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Debenham MIB, Franz CK, Berger MJ. Neuromuscular consequences of spinal cord injury: New mechanistic insights and clinical considerations. Muscle Nerve 2024; 70:12-27. [PMID: 38477416 DOI: 10.1002/mus.28070] [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: 10/20/2023] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024]
Abstract
The spinal cord facilitates communication between the brain and the body, containing intrinsic systems that work with lower motor neurons (LMNs) to manage movement. Spinal cord injuries (SCIs) can lead to partial paralysis and dysfunctions in muscles below the injury. While traditionally this paralysis has been attributed to disruptions in the corticospinal tract, a growing body of work demonstrates LMN damage is a factor. Motor units, comprising the LMN and the muscle fibers with which they connect, are essential for voluntary movement. Our understanding of their changes post-SCI is still emerging, but the health of motor units is vital, especially when considering innovative SCI treatments like nerve transfer surgery. This review seeks to collate current literature on how SCI impact motor units and explore neuromuscular clinical implications and treatment avenues. SCI reduced motor unit number estimates, and surviving motor units had impaired signal transmission at the neuromuscular junction, force-generating capacity, and excitability, which have the potential to recover chronically, yet the underlaying mechanisms are unclear. Furthermore, electrodiagnostic evaluations can aid in assessing the health lower and upper motor neurons, identify suitable targets for nerve transfer surgeries, and detect patients with time sensitive injuries. Lastly, many electrodiagnostic abnormalities occur in both chronic and acute SCI, yet factors contributing to these abnormalities are unknown. Future studies are required to determine how motor units adapt following SCI and the clinical implications of these adaptations.
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Affiliation(s)
- Mathew I B Debenham
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colin K Franz
- Biologics Laboratory, Shirley Ryan AbilityLab, Chicago, Illinois, USA
- Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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2
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Shigapova RR, Mukhamedshina YO. Electrophysiology Methods for Assessing of Neurodegenerative and Post-Traumatic Processes as Applied to Translational Research. Life (Basel) 2024; 14:737. [PMID: 38929721 PMCID: PMC11205106 DOI: 10.3390/life14060737] [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: 03/27/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
Electrophysiological studies have long established themselves as reliable methods for assessing the functional state of the brain and spinal cord, the degree of neurodegeneration, and evaluating the effectiveness of therapy. In addition, they can be used to diagnose, predict functional outcomes, and test the effectiveness of therapeutic and rehabilitation programs not only in clinical settings, but also at the preclinical level. Considering the urgent need to develop potential stimulators of neuroregeneration, it seems relevant to obtain objective data when modeling neurological diseases in animals. Thus, in the context of the application of electrophysiological methods, not only the comparison of the basic characteristics of bioelectrical activity of the brain and spinal cord in humans and animals, but also their changes against the background of neurodegenerative and post-traumatic processes are of particular importance. In light of the above, this review will contribute to a better understanding of the results of electrophysiological assessment in neurodegenerative and post-traumatic processes as well as the possibility of translating these methods from model animals to humans.
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Affiliation(s)
- Rezeda Ramilovna Shigapova
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan 420008, Russia;
| | - Yana Olegovna Mukhamedshina
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, Kazan 420008, Russia;
- Department of Histology, Cytology and Embryology, Kazan State Medical University, Kazan 420012, Russia
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3
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Phipps AM, Thompson AK. Altered cutaneous reflexes to non-noxious stimuli in the triceps surae of people with chronic incomplete spinal cord injury. J Neurophysiol 2023; 129:513-523. [PMID: 36722742 PMCID: PMC9970649 DOI: 10.1152/jn.00266.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/02/2023] Open
Abstract
Following spinal cord injury (SCI) task-dependent modulation of spinal reflexes are often impaired. To gain insight into the state of the spinal interneuronal pathways following injury, we studied the amplitude modulation of triceps surae cutaneous reflexes to non-noxious stimuli during standing and early-to-mid stance phase of walking in participants with and without chronic incomplete SCI. Reflex eliciting nerve stimulation was delivered to the superficial peroneal, sural, and distal tibial nerves about the ankle. Reflexes were analyzed in the short (SLR, 50-80 ms post stimulation onset) and the medium (MLR, 80-120 ms) latency response windows. Further, the relation between cutaneous and H-reflexes was also examined during standing. In participants without injuries the soleus SLR was modulated task-dependently with nerve specificity, and the soleus and medial gastrocnemius MLRs were modulated task-dependently. In contrast, participants with SCI, no task-dependent or nerve-specific modulation of triceps cutaneous reflexes was observed. The triceps surae cutaneous and H-reflexes were not correlated in either group (r = 0.01-0.37). The presence of cutaneous reflexes but the absence of significant amplitude modulation may suggest impaired function of spinal interneuronal pathways in this population. The lack of correlation between the cutaneous and H-reflexes may suggest that interneurons that are involved in H-reflex modulation and cutaneous reflex modulation do not receive common input, or the impact of the common input is outweighed by other input. Present findings highlight the importance of examining multiple spinal reflexes to better understanding spinal interneuronal pathways that affect motor control in people after SCI.
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Affiliation(s)
- Alan M Phipps
- Department of Health Science and Research, College of Health Professions, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Aiko K Thompson
- Department of Health Science and Research, College of Health Professions, Medical University of South Carolina, Charleston, South Carolina, United States
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Controversies and Clinical Applications of Non-Invasive Transspinal Magnetic Stimulation: A Critical Review and Exploratory Trial in Hereditary Spastic Paraplegia. J Clin Med 2022; 11:jcm11164748. [PMID: 36012986 PMCID: PMC9409717 DOI: 10.3390/jcm11164748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/25/2022] [Accepted: 08/11/2022] [Indexed: 11/22/2022] Open
Abstract
Magnetic stimulation is a safe, non-invasive diagnostic tool and promising treatment strategy for neurological and psychiatric disorders. Although most studies address transcranial magnetic stimulation, transspinal magnetic stimulation (TsMS) has received recent attention since trials involving invasive spinal cord stimulation showed encouraging results for pain, spasticity, and Parkinson’s disease. While the effects of TsMS on spinal roots is well understood, its mechanism of action on the spinal cord is still controversial. Despite unclear mechanisms of action, clinical benefits of TsMS have been reported, including improvements in scales of spasticity, hyperreflexia, and bladder and bowel symptoms, and even supraspinal gait disorders such as freezing and camptocormia. In the present study, a critical review on the application of TsMS in neurology was conducted, along with an exploratory trial involving TsMS in three patients with hereditary spastic paraplegia. The goal was to understand the mechanism of action of TsMS through H-reflex measurement at the unstimulated lumbosacral level. Although limited by studies with a small sample size and a low to moderate effect size, TsMS is safe and tolerable and presents consistent clinical and neurophysiological benefits that support its use in clinical practice.
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Baltin ME, Sabirova DE, Kiseleva EI, Kamalov MI, Abdullin TI, Petrova NV, Ahmetov NF, Sachenkov OA, Baltina TV, Lavrov IA. Comparison of systemic and localized carrier-mediated delivery of methylprednisolone succinate for treatment of acute spinal cord injury. Exp Brain Res 2021; 239:627-638. [PMID: 33388811 DOI: 10.1007/s00221-020-05974-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023]
Abstract
Localized carrier-mediated administration of drugs is a promising approach to treatment of acute phase of spinal cord injury (SCI) as it allows enhanced and/or sustained drug delivery to damaged tissues along with minimization of systemic side effects. We studied the effect of locally applied self-assembling micellar formulation of methylprednisolone succinate (MPS) with trifunctional block copolymer of ethylene oxide and propylene oxide (TBC) on functional recovery and tissue drug content after SCI in rats in comparison with local and systemic administration of MPS alone. Variations in the amplitude of motor evoked responses in the hindlimb muscles induced by epidural stimulation during acute phase of SCI and restoration of movements during chronic period after local vs. systemic application of MPS were evaluated in this study. Results demonstrate that local delivery of MPS in combination with TBC facilitates spinal cord sensorimotor circuitry, increasing the excitability. In addition, this formulation was found to be more effective in improvement of locomotion after SCI compared to systemic administration. LC-MS/MS data shows that the use of TBC carrier increases the glucocorticoid content in treated spinal cord by more than four times over other modes of treatment. The results of this study demonstrate that the local treatment of acute SCI with MPS in the form of mixed micelles with TBC can provide improved therapeutic outcome by promoting drug accumulation and functional restoration of the spinal cord.
