Beyond Ashworth: Electrophysiologic Quantification of Spasticity

Extracorporeal Shock Wave Therapy on Spasticity After Upper Motor Neuron Injury: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of the study was to evaluate the effectiveness and safety of extracorporeal shock wave therapy on spasticity after upper motor neuron injury.

DESIGN

Eight electronic databases were searched systematically from their inception to August 3, 2021, to provide robust evidence for the efficacy of extracorporeal shock wave therapy for spasticity and range of motion after upper motor neuron injury. Study screening, data extraction, risk of bias assessment, and evaluation of the certainty of evidence were performed independently by two independent reviewers. Data analysis was conducted using RevMan 5.3.5 and R 3.6.1 software.

RESULTS

Forty-two studies with 1973 patients who met the eligibility criteria were selected from articles published from 2010 to 2021, of which 34 were included in the meta-analysis. A comparison intervention revealed that extracorporeal shock wave therapy significantly decreased the Modified Ashworth Scale score and increased the passive range of motion of a joint. Regarding the safety of extracorporeal shock wave therapy, slightly adverse effects, such as skin injury, bone distortion, muscle numbness, pain, petechiae, and weakness, were reported in five studies.

CONCLUSIONS

Extracorporeal shock wave therapy may be an effective and safe treatment for spasticity after upper motor neuron injury. However, because of poor methodological qualities of the included studies and high heterogeneity, this conclusion warrants further investigation.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME.

CME OBJECTIVES

Upon completion of this article, the reader should be able to: (1) Determine the impact of extracorporeal shock wave therapy on spasticity after upper motor neuron injury; (2) Describe the factors that affect the efficacy of extracorporeal shock wave therapy on spasticity; and (3) Discuss the mechanism of action of extracorporeal shock wave therapy on spasticity.

LEVEL

Advanced.

ACCREDITATION

The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Respective Contributions of Instrumented 3D Gait Analysis Data and Tibial Motor Nerve Block on Presurgical Spastic Equinus Foot Assessment: A Retrospective Study of 40 Adults

Spastic equinus foot is a common deformity in neurologic patients who compromise walking ability. It is related to the imbalance between weak dorsiflexion and overactive plantar flexor muscles. To achieve the best functional results after surgical management, the challenge is to identify the relevant components involved in the deformity using several methods, namely, examination in the supine position, motor nerve blocks allowing transient anesthesia of suspected overactive muscles, and kinematic and electromyographic data collected during an instrumented 3D gait analysis. The procedure is not standardized; its use varies from one team to another. Access to gait analysis laboratories is limited, and some teams do not perform motor nerve blocks. When both examinations are available, instrumental data from the instrumented 3D gait analysis can be used to specify muscle targets for motor blocks, but data collected from both examinations are sometimes considered redundant. This retrospective cohort analysis compared examination in the supine position, temporary motor nerve blocks, and instrumented 3D gait analysis data in 40 adults after brain or spinal cord injuries. Clinical data collected before motor nerve block was not associated with instrumental data to assess calf muscle's overactivity and tibialis anterior function. Improvement of ankle dorsiflexion in the swing phase after tibial motor nerve block was associated with soleus spastic co-contraction during this phase corroborating its involvement in ankle dorsiflexion defects. This study showed the relevance of tibial motor nerve block to remove spastic calf dystonia and facilitate the assessment of calf contracture. It also underlined the need for complementary and specific analyses of the tibialis anterior abnormal activation pattern after motor nerve block to confirm or deny their pathological nature.

In vivo non-invasive near-infrared spectroscopy distinguishes normal, post-stroke, and botulinum toxin treated human muscles

In post-stroke hemiparesis, neural impairment alters muscle control, causing abnormal movement and posture in the affected limbs. A decrease in voluntary use of the paretic arm and flexed posture during rest also induce secondary tissue transformation in the upper limb muscles. To obtain a specific, accurate, and reproducible marker of the current biological status of muscles, we collected visible (VIS) and short-wave Infrared (SWIR) reflectance spectra in vivo using a portable spectroradiometer (350–2500 nm), which provided the spectral fingerprints of the elbow flexors and extensors. We compared the spectra for the affected and unaffected sides in 23 patients with post-stroke hemiparesis (25–87 years, 8 women) and eight healthy controls (33–87 years, 5 women). In eight patients, spectra were collected before and after botulinum toxin injection. Spectra underwent off-line preprocessing, principal component analysis, and partial least-squares discriminant analysis. Spectral fingerprints discriminated the muscle (biceps vs. triceps), neurological condition (normal vs. affected vs. unaffected), and effect of botulinum toxin treatment (before vs. 30 to 40 days vs. 110 to 120 days after injection). VIS-SWIR spectroscopy proved valuable for non-invasive assessment of optical properties in muscles, enabled more comprehensive evaluation of hemiparetic muscles, and provided optimal monitoring of the effectiveness of medication.

