Spasticity In Spinal Cord Injury Research Articles

Breathing-controlled Electrical Stimulation (BreEStim) for Management of Neuropathic Pain and Spasticity

Electrical stimulation (EStim) refers to the application of electrical current to muscles or nerves in order to achieve functional and therapeutic goals. It has been extensively used in various clinical settings. Based upon recent discoveries related to the systemic effects of voluntary breathing and intrinsic physiological interactions among systems during voluntary breathing, a new EStim protocol, Breathing-controlled Electrical Stimulation (BreEStim), has been developed to augment the effects of electrical stimulation. In BreEStim, a single-pulse electrical stimulus is triggered and delivered to the target area when the airflow rate of an isolated voluntary inspiration reaches the threshold. BreEStim integrates intrinsic physiological interactions that are activated during voluntary breathing and has demonstrated excellent clinical efficacy. Two representative applications of BreEStim are reported with detailed protocols: management of post-stroke finger flexor spasticity and neuropathic pain in spinal cord injury.

The effects of functional electrically stimulated (FES)-arm ergometry on upper limb function and resting cardiovascular outcomes in individuals with tetraplegia: A pilot study

Background: Functional electrically stimulated (FES)-arm ergometry has been shown to increase peak power output and aerobic capacity in individuals with cervical SCI. However, the functional benefits remain unknown. Objective: To determine the effects of FES-arm ergometry on exercise performance, upper limb function and resting cardiovascular function in individuals with tetraplegia. Methods: Five individuals (43.8 ± 15.4 years old) with SCI (C3-C5, AIS C-D, 14.0 ± 11.1 years post-injury) completed 12 weeks FES-arm ergometry. Exercise performance (time and distance to fatigue), perceived upper limb function [Capabilities of Upper Extremity Questionnaire (CUE), short form-Quadriplegia Index of Function Questionnaire (sf-QIF) and Spinal Cord Injury Spasticity Evaluation Tool (SCI-SET)] and resting mean arterial pressure (MAP) and heart rate (HR) were measured pre and post. Results: Following training, MAP significantly decreased (91.1 ± 14.0 to 87.7 ± 14.7 mmHg; p = 0.04), and there was a trend for an increased time to fatigue (804.6 ± 359.4 to 1483.8 ± 1110.2 sec; p = 0.08), distance to fatigue (3508.4 ± 3524.5 to 7412.6 ± 7773.1 m, p = 0.08) and the CUE scores pertaining to hand function (31.6 ± 12.8 to 38.0 ± 17.7; p = 0.07). Conclusion: Twelve-week FES-arm ergometry was associated with decreased resting MAP in individuals with tetraplegia, and may show promise as a means to increase exercise performance and hand function. Further research is required to verify these preliminary findings.

Constitutively active 5-HT2/α1 receptors facilitate muscle spasms after human spinal cord injury

In animals, the recovery of motoneuron excitability in the months following a complete spinal cord injury is mediated, in part, by increases in constitutive serotonin (5-HT2) and norepinephrine (α1) receptor activity, which facilitates the reactivation of calcium-mediated persistent inward currents (CaPICs) without the ligands serotonin and norepinephrine below the injury. In this study we sought evidence for a similar role of constitutive monoamine receptor activity in the development of spasticity in human spinal cord injury. In chronically injured participants with partially preserved sensory and motor function, the serotonin reuptake inhibitor citalopram facilitated long-lasting reflex responses (spasms) previously shown to be mediated by CaPICs, suggesting that in incomplete spinal cord injury, functional descending sources of monoamines are present to activate monoamine receptors below the lesion. However, in participants with motor or motor/sensory complete injuries, the inverse agonist cyproheptadine, which blocks both ligand and constitutive 5-HT2/α1 receptor activity, decreased long-lasting reflexes, whereas the neutral antagonist chlorpromazine, which only blocks ligand activation of these receptors, had no effect. When tested in noninjured control participants having functional descending sources of monoamines, chlorpromazine was effective in reducing CaPIC-mediated motor unit activity. On the basis of these combined results, it appears that in severe spinal cord injury, facilitation of persistent inward currents and muscle spasms is mainly mediated by the activation of constitutive 5-HT2 and α1 receptor activity. Drugs that more selectively block these constitutively active monoamine receptors may provide better oral control of spasticity, especially in motor complete spinal cord injury where reducing motoneuron excitability is the primary goal.

