Spasticity-assessment: a review

Clinical efficacy observation of repetitive magnetic stimulation for treating upper limb spasticity after stroke

To investigate the efficacy of repetitive transcranial magnetic stimulation (rTMS) for managing upper limb muscular spasticity after stroke, and to examine its therapeutic effects on spasticity and motor function in the upper limb. A total of 110 post-stroke patients with upper limb spasticity were randomly assigned to the experimental or the control group. The experimental group received rTMS in conjunction with conventional rehabilitation therapy. The affected side of the head received daily treatment for 20 min each at Erb's point and the stimulation point, totaling 15 sessions over six days per week. The stimulation frequencies were 10 Hz (high frequency, M1 region) and 1 Hz (low frequency, Erb's point), with an intensity at 120% of the threshold. The control group received sham stimulation alongside conventional rehabilitation therapy. Assessments including the Modified Ashworth Scale (MAS) and Fugl-Meyer Assessment for Upper Extremity (FM-UE), were also conducted before treatment initiation and after 15 rounds of rTMS. Post hoc subgroup analyses were conducted using independent-sample t-tests for FM-UE scores and Mann-Whitney U tests for MAS scores to assess heterogeneity in treatment responses by stroke type (cerebral infarction vs. intracerebral hemorrhage). Among these 110 patients, 25 patients were excluded from the study for various reasons. Hence, 53 patients were included in the control group and 32 patients were included in the experimental group. Following 15 rounds of rTMS, the experimental group exhibited a reductions in MAS score (P = 0.004). FM-UE scores increased significantly in both groups (both P < 0.05), with significant improvement observed in the experimental group (P < 0.05). Subgroup analyses revealed no significant differences in FM-UE or MAS outcomes between stroke types, likely due to the limited sample size of intracerebral hemorrhage participants (experimental group: n = 8; control group: n = 16). rTMS effectively alleviates upper limb spasticity and enhances motor function after stroke by modulating cortical and spinal nerve excitability.

The SpasT-SCI-T trial protocol: Investigating calpain-mediated sodium channel fragments as biomarkers for traumatic CNS injuries and spasticity prediction

Spinal cord injury and traumatic brain injury are major causes of long-term disability and are often complicated by spasticity, a motor disorder characterized by increased muscle tone and exaggerated reflexes that significantly impair quality of life. Current diagnostic methods lack the sensitivity needed to accurately predict the severity of injury or the onset and progression of spasticity. Trauma-induced calcium dysregulation activates calpains, a family of proteases that cleave sodium channels, disrupting their inactivation and increasing persistent sodium currents. This cascade drives the overexcitability of motoneurons, contributing to the development of spasticity. Consequently, sodium channel fragments have emerged as promising biomarkers that link injury mechanisms to clinical outcomes. The present SpasT-SCI-T clinical trial protocol aims to evaluate sodium channel fragments as blood biomarkers for assessing the severity of spinal cord and traumatic brain injuries, as well as their potential to predict clinical outcomes, including the development of spasticity. This prospective, multicenter, case-control and cohort study involves 40 participants: 20 individuals with spinal cord injury, 10 individuals with traumatic brain injury, and 10 healthy controls. Blood samples are collected within six hours of injury and at follow-up points over six months. Clinical outcomes, including spasticity (assessed using the Modified Ashworth Scale), neurological recovery (measured by the American Spinal Injury Association Impairment Scale and Glasgow Coma Scale), and quality of life (evaluated using the Short Form-36 Health Survey), are analyzed in correlation with biomarker levels. We anticipate that calpain-mediated sodium channel fragments will transform the management of central nervous system injuries by enabling early diagnosis, improving prognostic accuracy, and guiding personalized therapeutic strategies. The clinical trial is registered on ClinicalTrials.gov (NCT06532760, January 10, 2024), with Assistance Publique-Hôpitaux de Marseille as the sponsor.