Duration of Treatment Effect of Extracorporeal Shock Wave on Spasticity and Subgroup-Analysis According to Number of Shocks and Application Site: A Meta-Analysis

Objective

To investigate duration of the treatment effect of extracorporeal shockwave therapy (ESWT) on spasticity levels measured with Modified Ashworth Scale (MAS) regardless of the patient group (stroke, multiple sclerosis, and cerebral palsy) and evaluate its spasticity-reducing effect depending on the number of shocks and site of application.

Methods

PubMed, EMBASE, the Cochrane Library, and Scopus were searched from database inception to February 2018. Randomized controlled trials and cross-over trials were included. All participants had spasticity regardless of cause. ESWT was the main intervention and MAS score was the primary outcome. Among 122 screened articles, 9 trials met the inclusion criteria.

Results

The estimate of effect size showed statistically significant MAS grade reduction immediately after treatment (standardized mean difference [SMD]=-0.57; 95% confidence interval [CI], -1.00 to -0.13; p=0.012), 1 week after (SMD=-1.81; 95% CI, -3.07 to -0.55; p=0.005), 4 weeks after (SMD=-2.35; 95% CI, -3.66 to -1.05; p<0.001), and 12 weeks after (SMD=-1.07; 95% CI, -2.04 to -0.10; p=0.03). Meta-regression and subgroup analysis were performed for the ‘immediately after ESWT application’ group. The prediction equation obtained from metaregression was -1.0824+0.0002^* (number of shocks), which was not statistically significant. Difference in MAS grade reduction depending on site of application was not statistically significant either in subgroup analysis (knee and ankle joints vs. elbow, wrist, and finger joints).

Conclusion

ESWT effectively reduced spasticity levels measured with MAS regardless of patient group. Its effect maintained for 12 weeks. The number of shocks or site of application had no significant influence on the therapeutic effect of ESWT in reducing spasticity. Ongoing trials with ESWT are needed to address optimal parameters of shock wave to reduce spasticity regarding intensity, frequency, and numbers.

Profiling walking dysfunction in multiple sclerosis: characterisation, classification and progression over time

Gait dysfunction is a common and relevant symptom in multiple sclerosis (MS). This study aimed to profile gait pathology in gait-impaired patients with MS using comprehensive 3D gait analysis and clinical walking tests. Thirty-seven patients with MS walked on the treadmill at their individual, sustainable speed while 20 healthy control subjects walked at all the different patient's paces, allowing for comparisons independent of walking velocity. Kinematic analysis revealed pronounced restrictions in knee and ankle joint excursion, increased gait variability and asymmetry along with impaired dynamic stability in patients. The most discriminative single gait parameter, differentiating patients from controls with an accuracy of 83.3% (χ2 test; p = 0.0001), was reduced knee range of motion. Based on hierarchical cluster and principal component analysis, three principal pathological gait patterns were identified: a spastic-paretic, an ataxia-like, and an unstable gait. Follow-up assessments after 1 year indicated deterioration of walking function, particularly in patients with spastic-paretic gait patterns. Our findings suggest that impaired knee/ankle control is common in patients with MS. Personalised gait profiles and clustering algorithms may be promising tools for stratifying patients and to inform patient-tailored exercise programs. Responsive, objective outcome measures are important for monitoring disease progression and treatment effects in MS trials.

Development of a clinical spasticity scale for evaluation of dogs with chronic thoracolumbar spinal cord injury

OBJECTIVE To develop a spasticity scale for dogs with chronic deficits following severe spinal cord injury (SCI) for use in clinical assessment and outcome measurement in clinical trials. ANIMALS 20 chronically paralyzed dogs with a persistent lack of hind limb pain perception caused by an acute SCI at least 3 months previously. PROCEDURES Spasticity was assessed in both hind limbs via tests of muscle tone, clonus, and flexor and extensor spasms adapted from human scales. Measurement of patellar clonus duration and flexor spasm duration and degree was feasible. These components were used to create a canine spasticity scale (CSS; overall score range, 0 to 18). Temporal variation for individual dogs and interrater reliability were evaluated. Gait was quantified with published gait scales, and CSS scores were compared with gait scores and clinical variables. Owners were questioned regarding spasticity observed at home. RESULTS 20 dogs were enrolled: 18 with no apparent hind limb pain perception and 2 with blunted responses; 5 were ambulatory. Testing was well tolerated, and scores were repeatable between raters. Median overall CSS score was 7 (range, 3 to 11), and flexor spasms were the most prominent finding. Overall CSS score was not associated with age, SCI duration, lesion location, or owner-reported spasticity. Overall CSS score and flexor spasm duration were associated with gait scores. CONCLUSIONS AND CLINICAL RELEVANCE The CSS could be used to quantify hind limb spasticity in dogs with chronic thoracolumbar SCI and might be a useful outcome measure. Flexor spasms may represent an integral part of stepping in dogs with severe SCI.

