Contractures were assessed by quantifying the resting posture, resistance to passive movement and passive range of movement. Upper limb function was measured using the Action Research Arm Test and the Nine-Hole Peg Test. Active range of extension, wrist extension strength (isometric), grip strength and neglect were also measured. REPEATED MEASURES: Following an initial assessment, repeated measurements were taken at 4, 8, 20 and 32 weeks after recruitment. RESULTS Two distinct subgroups, one capable of some functional movement (F group; 8 subjects) and another which was not (NF group; 14 subjects), were identified at the start of the study. The NF group showed changes associated with contracture formation at the wrist, i.e., reduction in the passive range of movement, an increase in resistance to passive movement and a worsening of the flexion posture. Changes were observed from the time of recruitment even though neglect improved. The F group showed improvements in upper limb function and there was no evidence to support contracture formation. CONCLUSIONS Subjects most prone to contracture formation were those who showed no signs of early functional recovery (2-4 weeks after the stroke). Changes consistent with adaptive shortening were seen from week 4 of the study period.
Collapse
Affiliation(s)
- A D Pandyan
- Department of Physiotherapy Studies, Keele University, Staffordshire, Scotland, UK.
| | | | | | | | | |
Collapse
|
45
|
Le Cavorzin P, Poudens SA, Chagneau F, Carrault G, Allain H, Rochcongar P. A comprehensive model of spastic hypertonia derived from the pendulum test of the leg. Muscle Nerve 2001; 24:1612-21. [PMID: 11745970 DOI: 10.1002/mus.1196] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We propose a comprehensive model of spastic hypertonia based on clinical neurophysiology and validated using experimental data obtained from the pendulum test of the leg in 8 healthy volunteers and 15 spastic patients. This nonlinear computational model includes mechanical parameters and a stretch reflex representation involving three neural parameters: a threshold coefficient, the gain of the stretch reflex, and a time lag accounting for the reflex loop latency and the electromechanical coupling delay. Variation of the threshold coefficient alone allowed an overall reproduction of experimental data obtained from spastic and healthy subjects. We propose that this parameter could represent the supraspinal drive, supposed to be preserved in control subjects and decreased in spastic patients. No subsequent variation of the reflex gain was required to simulate spastic traces. Adjustment of the time lag influenced the duration of the swinging phase and oscillatory phenomena possibly occurring during the pendulum test. It could be related to the involvement of either short- or long-latency stretch reflex loops. With respect to current neurophysiological concepts of motor control, this modeling approach may help in understanding mechanisms underlying spastic hypertonia, and in predicting the clinical effect of antispasticity agents.
Collapse
Affiliation(s)
- P Le Cavorzin
- Laboratoire de Pharmacologie Expérimentale et Clinique, Faculté de Médecine de Rennes, 2 Avenue du Professeur Léon Bernard, 35043 Rennes, France.
| | | | | | | | | | | |
Collapse
|
46
|
Marque P, Simonetta-Moreau M, Maupas E, Roques CF. Facilitation of transmission in heteronymous group II pathways in spastic hemiplegic patients. J Neurol Neurosurg Psychiatry 2001; 70:36-42. [PMID: 11118245 PMCID: PMC1763478 DOI: 10.1136/jnnp.70.1.36] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE A potent heteronymous group II excitation of quadriceps motor neurons has been recently demonstrated in normal subjects. The present study was undertaken to investigate whether this heteronymous group II excitation also contributes to spasticity in hemiplegic patients. METHOD The early and late facilitations of the quadriceps H reflex elicited by a conditioning volley to the common peroneal nerve at three times motor threshold, attributed to non-monosynaptic group I and group II excitations respectively, were investigated. The comparison was drawn between results obtained in 20 patients after stroke, with hemiplegia due to a vascular lesion in the territory of the middle cerebral artery, and 20 age and sex matched normal subjects. RESULTS A significant increase in the group I as well as in the group II common peroneal nerve induced facilitation of the quadriceps H reflex was seen on the spastic side of the patients (group I: 159 (SEM 10)% of control H reflex; group II: 165 (SEM 8)%) compared with their unaffected side (group I: 126 (SEM 4)%; group II: 128 (SEM 5)%) (Wilcoxon signed rank test, p<0. 01), or to the right (group I: 132 (SEM 4)%; group II: 131 (SEM 5)%) or left (group I: 130 (SEM 3)%; group II: 135 (SEM 6)%) side of controls (Mann-Whitney U test, p<0.01). No significant correlation (Spearman rank test) was found between the degree of group I and group II induced facilitations on the spastic side of the patients and the degree of clinically assessed spasticity (Ashworth scale). CONCLUSION These results reflect a facilitation of the transmission in the interneuronal pathway coactivated by group I and group II afferents, probably resulting from a change in their descending control in spastic hemiplegic patients.
Collapse
Affiliation(s)
- P Marque
- Service de Médecine Physique et Réadaptation CHU Rangueil, 1 av J. Poulhès 31403 Toulouse cx France
| | | | | | | |
Collapse
|