Comparison of the effects of body-weight-supported treadmill training and tilt-table standing on spasticity in individuals with chronic spinal cord injury

ObjectiveDetermine the effects of body-weight-supported treadmill training (BWSTT) and tilt-table standing (TTS) on clinically assessed and self-reported spasticity, motor neuron excitability, and related constructs in individuals with chronic spinal cord injury (SCI).DesignRandom cross-over.MethodsSeven individuals with chronic SCI and spasticity performed thrice-weekly BWSTT for 4 weeks and thrice-weekly TTS for 4 weeks, separated by a 4-week wash-out. Clinical (Modified Ashworth Scale, Spinal Cord Assessment Tool for Spinal reflexes) and self-report (Spinal Cord Injury Spasticity Evaluation Tool, Penn Spasm Frequency Scale) assessments of spasticity, quality of life (Quality of Life Index Spinal Cord Injury Version – III), functional mobility (FIM Motor Subscale), plus soleus H-reflex were measured at baseline, after the first training session and within 2 days of completing each training condition.ResultsIn comparison with TTS, a single session of BWSTT had greater beneficial effects for muscle tone (effect size (ES) = 0.69), flexor spasms (ES = 0.57), and the H/M ratio (ES = 0.50). Similarly, flexor spasms (ES = 0.79), clonus (ES = 0.66), and self-reported mobility (ES = 1.27) tended to benefit more from 4 weeks of BWSTT than of TTS. Participation in BWSTT also appeared to be favorable for quality of life (ES = 0.50). In contrast, extensor spasms were reduced to a greater degree with TTS (ES = 0.68 for single session; ES = 1.32 after 4 weeks).ConclusionWhile both BWSTT and TTS may provide specific benefits with respect to spasticity characteristics, data from this pilot study suggest that BWSTT may result in a broader range of positive outcomes.

Latest approaches for the treatment of spasticity and autonomic dysreflexia in chronic spinal cord injury.

Two of the most prevalent secondary complications following spinal cord injury (SCI), besides loss of function and/or sensation below the level of injury, are uncontrolled muscle spasticity and hypertensive autonomic dysreflexia. Despite the desires of the SCI community, there have been few advances in the treatment and/or management of these fundamental impediments to the quality of life associated with chronic SCI. Therefore, the purpose of this review is to focus on current drug treatment strategies that alleviate symptoms of spasticity and autonomic dysfunction. Subsequently, looking ahead, we discuss whether individuals suffering from autonomic dysreflexia and/or muscle spasms can take certain compounds that specifically and rapidly block the neurotransmission of pain into the injured spinal cord to get rapid relief for both aberrant reflexes for which painful stimuli below the level of SCI are common precipitants.