Effects of one session radial extracorporeal shockwave therapy on post-stroke plantarflexor spasticity: a single-blind clinical trial

Purpose To examine the effects of radial extracorporeal shockwave therapy (rESWT) on plantarflexor spasticity after stroke. Method Twelve patients with stroke were randomly included for this prospective, single-blind clinical trial. Patients received one rESWT session (0.340 mJ/mm², 2000 shots) on plantarflexor muscle. The Modified Modified Ashworth Scale (MMAS), H-reflex tests, ankle range of motion (ROM), passive plantarflexor torque (PPFT) and timed up and go test (TUG) were measured at baseline (T₀), immediately after treatment (T₁) and one hour after the end of the treatment (T₂). Results Patients had improved the MMAS scores for both the gastrocnemius and the soleus muscles, active and passive ROM, PPFT and TUG over time after rESWT. For the PPFT, it was greater at high velocity than at low velocity, and there was a significant three-way interaction between time, knee position (extended/flexed) and velocity (low/high). The H-reflex latency had decreased at T₁, but there was no significant effect on H_max/M_max ratio. Conclusions The rESWT improved plantarflexor spasticity, and the effects sustained for one hour, whereas it was not effective in improving spinal excitability. Implications for Rehabilitation One session radial extracorporeal shock wave therapy (rESWT) is safe and effective in improving post stroke plantarflexor spasticity, ankle active and passive range of motion, passive torque, and walking capability. The spasticity scores improved for both the gastrocnemius and the soleus muscles and persisted one hour after rESWT. The magnitude of resistive plantarflexor passive torque in the knee extended position and high velocity was larger over time suggesting greater gastrocnemius spasticity than soleus. The rESWT had no significant effects on alpha motorneuron excitability.

A single group, pretest-posttest clinical trial for the effects of dry needling on wrist flexors spasticity after stroke

BACKGROUND

Spasticity is a common complication after stroke. Dry needling (DN) is suggested as a novel method for treatment of muscle spasticity.

OBJECTIVE

To explore the effects of DN on wrist flexors spasticity poststroke.

METHODS

A single group, pretest-posttest clinical trial was used. Twenty nine patients with stroke (16 male; mean age 54.3 years) were tested at baseline (T0), immediately after DN (T1), and one hour after DN (T2). DN was applied for flexor carpi radialis (FCR) and flexor carpi ulnaris on the affected arm for single session, one minute per muscle. The Modified Modified Ashworth Scale (MMAS), passive resistance force, wrist active and passive range of motion, Box and Block Test, and FCR H-reflex were outcome measures.

RESULTS

Significant reductions in MMAS scores were seen both immediately after DN and at 1-hour follow-up (median 2 at T0 to 1 at T1 and T2). There were significant improvements in other measures between the baseline values at T0 and those recorded immediately after the DN at T1 or one hour later at T2.

CONCLUSIONS

This study suggests that DN reduced wrist flexors spasticity and alpha motor neuron excitability in patients with stroke, and improvements persisted for one hour after DN.

Effects of robotic-locomotor training on stretch reflex function and muscular properties in individuals with spinal cord injury

OBJECTIVE

We sought to determine the therapeutic effect of robotic-assisted step training (RAST) on neuromuscular abnormalities associated with spasticity by characterization of their recovery patterns in people with spinal cord injury (SCI).

METHODS

Twenty-three motor-incomplete SCI subjects received one-hour RAST sessions three times per week for 4 weeks, while an SCI control group received no training. Neuromuscular properties were assessed using ankle perturbations prior to and during the training, and a system-identification technique quantified stretch reflex and intrinsic stiffness magnitude and modulation with joint position. Growth-mixture modeling classified subjects based on similar intrinsic and reflex recovery patterns.

RESULTS

All recovery classes in the RAST group presented significant (p<0.05) reductions in intrinsic and reflex stiffness magnitude and modulation with position; the control group presented no changes over time. Subjects with larger baseline abnormalities exhibited larger reductions, and over longer training periods.

CONCLUSIONS

Our findings demonstrate that RAST can effectively reduce neuromuscular abnormalities, with greater improvements for subjects with higher baseline abnormalities.

SIGNIFICANCE

Our findings suggest, in addition to its primary goal of improving locomotor patterns, RAST can also reduce neuromuscular abnormalities associated with spasticity. These findings also demonstrate that these techniques can be used to characterize neuromuscular recovery patterns in response to various types of interventions.

Clinical assessment of ankle plantarflexor spasticity in adult patients after stroke: inter-and intra-rater reliability of the Modified Tardieu Scale

PRIMARY OBJECTIVE

To evaluate the reliability of the Modified Tardieu Scale (MTS) in the measurement of ankle plantarflexor spasticity in patients after stroke.

RESEARCH DESIGN

Inter- and intra-rater reliability study.

INTERVENTIONS

Not applicable.

METHODS AND PROCEDURES

Adult patients after stroke participated. Patients were tested by two raters for inter-rater reliability. Patients were re-tested by one rater at least 1 week later for intra-rater reliability. The plantarflexors on the hemiparetic side were tested.

MAIN OUTCOMES AND RESULTS

The ICCs of inter and intra-rater reliability across all components of MTS were moderate and moderately high (range 0.40-0.71). Inter- and intra-rater reliability for the dynamic component of spasticity (R2-R1) were moderate (ICC = 0.57 and 0.40, respectively). The difference between the two raters for R2 was statistically significant (p = 0.001).

CONCLUSIONS

The reliability of the Modified Tardieu Scale in the measurement of ankle plantarflexor spasticity in adult patients after stroke was insufficient for routine use in clinical settings and research.