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Affiliation(s)
- Maxim E Baltin
- Rehabilitation in Movement Disorders Laboratory, Kazan Federal University, 18 Kremlyovskaya Str., Kazan, 420008, Russian Federation
| | - Diana E Sabirova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya Str., Kazan, 420008, Russian Federation
| | - Elvira I Kiseleva
- Rehabilitation in Movement Disorders Laboratory, Kazan Federal University, 18 Kremlyovskaya Str., Kazan, 420008, Russian Federation
| | - Marat I Kamalov
- Laboratory of Bioactive Polymers and Peptides, Institute of Fundamental Medicine and Biology, Kazan Federal University, 9 Parizhskoy Kommuny Str, Kazan, 420021, Russian Federation
| | - Timur I Abdullin
- Laboratory of Bioactive Polymers and Peptides, Institute of Fundamental Medicine and Biology, Kazan Federal University, 9 Parizhskoy Kommuny Str, Kazan, 420021, Russian Federation
| | - Natalia V Petrova
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, Lobachevsky Str., 2/31, Kazan, 420111, Russian Federation
| | - Nafis F Ahmetov
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya Str., Kazan, 420008, Russian Federation
| | - Oscar A Sachenkov
- Department of Theoretical Mechanics, Institute of Mathematics and Mechanics, Kazan Federal University, 18 Kremlyovskaya Str, Kazan, 420008, Russian Federation
| | - Tatiana V Baltina
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya Str., Kazan, 420008, Russian Federation.
| | - Igor A Lavrov
- Rehabilitation in Movement Disorders Laboratory, Kazan Federal University, 18 Kremlyovskaya Str., Kazan, 420008, Russian Federation
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Singh R, Wadhwani J, Meena VS, Sharma P, Kaur K, Svareen. Electrophysiological Study in Acute Spinal Cord Injury Patients: Its Correlation to Neurological Deficit and Subsequent Recovery Assessment by ASIA Score. Indian J Orthop 2020; 54:678-686. [PMID: 32850033 PMCID: PMC7429802 DOI: 10.1007/s43465-020-00108-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 04/07/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND To investigate the relationship between neurological deficit and subsequent recovery as assessed by ASIA score and findings of electrodiagnostic study in acute spinal cord injury (SCI) patients. METHODS Thirty-five patients with acute SCI presenting within 48 h of injury were clinically evaluated for the level, extent, and severity of SCI according to the ASIA standards in a tertiary-level care center. Electrodiagnostic studies of bilateral two motor (tibial and peroneal), one sensory (sural) nerves, and five muscles [iliopsoas, vastus medialis, tibialis anterior, gastrocnemius, and extensor hallucis longus (EHL)] were conducted and repeated at 3 months and 6 months. RESULTS The neurological recovery was highly significant (p < 0.001) at 6 months. The difference in mean amplitude was statistically significant (p < 0.05) for all the nerves; mean conduction velocity significant for peroneal and sural nerves, and with no significant difference in mean latency. The differences in mean recruitment of motor unit potential (MUP) and mean peak-to-peak amplitude were highly significant (p < 0.001). Statistically significant kappa agreement between neurological recovery according to ASIA score and nerve conduction velocity was found for right tibial nerve (K = 0.324); electromyography finding of recruitment of MUP with right and left tibialis anterior (k = 0.400) and left EHL (k = 0.407); peak-to-peak amplitude with right tibialis anterior (k = 0.211), right gastrocnemius (k = 0.390), and right EHL (k = 0.211). CONCLUSIONS There is a strong relationship between electrodiagnostic findings and ASIA scoring to predict neurological deficit and subsequent recovery after acute traumatic SCI. Serial neurologic evaluation by ASIA score and electrodiagnostic studies may help in designing customized rehabilitation programs for the patients according to the expected neurological recovery; and evaluating future research in the field of SCI with more scientific authenticity.
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Affiliation(s)
- Roop Singh
- Department of Orthopaedic Surgery, Paraplegia and Rehabilitation, Pt. B.D. Sharma PGIMS, 52/9-J, Medical Enclave, Rohtak, Haryana 124001 India
| | - Jitendra Wadhwani
- Department of Orthopaedic Surgery, Paraplegia and Rehabilitation, Pt. B.D. Sharma PGIMS, 52/9-J, Medical Enclave, Rohtak, Haryana 124001 India
| | - Vijay Singh Meena
- Department of Orthopaedic Surgery, Paraplegia and Rehabilitation, Pt. B.D. Sharma PGIMS, 52/9-J, Medical Enclave, Rohtak, Haryana 124001 India
| | - Pankaj Sharma
- Department of Orthopaedic Surgery, Paraplegia and Rehabilitation, Pt. B.D. Sharma PGIMS, 52/9-J, Medical Enclave, Rohtak, Haryana 124001 India
| | - Kiranpreet Kaur
- Department of Anaesthesiology and Critical Care, Pt. B.D. Sharma PGIMS, Rohtak, Haryana 124001 India
| | - Svareen
- Baba Saheb Ambedkar Medical College, Rohini, New Delhi, India
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Modulation of soleus stretch reflexes during walking in people with chronic incomplete spinal cord injury. Exp Brain Res 2019; 237:2461-2479. [PMID: 31309252 PMCID: PMC6751142 DOI: 10.1007/s00221-019-05603-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/08/2019] [Indexed: 12/28/2022]
Abstract
In people with spasticity due to chronic incomplete spinal cord injury (SCI), it has been presumed that the abnormal stretch reflex activity impairs gait. However, locomotor stretch reflexes across all phases of walking have not been investigated in people with SCI. Thus, to understand modulation of stretch reflex excitability during spastic gait, we investigated soleus stretch reflexes across the entire gait cycle in nine neurologically normal participants and nine participants with spasticity due to chronic incomplete SCI (2.5–11 year post-injury). While the participant walked on the treadmill at his/her preferred speed, unexpected ankle dorsiflexion perturbations (6° at 250°/s) were imposed every 4–6 steps. The soleus H-reflex was also examined. In participants without SCI, spinal short-latency “M1”, spinal medium latency “M2”, and long-latency “M3” were clearly modulated throughout the step cycle; the responses were largest in the mid-stance and almost completely suppressed during the stance-swing transition and swing phases. In participants with SCI, M1 and M2 were abnormally large in the mid–late-swing phase, while M3 modulation was similar to that in participants without SCI. The H-reflex was also large in the mid–late-swing phase. Elicitation of H-reflex and stretch reflexes in the late swing often triggered clonus and affected the soleus activity in the following stance. In individuals without SCI, moderate positive correlation was found between H-reflex and stretch reflex sizes across the step cycle, whereas in participants with SCI, such correlation was weak to non-existing, suggesting that H-reflex investigation would not substitute for stretch reflex investigation in individuals after SCI.
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8
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Gómez-Soriano J, Serrano-Muñoz D, Bravo-Esteban E, Avendaño-Coy J, Ávila-Martin G, Galán-Arriero I, Taylor J. Afferent stimulation inhibits abnormal cutaneous reflex activity in patients with spinal cord injury spasticity syndrome. NeuroRehabilitation 2018; 43:135-146. [PMID: 30040758 DOI: 10.3233/nre-172404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Tibialis Anterior (TA) cutaneous reflex (CR) activity evoked following cutaneous stimulation of the plantar (Pl) surface (Pl-TA CR) has demonstrated hyperreflexia and damage of inhibitory mechanisms in subjects with spinal cord injury (SCI) and spasticity. OBJECTIVES To modulate Pl-TA CR and Soleus H-reflex activity with transcutaneous electrical nerve stimulation (TENS) and vibratory stimulation of the plantar pad during rest and controlled isometric plantarflexion. METHODS Non-injured subjects (n = 11) and individuals with incomplete SCI with (n = 14) and without spasticity (n = 14) were recruited. The effect of TENS and vibratory stimuli on Pl-TA CR and soleus H-reflex activity were assessed during rest and controlled ramp-and-hold plantarflexion. RESULTS Vibration failed to inhibit H-reflex activity during rest or plantarflexoin following SCI compared to healthy subjects. In contrast, vibration-induced inhibition of Pl-TA CR was specifically detected in SCI spastic subjects during both rest and the hold phase of plantarflexion. TENS inhibited Pl-TA CR activity in the SCI spasticity group only during hold plantarflexion. CONCLUSIONS Plantar vibratory stimuli inhibited the pl-TA CR, but not the H reflex, during rest and controlled movement in SCI spastic subjects. Assessment of Pl-TA CR modulation should contribute to the development of modality-specific sensory stimuli programmes for the neurorehabilitation of SCI spasticity.
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Affiliation(s)
- Julio Gómez-Soriano
- Toledo Physiotherapy Research Group (GIFTO), Nursing and Physiotherapy School, Castilla La Mancha University, Toledo, Spain.,Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
| | - Diego Serrano-Muñoz
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
| | - Elisabeth Bravo-Esteban
- Toledo Physiotherapy Research Group (GIFTO), Nursing and Physiotherapy School, Castilla La Mancha University, Toledo, Spain
| | - Juan Avendaño-Coy
- Toledo Physiotherapy Research Group (GIFTO), Nursing and Physiotherapy School, Castilla La Mancha University, Toledo, Spain
| | - Gerardo Ávila-Martin
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
| | - Iriana Galán-Arriero
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
| | - Julian Taylor
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain.,Stoke Mandeville Spinal Research, National Spinal Injuries Centre, Buckinghamshire Healthcare Trust, NHS, Aylesbury, UK.,Harris Manchester College, Oxford University, UK
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Lee-Kubli C, Marshall AG, Malik RA, Calcutt NA. The H-Reflex as a Biomarker for Spinal Disinhibition in Painful Diabetic Neuropathy. Curr Diab Rep 2018; 18:1. [PMID: 29362940 PMCID: PMC6876556 DOI: 10.1007/s11892-018-0969-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW Neuropathic pain may arise from multiple mechanisms and locations. Efficacy of current treatments for painful diabetic neuropathy is limited to an unpredictable subset of patients, possibly reflecting diversity of pain generator mechanisms, and there is a lack of targeted treatments for individual patients. This review summarizes preclinical evidence supporting a role for spinal disinhibition in painful diabetic neuropathy, the physiology and pharmacology of rate-dependent depression (RDD) of the spinal H-reflex and the translational potential of using RDD as a biomarker of spinally mediated pain. RECENT FINDINGS Impaired RDD occurs in animal models of diabetes and was also detected in diabetic patients with painful vs painless neuropathy. RDD status can be determined using standard neurophysiological equipment. Loss of RDD may provide a clinical biomarker of spinal disinhibition, thereby enabling a personalized medicine approach to selection of current treatment options and enrichment of future clinical trial populations.