Decrease of spasticity with muscle vibration in patients with spinal cord injury

Objective Spasticity is common after spinal cord injury (SCI). Exaggerated tendon jerks, clonus, and spasms are key features of spasticity that result from hyperexcitability of the stretch reflex circuit. Here we studied the effects of vibration on the rectus femoris muscle (RF) on clinical and electrophysiological measures of spasticity in the leg. Methods Nineteen SCI patients with spasticity and nine healthy subjects were studied at baseline and under stimulation (vibration at 50 Hz during 10 min on the thigh). Neurophysiological studies included evaluation of the soleus T wave and Hmax/Mmax ratio. Clinical measurements of spasticity were the score in the Modified Ashworth Scale (MAS), range of motion (ROM), and duration and frequency of clonus. Results Patients with incomplete SCI (iSCI) presented higher number of cycles and longer duration of clonus than patients with complete SCI (cSCI). The Hmax/Mmax ratio and T wave amplitude at baseline were significantly larger in iSCI patients than in cSCI or healthy subjects. During vibration, we found a significant reduction of MAS and duration of clonus, and an increase in ROM, in all patients as a group. The Hmax/Mmax ratio and the T wave amplitude decreased significantly in both, patients and controls. Conclusions Prolonged vibration on proximal lower extremity muscles decreased limb spasticity in patients with spinal cord injury, regardless of whether the lesion is complete or incomplete. Significance Muscle vibration may be useful for physical therapy, by facilitating passive and active movements of the extremities in spastic SCI patients.

Spasticity therapy reacts to astrocyte GluA1 receptor upregulation following spinal cord injury

For almost three decades intrathecal baclofen therapy has been the standard treatment for spinal cord injury spasticity when oral medication is ineffective or produces serious side effects. Although intrathecal baclofen therapy has a good clinical benefit-risk ratio for spinal spasticity, tolerance and the life-threatening withdrawal syndrome present serious problems for its management. Now, in an experimental model of spinal cord injury spasticity, AMPA receptor blockade with NGX424(Tezampanel) has been shown to reduce stretch reflex activity alone and during tolerance to intrathecal baclofen therapy.These results stem from the observation that GluA1 receptors are overexpressed on reactive astrocytes following experimental ischaemic spinal cord injury. Although further validation is required, the appropriate choice of AMPA receptor antagonists for treatment of stretch hyperreflexia based on our recent understanding of reactive astrocyte neurobiology following spinal cord injury may lead to the development of a better adjunct clinical therapy for spasticity without the side effects of intrathecal baclofen therapy.

Role of inhibition in the suppression of α-motoneuron hyper-excitability following chronic spinal cord injury

Introduction The monosynaptic spinal stretch reflex consists of glutamatergic Ia muscle spindle afferents synapsing on αmotoneuron (α-MN) dendrites. Also, renshaw cells (RC) mediate a direct recurrent inhibition of α-MNs potentially via GABAA and glycinergic receptors. The RC synapses are confined to α-MN dendrites. Several studies have implicated a GABAB receptor mediated pre-synaptic inhibition of the Ia terminal during reflex generation. Supra-spinal inputs further modulate the efficacy of the synaptic inputs to the α-MN, e.g. brainstem nuclei exert a tonic monoaminergic inhibition on RCs. Following spinal cord injury (SCI), hyper-reflexia and motor spasticity occur with concomitant α-MN hyper-excitability. The hyper-excitability has largely been attributed to an enhancement of dendritic persistent inward currents (PICs), while inhibitory pathways may also play a role. However, the effect of a combination of PIC enhancement and changes in inhibitory inputs on α-MN excitability is yet unclear [1]. In this study, we use a network model for the monosynaptic stretch reflex with RC-type recurrent inhibition of the αMN to test the hypothesis that GABAergic inputs are essential for suppressing α-MN hyper-excitability after chronic SCI.

FES-propelled cycling of SCI subjects with highly spastic leg musculature

The presence of spasms precludes the use of artificial electrical activation of the muscles to restore mobility. The prospect of using an electrical stimulus that produces motor activation without causing unwanted reflex activation in patients with high levels of spasticity is an appealing one. The purpose of the study was to determine the efficacy of modulated middle frequency alternating current (MFAC) muscle stimulation compared to the conventional method of standard low frequency rectangular pulse (LFRP) stimulation used in cycling of persons with spinal cord injury (SCI) and pronounced spasticity. To evaluate cycling-relevant differences between stimulation modes, 13 subjects with SCI (ASIA-A), 11 of them with strong spasticity, underwent isometric and cycling measurements using both 20 Hz LFRP and 4 KHz modulated with 50 Hz MFAC. The isometric long-lasting reflex torque response in the quadriceps and hamstrings muscles, and the dynamic work during 1000 sec of ergometric cycling as well as the number of involuntary stops caused by hyperreflexia were recorded. The long-lasting reflex torque response was significantly lower when using MFAC than with LFRP stimulation. During MFAC stimulation work generated was on average 374% higher (p = 0.002) and the number of involuntary stops was on average 32% lower (p < 0.001) than during standard LFRP stimulation-propelled cycling. These findings suggest that MFAC-stimulated cycling of strongly spastic SCI subjects is more effective in terms of generated isometric torque and power than stimulation with LFRP. Thus, more health benefits, e.g., cardiovascular and muscular training and spasticity-decreasing effects, can be expected faster using MFAC instead of LFRP in stimulation-propelled cycling.