Prediction of stroke motor recovery using reflex stiffness measures at one month

This study characterizes the recovery patterns of motor impairment after stroke, and uses neuromuscular measures of the elbow joint at one month after the event to predict the ensuing recovery patterns over 12 months. Motor impairment was assessed using the Fugl-Meyer Assessment (FMA) of the upper extremity at various intervals after stroke. A parallel-cascade system identification technique characterized the intrinsic and reflex stiffness at various elbow angles. We then used "growth-mixture" modeling to identify three distinct recovery classes for FMA. While class 1 and class 3 subjects both started with low FMA, those in class 1 increased FMA significantly over 12-month recovery period, whereas those in class 3 presented no improvement. Class 2 subjects started with high FMA and also exhibited significant FMA improvement, but over a smaller range and at a slower recovery rate than class 1. Our results showed that the one-month reflex stiffness was able to distinguish between classes 1 and 3 even though both showed similarly low month-1 FMA. These findings demonstrate that, using reflex stiffness, we were able to accurately predict arm function recovery in stroke subjects over one year and beyond. This information is clinically significant and can be helpful in developing targeted therapeutic interventions.

Robotic training and kinematic analysis of arm and hand after incomplete spinal cord injury: a case study

Regaining upper extremity function is the primary concern of persons with tetraplegia caused by spinal cord injury (SCI). Robotic rehabilitation has been inadequately tested and underutilized in rehabilitation of the upper extremity in the SCI population. Given the acceptance of robotic training in stroke rehabilitation and SCI gait training, coupled with recent evidence that the spinal cord, like the brain, demonstrates plasticity that can be catalyzed by repetitive movement training such as that available with robotic devices, it is probable that robotic upper-extremity training of persons with SCI could be clinically beneficial. The primary goal of this pilot study was to test the feasibility of using a novel robotic device for the upper extremity (RiceWrist) and to evaluate robotic rehabilitation using the RiceWrist in a tetraplegic person with incomplete SCI. A 24-year-old male with incomplete SCI participated in 10 sessions of robot-assisted therapy involving intensive upper limb training. The subject successfully completed all training sessions and showed improvements in movement smoothness, as well as in the hand function. Results from this study provide valuable information for further developments of robotic devices for upper limb rehabilitation in persons with SCI.

Spasticity and electrophysiologic changes after extracorporeal shock wave therapy on gastrocnemius

Objective

To evaluate the spasticity and electrophysiologic effects of applying extracorporeal shock wave therapy (ESWT) to the gastrocnemius by studying F wave and H-reflex.

Method

Ten healthy adults and 10 hemiplegic stroke patients with ankle plantarflexor spasticity received one session of ESWT on the medial head of the gastrocnemius. The modified Ashworth scale (MAS), tibial nerve conduction, F wave, and H-reflex results were measured before and immediately after the treatment. The Visual Analogue Scale (VAS) was used during ESWT to measure the side effects, such as pain.

Results

There were no significant effects of ESWT on the conduction velocity, distal latency and amplitude of tibial nerve conduction, minimal latency of tibial nerve F wave, latency, or H-M ratio of H-reflex in either the healthy or stroke group. However, the MAS of plantarflexor was significantly reduced from 2.67±1.15 to 1.22±1.03 (p<0.05) after applying ESWT in the stroke group.

Conclusion

After applying ESWT on the gastrocnemius in stroke patients, the spasticity of the ankle plantarflexor was significantly improved, with no changes of F wave or H-reflex parameters. Further studies are needed to evaluate the mechanisms of the antispastic effect of ESWT.

Validation of the Santa Casa evaluation of spasticity scale

Spasticity is a clinical condition that has negative repercussions on function. A scale capable of quantifying the severity and impact of an injury is fundamental to the rehabilitation process. The objective of this study was to retest and validate the Santa Casa evaluation of spasticity scale, a descriptive assessment of activities of daily living, transfers and locomotion. We analyzed spasticity and functional status in 97 hemiparetic patients. With statistical significance (p<0.05), this new scale demonstrated reliability in assessing clinical-functional conditions and reproducibility as a daily assessment scale for use during rehabilitation.

A neurophysiological and clinical study of Brunnstrom recovery stages in the upper limb following stroke

PRIMARY OBJECTIVE

To determine the extent to which the Brunnstrom recovery stages of upper limb in hemiparetic stroke patients are correlated to neurophysiological measures and the spasticity measure of Modified Modified Ashworth Scale (MMAS).

RESEARCH DESIGN

A concurrent criterion-related validity study.

INTERVENTIONS

Not applicable.

METHODS AND PROCEDURES

Thirty patients (15 men and 15 women; mean ± SD = 58.8 ± 11.5 years) with upper limb spasticity after stroke were recruited. Wrist flexor spasticity was rated using the MMAS. The neurophysiological measures were Hslp/Mslp ratio, H(max)/M(max) ratio and Hslp.

MAIN OUTCOMES AND RESULTS

There was a significant moderate correlation between the Brunnstrom recovery stages and the neurophysiological measures. The Brunnstrom recovery stages were highly correlated to the MMAS scores (r = -0.81, p < 0.0001).