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Affiliation(s)
| | - Andrew G Marshall
- Faculty of Medical and Human Sciences, Institute of Cardiovascular Sciences, University of Manchester and National Institute for Healthy Research/Wellcome Trust Clinical Research Facility, Manchester, UK
- Department of Clinical Neurophysiology, Salford Royal Hospital, National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Rayaz A Malik
- Faculty of Medical and Human Sciences, Institute of Cardiovascular Sciences, University of Manchester and National Institute for Healthy Research/Wellcome Trust Clinical Research Facility, Manchester, UK
- Department of Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA.
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Zheng C, Zhu Y, Lu F, Zhu D, Yang S, Ma X, Xia X, Weber R, Jiang J. Changes in the soleus H-reflex test and correlations between its results and dynamic magnetic resonance imaging abnormalities in patients with Hirayama disease. Clin Neurophysiol 2017; 128:2375-2381. [PMID: 29096208 DOI: 10.1016/j.clinph.2017.09.103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 07/28/2017] [Accepted: 09/10/2017] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To investigate changes in soleus H-reflex tests in patients with Hirayama disease (HD) and to analyse correlations between these changes and forward-shifting of the cervical cord during neck flexion. METHODS The amplitude of the soleus H-reflex with and without vibration on the Achilles tendon was recorded bilaterally in 81 HD patients and 34 controls to measure both the vibratory inhibition index (VII) and the Hmax/Mmax ratio. The maximum forward-shifting degree of cervical cord during neck flexion was measured using dynamic magnetic resonance imaging in all HD patients. RESULTS Significantly higher VII was recorded in 6/81 (7.4%) HD patients, along with abnormal Hmax/Mmax ratios in 5 of 6 cases. Compared to illness duration (r = 0.29-0.36, p < 0.05), the maximum forward-shifting degree of the cervical cord was more strongly correlated with both VII and the Hmax/Mmax ratio (r = 0.51-0.81, p < 0.05). CONCLUSIONS HD patients may develop cervical spinal cord injury with disease progression, and these lesions may be more likely to occur in cases with relatively severe cervical-flexion structural abnormalities even during early stages. SIGNIFICANCE More caution should be taken when managing HD patients with severe cervical-flexion abnormalities because of the possible early occurrence of upper motor neuron lesions.
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Affiliation(s)
- Chaojun Zheng
- Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Yu Zhu
- Department of Physical Medicine and Rehabilitation, Upstate Medical University, State University of New York at Syracuse, Syracuse, NY 10212, USA
| | - Feizhou Lu
- Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai 200040, China; Department of Orthopedics, The Fifth People's Hospital, Fudan University, Shanghai 200240, China
| | - Dongqing Zhu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Shuo Yang
- Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Xiaosheng Ma
- Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Xinlei Xia
- Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Robert Weber
- Department of Physical Medicine and Rehabilitation, Upstate Medical University, State University of New York at Syracuse, Syracuse, NY 10212, USA
| | - Jianyuan Jiang
- Department of Orthopedics, Huashan Hospital, Fudan University, Shanghai 200040, China.
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Lewis MJ, Howard JF, Olby NJ. The Relationship between Trans-Lesional Conduction, Motor Neuron Pool Excitability, and Motor Function in Dogs with Incomplete Recovery from Severe Spinal Cord Injury. J Neurotrauma 2017; 34:2994-3002. [PMID: 28462632 DOI: 10.1089/neu.2017.5012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Spontaneous, acute, complete thoracolumbar spinal cord injury (TL-SCI) in dogs frequently results in permanent deficits modeling chronic paralysis in people. Recovery of walking without recovery of sensation has been interpreted in dogs as reflexive spinal walking. To evaluate this assumption, this study characterized the electrophysiological status of motor and sensory long tracts and local reflex circuitry in dogs with absent recovery of sensation after acute TL-SCI and correlated findings to gait scores. Twenty dogs with permanent deficits after acute, clinically complete TL-SCI and 6 normal dogs were prospectively enrolled. Transcranial magnetic motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), H-reflex, and F-waves were evaluated. Gait was quantified using an ordinal, open field scale (OFS) and treadmill-based stepping and coordination scores (SS, RI). MEP latency and H-reflex variables were compared between cases and controls. Associations between presence of MEPs, SSEPs, F-waves or H-reflex variables, and gait scores were determined. Pelvic limb MEPs were detected in 4 cases; no case had trans-lesional sensory conduction. Latency was longer and conduction velocity slower in cases than controls (pa = 0.0064, 0.0023, respectively). Three of 4 cases with pelvic limb MEPs were ambulatory, and gait scores (OFS, SS, RI) were each associated with presence of trans-lesional conduction (pa = 0.006, 0.006, 0.003, respectively). H threshold in cases (mean, 3.2mA ±2.5) was lower than controls (mean, 7.9mA ±3.1; pa = 0.011) and was inversely associated with treadmill-based scores, SS, and RI (pa = 0.042, 0.043, respectively). The association between pelvic limb MEPs and gait scores supports the importance of descending influence on regaining walking after severe TL-SCI in dogs rather than just activation of spinal walking. The inverse association between H-reflex threshold and gait scores implies that increases in motor neuron pool excitability might also contribute to motor recovery.
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Affiliation(s)
- Melissa J Lewis
- 1 Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University , Raleigh, North Carolina.,2 Comparative Medicine Institute, North Carolina State University , Raleigh, North Carolina
| | - James F Howard
- 3 Department of Neurology, School of Medicine, University of North Carolina , Chapel Hill, North Carolina
| | - Natasha J Olby
- 1 Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University , Raleigh, North Carolina.,2 Comparative Medicine Institute, North Carolina State University , Raleigh, North Carolina
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Mayo M, DeForest BA, Castellanos M, Thomas CK. Characterization of Involuntary Contractions after Spinal Cord Injury Reveals Associations between Physiological and Self-Reported Measures of Spasticity. Front Integr Neurosci 2017; 11:2. [PMID: 28232792 PMCID: PMC5299008 DOI: 10.3389/fnint.2017.00002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 01/16/2017] [Indexed: 12/02/2022] Open
Abstract
Correlations between physiological, clinical and self-reported assessments of spasticity are often weak. Our aims were to quantify functional, self-reported and physiological indices of spasticity in individuals with thoracic spinal cord injury (SCI; 3 women, 9 men; 19–52 years), and to compare the strength and direction of associations between these measures. The functional measure we introduced involved recording involuntary electromyographic activity during a transfer from wheelchair to bed which is a daily task necessary for function. High soleus (SL) and tibialis anterior (TA) F-wave/M-wave area ratios were the only physiological measures that distinguished injured participants from the uninjured (6 women, 13 men, 19–67 years). Hyporeflexia (decreased SL H/M ratio) was unexpectedly present in older participants after injury. During transfers, the duration and intensity of involuntary electromyographic activity varied across muscles and participants, but coactivity was common. Wide inter-participant variability was seen for self-reported spasm frequency, severity, pain and interference with function, as well as tone (resistance to imposed joint movement). Our recordings of involuntary electromyographic activity during transfers provided evidence of significant associations between physiological and self-reported measures of spasticity. Reduced low frequency H-reflex depression in SL and high F-wave/M-wave area ratios in TA, physiological indicators of reduced inhibition and greater motoneuron excitability, respectively, were associated with long duration SL and biceps femoris (BF) electromyographic activity during transfers. In turn, participants reported high spasm frequency when transfers involved short duration TA EMG, decreased co-activation between SL and TA, as well as between rectus femoris (RF) vs. BF. Thus, the duration of muscle activity and/or the time of agonist-antagonist muscle coactivity may be used by injured individuals to count spasms. Intense electromyographic activity and high tone related closely (possibly from joint stabilization), while intense electromyographic activity in one muscle of an agonist-antagonist pair (especially in TA vs. SL, and RF vs. BF) likely induced joint movement and was associated with severe spasms. These data support the idea that individuals with SCI describe their spasticity by both the duration and intensity of involuntary agonist-antagonist muscle coactivity during everyday tasks.
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Affiliation(s)
- Meagan Mayo
- The Miami Project to Cure Paralysis, University of Miami Miami, FL, USA
| | | | | | - Christine K Thomas
- The Miami Project to Cure Paralysis, University of MiamiMiami, FL, USA; Department of Neurological Surgery, University of MiamiMiami, FL, USA; Department of Physiology and Biophysics, University of MiamiMiami, FL, USA
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Training-Specific Neural Plasticity in Spinal Reflexes after Incomplete Spinal Cord Injury. Neural Plast 2016; 2016:6718763. [PMID: 27725887 PMCID: PMC5048024 DOI: 10.1155/2016/6718763] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/27/2016] [Accepted: 08/03/2016] [Indexed: 11/17/2022] Open
Abstract
The neural plasticity of spinal reflexes after two contrasting forms of walking training was determined in individuals with chronic, motor-incomplete spinal cord injury (SCI). Endurance Training involved treadmill walking for as long as possible, and Precision Training involved walking precisely over obstacles and onto targets overground. Twenty participants started either Endurance or Precision Training for 2 months and then crossed over after a 2-month rest period to the other form of training for 2 months. Measures were taken before and after each phase of training and rest. The cutaneomuscular reflex (CMR) during walking was evoked in the soleus (SOL) and tibialis anterior muscles by stimulating the posterior tibial nerve at the ankle. Clonus was estimated from the EMG power in the SOL during unperturbed walking. The inhibitory component of the SOL CMR was enhanced after Endurance but not Precision Training. Clonus did not change after either form of training. Participants with lower reflex excitability tended to be better walkers (i.e., faster walking speeds) prior to training, and the reduction in clonus was significantly correlated with the improvement in walking speed and distance. Thus, reflex excitability responded in a training-specific way, with the reduction in reflex excitability related to improvements in walking function. Trial registration number is NCT01765153.
