Dynamometer-based measure of spasticity confirms limited association between plantarflexor spasticity and walking function in persons with multiple sclerosis

Gait training facilitates push-off and improves gait symmetry in children with cerebral palsy

BACKGROUND

Human walking involves a rapid and powerful contraction of ankle plantar flexors during push-off in late stance.

OBJECTIVE

Here we investigated whether impaired push-off force contributes to gait problems in children with cerebral palsy (CP) and whether it may be improved by intensive gait training.

METHODS

Sixteen children with CP (6-15 years) and fourteen typically developing (TD) children (4-15 years) were recruited. Foot pressure was measured by insoles and gait kinematics were recorded by 3-dimensional video analysis during treadmill and overground walking. The peak derivative of ground reaction force at push off (dPF) was calculated from the foot pressure measurements. Maximal voluntary plantar flexion (MVC) was measured while seated. Measurements were performed before and after a control period and after 4 weeks of 30 minutes daily inclined treadmill training.

RESULTS

dPF and MVC were significantly lower in children with CP on the most affected (MA) as compared to TD children (p < .001). dPF was lower on the MA leg as compared to the less affected (LA) leg in children with CP (p < .05). Following gait training, increases in dPF (p < .001) and MVC (p < .01) were observed for the MA leg. Following gait training children with CP showed similar timing of dPF and similar stance phase duration on both legs indicating improved symmetry of gait. These effects were also shown during overground walking.

CONCLUSION

Impaired ability to voluntarily activate ankle plantar flexors and produce a rapid and powerful push-off during late stance are of importance for impaired gait function in children with CP. Intensive treadmill training may facilitate the drive to ankle plantar flexors and reduce gait asymmetry during both treadmill and overground walking.

Assessment and Measurement of Spasticity in MS: State of the Evidence

PURPOSE OF REVIEW

The purpose of this review is to familiarize the reader with assessments and measurement of spasticity in people with multiple sclerosis (MS). Spasticity affects 60-84% of people with MS, worsening as disability worsens and impacting activity, participation, and quality of life. Spasticity manifests in many ways, including spasms, resistance to passive stretch, pain, and perception of tightness, and can affect muscles throughout the body, making assessment and quantification of spasticity challenging but important. Assessment tools include those quantified by clinicians, instrumentation, and patients.

RECENT FINDINGS

Most tools for measuring spasticity are based on clinician scoring, were developed many years ago, and have undergone minimal recent advances. More recent developments are patient-reported outcome measures for spasticity, including the Numeric Rating Scale for Spasticity (NRS-S) and the disease-specific Multiple Sclerosis Spasticity Scale-88 (MSSS), and, most recently, imaging through elastography. MS-related spasticity is common and often disabling. There are various spasticity measurement tools available, each with advantages and limitations. Newer tools are likely to be developed as our understanding of spasticity in MS grows.

Spasticity, gait, and balance in patients with multiple sclerosis: A cross-sectional study

OBJECTIVE

More than 80% of people with multiple sclerosis (MS) are affected by spasticity. Spasticity is known to reduce quality of life and contribute to additional symptoms, such as pain and reduced mobility, but the association between spasticity, balance, and mobility has not yet been established. Our aim was to examine whether a relationship exists between spasticity in the lower limbs, balance, and gait, as well as to explore the involvement of different muscle groups.

METHODS

This study employed a cross-sectional design. Thirty patients with MS were included. The Modified Ashworth Scale (MAS) was used to examine spasticity in the ankle plantar flexors, knee extensors, and hip adductors. Balance was measured using the Mini-Balance Evaluation Systems Test, and gait with the 2-Minute Walk Test. The participants were tested once with no additional follow-up. Spearman's correlation, recursive partitioning, and linear regression analyses were used to explore the association.

RESULTS

A significant correlation between gait distance and spasticity in the ankle plantar flexors (ρ = -.69, p < .001) and knee extensors (ρ = -.45, p = .012) was observed. Balance significantly correlated with spasticity in ankle plantar flexors (ρ = -.69, p < .001), knee extensors (ρ = -.52, p = .003), and hip adductors (ρ = -.5, p = .005). The relationship between spasticity in ankle plantar flexors and hip adductors was significant, even from low levels of spasticity, whereas MAS score ≥ 2 was clinically correlated with a decrease in gait and balance function. Adjustments for sex, age, or years since diagnosis had only minor impact on the results.

CONCLUSIONS

This study indicates that spasticity in the lower limbs is clinically significantly associated with mobility in people with MS.

Cryotherapy reduces muscle hypertonia, but does not affect lower limb strength or gait kinematics post-stroke: a randomized controlled crossover study

BACKGROUND

Based on the premise that spasticity might affect gait post-stroke, cryotherapy is among the techniques used to temporarily reduce spasticity in neurological patients. This effective technique would enhance muscle performance, and ultimately, functional training, such as walking. However, understanding whether a decrease in spasticity level, if any, would lead to improving muscle performance and gait parameters is not based on evidence and needs to be clarified.

OBJECTIVES

to investigate the immediate effects of cryotherapy, applied to spastic plantarflexor muscles of subjects post-stroke, on tonus level, torque generation capacity of plantarflexors and dorsiflexors, and angular/spatiotemporal gait parameters.

METHODS

Sixteen chronic hemiparetic subjects participated in this randomized controlled crossover study. Cryotherapy (ice pack) or Control (room temperature sand pack) were applied to the calf muscles of the paretic limb. The measurements taken (before and immediately after intervention) were: 1) Tonus according to the Modified Ashworth Scale; 2) Torque assessments were performed using an isokinetic dynamometer; and 3) Spatiotemporal and angular kinematics of the hip, knee, and ankle (flexion/extension), obtained using a tridimensional movement analysis system (Qualisys).

