The effects of isotonic and isokinetic muscle stretch on the excitability of the spinal alpha motor neurones in patients with muscle spasticity

Outcome measures for assessing the effectiveness of physiotherapy interventions on equinus foot deformity in post-stroke patients with triceps surae spasticity: A scoping review

OBJECTIVE

Equinus foot deformity (EFD) is the most common deviation after stroke. Several physiotherapy interventions have been suggested to treat it. However, studies evaluating the efficacy of these treatments vary widely in terms of assessment modalities, type of data analysis, and nomenclature. This scoping review aimed to map current available evidence on outcome measures and the modalities employed to assess the effectiveness of physiotherapy programs for the reduction of triceps surae (TS) spasticity and EFD in patients with stroke.

METHODS

Scoping review methodological frameworks have been used. Three databases were investigated. Primary literature addressing TS spasticity in adult patients with stroke using physiotherapy interventions was included. Findings were systematically summarized in tables according to the intervention used, intervention dosage, control group, clinical, and instrumental outcome measures.

RESULTS

Of the 642 retrieved studies, 53 papers were included. TS spasticity was assessed by manual maneuvers performed by clinicians (mainly using the Ashworth Scale), functional tests, mechanical evaluation through robotic devices, or instrumental analysis and imaging (such as the torque-angle ratio, the H-reflex, and ultrasound images). A thorough critical appraisal of the construct validity of the scales and of the statistics employed was provided, particularly focusing on the choice of parametric and non-parametric approaches when using ordinal scales. Finally, the complexity surrounding the concept of "spasticity" and the possibility of assessing the several underlying active and passive causes of EFD, with a consequent bespoke treatment for each of them, was discussed.

CONCLUSION

This scoping review provides a comprehensive description of all outcome measures and assessment modalities used in literature to assess the effectiveness of physiotherapy treatments, when used for the reduction of TS spasticity and EFD in patients with stroke. Clinicians and researchers can find an easy-to-consult summary that can support both their clinical and research activities.

Physical therapy interventions for the correction of equinus foot deformity in post-stroke patients with triceps spasticity: A scoping review

Objective

Equinus foot deformity (EFD) is the most common deformity following a stroke. Several approaches have been suggested for its correction, including pharmacological, surgical, and physical therapy (PT) interventions. This scoping review aims to map and synthesize the available evidence focusing on physical therapy treatments for EFD caused by triceps surae (TS) spasticity.

Methods

Scoping review methodological frameworks have been used. Pubmed, Cinahl, and Cochrane databases were searched for primary literature. Studies focusing on the treatment of EFD in adult stroke patients were included only when the intervention involved PT treatments and presented at least one outcome measure for the functional and/or structural condition of the TS. Data were systematically collected and reported in tables inclusive of type of intervention, sample characteristics, dosage, comparators, outcomes, follow-up timeline, and treatment efficacy. A narrative synthesis was also added.

Results

Of the 642 experimental or observational screened studies, 53 were included, focusing on stretching exercises, shock waves, electrical stimulation, dry needling, TENS, vibration therapy, ultrasounds, cryotherapy, and active physiotherapy. Patients with EFD benefited from specific physical therapy treatments. These usually resulted in Modified Ashworth Scale reduction, typically by 1 point, and an increase in ROM. Interventions consisting of shock waves, dry needling, and electrostimulation showed the best results in reducing EFD. Heterogeneous dosage and delivery mode generally limited conclusions.

Conclusions

This scoping review summarized available primary literature based on PT treatments for the correction of EFD. By highlighting the remaining gaps in knowledge, it provides a reference for future studies on this pathology. Further investigations are necessary to pinpoint the best dosage and delivery methods. Future studies should investigate whether early rehabilitation programs started during the acute phase might help prevent or limit the development of secondary deformities.

Effectiveness of Stretching in Post-Stroke Spasticity and Range of Motion: Systematic Review and Meta-Analysis

Spasticity is one of the most frequent and disabling clinical manifestations of patients with stroke. In clinical practice, stretching is the most widely used physiotherapeutic intervention for this population. However, there is no solid evidence for its effectiveness. The aim of this study was to evaluate the effectiveness of different types of stretching in reducing post-stroke spasticity. Research was carried out until March 2021 in the following scientific databases: PubMed, CINAHL, Scopus, Cochrane Library, Web of Science, and PEDro. The PEDro scale and the Cochrane collaboration tool were used to assess the methodological quality and risk of bias of the studies. Eight articles were selected for qualitative analysis; six of them contributed information to the meta-analysis. No conclusive evidence was obtained on the effectiveness of stretching in terms of treating spasticity and range of motion in patients with stroke. Further research is necessary in order to determine the effectiveness of the use of stretching in this population, considering the different types of stretching (static and dynamic), the time of application, the measurement of the different components of spasticity, and the extrapolation of functional results.