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Andrews JC, Stein RB, Jones KE, Hedden DM, Mahood JK, Moreau MJ, Huang EM, Roy FD. Intraoperative spinal cord monitoring using low intensity transcranial stimulation to remove post-activation depression of the H-reflex. Clin Neurophysiol 2016; 127:3378-84. [PMID: 27590206 DOI: 10.1016/j.clinph.2016.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/20/2016] [Accepted: 08/10/2016] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To investigate whether low intensity transcranial electrical stimulation (TES) can be used to condition post-activation depression of the H-reflex and simultaneously monitor the integrity of spinal motor pathways during spinal deformity correction surgery. METHODS In 20 pediatric patients undergoing corrective surgery for spinal deformity, post-activation depression of the medial gastrocnemius H-reflex was initiated by delivering two pulses 50-125ms apart, and the second H-reflex was conditioned by TES. RESULTS Low intensity TES caused no visible shoulder or trunk movements during 19/20 procedures and the stimulation reduced post-activation depression of the H-reflex. The interaction was present in 20/20 patients and did not diminish throughout the surgical period. In one case, the conditioning effect was lost within minutes of the disappearance of the lower extremity motor evoked potentials. CONCLUSION Post-activation depression was used to detect the arrival of a subthreshold motor evoked potential at the lower motor neuron. The interaction produced minimal movement within the surgical field and remained stable throughout the surgical period. SIGNIFICANCE This is the first use of post-activation depression during intraoperative neurophysiological monitoring to directly assess the integrity of descending spinal motor pathways.
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Affiliation(s)
- Jennifer C Andrews
- Department of Physiology, University of Alberta, Edmonton, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Richard B Stein
- Department of Physiology, University of Alberta, Edmonton, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Kelvin E Jones
- Department of Physical Education and Recreation, University of Alberta, Edmonton, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | | | - James K Mahood
- Division of Orthopaedic Surgery, University of Alberta, Edmonton, Canada
| | - Marc J Moreau
- Division of Orthopaedic Surgery, University of Alberta, Edmonton, Canada
| | - Eric M Huang
- Division of Orthopaedic Surgery, University of Alberta, Edmonton, Canada
| | - François D Roy
- Department of Surgery, University of Alberta, Edmonton, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada.
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15
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Kumru H, Albu S, Valls-Sole J, Murillo N, Tormos JM, Vidal J. Influence of spinal cord lesion level and severity on H-reflex excitability and recovery curve. Muscle Nerve 2015; 52:616-22. [DOI: 10.1002/mus.24579] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 01/02/2015] [Accepted: 01/12/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Hatice Kumru
- Institut Guttmann; Institut Universitari de Neurorehabilitació adscrit a la UAB; 08916 Badalona and Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona Barcelona Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès); Spain
- Fundació Institut d‘Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona, Barcelona Spain
| | - Sergiu Albu
- Texas A&M University; College Station, Texas 77843-4235 USA
| | | | - Narda Murillo
- Institut Guttmann; Institut Universitari de Neurorehabilitació adscrit a la UAB; 08916 Badalona and Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona Barcelona Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès); Spain
- Fundació Institut d‘Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona, Barcelona Spain
| | - Josep Maria Tormos
- Institut Guttmann; Institut Universitari de Neurorehabilitació adscrit a la UAB; 08916 Badalona and Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona Barcelona Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès); Spain
- Fundació Institut d‘Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona, Barcelona Spain
| | - Joan Vidal
- Institut Guttmann; Institut Universitari de Neurorehabilitació adscrit a la UAB; 08916 Badalona and Fundació Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona Barcelona Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès); Spain
- Fundació Institut d‘Investigació en Ciències de la Salut Germans Trias i Pujol; Badalona, Barcelona Spain
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Bandaru SP, Liu S, Waxman SG, Tan AM. Dendritic spine dysgenesis contributes to hyperreflexia after spinal cord injury. J Neurophysiol 2014; 113:1598-615. [PMID: 25505110 DOI: 10.1152/jn.00566.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Hyperreflexia and spasticity are chronic complications in spinal cord injury (SCI), with limited options for safe and effective treatment. A central mechanism in spasticity is hyperexcitability of the spinal stretch reflex, which presents symptomatically as a velocity-dependent increase in tonic stretch reflexes and exaggerated tendon jerks. In this study we tested the hypothesis that dendritic spine remodeling within motor reflex pathways in the spinal cord contributes to H-reflex dysfunction indicative of spasticity after contusion SCI. Six weeks after SCI in adult Sprague-Dawley rats, we observed changes in dendritic spine morphology on α-motor neurons below the level of injury, including increased density, altered spine shape, and redistribution along dendritic branches. These abnormal spine morphologies accompanied the loss of H-reflex rate-dependent depression (RDD) and increased ratio of H-reflex to M-wave responses (H/M ratio). Above the level of injury, spine density decreased compared with below-injury spine profiles and spine distributions were similar to those for uninjured controls. As expected, there was no H-reflex hyperexcitability above the level of injury in forelimb H-reflex testing. Treatment with NSC23766, a Rac1-specific inhibitor, decreased the presence of abnormal dendritic spine profiles below the level of injury, restored RDD of the H-reflex, and decreased H/M ratios in SCI animals. These findings provide evidence for a novel mechanistic relationship between abnormal dendritic spine remodeling in the spinal cord motor system and reflex dysfunction in SCI.
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Affiliation(s)
- Samira P Bandaru
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Shujun Liu
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
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17
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Effects of Vibration on Spasticity in Individuals with Spinal Cord Injury. Am J Phys Med Rehabil 2014; 93:995-1007. [DOI: 10.1097/phm.0000000000000098] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Iafarova GG, Tumakaev RF, Hazieva AR, Baltina TV. Effect of local hypothermia on H- and M-responses after spinal cord contusion in dogs. Biophysics (Nagoya-shi) 2014. [DOI: 10.1134/s0006350914050303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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19
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Sayenko DG, Angeli C, Harkema SJ, Edgerton VR, Gerasimenko YP. Neuromodulation of evoked muscle potentials induced by epidural spinal-cord stimulation in paralyzed individuals. J Neurophysiol 2013; 111:1088-99. [PMID: 24335213 DOI: 10.1152/jn.00489.2013] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Epidural stimulation (ES) of the lumbosacral spinal cord has been used to facilitate standing and voluntary movement after clinically motor-complete spinal-cord injury. It seems of importance to examine how the epidurally evoked potentials are modulated in the spinal circuitry and projected to various motor pools. We hypothesized that chronically implanted electrode arrays over the lumbosacral spinal cord can be used to assess functionally spinal circuitry linked to specific motor pools. The purpose of this study was to investigate the functional and topographic organization of compound evoked potentials induced by the stimulation. Three individuals with complete motor paralysis of the lower limbs participated in the study. The evoked potentials to epidural spinal stimulation were investigated after surgery in a supine position and in one participant, during both supine and standing, with body weight load of 60%. The stimulation was delivered with intensity from 0.5 to 10 V at a frequency of 2 Hz. Recruitment curves of evoked potentials in knee and ankle muscles were collected at three localized and two wide-field stimulation configurations. Epidural electrical stimulation of rostral and caudal areas of lumbar spinal cord resulted in a selective topographical recruitment of proximal and distal leg muscles, as revealed by both magnitude and thresholds of the evoked potentials. ES activated both afferent and efferent pathways. The components of neural pathways that can mediate motor-evoked potentials were highly dependent on the stimulation parameters and sensory conditions, suggesting a weight-bearing-induced reorganization of the spinal circuitries.
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Affiliation(s)
- Dimitry G Sayenko
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
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20
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The use of poly(N-[2-hydroxypropyl]-methacrylamide) hydrogel to repair a T10 spinal cord hemisection in rat: a behavioural, electrophysiological and anatomical examination. ASN Neuro 2013; 5:149-66. [PMID: 23614684 PMCID: PMC3667642 DOI: 10.1042/an20120082] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
There have been considerable interests in attempting to reverse the deficit because of an SCI (spinal cord injury) by restoring neural pathways through the lesion and by rebuilding the tissue network. In order to provide an appropriate micro-environment for regrowing axotomized neurons and proliferating and migrating cells, we have implanted a small block of pHPMA [poly N-(2-hydroxypropyl)-methacrylamide] hydrogel into the hemisected T10 rat spinal cord. Locomotor activity was evaluated once a week during 14 weeks with the BBB rating scale in an open field. At the 14th week after SCI, the reflexivity of the sub-lesional region was measured. We also monitored the ventilatory frequency during an electrically induced muscle fatigue known to elicit the muscle metaboreflex and increase the respiratory rate. Spinal cords were then collected, fixed and stained with anti-ED-1 and anti-NF-H antibodies and FluoroMyelin. We show in this study that hydrogel-implanted animals exhibit: (i) an improved locomotor BBB score, (ii) an improved breathing adjustment to electrically evoked isometric contractions and (iii) an H-reflex recovery close to control animals. Qualitative histological results put in evidence higher accumulation of ED-1 positive cells (macrophages/monocytes) at the lesion border, a large number of NF-H positive axons penetrating the applied matrix, and myelin preservation both rostrally and caudally to the lesion. Our data confirm that pHPMA hydrogel is a potent biomaterial that can be used for improving neuromuscular adaptive mechanisms and H-reflex responses after SCI.