RESULTS

Cryotherapy decreased plantarflexor tonus but did not change muscle torque generation capacity and did not affect spatiotemporal or angular parameters during gait compared to control application. These findings contribute to the evidence-based approach to clinical rehabilitation post-stroke.

CONCLUSIONS

The findings of this study suggest that cryotherapy applied to the calf muscles of subjects with chronic hemiparesis reduces muscle hypertonia but does not improve dorsiflexors and plantarflexors performance and gait parameters.

Temporal Indices of Ankle Clonus and Relationship to Electrophysiologic and Clinical Measures in Persons With Spinal Cord Injury

BACKGROUND AND PURPOSE

Clonus arising from plantar flexor hyperreflexia is a phenomenon that is commonly observed in persons with spastic hypertonia. We assessed the temporal components of a biomechanical measure to quantify ankle clonus, and validated these in persons with spasticity due to spinal cord injury.

METHODS

In 40 individuals with chronic (>1 year) spinal cord injury, we elicited ankle clonus using a standardized mechanical perturbation (drop test). We examined reliability and construct validity of 2 components of the drop test: clonus duration (timed with a stopwatch) and number of oscillations in the first 10-second interval (measured via optical motion capture). We compared these measures to the Spinal Cord Assessment Tool for Spastic reflexes (SCATS) clonus score and H-reflex/M-wave (H/M) ratio, a clinical and electrophysiologic measure, respectively.

RESULTS

Intra- and interrater reliability of clonus duration measurement was good [intraclass correlation coefficient, ICC (2, 1) = 1.00]; test-retest reliability was good both at 1 hour [ICC (2, 2) = 0.99] and at 1 week [ICC (2, 2) = 0.99]. Clonus duration was moderately correlated with SCATS clonus score (r = 0.58). Number of oscillations had good within-session test-retest reliability [ICC (2, 1) > 0.90] and strong correlations with SCATS clonus score (r = 0.86) and soleus H/M ratio (r = 0.77).

DISCUSSION AND CONCLUSIONS

Clonus duration and number of oscillations as measured with a standardized test are reliable and valid measures of plantar flexor hyperreflexia that are accessible for clinical use. Tools for objective measurement of ankle clonus are valuable for assessing effectiveness of interventions directed at normalizing reflex activity associated with spasticity.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A179).

Increases in fatigue do not change spasticity scores in persons with multiple sclerosis

AIM

Fatigue is a common finding in multiple sclerosis (MS) which may result in worsening of gait, function and other MS symptoms, like spasticity. Although the worsening of spasticity with fatigue has been reported by persons with MS, the effect of fatigue on spasticity has not been measured.

PURPOSE

The purpose of this study was to compare lower extremity Modified Ashworth Scale (MAS) scores of persons with mild-to-moderate MS symptoms before and after fatigued and unfatigued conditions.

METHODS

Using a randomized crossover design, MS subjects underwent 6-min walk to induce fatigue and 6-min supine rests, with lower extremity spasticity measured before and after each condition. Friedman tests gave paired comparisons of MAS before and after each condition.

RESULTS

16 subjects with mild-to-moderate MS completed the study (mean age = 56; standard deviation = 11.7). Friedman tests showed a significant decrease in mean rank for overall average MAS for both lower extremities (p = 0.031) when comparing fatigued to unfatigued conditions. This appeared to be driven by the right lower extremity average MAS (p = 0.002) and, more specifically, in post hoc pre to post-test comparisons for right knee flexor (p = 0.002 fatigued; p = 0.059 unfatigued) and right knee extensor (p = 0.001 fatigued; p = 0.020 unfatigued) MAS mean rank differences. Fatigue did not result in increased spasticity.

CONCLUSION

Spasticity in these subjects with MS was not worsened by fatigue suggesting that worsening of gait with fatigue may be due to causes other than spasticity.

Correlates of the timed 25 foot walk in a multiple sclerosis outpatient rehabilitation clinic

The Timed 25 Foot Walk (T25FW), a test of maximum walking speed on a short distance, is commonly used to monitor ambulation status and to assess treatment outcomes in multiple sclerosis (MS). The main aim of this study was to determine how walking speed on the T25FW correlates with other clinician-reported and patient-reported measures in an outpatient MS rehabilitation clinic. We analyzed cross-sectional data systematically collected during a physiatry evaluation for the management of spasticity and walking limitations. In addition to demographic variables and the Expanded Disability Status Scale (EDSS), measures of body functions [lower extremity manual muscle testing (LE MMT), lower extremity Modified Ashworth Scale, Fatigue Severity Scale, leg pain], and measures of activity and quality of life (reported frequency of falls, Incapacity Status Scale, Rivermead Mobility Index, EQ5D health questionnaire, and Patient Health Questionnaire-9 items) were administered. A multivariate regression analysis was carried out. 199 patients were included in the analysis [age 49.41 (9.89) years, disease duration 15.40 (10.22) years, EDSS score 5.6 (1.2), and T25FW speed 70.93 (44.13) cm/s]. Both EDSS and LE MMT were correlated significantly with T25FW speed (R=0.692, P<0.001). After adjusting for EDSS and LE MMT, lower T25FW speed was associated with higher Incapacity Status Scale scores (R=0.316, P<0.001), lower Rivermead Mobility Index scores (R=0.540, P<0.001), and higher frequency of falls. EQ5D and Patient Health Questionnaire-9 items were not significantly associated with T25FW speed. Our findings support the clinical relevance of the T25FW in the rehabilitation of patients with MS.