Neurologic and musculoskeletal effects of tilt-table standing on adults: a systematic review

[Purpose] Tilt table use is associated, most often, with the assessment of syncope. However, it also has applications for patients with neurologic and orthopedic problems. These applications do not appear to be widely applied. The purpose of this review, therefore, was to summarize the research literature addressing the use of tilt tables for treating specific musculoskeletal and neurologic impairments in adults. [Methods] Relevant literature was identified by searches of the PubMed, CINAHL, and Scopus databases and hand searches (December 2018 and October 2020). The methodological quality of the identified research articles was assessed using the PEDro scale. [Results] Of 482 unique articles identified, 20 matched the eligibility criteria of the review and were included. The studies varied widely in the populations studied, procedures used, and responses reported. The studies provide limited support for tilt table standing as an intervention. [Conclusion] However, evidence that some patients with neurologic conditions may respond positively to tilt-table standing is available. Among such individuals are those with decreased ankle range of motion, positive neurologic signs in the lower limbs, and decreased levels of consciousness.

Integration of Convergent Sensorimotor Inputs Within Spinal Reflex Circuits in Healthy Adults

The output from motor neuron pools is influenced by the integration of synaptic inputs originating from descending corticomotor and spinal reflex pathways. In this study, using paired non-invasive brain and peripheral nerve stimulation, we investigated how descending corticomotor pathways influence the physiologic recruitment order of the soleus Hoffmann (H-) reflex. Eleven neurologically unimpaired adults (9 females; mean age 25 ± 3 years) completed an assessment of transcranial magnetic stimulation (TMS)-conditioning of the soleus H-reflex over a range of peripheral nerve stimulation (PNS) intensities. Unconditioned H-reflex recruitment curves were obtained by delivering PNS pulses to the posterior tibial nerve. Subsequently, TMS-conditioned H-reflex recruitment curves were obtained by pairing PNS with subthreshold TMS at short (−1.5 ms) and long (+10 ms) intervals. We evaluated unconditioned and TMS-conditioned H-reflex amplitudes along the ascending limb, peak, and descending limb of the H-reflex recruitment curve. Our results revealed that, for long-interval facilitation, TMS-conditioned H-reflex amplitudes were significantly larger than unconditioned H-reflex amplitudes along the ascending limb and peak of the H-reflex recruitment curve. Additionally, significantly lower PNS intensities were needed to elicit peak H-reflex amplitude (Hmax) for long-interval facilitation compared to unconditioned. These findings suggest that the influence of descending corticomotor pathways, particularly those mediating long-interval facilitation, contribute to changing the recruitment gain of the motor neuron pool, and can inform future methodological protocols for TMS-conditioning of H-reflexes. By characterizing and inducing short-term plasticity in circuitry mediating short- and long-interval TMS-conditioning of H-reflex amplitudes, future studies can investigate supraspinal and spinal circuit contributions to abnormal motor control, as well as develop novel therapeutic targets for neuromodulation.

Comparing the acute effect of myofascial release techniques and passive stretching on hind foot dynamic loading in patients with multiple sclerosis: A cohort-blinded study

Study aim: It is important for therapists to incorporate new practical methods into therapy programs when they have demonstrable efficacy in the treatment of multiple sclerosis. Investigating the acute effects of myofascial release techniques (MFR) and passive stretching (PS) on hind foot loading and the severity of spasticity in individuals with multiple sclerosis (MS) was the aim of the study.

Material and methods: Following the initial evaluation, 10 participants with MS (n = 20 feet) were given MFR for the plantar flexor muscle group. After the day following the first visit, participants were asked to come again and PS was applied to the plantar flexor muscle groups after the evaluation. The severity of spasticity was assessed with the Modified Ashworth Scale (MAS). Dynamic loading parameters of the hind foot – medial and lateral maximum pressure (N/cm2), active contact areas (cm2), contact percentiles (%) – were evaluated with dynamic pedobarography. Participants of the study were evaluated four times: (1) at the initial evaluation, (2) after MFR application, (3) 24 hours after the initial evaluation (pre-PS), (4) after PS.