CONCLUSIONS

The Brunnstrom recovery stages are moderately correlated with neurophysiological measures and highly correlated with the MMAS regarding the evaluation of motor recovery in stroke patients. The Brunnstrom recovery stages can be used as a valid test for the assessment of patients with post-stroke hemiplegia.

Reliability of Ashworth and Modified Ashworth scales in children with spastic cerebral palsy

BACKGROUND

Measurement of spasticity is a difficult and unresolved problem, partly due to its complexity and the fact that there are many factors involved. In the assessment of spasticity in the pediatric disabled population, methods that are easily used in practice are ordinal scales that still lack reliability. A prospective cross-sectional observational study was planned to determine the reliability of the Ashworth Scale (AS) and the Modified Ashworth Scale (MAS) in children with spastic cerebral palsy (CP).

METHODS

The study included 38 children with spastic diplegic CP. The mean age for the children was 52.9 months (SD: 19.6) ranging from 18 to 108 months. The functional levels of children were classified according to the Gross Motor Function Classification System. 20 children were in Level II (52.6%), 18 were in Level III (47.4%) and 9 were in Level I (23.7%). Spasticity in hip flexors, adductors, internal rotators, hamstrings, gastrocnemius were assessed by AS and MAS. Each child was assessed by three physiotherapists in two different sessions, a week apart. The intrarater reliability was determined by paired comparison of measurements for each therapist for the two assessments. Interrater reliability was determined by paired comparisons of the three therapists' measurements on the same day. The inter and intrarater reliability of the scales were evaluated by the intraclass correlation coefficient (ICC).

RESULTS

According to ICC scores, interrater reliability of AS and MAS varied from moderate to good. ICC scores of AS were between 0.54 and 0.78 and MAS were between 0.61-0.87. Test-retest results of AS and MAS varied from poor to good. ICC values were between 0.31 and 0.82 for AS and between 0.36 and 0.83 for MAS.

CONCLUSION

The interrater and intrarater reliability of AS and MAS are related to muscle and joint characters. The repetition of measurements by the same physiotherapist, and experience may not affect reliability. These scales are not very reliable and assessments of spasticity using these scales should be therefore interpreted with great caution.

Mechanical abnormalities of the spastic ankle in chronic stroke subjects

We examined the intrinsic and reflex contributions to ankle stiffness in people with chronic stroke and healthy subjects using the parallel system identification technique. Modulation of intrinsic and reflex stiffness was characterized by applying pseudorandom binary sequence (PRBS) perturbations to the ankle at different initial ankle joint over the entire range of motion (ROM). The experiments were performed for both paretic (stroke) and contralateral (control) side. Healthy (normal) subjects were used a secondary control. Reflex stiffness gain significantly increased in stroke than in control side at most positions. Intrinsic stiffness gain also increased significantly at dorsiflexing positions. These changes were position dependent. Thus, the abnormalities in intrinsic stiffness gain increased continuously from middle plantarflexion to full dorsiflexion while the major increase in reflex stiffness happened at the middle ROM. No significant changes were found in other intrinsic and reflex stiffness parameters. As compared to the normal ankle, the reflex stiffness gain of the control side was significantly larger, indicating that the control side is not normal. These findings demonstrate that both intrinsic and reflex stiffness contribute significantly to the mechanical abnormality associated with spastic ankle in hemiplegic stroke subjects. The results also suggest that the contralateral limb may not be used as a suitable control.

Muscle and reflex changes with varying joint angle in hemiparetic stroke

Background

Despite intensive investigation, the origins of the neuromuscular abnormalities associated with spasticity are not well understood. In particular, the mechanical properties induced by stretch reflex activity have been especially difficult to study because of a lack of accurate tools separating reflex torque from torque generated by musculo-tendinous structures. The present study addresses this deficit by characterizing the contribution of neural and muscular components to the abnormally high stiffness of the spastic joint.

Methods

Using system identification techniques, we characterized the neuromuscular abnormalities associated with spasticity of ankle muscles in chronic hemiparetic stroke survivors. In particular, we systematically tracked changes in muscle mechanical properties and in stretch reflex activity during changes in ankle joint angle. Modulation of mechanical properties was assessed by applying perturbations at different initial angles, over the entire range of motion (ROM). Experiments were performed on both paretic and non-paretic sides of stroke survivors, and in healthy controls.

Results

Both reflex and intrinsic muscle stiffnesses were significantly greater in the spastic/paretic ankle than on the non-paretic side, and these changes were strongly position dependent. The major reflex contributions were observed over the central portion of the angular range, while the intrinsic contributions were most pronounced with the ankle in the dorsiflexed position.

Conclusion

In spastic ankle muscles, the abnormalities in intrinsic and reflex components of joint torque varied systematically with changing position over the full angular range of motion, indicating that clinical perceptions of increased tone may have quite different origins depending upon the angle where the tests are initiated.

Furthermore, reflex stiffness was considerably larger in the non-paretic limb of stroke patients than in healthy control subjects, suggesting that the non-paretic limb may not be a suitable control for studying neuromuscular properties of the ankle joint.