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21
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Bianco J, Gueye Y, Marqueste T, Alluin O, Risso JJ, Garcia S, Lavault MN, Khrestchatisky M, Feron F, Decherchi P. Vitamin D₃ improves respiratory adjustment to fatigue and H-reflex responses in paraplegic adult rats. Neuroscience 2011; 188:182-92. [PMID: 21571043 DOI: 10.1016/j.neuroscience.2011.04.066] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 04/11/2011] [Accepted: 04/29/2011] [Indexed: 11/29/2022]
Abstract
We previously demonstrated that vitamin D₂ (ergocalciferol) triggers axon regeneration in a rat model of peripheral nerve transection. In order to confirm the regenerative potential of this neuroactive steroid, we performed a study in which vitamin D₃ (cholecalciferol) was delivered at various doses to paralytic rats. After spinal cord compression at the T10 level, rats were given orally either vehicle or vitamin D₃ at the dose of 50 IU/kg/day or 200 IU/kg/day. Three months later, M and H-waves were recorded from rat Tibialis anterior muscle in order to quantify the maximal H-reflex (H(max)) amplitude. We also monitored the ventilatory frequency during an electrically induced muscle fatigue known to elicit the muscle metaboreflex and an increase in respiratory rate. Spinal cords were then collected, fixed and immunostained with an anti-neurofilament antibody. We show here that vitamin D-treated animals display an increased number of axons within the lesion site. In addition, rats supplemented with vitamin D₃ at the dose of 200 IU/kg/day exhibit (i) an improved breathing when hindlimb was electrically stimulated; (ii) an H-reflex depression similar to control animals and (iii) an increased number of axons within the lesion and in the distal area. Our data confirm that vitamin D is a potent molecule that can be used for improving neuromuscular adaptive mechanisms and H-reflex responses.
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Affiliation(s)
- J Bianco
- Institut des Sciences du Mouvement, Etienne-Jules MAREY, UMR CNRS 6233, Université de la Méditerranée (Aix-Marseille II,Aix-Marseille Université), Parc Scientifique et Technologique de Luminy, Faculté des Sciences du Sport de Marseille, 13288 Marseille Cedex 09, France
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22
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Acute effects of whole body vibration during passive standing on soleus H-reflex in subjects with and without spinal cord injury. Neurosci Lett 2010; 482:66-70. [DOI: 10.1016/j.neulet.2010.07.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 06/15/2010] [Accepted: 07/06/2010] [Indexed: 11/18/2022]
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Ollivier-Lanvin K, Keeler BE, Siegfried R, Houlé JD, Lemay MA. Proprioceptive neuropathy affects normalization of the H-reflex by exercise after spinal cord injury. Exp Neurol 2009; 221:198-205. [PMID: 19913536 DOI: 10.1016/j.expneurol.2009.10.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 10/29/2009] [Accepted: 10/31/2009] [Indexed: 11/25/2022]
Abstract
The H-reflex habituates at relatively low frequency (10 Hz) stimulation in the intact spinal cord, but loss of descending inhibition resulting from spinal cord transection reduces this habituation. There is a return towards a normal pattern of low-frequency habituation in the reflex activity with cycling exercise of the affected hind limbs. This implies that repetitive passive stretching of the muscles in spinalized animals and the accompanying stimulation of large (Group I and II) proprioceptive fibers has modulatory effects on spinal cord reflexes after injury. To test this hypothesis, we induced pyridoxine neurotoxicity that preferentially affects large dorsal root ganglia neurons in intact and spinalized rats. Pyridoxine or saline injections were given twice daily (IP) for 6 weeks and half of the spinalized animals were subjected to cycling exercise during that period. After 6 weeks, the tibial nerve was stimulated electrically and recordings of M and H waves were made from interosseous muscles of the hind paw. Results show that pyridoxine treatment completely eliminated the H-reflex in spinal intact animals. In contrast, transection paired with pyridoxine treatment resulted in a reduction of the frequency-dependent habituation of the H-reflex that was not affected by exercise. These results indicate that normal Group I and II afferent input is critical to achieve exercise-based reversal of hyper-reflexia of the H-reflex after spinal cord injury.
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Affiliation(s)
- Karen Ollivier-Lanvin
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
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Thompson AK, Estabrooks KL, Chong S, Stein RB. Spinal reflexes in ankle flexor and extensor muscles after chronic central nervous system lesions and functional electrical stimulation. Neurorehabil Neural Repair 2008; 23:133-42. [PMID: 19023139 DOI: 10.1177/1545968308321067] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Spinal reciprocal inhibitory and excitatory reflexes of ankle extensor and flexor muscles were investigated in ambulatory participants with chronic central nervous system (CNS) lesions causing foot drop as a function of time after lesion and stimulator use. METHODS Thirty-nine participants with progressive (eg, secondary progressive MS) and 36 with generally nonprogressive (eg, stroke) conditions were studied. The tibialis anterior (TA) and soleus maximum H-reflex/M-wave (Hmax/Mmax) ratios and maximum voluntary contractions (MVC) were measured and compared with those in age-matched control participants. Reciprocal inhibition was measured as a depression of the ongoing electromyographic (EMG) activity produced by antagonist muscle-nerve stimulation. RESULTS Participants with CNS lesions had significantly higher soleus Hmax/Mmax ratios than control participants, and reduced voluntary modulation of the reflexes occurred in both muscles. Reciprocal inhibition of soleus from common peroneal (CP) nerve stimulation was not significantly different from controls in either group. Inhibition of the TA by tibial nerve stimulation decreased and was eventually replaced by excitation in participants with nonprogressive disorders. No significant change occurred in progressive disorders. Use of a foot drop stimulator increased the TA, but not the soleus MVC overall. H-reflexes only showed small changes. Reciprocal inhibition of the TA increased considerably, while that of the soleus muscle decreased toward control values. CONCLUSIONS Disorders that produce foot drop also produce reflex changes, some of which only develop over a period of years or even decades. Regular use of a foot drop stimulator strengthens voluntary pathways and changes some reflexes toward control values. Thus, stimulators may provide multiple benefits to people with foot drop.
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Affiliation(s)
- Aiko K Thompson
- Center for Neuroscience, University of Alberta, Edmonton, Canada
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Phadke CP, Wu SS, Thompson FJ, Behrman AL. Comparison of Soleus H-Reflex Modulation After Incomplete Spinal Cord Injury in 2 Walking Environments: Treadmill With Body Weight Support and Overground. Arch Phys Med Rehabil 2007; 88:1606-13. [DOI: 10.1016/j.apmr.2007.07.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2007] [Revised: 06/28/2007] [Accepted: 07/17/2007] [Indexed: 11/28/2022]
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Influence of posture and stimulus parameters on post-activation depression of the soleus H-reflex in individuals with chronic spinal cord injury. Neurosci Lett 2006; 410:37-41. [PMID: 17046161 DOI: 10.1016/j.neulet.2006.09.058] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 09/22/2006] [Accepted: 09/24/2006] [Indexed: 10/24/2022]
Abstract
In non-disabled (ND) individuals, reflexes are modulated by influences related to physiologic state (e.g., posture, joint position, load) and activation history. Repeated activation of the H-reflex results in post-activation depression (PAD) of the response amplitude. The modulation associated with physiologic state and activation history is suppressed or abolished in individuals with spinal cord injury (SCI). While posture is known to affect H-reflex amplitude and PAD in non-disabled individuals, the effect of posture on PAD in SCI individuals is not known. Further, while the amount of PAD is also known to be influenced by the stimulus rate and by the amplitude of the evoked reflex, the interaction of posture with stimulus parameters has not been previously investigated in either group. We investigated differences in PAD of the soleus H-reflex between SCI subjects and ND subjects during sitting versus supported standing. Subjects were tested using paired conditioning-test stimulus pulses of 2.5s and 5s interpulse intervals (ISI) and with stimulus intensity adjusted to evoke reflex responses of 20% and 40% of the maximum motor response. We found standing posture to be associated with significantly less PAD in SCI subjects compared to ND subjects. In both groups, shorter ISIs and smaller reflex amplitudes were associated with greater PAD of the H-reflex. These results indicate that postural influences on post-activation modulation, while present, are impaired in individuals with chronic incomplete SCI.
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27
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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: 25] [Impact Index Per Article: 1.4] [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.