Results: There were no differences in MAS (p > 0.05) according to time-dependent analyses (p > 0.05). After MFR, the maximum pressure of the medial heel and active contact area were increased (p < 0.05) and there was a carryover effect on the maximum pressure of the right foot.

Conclusions: This study showed that MFR was an effective method for management of plantar flexor spasticity in patients with multiple sclerosis in the short term and there was a carryover effect in favor of MFR. There was no additional effect of PS.

The evidence for prolonged muscle stretching in ankle joint management in upper motor neuron lesions: considerations for rehabilitation - a systematic review

BACKGROUND

As clinicians, muscles stretching approaches are one of the most commonly used interventions in rehabilitation. However, there is a need for an in-depth evaluation of research on prolonged stretching in terms of the features of the stretching approaches, such as duration and frequency, as well as the compatible measures of a successful stretching approach.

OBJECTIVE

This review is an effort to synthesize findings from studies on "prolonged" stretching approaches in patients with UMNs including stroke, spinal cord injuries, and traumatic brain injuries. We investigated the compatible features of successful stretching regimens in terms of reducing spasticity, improving the Active Range of Motion (AROM), Passive Range of Motion (PROM), and gait training of spastic patient with upper motor neuron lesions.

METHODS

Studies evaluating the effectiveness of "prolonged" stretching on spastic ankle planterflexor muscles and its complications were critically reviewed, and the level of evidence was analyzed.

RESULTS

There is a sufficient level of evidence to support the use of stretching as and effective techniques in rehabilitation. However, more research is yet to be done to objectively examine the ideal parameters of a successful stretching approach using functional assessments, such as walking, speed, walking capacity, and balance.

CONCLUSION

The review adds stronger understanding with regard to stretching considerations in rehabilitation following UMNs. The ideal approach, as well as the functional implications on motor performance are yet to be further studied.

Development and assessment of a novel ankle rehabilitation system for stroke survivors

Spasticity after stroke is a common occurrence and requires treatment with rehabilitative regimens (e.g., stretching exercise). Unfortunately, many challenges (e.g., cost, limited availability of physical therapists, limited access to clinical facilities, etc.) can restrict participation in these rehabilitation regimens. Assistive technologies using robotic systems have been developed to provide an alternative to assist with rehabilitative exercises. However, existing assistive technologies are rarely available in clinical settings due to technical limitations (e.g., size, weight, complexity, etc.). This paper describes the development of a novel ankle rehabilitation system, called Motorized Ankle Stretcher (MAS). A proof-of-concept experiment was conducted to assess the effects of ankle stretching exercises with the MAS in a laboratory setting. Six stroke survivors participated in the proof-of-concept experiment. The participants' ankle range of motion (ROM) and walking performance (i.e., walking speed, step length, and cadence) were evaluated before and after a small number of the ankle stretching exercises using the MAS (i.e., 20 trials total) in a single training session. The results show that the ankle ROM was significantly increased after the exercises across all participants. However, no significant differences in walking speed, step length, and cadence were observed between pre- and post-exercises. Our investigation is a first attempt at developing a relatively small size, weight, and easy-to-use ankle rehabilitation system for stroke survivors.

The Effect of Functional Stretching Exercises on Neural and Mechanical Properties of the Spastic Medial Gastrocnemius Muscle in Patients with Chronic Stroke: A Randomized Controlled Trial

BACKGROUND

Following spasticity, neural and mechanical changes of the paretic muscle often occur, which affect the muscle function. The aim of this study was to investigate the effect of functional stretching exercises on neural and mechanical properties of the spastic muscle in patients with stroke.

MATERIALS AND METHODS

This study was a single-blinded, randomized control trial. Forty five patients with stroke (experimental group: n = 30; control group: n = 15) participated in this study. Subjects in the experimental group participated in a functional stretching program 3 times a week for 4 weeks. Subjects in both groups were evaluated before the training, at the end of training, and then during a 2-month follow-up. Neural properties, including H-reflex latency and Hmax/Mmax ratio, were acquired. Mechanical properties, including fascicle length, pennation angle, and muscle thickness in the spastic medial gastrocnemius muscle, were evaluated. Repeated measure analysis of variance was used in the analysis.