Our findings will help elucidate the origins of the neuromuscular abnormalities associated with stroke-induced spasticity.

Upper limb impairments associated with spasticity in neurological disorders

Background

While upper-extremity movement in individuals with neurological disorders such as stroke and spinal cord injury (SCI) has been studied for many years, the effects of spasticity on arm movement have been poorly quantified. The present study is designed to characterize the nature of impaired arm movements associated with spasticity in these two clinical populations. By comparing impaired voluntary movements between these two groups, we will gain a greater understanding of the effects of the type of spasticity on these movements and, potentially a better understanding of the underlying impairment mechanisms.

Methods

We characterized the kinematics and kinetics of rapid arm movement in SCI and neurologically intact subjects and in both the paretic and non-paretic limbs in stroke subjects. The kinematics of rapid elbow extension over the entire range of motion were quantified by measuring movement trajectory and its derivatives; i.e. movement velocity and acceleration. The kinetics were quantified by measuring maximum isometric voluntary contractions of elbow flexors and extensors. The movement smoothness was estimated using two different computational techniques.

Results

Most kinematic and kinetic and movement smoothness parameters changed significantly in paretic as compared to normal arms in stroke subjects (p < 0.003). Surprisingly, there were no significant differences in these parameters between SCI and stroke subjects, except for the movement smoothness (p ≤ 0.02). Extension was significantly less smooth in the paretic compared to the non-paretic arm in the stroke group (p < 0.003), whereas it was within the normal range in the SCI group. There was also no significant difference in these parameters between the non-paretic arm in stroke subjects and the normal arm in healthy subjects.

Conclusion

The findings suggest that although the cause and location of injury are different in spastic stroke and SCI subjects, the impairments in arm voluntary movement were similar in the two spastic groups. Our results also suggest that the non-paretic arm in stroke subjects was not distinguishable from the normal, and might therefore be used as an appropriate control for studying movement of the paretic arm.

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 (alpha) 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.

Neuromuscular abnormalities associated with spasticity of upper extremity muscles in hemiparetic stroke

Our objective was to assess the mechanical changes associated with spasticity in elbow muscles of chronic hemiparetic stroke survivors and to compare these changes with those recorded in the ankle muscles of a similar cohort. We first characterized elbow dynamic stiffness by applying pseudorandom binary positional perturbations to the joints at different initial angles, over the entire range of motion, with subjects relaxed. We separated this stiffness into intrinsic and reflex components using a novel parallel cascade system identification technique. In addition, for controls, we studied the nonparetic limbs of stroke survivors and limbs of age-matched healthy subjects as primary and secondary controls. We found that both reflex and intrinsic stiffnesses were significantly larger in the stroke than in the nonparetic elbow muscles, and the differences increased as the elbow was extended. Reflex stiffness increased monotonically with the elbow angle in both paretic and nonparetic sides. In contrast, the modulation of intrinsic stiffness with elbow position was different in nonparetic limbs; intrinsic stiffness decreased sharply from full- to mid-flexion in both sides, then it increased continuously with the elbow extension in the paretic side. It remained invariant in the nonparetic side. Surprisingly, reflex stiffness was larger in the nonparetic than in the normal control arm, yet intrinsic stiffness was smaller in the nonparetic arm. Finally, we compare the angular dependence of paretic elbow and ankle muscles and show that the modulation of reflex stiffness with position was strikingly different.

Measurement of plantarflexor spasticity in traumatic brain injury: correlational study of resistance torque compared with the modified Ashworth scale

OBJECTIVES

To examine the usefulness of a biomechanical measure, resistance torque (RT), in quantifying spasticity by comparing its use with a clinical scale, the modified Ashworth scale (MAS), and quantitative electrophysiological measures.

DESIGN

This is a correlational study of spasticity measurements in 34 adults with traumatic brain injury and plantarflexor spasticity. Plantarflexor spasticity was measured in the seated position before and after cryotherapy using the MAS and also by strapping each subject's foot and ankle to an apparatus that provided a ramp and hold stretch. The quantitative measures were (1) reflex threshold angle (RTA) calculated through electromyographic signals and joint angle traces, (2) Hdorsiflexion (Hdf)/Hcontrol (Hctrl) amplitude ratio obtained through reciprocal inhibition of the soleus H-reflex, (3) Hvibration (Hvib)/Hctrl ratio obtained through vibratory inhibition of the soleus H-reflex, and (4) RT calculated as the time integral of the torque graph between the starting and ending pulses of the stretch.

RESULTS

Correlation coefficients between RT and MAS scores in both pre-ice (0.41) and post-ice trials (0.42) were fair (P = 0.001). The correlation coefficients between RT scores and RTA scores in both the pre-ice (0.66) and post-ice trials (0.75) were moderate (P <or= 0.001).

CONCLUSION

RT is a measure of the cumulative torque during an imposed stretch. The MAS is a subjective measure of the cumulative resistance perceived by the clinician during an imposed stretch. RT seems to be a fair quantitative correlate of the MAS in assessing spasticity.