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Affiliation(s)
- Cheng-Ya Huang
- Institute of Allied Health Sciences, National Cheng Kung University, Tainan 701, Taiwan
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28
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Lavrov I, Gerasimenko YP, Ichiyama RM, Courtine G, Zhong H, Roy RR, Edgerton VR. Plasticity of spinal cord reflexes after a complete transection in adult rats: relationship to stepping ability. J Neurophysiol 2006; 96:1699-710. [PMID: 16823028 DOI: 10.1152/jn.00325.2006] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Changes in epidurally induced (S1) spinal cord reflexes were studied as a function of the level of restoration of stepping ability after spinal cord transection (ST). Three types of responses were observed. The early response (ER) had a latency of 2.5 to 3 ms and resulted from direct stimulation of motor fibers or motoneurons. The middle response (MR) had a latency of 5 to 7 ms and was monosynaptic. The late response (LR) had a latency of 9 to 11 ms and was polysynaptic. After a complete midthoracic ST, the LR was abolished, whereas the MR was facilitated and progressively increased. The LR reappeared about 3 wk after ST and increased during the following weeks. Restoration of stepping induced by epidural stimulation at 40 Hz coincided with changes in the LR. During the first 2 wk post-ST, rats were unable to step and electrophysiological assessment failed to show any LR. Three weeks post-ST, epidural stimulation resulted in a few steps and these coincided with reappearance of the LR. The ability of rats to step progressively improved from wk 3 to wk 6 post-ST. There was a continuously improved modulation of rhythmic EMG bursts that was correlated with restoration of the LR. These results suggest that restoration of polysynaptic spinal cord reflexes after complete ST coincides with restoration of stepping function when facilitated by epidural stimulation. Combined, these findings support the view that restoration of polysynaptic spinal cord reflexes induced epidurally may provide a measure of functional restoration of spinal cord locomotor networks after ST.
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Affiliation(s)
- Igor Lavrov
- Department of Physiological Science, University of California, Los Angeles, CA 90095-1527, USA
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Phadke CP, Wu SS, Thompson FJ, Behrman AL. Soleus H-reflex modulation in response to change in percentage of leg loading in standing after incomplete spinal cord injury. Neurosci Lett 2006; 403:6-10. [PMID: 16723187 DOI: 10.1016/j.neulet.2006.04.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2005] [Revised: 04/08/2006] [Accepted: 04/14/2006] [Indexed: 11/19/2022]
Abstract
Body weight support (BWS) is frequently used to retrain standing and walking in persons post spinal cord injury (SCI), but the effects of leg unloading using BWS on H-reflex excitability in this population are unknown. The purpose of the study was to assess the effect of two different loading conditions on soleus H-reflex while standing in persons with motor incomplete SCI (i-SCI) and non-injured persons. Eight persons with motor i-SCI (mean age 50.25 years) and five non-injured persons (mean age 48.6 years) participated in the study. Specific control of the loading conditions was achieved using a BWS system. To compare reflex modulation at 40% versus 0% BWS, soleus H-reflexes were evoked during standing and normalized to the maximum M wave amplitude. These studies revealed that (1) H-reflex excitability is significantly greater after SCI and is exhibited even during quiet standing; and (2) no significant modulation in reflex excitability was observed by change in loading conditions in either the non-injured or the i-SCI subjects. These findings suggest that non-injured persons and persons with i-SCI respond similarly to bilateral limb unloading during standing with no change in H-reflex amplitude. Our results suggest that BWS of up to 40% does not produce detectable changes in the excitability of the soleus H-reflex in persons with i-SCI.
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Affiliation(s)
- Chetan P Phadke
- Department of Physical Therapy, University of Florida, P.O. Box 100154, Gainesville, USA
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Nakazawa K, Kawashima N, Akai M. Enhanced stretch reflex excitability of the soleus muscle in persons with incomplete rather than complete chronic spinal cord injury. Arch Phys Med Rehabil 2006; 87:71-5. [PMID: 16401441 DOI: 10.1016/j.apmr.2005.08.122] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 08/09/2005] [Accepted: 08/24/2005] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To compare excitabilities of spinal stretch reflex among clinically complete spinal cord injury (SCI), incomplete SCI, elderly healthy, and young healthy subjects. DESIGN Case comparison. SETTING Research laboratory. PARTICIPANTS Volunteer sample of 12 complete SCI, 10 incomplete SCI, 10 elderly, and 11 young subjects. INTERVENTION Mechanically induced stretch reflex, H-reflex, and M response in electromyographic activity of the soleus muscle were recorded in all subjects. MAIN OUTCOME MEASURES Absolute peak-to-peak stretch reflex amplitude and maximum H-reflex (Hmax), and those values relative to the maximum M response (Mmax) amplitude (relative peak-to-peak stretch reflex amplitude) and H/M ratio. RESULTS Both the absolute and relative peak-to-peak stretch reflex amplitudes showed the greatest values in incomplete SCI among the 4 groups. Although absolute and relative peak-to-peak stretch reflex amplitudes of the incomplete SCI group were greater than those of the complete SCI group, the H/M ratios of both groups were comparable, and were greater than those of the younger and elderly groups. CONCLUSIONS The results suggest that the greater absolute and relative peak-to-peak stretch reflex amplitudes of incomplete SCI were mostly due to the greater maximum motor potential (Mmax), while the elevated spinal motoneuronal excitability shown by the increased H/M ratio was maintained in the chronic stage after both complete and incomplete SCIs.
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Affiliation(s)
- Kimitaka Nakazawa
- Department of Movement Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.
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31
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Butler JE, Godfrey S, Thomas CK. Depression of involuntary activity in muscles paralyzed by spinal cord injury. Muscle Nerve 2006; 33:637-44. [PMID: 16421880 DOI: 10.1002/mus.20500] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Involuntary muscle contractions are common after spinal cord injury (SCI). Increased sensitivity to Ia muscle afferent input may contribute to the development of these spasms. Since tendon vibration results in a period of postactivation depression of the Ia synapse, we sought to determine whether Achilles tendon vibration (80 HZ for 2 s) altered involuntary contractions evoked by superficial peroneal nerve (SPN) stimulation (5 pulses at 300 HZ) in paralyzed leg muscles of subjects with chronic (>1 year) SCI. Responses to SPN stimulation that were conditioned by vibration were reduced in 66% of trials (by 33+/-12% in tibialis anterior and 40+/-16% in soleus). These reductions in electromyographic activity are unlikely to be mediated by changes at the Ia synapse or motoneuron because vibration did not alter the magnitude of the soleus H reflex. The electromyographic reductions may involve long-lasting neuromodulatory effects on spinal inhibitory interneurons or synapses involved in the flexor reflex pathway. Vibration-evoked depression of electromyographic activity may be clinically useful in controlling involuntary muscle contractions after SCI.
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Affiliation(s)
- Jane E Butler
- The Miami Project to Cure Paralysis and Department of Neurological Surgery, University of Miami, 1095 NW 14th Terrace, R-48, Miami, Florida 33136, USA
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Frigon A, Rossignol S. Functional plasticity following spinal cord lesions. PROGRESS IN BRAIN RESEARCH 2006; 157:231-260. [PMID: 17167915 DOI: 10.1016/s0079-6123(06)57016-5] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Spinal cord injury results in marked modification and reorganization of several reflex pathways caudal to the injury. The sudden loss or disruption of descending input engenders substantial changes at the level of primary afferents, interneurons, and motoneurons thus dramatically influencing sensorimotor interactions in the spinal cord. As a general rule reflexes are initially depressed following spinal cord injury due to severe reductions in motoneuron excitability but recover and in some instances become exaggerated. It is thought that modified inhibitory connections and/or altered transmission in some of these reflex pathways after spinal injury as well as the recovery and enhancement of membrane properties in motoneurons underlie several symptoms such as spasticity and may explain some characteristics of spinal locomotion observed in spinally transected animals. Indeed, after partial or complete spinal lesions at the last thoracic vertebra cats recover locomotion when the hindlimbs are placed on a treadmill. Although some deficits in spinal locomotion are related to lesion of specific descending motor pathways, other characteristics can also be explained by changes in the excitability of reflex pathways mentioned above. Consequently it may be the case that to reestablish a stable walking pattern that modified afferent inflow to the spinal cord incurred after injury must be normalized to enable a more normal re-expression of locomotor rhythm generating networks. Indeed, recent evidence demonstrates that step training, which has extensively been shown to facilitate and ameliorate locomotor recovery in spinal animals, directly influences transmission in simple reflex pathways after complete spinal lesions.
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Affiliation(s)
- Alain Frigon
- Center and Group for Neurological Sciences, CIHR Group in Neurological Sciences, CIHR Regenerative Medicine and Nanomedicine Team, Faculty of Medicine, Université de Montréal, Montreal, QC, Canada
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Dietz V. G. Heiner Sell memorial lecture: neuronal plasticity after spinal cord injury: significance for present and future treatments. J Spinal Cord Med 2006; 29:481-8. [PMID: 17274486 PMCID: PMC1949033 DOI: 10.1080/10790268.2006.11753897] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent progress in the understanding of movement control allows us to define more precisely the requirements for successful rehabilitation of patients with neurologic deficits after a spinal cord injury (SCI). Load- and hip joint position-related afferent input seems to be of crucial importance for the generation and success of locomotor training. In addition, there is accumulating evidence from animal experiments that axonal regeneration can be induced after a SCI. Consequently, in the near future, new therapeutic approaches will be developed for the treatment of subjects with SCI. Functional training and regeneration represent complimentary approaches. Regenerating spinal tract fibers needs functional training to make the appropriate connections, and training effects will be enhanced by regenerating fibers. A clinical basis for monitoring the effects of novel interventional therapies is needed. Refined and combined clinical and neurophysiologic measures are needed for a precise qualitative and quantitative assessment of spinal cord function in patients with SCI at an early stage. This is a basic requirement for predicting functional outcome, as well as for recognizing any improvement in the recovery of function caused by a new treatment. To this aim, 14 European spinal cord injury centers involved in the rehabilitation of patients with acute SCI have built a close clinical collaboration using a standardized protocol for the assessment of the outcome after SCI and the extent of recovery achieved by actually applied therapies in a larger population of patients with SCI.