Spasticity outcome measures in spinal cord injury: psychometric properties and clinical utility

Comprehensive review and systematic analyses. Assess published psychometric evidence for spinal cord injury (SCI) spasticity outcome measures. Considerations about the influence of spasticity on function have also been identified to understand treatment effects and guide service delivery. London, Ontario and Vancouver, British Columbia, Canada. Review of measures was based on availability of psychometric data, application in clinical settings and evaluated in SCI patients. Ashworth and Modified Ashworth Scales (AS, MAS), Penn Spasm Frequency Scale (PSFS), Spinal Cord Assessment Tool for Spasticity (SCATS), Visual Analogue Scale self-rated scale of spasticity (VAS) and the Wartenberg Pendulum Test (WPT) were included in this review. The most frequently used tools for SCI spasticity measurement include the AS, MAS, PSFS and VAS, of which the latter two are self-report spasticity measures. The SCATS has been partially validated for SCI, but is not widely used. The WPT has been minimally validated despite its use in a large-scale SCI spasticity randomized controlled trial. Since spasticity is multidimensional, focusing on one or two spasticity outcome measures can misrepresent the extent and influence of spasticity on SCI patients. Different scales measure different aspects of spasticity and individual tools correlate weakly with each other. Spasticity may be better measured with an appropriate battery of tests, including the AS or MAS, along with PSFS. These tools would benefit from further reliability and responsiveness testing. Tools that assess the influence of spasticity on patient activities, participation and quality of life are important, but lacking.

The Effect of Hippotherapy on Spasticity and on Mental Well-Being of Persons With Spinal Cord Injury

Lechner HE, Kakebeeke TH, Hegemann D, Baumberger M. The effect of hippotherapy on spasticity and on mental well-being of persons with spinal cord injury. Objectives To determine the effect of hippotherapy on spasticity and on mental well-being of persons with spinal cord injury (SCI), and to compare it with the effects of other interventions. Design Crossover trial with 4 conditions. Setting Swiss paraplegic center. Participants A volunteer sample of 12 people with spastic SCI (American Spinal Injury Association grade A or B). Interventions Hippotherapy, sitting astride a Bobath roll, and sitting on a stool with rocking seat. Each session lasted 25 minutes and was conducted twice weekly for 4 weeks; the control condition was spasticity measurement without intervention. Main Outcome Measures Clinical rating by a blinded examiner of movement-provoked muscle resistance, using the Ashworth Scale; self-rating of spasticity by subjects on a visual analog scale (VAS); and mental well-being evaluated with the self-rated well-being scale Befindlichkeits-Skala of von Zerssen. Assessments were performed immediately after intervention sessions (short-term effect); data from the assessments were analyzed 3 to 4 days after the sessions to calculate the long-term effect. Results By analyzing the clinically rated spasticity, only the effect of hippotherapy reached significance compared with the control condition (without intervention); median differences in the Ashworth scores’ sum before and after hippotherapy sessions ranged between −8.0 and +0.5. There was a significant difference between the spasticity-reducing effect of hippotherapy and the other 2 interventions in self-rated spasticity by VAS; median differences of the VAS before and after hippotherapy sessions ranged between −4.6 and +0.05cm. There were no long-term effects on spasticity. Immediate improvements in the subjects’ mental well-being were detected only after hippotherapy ( P=.048). Conclusions Hippotherapy is more efficient than sitting astride a Bobath roll or on a rocking seat in reducing spasticity temporarily. Hippotherapy had a positive short-term effect on subjects’ mental well-being.