RESULTS

Time by group interaction in the pennation angle (P = .006), and in muscle thickness (P = .030) was significant. The results indicated that the H-reflex latency (P = .006), pennation angle (P < .001), and muscle thickness (P = .001) were altered after stretching training program and these changes were at significant level after 2-month follow-up.

CONCLUSION

The results indicated that the use of functional stretching exercises can cause significant differences in neural and mechanical properties of spastic medial gastrocnemius muscle in patients with chronic stroke.

Static standing, dynamic standing and spasticity in individuals with spinal cord injury

STUDY DESIGN

This was a cross-over efficacy study design.

OBJECTIVE

To determine spasticity differences between static and dynamic standing training in individuals with spinal cord injury (SCI).

SETTING

Vancouver, Canada.

METHODS

Ten individuals with SCI who could stand with or without bracing or supports participated in both dynamic and static standing training (one session each, 2 days apart) using a Segway. The primary outcome was spasticity as measured by Visual Analog Scale (VAS), Modified Ashworth Scale (MAS) and electromyography (EMG) of the quadriceps, hamstrings, adductors and gastrocnemius.

RESULTS

There was no statistically detectable difference in spasticity between dynamic and static standing training in individuals with SCI as measured by VAS, MAS or EMG, although there was a trend towards decreased spasticity after the dynamic training.

CONCLUSION

There is no significant difference in spasticity outcomes between static and dynamic standing training on a Segway for individuals with SCI.

SPONSORSHIP

This research was funded by Natural Sciences and Engineering Research Council of Canada and International Collaboration on Repair Discoveries.

Contributions of motoneuron hyperexcitability to clinical spasticity in hemispheric stroke survivors

OBJECTIVE

Muscle spasticity is one of the major impairments that limits recovery in hemispheric stroke survivors. One potential contributing mechanism is hyperexcitability of motoneurons. Previously, the response latency of the surface electromyogram (EMG) record evoked by joint rotation has been used to characterize motoneuron excitability. Given the limitations of this method, the objective of the current study was to reexamine the excitability of motoneurons in chronic stroke survivors by estimating reflex latency using single motor unit discharge.

METHODS

We quantified the excitability of spastic motoneurons using the response latency of a single motor unit discharge elicited by a position controlled tap on the biceps brachii tendon. We applied tendon taps of different amplitudes on the biceps tendons of both arms of the stroke survivors. Unitary reflex responses were recorded using intramuscular EMG recordings.

RESULTS

Our results showed that the latency of unitary discharge was systematically shorter in the spastic muscle compared with the contralateral muscle, and this effect was consistent across multiple tap amplitudes.

CONCLUSIONS

This method allowed us to quantify latencies more accurately, potentially enabling a more rigorous analysis of contributing mechanisms.

SIGNIFICANCE

The findings provide evidence supporting a contribution of hyperexcitable motoneurons to muscle spasticity.

Neurophysiological changes induced by the botulinum toxin type A injection in children with cerebral palsy

In the last few years botulinum toxin type A (BTX-A) has been widely used in the management of spasticity in children with cerebral palsy in order to reduce hypertonicity and improve functional outcomes enhancing motor skill development. The botulinum toxin injection seems to interact with intrafusal and extrafusal fibers producing a reduction of hypertone both through synaptic blockade and inhibition of stretch reflex loop and these changes may influence not only the spinal cord but also the central nervous system (CNS). The purpose of our study was to determine the neurophysiological changes induced by the BTX-A through an evaluation of cortical somatosensory Evoked Potential (SEP) and Soleus H wave, that is the index of excitability of stretch reflex loop. Eighteen children with Cerebral Palsy (CP), aged between 5 and 12, were recruited at Children's Hospital "Bambino Gesù" of Rome. All children were evaluated with appropriate clinical scales before and 1 month after the BTX-A injection. Neurophysiological measurements were performed before, and 1 month after botulinum toxin injection through lower limb SEPs, M-wave and Soleus H wave recording. After the injection the results showed a statistically significant improvement both of clinical scales and the neurophysiological variables. These findings suggest that spasticity itself can be considered as a factor affecting the cortical SEPs. And even though it seems that BTX-A does not have any direct central effect on sensory pathways we suppose an indirect mechanism on modulation of afferent fibers Ia due to the modification induced by BTX-A to central loop reflex.