Evaluation of Spastic Muscle in Stroke Survivors Using Magnetic Resonance Imaging and Resistance to Passive Motion

OBJECTIVE

To assess the feasibility of using magnetic resonance imaging (MRI) and resistance to passive movement to evaluate spastic muscle.

DESIGN

T2-weighted MRI scans of the upper arm were obtained at rest and after the performance of upper-arm exercise. In addition, resistance to passive movement was measured subjectively (Modified Ashworth Scale [MAS]) and objectively by an isokinetic device while the arm was moved at varying speeds (stretch reflex torque).

SETTING

Research laboratory.

PARTICIPANTS

Six hemiplegic stroke survivors (single group) with spasticity in the elbow flexors and extensors.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Strength, stretch reflex torque, MAS, MRI-derived muscle cross-sectional area (CSA), and transverse relaxation time (T2).

RESULTS

The affected sides exhibited spasticity (as assessed through MAS), with the extensors displaying a range of 0 to 3, and the flexors between 1 and 1+. The affected muscle groups were significantly weaker than the unaffected muscle groups (extensors: 61% less, flexors: 65% less; P< or =.05). The affected CSA of the triceps was 25% smaller than that of the unaffected side (P=.01), but the biceps muscle group was similar (5% less on the affected side, P> or =.05). There was a tendency (P=.07; effect size, .48) for the resting T2 to be higher in affected versus unaffected biceps, but triceps values were similar (P> or =.05). Both muscle groups showed an increase in T2 after exercise ( approximately 30%, P< or =.05); however, the affected sides did not show an increase (P> or =.05). For both muscle groups, the affected side had a greater stretch reflex torque, with the range of torque values being greater than the range of MAS scores.

CONCLUSIONS

MRI and quantitative resistance to passive movement may be useful in the evaluation of spasticity. This is clinically relevant for the development and evaluation of antispasticity treatments.

Ashworth Scales are unreliable for the assessment of muscle spasticity

Ashworth Scales are the most widely used tests to assess the severity of muscle spasticity. These scales offer qualitative and subjective information; consequently, there are issues concerning validity and reliability. This article presents the results of a study comparing interrater reliability of the original and of the modified Ashworth Scales for measuring muscle spasticity in elbow flexors. Fifteen patients with hemiplegia (nine men and six women) with a median age of 52 years (interquartile range, 28-64) participated in this study. Two physiotherapists rated the muscle tone of elbow flexors according to ratings criteria of the Ashworth and the modified Ashworth Scales. Kappa values for the original Ashworth and the modified Ashworth Scales were 0.17 (SE 0.21; p = 0.41) and 0.21 (SE = 0.12; p = 0.08), respectively. The scales showed similar levels of reliability (chi2= 0.0285, df=1, p = 0.7). The Ashworth Scales are not reliable for the assessment of muscle spasticity. In the absence of interrater reliability, the validity of the measurements may also be questioned.

Spasticity after spinal cord injury

Symptoms of spasticity are often experienced by individuals with spinal cord injury (SCI) following a period of spinal shock and, in many cases, these symptoms negatively affect quality of life. Despite its prevalence, spasticity as a syndrome in the SCI population is not always managed effectively. This is likely due to the fact that the syndrome can have various presentations, each with their own specific etiology. This overview summarizes the symptoms and pathophysiology of the various presentations of spasticity in the SCI population and discusses the currently accepted management techniques. There is a need for a better understanding of the syndrome of spasticity as well as the development of a valid and reliable assessment tool.

Identification of intrinsic and reflex ankle stiffness components in stroke patients

Reflex and intrinsic contributions to ankle stiffness were examined in 11 stroke patients with clinical evidence of ankle spasticity and nine gender-matched and age-matched controls. Subjects lay supine with one foot placed in a custom-fitted boot attached to an electro-hydraulic actuator. They were instructed to relax while pseudo-random binary sequence perturbations were applied to their ankle joint. The ankle position and torque, as well as EMG from the ankle dorsiflexors and plantarflexors were recorded. These were used to identify reflex and intrinsic components of ankle stiffness, using a non-linear, parallel-cascade, system identification method. Results demonstrated that the majority of stroke patients (7/11) had ankle stiffness similar to that of control subjects. In contrast, a minority of stroke patients (4/11) had an abnormal increase in ankle stiffness, most of which could be attributed to an increased reflex gain. Reflex stiffness increased as the ankle was dorsiflexed in all subjects. These results differ from a previous study showing that reflex gain and intrinsic stiffness were increased in all patients with spinal cord injury. This difference may reflect the different topography of the lesions in the two neurological conditions.

Interest of peripheral anesthetic blocks as a diagnosis and prognosis tool in patients with spastic equinus foot: A clinical and electrophysiological study of the effects of block of nerve branches to the triceps surae muscle

OBJECTIVE

To evaluate clinically and electrophysiologically the effects of selective anesthetic blocks of motor nerve branches to the triceps surae muscle on lower limb stretch reflex in patients with spastic equinus foot.