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Affiliation(s)
- Volker Dietz
- Spinal Cord Injury Center, University Hospital Balgrist, Zurich, Switzerland.
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34
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Thompson AK, Doran B, Stein RB. Short-term effects of functional electrical stimulation on spinal excitatory and inhibitory reflexes in ankle extensor and flexor muscles. Exp Brain Res 2005; 170:216-26. [PMID: 16317575 DOI: 10.1007/s00221-005-0203-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Accepted: 08/18/2005] [Indexed: 11/27/2022]
Abstract
The purpose of this study was to investigate short-term effects of walking with functional electrical stimulation (FES) on inhibitory and excitatory spinal reflexes in healthy subjects. The FES was applied to the common peroneal (CP) nerve during the swing phase of the step cycle when the ankle flexors are active. We have previously shown that corticospinal excitability for the tibialis anterior (TA) muscle increased after 30 min of FES-assisted walking. An increase of corticospinal excitability could be due to the changes in spinal and/or cortical excitability. Thus, we wished to examine whether a short-term application of FES would increase spinal motoneuronal excitability. Changes could also result from effects on inhibitory as well as excitatory pathways, but to our knowledge no studies have investigated short-term effects of FES on spinal inhibitory pathways. Therefore, we measured reciprocal and presynaptic inhibition, as well as reflex excitability, before and after FES-assisted walking. As controls, effects of FES-like stimulation at rest and walking without stimulation were tested in separate sessions. The TA H-reflex amplitude did not increase after FES in any of the conditions tested, so we have no evidence that FES increases spinal excitability for the TA. The soleus H-reflex decreased slightly (10%) after FES-assisted walking, and remained decreased for at least 30 min. However, the control experiment indicated that this decrease was associated with walking and not with stimulation. Thirty minutes of FES did not produce any significant effects on spinal inhibitory pathways examined in the present study. In conclusion, the soleus H-reflex showed a small but consistent decrease and no spinal circuits examined showed an increase, as was observed in the corticospinal excitability. Thus, we suggest that a short-term application of FES increases the excitability of the cortex or its connections to the spinal cord more effectively than that of spinal pathways.
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Affiliation(s)
- Aiko K Thompson
- Centre for Neuroscience and Department of Physiology, University of Alberta, 513 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada
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35
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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.
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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.
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36
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Abstract
Today, there is accumulating evidence from animal experiments that axonal regeneration and an enhanced level of functional repair can be induced after a spinal cord injury (SCI). Consequently, in the near future, new therapeutic approaches will be developed for the treatment of patients with SCI. The aim of the project presented here is to provide the required clinical basis for the implementation of novel interventional therapies. Refined and combined clinical and neurophysiological measures are needed for a precise qualitative and quantitative assessment of spinal cord function in patients with SCI at an early stage. This represents a basic requirement for recognizing any improvement in the recovery of function and to monitor any significant effect of a new treatment. The paper presents objective and refined tools as a basis for monitoring the effects of new treatment strategies.
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Affiliation(s)
- A Curt
- Paraplegikerzentrum, Uniklinik Balgrist, Zürich
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37
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Schindler-Ivens S, Shields RK. The authors reply. Arch Phys Med Rehabil 2004. [DOI: 10.1016/j.apmr.2004.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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38
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Schindler-Ivens SM, Shields RK. Soleus H-reflex recruitment is not altered in persons with chronic spinal cord injury 11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors(s) or upon any organization with which the author(s) is/are associated. Arch Phys Med Rehabil 2004; 85:840-7. [PMID: 15129411 PMCID: PMC3298881 DOI: 10.1016/j.apmr.2003.08.087] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To determine whether spasticity in persons with spinal cord injury (SCI) is associated with elevated monosynaptic reflex excitability. DESIGN One-way experimental. SETTING Research laboratory. PARTICIPANTS Convenience sample of 9 subjects (8 men, 1 woman) with chronic and complete SCI and 20 persons (14 men, 6 women) with no neurologic impairment. Subjects with SCI exhibited lower-extremity spasticity as indicated by velocity-dependent increased resistance to passive muscle stretch, abnormally brisk deep tendon reflexes, involuntary lower-extremity flexion and/or extension spasms, and clonus. INTERVENTION Soleus H-reflex recruitment curves were elicited in all subjects. MAIN OUTCOME MEASURES Soleus H-reflex threshold (HTH), gain (HGN), and amplitude (HPP). RESULTS There was no difference between subjects with and without SCI in HTH, HGN, or HPP. CONCLUSIONS Spasticity in people with chronic and complete SCI was not associated with increased excitability of the connections between Ia afferent projections and motoneurons. Factors extrinsic to these connections may have a role in spasticity caused by SCI.
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Affiliation(s)
- Sheila M Schindler-Ivens
- Graduate Program in Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA.
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39
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Curt A, Schwab ME, Dietz V. Providing the clinical basis for new interventional therapies: refined diagnosis and assessment of recovery after spinal cord injury. Spinal Cord 2004; 42:1-6. [PMID: 14713937 DOI: 10.1038/sj.sc.3101558] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Today, there is accumulating evidence from animal experiments that axonal regeneration and an enhanced level of functional repair can be induced after a spinal cord injury (SCI). Consequently, in the near future, new therapeutic approaches will be developed for the treatment of patients with SCI. The aim of the project presented here is to provide the required clinical basis for the implementation of novel interventional therapies. Refined and combined clinical and neurophysiological measures are needed for a precise qualitative and quantitative assessment of spinal cord function in patients with SCI at an early stage. This represents a basic requirement to recognise any improvement in the recovery of function and to monitor any significant effect of a new treatment. To this aim, five European Spinal Cord Injury Centres involved in the rehabilitation of acute SCI patients have built up a close clinical collaboration to develop a standardised protocol for the assessment of the outcome after SCI and the extent of recovery achieved by actually applied therapies in a larger population of SCI patients. The project's aim is to establish objective, refined tools as a basis for monitoring the effects of new treatment strategies.
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Affiliation(s)
- A Curt
- Spinal Cord Injury Centre, University Hospital Balgrist, Switzerland
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40
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Dietz V, Colombo G. Recovery from spinal cord injury--underlying mechanisms and efficacy of rehabilitation. ACTA NEUROCHIRURGICA. SUPPLEMENT 2004; 89:95-100. [PMID: 15335107 DOI: 10.1007/978-3-7091-0603-7_13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Patients with an acute complete spinal cord injury (SCI) present a syndrome called "spinal shock". During spinal shock the loss of tendon reflexes and flaccid muscle tone is associated with a low persistence of F-waves and loss of flexor reflexes while H-reflexes are well elicitable. When clinical signs of spasticity become established, the electrophysiological parameters show little change. The divergent course of clinical signs of spasticity in their possible neuronal correlates indicate the occurrence of non-neuronal changes contributing to spasticity. - When signs of spinal shock had disappeared in patients with incomplete and complete paraplegia a locomotor pattern can be induced and trained under conditions of body unlaoding using a moving treadmill. In complete and incomplete paraplegic patients an increase of gastrocnemius electromyographic activity occurs during the stance phase of a step cycle with a daily locomotor training, coincident with a significant decrease of body unloading. In contrast to this, neither clinical nor electrophysiological examination scores improve. The locomotor pattern depends on the level of lesion: the higher the level of spinal cord lesion the more 'normal' is the locomotor pattern. This suggests that neuronal circuits underlying 'locomotor pattern generation' in man is not restricted to any specific level of the spinal cord, but extends from thoraco-lumbal to cervical levels.
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Affiliation(s)
- V Dietz
- ParaCare, Swiss Paraplegic Centre of the University Hospital Bagrlist, Zurich, Switzerland.
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41
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Thompson FJ, Reier PJ, Uthman B, Mott S, Fessler RG, Behrman A, Trimble M, Anderson DK, Wirth ED. Neurophysiological assessment of the feasibility and safety of neural tissue transplantation in patients with syringomyelia. J Neurotrauma 2001; 18:931-45. [PMID: 11565604 DOI: 10.1089/089771501750451848] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The feasibility and safety of a procedure involving fetal spinal cord tissue transplantation in patients with syringomyelia was assessed using a neurophysiological protocol designed to quantitate peripheral nerve function, spinal cord reflex excitability, and spinal cord conduction pathways essential for somatosensory evoked potentials. We report here data obtained before and for 18 months following the transplantation procedure performed on the first two patients in this study. The neurophysiological assessment protocols included measures of cortical and spinal cord evoked potentials, H-reflex excitability, and peripheral nerve conduction. Prior to the procedure, both patients had significant deficits on some of the neurophysiological measures, for example, lower extremity cortical evoked potentials. However, robust measures of intact pathways, such as upper extremity cortical evoked potentials, were also observed preoperatively in both patients. Thus, it was anticipated that conduction in these intact pathways could be at risk either from complications from the transplantation procedure and/or from continued expansion of the syrinx. Following the transplantation procedure, no negative changes were observed in any of the neurophysiological measures in either patient. In addition, patient 1 showed a decrease in the rate potentiation of tibial H-reflexes on the right side and an increase in the response probability of left tibial H-reflexes. The results of this postoperative longitudinal assessment provide a first-level demonstration of the safety of the intraspinal neural tissue transplantation procedure. However, the consideration of safety is currently limited to the grafting procedure itself, since the long-term fates of the donor tissue in these two patients remain to be shown more definitively.