Neuromusculoskeletal modeling of spasticity: A scoping review

INTRODUCTION

This scoping review aimed to provide an overview of neuromusculoskeletal models used to investigate the mechanisms underlying spasticity and identify issues to be addressed in future models.

MATERIALS AND METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews (PRISMA-ScR) guidelines and searched four bibliographic databases (PubMed, Compendex Engineering Village, IEEE Xplore, and Science Direct). Inclusion criteria were original studies written in English that investigated the underlying mechanisms of spasticity in humans with no age restrictions. Two independent reviewers selected studies.

RESULTS

Eighteen studies met the inclusion criteria. Stroke was the neurological condition addressed by most studies, followed by cerebral palsy. The studies focused mainly on passive tasks with the knee joint as the primary target. All studies considered that spasticity was associated with alterations in the stretch reflex loop. Among the parameters tested by the studies, the reflex gains and thresholds were the parameters that could better represent levels of severity or effects of botulinum toxin type-A treatment. Recent studies proposed that stretching acceleration, muscle force, and force rate could be fed back into the feedback loop besides the muscle length and stretching velocity. However, no consensus was found among them. Finally, it has been that stiffness and viscosity of muscle-tendon-unit are also relevant for describing resistance to passive movement.

CONCLUSION

In order to provide relevant clinical and physiological information, future modeling should include supraspinal mechanisms in-depth, use image-based data to personalize non-neural parameters, specify models according to etiology and tasks, especially the active tasks of daily life activities.

In-silico neuro-musculoskeletal model demonstrates spasticity progression with descending motor tracts loss in simulated clinical triage

Our study explores the complex mechanisms of spasticity using a multi-scale neuro-musculoskeletal model to investigate its emergence and characteristics following spinal cord injury. We built a large-scale, biologically realistic, closed-loop spino-musculoskeletal model of the lower limb using the NEUROiD co-simulation platform. The in-silico spinal cord incorporated around 50 spinal pathways, 40,000 alpha motor neurons, and approximately 12 million interconnections spanning L2-S2 and was simulated on NEURON. The musculoskeletal model contained 92 muscles and was simulated on OpenSim. We conducted in-silico triage of two clinical assessments of spasticity, the Modified Tardieu Test and Pendulum Test, on this model and compared results with published literature. We also demonstrated subject-specific customized models (virtual subjects) using motion capture data. Our model demonstrated the clasp-knife effect in the Modified Tardieu Test simulations and damped knee oscillations with increased spinal injury in Pendulum Test simulations. We also demonstrated how spastic behavior emerges with varying degrees of supra-spinal disruption. Further, using data from motion capture experiments, we explore subject-specificity in our model. Our work presents methods for creating a virtual subject with triaging capabilities that can demonstrate the onset of spasticity symptoms and its possible subject-specific variances.

Evaluation of spasticity: IFCN Handbook Chapter

There is no generally accepted definition of spasticity, but hyperexcitable stretch reflexes, exaggerated tendon jerks, clonus, spasms, cramps, increased resistance to passive joint movement, sustained involuntary muscle activity and aberrant muscle activation, including co-contraction of antagonist muscles are all signs and symptoms which are usually associated clinically to the term spasticity. This review describes how biomechanical and electrophysiological techniques may be used to provide quantitative and objective measures of each of these signs and symptoms. The review further describes how neurophysiological techniques may be used to evaluate pathophysiological changes in spinal motor control mechanisms. It is emphasized that understanding the pathophysiology and distinguishing the specific signs and symptoms associated with spasticity, using objective, valid, and reproducible measurements, is essential for providing optimal therapy.