The Spinal Cord Injury Spasticity Evaluation Tool: Development and Evaluation

Adams MM, Martin Ginis KA, Hicks AL. The Spinal Cord Injury Spasticity Evaluation Tool: development and evaluation. Objective To develop and assess the reliability and validity of a new scale designed to measure the impact of spasticity on daily life in people with spinal cord injury (SCI). Design Scale development and assessment. Setting General community. Participants Community-dwelling persons with chronic SCI and spasticity participated in study 1 (n=9), study 2 (n=19), and study 3 (n=61). Interventions Not applicable. Main Outcome Measures Study 1: participant definitions of spasticity and list of scale items. Study 2: scale refinement, face validity, and time to complete. Study 3: internal consistency, test-retest reliability, and construct validity. Results The Spinal Cord Injury Spasticity Evaluation Tool (SCI-SET) is a 7-day recall self-report questionnaire that takes into account both the problematic and useful effects of spasticity on daily life in people with SCI. The scale exhibited good face validity and required 6.8±2.6 minutes to complete. The internal consistency (α) and intraclass correlation coefficient of the SCI-SET were .90 and .91, respectively. Construct validity was supported by correlations ( r range, −.48 to .68; P<.01) between SCI-SET scores and theoretically meaningful constructs. Conclusions The SCI-SET fills a need for a reliable and valid self-report measure of the impact of spasticity on daily life in people with SCI, taking into account both the problematic and useful effects of spasticity.

Spasticity After Spinal Cord Injury: An Evidence-Based Review of Current Interventions

Purpose: To provide an overview of evidence for spinal cord injury (SCI) spasticity interventions in peerreviewed, published literature. Method: Structured review and synthesis of spasticity treatments in the literature. Each publication was rated according to the Downs and Black methodology for assessing nonrandomized studies and according to the Physiotherapy Evidence Database (PEDro) scale for assessing randomized controlled trials. Results: Level 1 evidence supports the use of transcutaneous electrical nerve stimulation (TENS), penile vibration, baclofen, tizanidine, clonidine, cyproheptadine, gabapentin, and Lthreonine to reduce spasticity in SCI. Conclusion: Although spasticity is a common complication following SCI, there is relatively little evidence for the treatment of spasticity and even less evidence that has been confirmed by independent replication. TENS is the only routine nonpharmacological treatment for spasticity that is supported by adequate level 1 evidence. Several pharmacological treatments, including baclofen, tizanidine, and clonidine, are supported by level 1 evidence. There is level 1 evidence to support test doses of intrathecal baclofen for the short-term reduction of spasticity in SCI but not for its long-term use. The lack of level 1 evidence for spasticity interventions does not necessarily reflect a lack of effective treatments, but it does emphasize the need for further studies. All other interventions reviewed would benefit from further study.

Modulation of locomotor activity in complete spinal cord injury

The aim of this study was to evaluate the modulation of muscle activity during locomotor-like movements by different walking speeds in subjects with a motor complete spinal cord injury (SCI) compared to actively--and passively-walking control subjects without neurological deficit. Stepping movements on a treadmill were induced and assisted by a driven gait orthosis. Electromyographic (EMG) muscle activity of one leg (rectus and biceps femoris, tibialis anterior and gastrocnemius) was recorded and analyzed at three stepping velocities with similar body weight support in both subject groups. In SCI subjects, the EMG amplitude of biceps femoris, tibialis anterior and gastrocnemius was in general similar or weaker than in passively- and actively-stepping control subjects, but that of rectus femoris was larger. The degree of co-activation between tibialis anterior and gastrocnemius was higher in SCI than in control subjects. A significant velocity-dependent EMG modulation was present in all four-leg muscles in both subject groups. In SCI subjects, this EMG modulation was similar to that in actively stepping control subjects. It is concluded that in complete spastic SCI subjects, spinal neuronal circuits underlying locomotion can to a large extent adequately respond to a change in external drive to adapt the neuronal pattern to a new locomotion speed. The application of various speeds might enhance the effect of locomotor training in incomplete SCI subjects.