METHODS

Eleven patients were assessed before and after selective anesthetic block of the superior soleus nerve or the gastrocnemius nerves, performed by lidocaine injection. The stretch reflex (SR) of the ankle with the knee flexed or extended and the Achilles tendon reflex (TR) were scored clinically. Additionally, the direct M response and the H reflex to tibial nerve stimulation were recorded on the three heads of the triceps surae muscle. The ratio of H reflex to M response of maximal amplitudes (H(max)/M(max)) was calculated.

RESULTS

The SR and TR mean scores were significantly reduced after soleus nerve block but not after gastrocnemius nerve block. Electrophysiologically, H(max) and H(max)/M(max) ratios were significantly reduced for the soleus muscle after soleus nerve block and for the lateral (but not medial) gastrocnemius muscle after gastrocnemius nerve block.

CONCLUSIONS

Soleus nerve block appeared more appropriate than gastrocnemius nerve block to relieve spasticity clinically. In addition, the decrease in H(max)/M(max) ratio suggested that lidocaine preferentially blocked proprioceptive Ia fibers rather than A-alpha motor fibers.

SIGNIFICANCE

Selective anesthetic blocks of nerve branches to the triceps surae muscle are useful in the assessment of lower limb spasticity and can benefit from H reflex investigation. H reflex recordings showed a preferential susceptibility of muscle spindle afferents to local anesthetics and supported the hypothesis of a prominent role of the soleus muscle in spastic ankle. The clinical and electrophysiological effects induced by anesthetic blocks may help to guide therapeutic interventions, such as neurotomy, neurolysis or botulinum toxin injection.

Spasticity

Spasticity is a sensorimotor phenomenon related to the integration of the nervous system motor responses to sensory input. Although most commonly considered a velocity-dependent increase to tonic stretch, it is related to hypersensitivity of the reflex arc and changes that occur within the central nervous system, most notably, the spinal cord. Injury to the central nervous system results in loss of descending inhibition, allowing for the clinical manifestation of abnormal impulses. Muscle activity becomes overactive. This is mediated at several areas of the stretch-reflex pathway. Although spasticity is part of the upper motor neuron syndrome, it is frequently tied to the other presentations of the said syndrome. Contracture, hypertonia, weakness, and movement disorders can all coexist as a result of the upper motor neuron syndrome. Although basic science descriptions of spasticity are being elucidated, clinically, confusion exists.

Outcome Assessment for Spasticity Management in the Patient With Traumatic Brain Injury

The objective of this article was to (1) review the engineering and medical literature to structure the available information concerning the assessment of spasticity in the neurological population; (2) to discuss the strengths and weaknesses of the different methods currently in use in spasticity assessment; and (3) make recommendations for future efforts in spasticity outcome assessment. Spasticity textbooks, Web sites, and OVID, IEEE, and Medline searches from 1966 through 2003 of spasticity, quantitative measure, or outcome assessment in the rehabilitation population were used as data sources. Over 500 articles were reviewed. Articles that discussed outcome measures used to assess interventions and evaluation of spasticity were included. Authors reviewed the articles looking at inclusion criteria, data collection, methodology, assessment methods, and conclusions for validity and relevance to this article. Issues such as clinical relevance, real-world function and lack of objectivity, and time consumed during performance are important issues for spasticity assessment. Some measures such as the Ashworth Scale remain in common use secondary to ease of use despite their obvious functional limitations. More functional outcome goals are plagued by being more time consuming and a general inability to demonstrate changes after an intervention. This may be secondary to the other factors that combine with spasticity to cause dysfunction at that level. Quantitative metrics can provide more objective measurements but their clinical relevance is sometimes problematic. The assessment of spasticity outcome is still somewhat problematic. Further work is necessary to develop measures that have real-world functional significance to both the individuals being treated and the clinicians. A lack of objectivity is still a problem. In the future it is important for clinicians and the engineers to work together in the development of better outcome measures.

The importance of posture on the isokinetic assessment of spasticity

OBJECTIVE

To measure spasticity of the knee flexors and extensor muscles in two different hip positions.

SETTING

Swiss Paraplegic Center Nottwil, Switzerland.

METHODS

Twenty spinal cord injured (SCI) patients with complete lesions were tested with a torque-velocity dynamometer in the following positions: (1) supine with a hip angle of 0 degrees; (2) sitting with a hip angle of 90 degrees. The excursion of the knee was measured for both positions using a goniometer. Two flexion/extension movements of the knee were performed at a speed of 10 degrees per sec. A further four flexion/extension movements over the same trajectory were made at a speed of 120 degrees per sec. Eccentric peak torques were measured continuously during movement of both legs for both speeds.

RESULTS

At a speed of 120 degrees per second, there was a significant difference in stretch reflex of the hamstrings and quadriceps femoris muscles for the two positions (Wilcoxon's paired t-test, P<0.05). Excitability was higher for the quadriceps femoris muscles in supine than in sitting position. For the hamstrings, the effect was reversed. Significant differences between sitting and supine position were not found for the speed of 10 degrees per sec. Test-retest reliability was high for the movements of 120 degrees per sec but low for 10 degrees per sec.

CONCLUSIONS

Our findings indicate that for a reliable and comparable measurement of spasticity, an exact description of test position and procedure is essential.