Preparation, characterisation, and testing of reservoir-based implantable devices loaded with tizanidine and lidocaine

Multiple sclerosis is a chronic neuroimmunological disorder that causes progressive disability, primarily in young adults. It places a significant burden on healthcare systems due to high medication costs and long-term care needs. Implantable devices offer a promising alternative for delivering sustained drug doses in the treatment of chronic conditions. This study introduces a novel long-acting subcutaneous implant for dual-drug delivery: tizanidine (TZ) for spasticity management and lidocaine (LD) for post-insertion pain relief. Reservoir-type implants were developed with TZ in the core and LD in the shell. Two fabrication methods-direct compression and vacuum compression moulding (VCM)-were evaluated for TZ-loaded pellets (3 mm diameter, ~ 10 mm length) using TZ base and TZ hydrochloride. Pellets were encapsulated inside a biodegradable polycaprolactone (PCL) tubular membrane to control drug release. Direct compression pellets, made with poly(vinyl pyrrolidone) and hydroxypropyl-β-cyclodextrin, disintegrated quickly, releasing TZ over 20 days. VCM pellets, formulated with PCL or PCL/poly(ethylene glycol) (PEG), offered prolonged release: up to 200 days for TZ base and 80 days for TZ hydrochloride. Adding PEG accelerated TZ release, reducing duration to 20 days (TZ base) and 125 days (TZ hydrochloride). LD was incorporated into the PCL membrane, providing up to three days of sustained release. Physicochemical analysis confirmed formulation homogeneity and no covalent interactions. These findings highlight the potential of this implant system for MS-related spasticity management, supporting further research into long-acting implants to improve treatment adherence and patient outcomes.

MyoGestic: EMG interfacing framework for decoding multiple spared motor dimensions in individuals with neural lesions

Restoring motor function in individuals with spinal cord injuries (SCIs), strokes, or amputations is a crucial challenge. Recent studies show that spared motor neurons can still be voluntarily controlled using surface electromyography (EMG), even without visible movement. To harness these signals, we developed a wireless, high-density EMG bracelet and a software framework, MyoGestic. Our system enables rapid adaptation of machine learning models to users' needs, allowing real-time decoding of spared motor dimensions. In our study, we successfully decoded motor intent from two participants with traumatic SCI, two with spinal stroke, and three with amputations in real time, achieving multiple controllable motor dimensions within minutes. The decoded neural signals could control a digitally rendered hand, an orthosis, a prosthesis, or a two-dimensional cursor. MyoGestic's participant-centered approach allows a collaborative and iterative development of myocontrol algorithms, bridging the gap between researcher and participant, to advance intuitive EMG interfaces for neural lesions.

Assessing Linearity in Multi-Joint Upper Limb Dynamics Under Small Perturbations for Reliable Mechanical Impedance Estimation

This study investigates the linear behavior of multi-joint upper limb dynamics under small perturbations, a prerequisite for stochastic estimation of upper limb mechanical impedance, which is crucial for understanding motor control and has the potential to assess neurological disorders. Conflicting reports exist on the linearity of upper limb dynamics under small perturbations, even for healthy individuals. We hypothesized that the multi-joint upper limb behaves linearly under small perturbations and that uncompensated nonlinear robot joint frictions degrade impedance estimation reliability. The upper limb multi-joint mechanical impedance of ten healthy individuals was estimated using a 2-degree-of-freedom direct-drive robot similar to MIT-MANUS, known for small joint frictions, under two conditions: without (using Cartesian proportional-derivative control) and with (using internal model based impedance control) friction compensation. Multiple and partial coherences were close to unity with friction compensation and significantly higher than without it, confirming that the upper limb behaves linearly under small perturbations and that previously reported nonlinearity detected by low coherences was due to small but significant robot joint frictions. It is expected that confirming the linearity of the upper limb under small perturbations allows for confident upper limb impedance estimation, thereby promoting motor control studies and complementing the diagnosis of the altered upper-limb dynamics post-stroke.