Comparison of Electric Stimulation Methods for Reduction of Triceps Surae Spasticity in Spinal Cord Injury

van der Salm A, Veltink PH, IJzerman MJ, Groothuis-Oudshoorn KC, Nene AV, Hermens HJ. Comparison of electric stimulation methods for reduction of triceps surae spasticity in spinal cord injury. Objectives To compare the effect of 3 methods of electric stimulation to reduce spasticity of the triceps surae in patients with complete spinal cord injury (SCI) and to investigate the carryover effect. Design Placebo-controlled study with repeated measurements after the interventions. Setting Research department affiliated with a rehabilitation hospital in the Netherlands. Participants Ten patients with a complete SCI were recruited from the outpatient population of the rehabilitation hospital. All subjects had American Spinal Injury Association grade A impairment scores, except for one, who had grade C. The patients had no voluntary triceps surae contractibility. Interventions Forty-five minutes of cyclic electric stimulation of the agonist, antagonist, or dermatome of the triceps surae or a placebo approach. Main Outcome Measures Outcome measures were the Modified Ashworth Scale (MAS), clonus score, and the H-reflex and M wave (H/M) ratio. The electromyographic response to a stretch of the soleus over the whole range of motion was also determined. The magnitude and ankle angle at which the electromyographic response started were calculated. Results Stimulation of the agonist provided a significant reduction in the MAS compared with the placebo approach ( P<.001). There was no significant change in the H/M ratio or the electromyographic response amplitude after any of the stimulation methods, whereas stimulation of the antagonist muscle resulted in a significant reduction in the ankle angle at which the electromyographic response started, compared with the placebo approach ( P<.037). Conclusions Triceps surae stimulation reduces the MAS for that specific muscle, whereas the angle at which the reflex starts changes after antagonist stimulation.

Relationship Between Self- and Clinically Rated Spasticity in Spinal Cord Injury

Lechner HE, Frotzler A, Eser P. Relationship between self- and clinically rated spasticity in spinal cord injury. Objectives To assess the relation between self- and clinically rated spasticity in spinal cord injury (SCI) and to determine the extent to which symptoms like pain are included in the patients’ self-rating of spasticity. Design Part 1: an observational, prospective, cross-sectional study and part 2: an observational, prospective, longitudinal study. Setting Swiss paraplegic center. Participants Forty-seven (part 1) and 8 (part 2) persons with spastic SCI (American Spinal Injury Association grade A or B). Interventions Not applicable. Main Outcome Measures Clinical rating of movement-provoked spasticity using the Ashworth Scale; self-rating of general and present spasticity by the subject on a 4-point spasm severity scale and by using a visual analog scale (VAS); and questionnaires asking for antispasticity medication, impact of spasticity on daily life, body segment affected by spasticity, and symptoms associated with its occurrence. Results There was a poor correlation (ρ=.36) between clinically rated (Ashworth Scale) spasticity and self-rated general spasticity and a modest correlation (ρ=.70) between Ashworth Scale and self-rated present spasticity in the cross-sectional study in 47 subjects. Questionnaires showed that symptoms like pain and other sensations were associated by the patients with spasticity. There was a significant, but weak, correlation between VAS and Ashworth Scale in the longitudinal study in 3 of the 8 subjects and nonsignificant correlations in the remaining 5 subjects. Conclusions A single clinical assessment of spasticity is a poor indication of a patient’s general spasticity. Clinical measures of muscle tone–related spasticity should be complemented by self-rating that distinguishes muscle tone–related spasticity from spasticity affecting the sensory nervous system.