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Affiliation(s)
- F J Thompson
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, USA.
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42
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Chen XY, Feng-Chen KC, Chen L, Stark DM, Wolpaw JR. Short-Term and medium-term effects of spinal cord tract transections on soleus H-reflex in freely moving rats. J Neurotrauma 2001; 18:313-27. [PMID: 11284551 DOI: 10.1089/08977150151070973] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal cord function is normally influenced by descending activity from supraspinal structures. When injury removes or distorts this influence, function changes and spasticity and other disabling problems eventually appear. Understanding how descending activity affects spinal cord function could lead to new means for inducing, guiding, and assessing recovery after injury. In this study, we investigated the short-term and medium-term effects of spinal cord bilateral dorsal column (DC), unilateral (ipsilateral) lateral column (LC), bilateral dorsal column ascending tract (DA), or bilateral dorsal column corticospinal tract (CST) transection at vertebral level T8-T9 on the soleus H-reflex in freely moving rats. Data were collected continuously for 10-20 days before and for 20-155 days after bilateral DC (13 rats), DA (10 rats), CST (eight rats), or ipsilateral LC (seven rats) transection. Histological examination showed that transections were 98(+/- 3 SD)% complete for DC rats, 80(+/- 20)% complete for LC rats, 91(+/- 13 SD)% complete for DA rats, and 95(+/-13)% complete for CST rats. LC, CST, and DA transections produced an immediate (i.e., first-day) increase in H-reflex amplitude. LC transection also produced a small decrease in background activity in the first few posttransection days. Other than this small decrease, none of the transections produced evidence for the phenomenon of spinal shock. For all transections, all measures returned to or neared pretransection values within 2 weeks. DA and LC transections were associated with modest increase in H-reflex amplitude 1-3 months after transection. These medium-term effects must be taken into account when assessing transection effects on operant conditioning of the H-reflex. At the same time, the results are consistent with other evidence that, while H-reflex rate dependence and H-reflex operant conditioning are sensitive measures of spinal cord injury, the H-reflex itself is not.
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Affiliation(s)
- X Y Chen
- Wadsworth Center, New York State Department of Health and State University of New York, Albany 12201-0509, USA.
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43
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Abstract
Electrophysiological recordings of the H-reflex and nonnociceptive flexion reflex were obtained from pentobarbital-anesthetized Intact rats and from both, anesthetized and unanesthetized groups of Acute and Chronic Spinal rats. Results showed that the flexor, but not H-reflex, of Chronic Spinal rats was significantly larger than that of all other groups, which did not differ among themselves. The antispastic drug baclofen dose-dependently decreased the flexion response of Chronic Spinal rats (A(50)=4.3 mg/kg+/-2.1 and 9.0 mg/kg).
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Affiliation(s)
- M Duke
- Department of Psychology 236 Audubon Hall Louisiana State University, 70803, Baton Rouge, LA, USA
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44
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Chen XY, Wolpaw JR, Jakeman LB, Stokes BT. Operant conditioning of H-reflex increase in spinal cord--injured rats. J Neurotrauma 1999; 16:175-86. [PMID: 10098962 DOI: 10.1089/neu.1999.16.175] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Operant conditioning of the spinal stretch reflex or its electrical analog, the H-reflex, is a new model for exploring the mechanisms of long-term supraspinal control over spinal cord function. Primates and rats can gradually increase (HRup conditioning mode) or decrease (HRdown conditioning mode) the H-reflex when reward is based on H-reflex amplitude. An earlier study indicated that HRdown conditioning of the soleus H-reflex in rats is impaired following contusion injury to thoracic spinal cord. The extent of impairment was correlated with the percent of white matter lost at the injury site. The present study investigated the effects of spinal cord injury on HRup conditioning. Soleus H-reflexes were elicited and recorded with chronically implanted electrodes from 14 rats that had been subjected to calibrated contusion injuries to the spinal cord at T8. At the lesion epicenter, 12-39% of the white matter remained. After control-mode data were collected, each rat was exposed to the HRup conditioning mode for 50 days. Final H-reflex amplitudes after HRup conditioning averaged 112% (+/-22% SD) of control. This value was significantly smaller than that for 13 normal rats exposed to HRup conditioning, in which final amplitude averaged 153% (+/-51%) SD of control. As previously reported for HRdown conditioning after spinal cord injury, success was inversely correlated with the severity of the injury as assessed by white matter preservation and by time to return of bladder function. HRup and HRdown conditioning are similarly sensitive to injury. These results further demonstrate that H-reflex conditioning is a sensitive measure of the long-term effects of injury on supraspinal control over spinal cord functions and could prove a valuable measure of therapeutic efficacy.
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Affiliation(s)
- X Y Chen
- Wadsworth Center, New York State Department of Health and State University of New York, Albany, USA.
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45
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Sehgal N, McGuire JR. Beyond Ashworth: Electrophysiologic Quantification of Spasticity. Phys Med Rehabil Clin N Am 1998. [DOI: 10.1016/s1047-9651(18)30243-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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46
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Hilgevoord A, Koelman J, Bour L, de Visser B. The relationship between the soleus H-reflex amplitude and vibratory inhibition in controls and spastic subjects. I. Experimental results. J Electromyogr Kinesiol 1996; 6:253-8. [DOI: 10.1016/s1050-6411(96)00006-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/1995] [Revised: 10/20/1995] [Accepted: 10/30/1995] [Indexed: 10/18/2022] Open
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47
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Effects of exercise and fetal spinal cord implants on the H-reflex in chronically spinalized adult rats. Brain Res 1996. [DOI: 10.1016/0006-8993(96)00556-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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48
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Abstract
Brainstem and spinal pathways of untreated patients with idiopathic restless legs syndrome (RLS) were examined using magnetic resonance imaging (MRI), blink reflex, first and second exteroceptive suppression (ES1, ES2) of temporalis muscle, and H reflex. MRI of 25 patients elicited no structural lesions beyond age-related atrophy or white matter lesions on proton density- and T2-weighted coronal and axial images. All patients showed a normal latency of the soleus H reflex (mean +/- SD latency = 31.22 +/- 2.81 ms) and the H/M ratio was 48 +/- 17%. The duration and onset latency of the direct and indirect blink reflex responses were normal in all patients compared with those of controls (p > 0.5). There was no significant difference in ES1 and ES2 latencies or duration between patients and controls (p > 0.5). These results suggest that the etiology of RLS symptoms does not involve structural lesions.
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Affiliation(s)
- S F Bucher
- Department of Neurology, Ludwig-Maximilians University, Munich, Germany
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49
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Abstract
The term "spinal shock" applies to all phenomena surrounding physiologic or anatomic transection of the spinal cord that results in temporary loss or depression of all or most spinal reflex activity below the level of the injury. Hypotension due to loss of sympathetic tone is a possible complication, depending on the level of the lesion. The mechanism of injury that causes spinal shock is usually traumatic in origin and occurs immediately, but spinal shock has been described with mechanisms of injury that progress over several hours. Spinal cord reflex arcs immediately above the level of injury may also be severely depressed on the basis of the Schiff-Sherrington phenomenon. The end of the spinal shock phase of spinal cord injury is signaled by the return of elicitable abnormal cutaneospinal or muscle spindle reflex arcs. Autonomic reflex arcs involving relay to secondary ganglionic neurons outside the spinal cord may be variably affected during spinal shock, and their return after spinal shock abates is variable. The returning spinal cord reflex arcs below the level of injury are irrevocably altered and are the substrate on which rehabilitation efforts are based.
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Affiliation(s)
- P P Atkinson
- Department of Neurology, Mayo Clinic Rochester, MN 55905 USA
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50
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Koelman JH, Willemse RB, Bour LJ, Hilgevoord AA, Speelman JD, Ongerboer de Visser BW. Soleus H-reflex tests in dystonia. Mov Disord 1995; 10:44-50. [PMID: 7885355 DOI: 10.1002/mds.870100109] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Vibratory inhibition, the homonymous recovery curve and the ratio of the maximal H-reflex to direct muscle potential (H/M ratio) of the soleus H-reflex were assessed in 10 patients with leg dystonia and in six patients with arm or neck dystonia. The results were compared with those obtained in 48 healthy control subjects. H-reflex variables most helpful for the discrimination of patients and healthy subjects were identified. In patients with leg dystonia, vibratory inhibition was less marked than in control subjects, whereas late facilitation of the recovery curve was increased. In patients with leg dystonia, area values of test reflexes in the late facilitatory phase of the recovery curve exceeded peak-peak values, in contrast to findings in control subjects. This finding may be attributable to less synchronization of enhanced test reflexes in dystonia than in the control condition. In differentiating patients with leg dystonia from control subjects, a combination of parameters of vibratory inhibition and the late facilitatory phase of the recovery curve appeared most useful. In patients with arm or neck dystonia and in the unaffected legs of hemidystonic patients, soleus H-reflex test results were in the normal range. Abnormalities in the results of the soleus H-reflex tests we used appear to be related to the presence of clinical signs in the extremity under examination and not to the severity of features.
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Affiliation(s)
- J H Koelman
- Department of Neurology, Graduate School Neurosciences Amsterdam, The Netherlands
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