Assessment of Spinal Cord Injury Spasticity in Clinical Trials

Spasticity continues to be a significant problem for many people with spinal cord injury, and current therapies are not ideal. Attempts to identify and test new interventions for spasticity are hampered by the lack of a consensus definition of spasticity. Because of the complexity of this disorder, a multidimensional approach to assessment is necessary to understand the scope of functionally important symptoms experienced by patients. This multidimensional assessment should include both objective and subjective assessments of tonic spasticity, phasic spasticity, and involuntary spasms as well as function and quality of life. Measuring only one component of spasticity in a clinical trial is likely to underestimate the benefits of a new intervention.

Flexor reflex responses triggered by imposed knee extension in chronic human spinal cord injury

Hypersensitivity of the flexor reflex pathways to input from force-sensitive muscle afferents may contribute to the prevalence and severity of muscle spasms in patients with spinal cord injury (SCI). In this study, we triggered flexor reflexes with constant velocity knee movements in 15 subjects with SCI. Ramp and hold knee extension perturbations were imposed on one leg while the hip and ankle were held in an isometric position using an instrumented leg brace. Knee, ankle and hip torque responses and electromyograms from six muscles of the leg were recorded following controlled knee extension at four different velocities. Tests were conducted with the hip in both flexed and extended positions. During the movement into knee extension, a velocity-dependent stretch reflex, represented by a progressively increasing knee flexion torque, was observed. In addition, another type of reflex that resembled a flexor reflex (flexion of the hip and ankle) was also triggered by the imposed knee extension. The magnitude of the ankle dorsiflexion torque responses was significantly correlated to the stretch reflex torque at the knee in 9 of the 15 subjects. We concluded that stretch reflexes initiate a muscle contraction that then can contribute to a flexor reflex response, possibly through muscle group III/IV afferent pathways. These results suggest that spasticity in SCI consists of a myriad of complex reflex responses that extend beyond stretch reflexes.

Poster 213: Effects of Botulinum Toxin Type A on Spasticity in Spinal Cord Injury: A Retrospective Chart Review

Objective: To evaluate the effect of botulinum toxin type A (BTX-A) injection in patients with a spinal cord injury (SCI) and focal spasticity. Design: Retrospective chart review. Setting: Outpatient clinic in a freestanding urban rehabilitation hospital. Participants: 39 historical patient charts. Intervention: Electromyographically guided intramuscular BTX-A injections. Main Outcome Measures: Charts were reviewed for history and level of SCI, Ashworth Scale before and after BTX-A, subjective rating of problem severity before and after injection including indication for BTX-A, and functional outcome on clinical follow-up.

Extensor spasms triggered by imposed knee extension in chronic human spinal cord injury

Extensor spasms, which are a significant component of spasticity in spinal cord injury (SCI), are still incompletely understood. In this study, contributions of knee proprioceptors to the origination of extensor spasms were examined in fifteen subjects with SCI. Ramp and hold knee extension perturbations were imposed to one leg while the hip and ankle were held in an isometric position using an instrumented leg brace. Isometric joint torques of knee, ankle and hip, and electromyograms (EMGs) from six muscles of the leg were recorded following controlled knee extension at four different velocities. Tests were conducted with the hip in both flexed and extended positions. A stereotypical torque response consisting of hip flexion, knee extension, and ankle plantar flexion was observed following knee perturbations, although not all components were demonstrated in every subject. During the hold periods with the knee extended, EMG activity recorded from the vastus medialis, medial gastrocnemius and rectus femoris demonstrated patterns consistent with clinical observations of extensor spasms. Furthermore, larger responses were observed with the hip in the extended vs. flexed position (p<0.05). Such behaviors emphasize the role of knee and hip proprioceptors in the initiation of extensor spasms in human SCI. This knowledge may be especially helpful in identifying rehabilitation strategies for producing functional movements in human SCI.