Severe Case of Intrathecal Baclofen Withdrawal: A Case Report

Baclofen is a medication that helps manage muscle spasticity by targeting gamma-aminobutyric acid B receptors in the nervous system. Discontinuing baclofen therapy generally leads to the recurrence of baseline spasticity and rigidity; however, abrupt cessation may also result in neurological, autonomic, and psychiatric symptoms. Baclofen withdrawal syndrome is one of the most serious complications of baclofen therapy, with the potential for rapid progression and significant morbidity and mortality. Prompt recognition and effective treatment are crucial. We present a severe case of intrathecal baclofen withdrawal following the sudden cessation of therapy, emphasizing the critical need for careful monitoring and early intervention to prevent serious complications.

Remote Monitoring for the Management of Spasticity: Challenges, Opportunities and Proposed Technological Solution

Spasticity is disabling feature of long-term neurological conditions that has substantial impact on people' quality of life. Assessing spasticity and determining the efficacy of current treatments is limited by the measurement tools available in clinical practice. We convened an expert panel of clinicians and engineers to identify a solution to this urgent clinical need. We established that a reliable ambulatory spasticity monitoring system that collates clinically meaningful data remotely would be useful in the management of this complex condition. This paper provides an overview of current practices in managing and monitoring spasticity. Then, the paper describes how a remote monitoring system can help in managing spasticity and identifies challenges in development of such a system. Finally the paper proposes a monitoring system solution that exploits recent advancements in low-energy wearable systems comprising of printable electronics, a personal area network (PAN) to low power wide area networks (LPWAN) alongside back-end cloud infrastructure. The proposed technology will make an important contribution to patient care by allowing, for the first time, longitudinal monitoring of spasticity between clinical follow-up, and thus has life altering and cost-saving implications. This work in spasticity monitoring and management serves as an exemplar for other areas of rehabilitation.

Paired nerve stimulation with selective compensation effect

Background

In this study we investigate the selective compensation of paired peripheral nerves in healthy humans, focusing on distinct axonal conduction velocities in different fibre types. Using paired associative stimulation (PAS) with adjustable parameters, we aimed to modulate and compensate for neuronal activity along the median nerve.

Methods

Six healthy volunteers (3 male, 3 female, aged: 22-49) participated in the current study. We conducted 30 experiments with the following protocol. A pair of pulses with the following parameters were applied to each volunteer: amplitude, pulse width and inter-pulse delay was generated by the dual-core programmed microcontroller STM32H745xI/G while values were set by one-board computer Jetson Nano. The microcontroller provided a pair of pulses to the DAC that applied it to nerve stimulation sites via a stimulator. During experiments, we used the following ranges: (a) current amplitudes [0-20mA], (b) pulse width [250-500 μs] and (c) delays [50-250 μs]. As the measurement of the stimulation effectiveness, we used the finger's contraction angles.

Results

Our findings reveal a significant selective compensation (inhibitory) effect over the motor responses, demonstrated through variations in finger displacement angles. By optimizing individual parameters-pulse width, inter-pulse delay, and compensatory currents-we successfully induced motor response compensation effects. Notably, consistent compensatory effects were observed across all volunteers using a pulse width of (250 μs) and an inter-pulse delay of (50 μs).

Discussion

These results highlight PAS's potential for developing non-invasive neuromodulation devices. However, further research is required to evaluate its efficacy in individuals with spasticity and upper motor neuron deficits.

Transcutaneous spinal cord stimulation neuromodulates pre- and postsynaptic inhibition in the control of spinal spasticity

Aside from enabling voluntary control over paralyzed muscles, a key effect of spinal cord stimulation is the alleviation of spasticity. Dysfunction of spinal inhibitory circuits is considered a major cause of spasticity. These circuits are contacted by Ia muscle spindle afferents, which are also the primary targets of transcutaneous lumbar spinal cord stimulation (TSCS). We hypothesize that TSCS controls spasticity by transiently strengthening spinal inhibitory circuit function through their Ia-mediated activation. We show that 30 min of antispasticity TSCS improves activity in post- and presynaptic inhibitory circuits beyond the intervention in ten individuals with traumatic spinal cord injury to normative levels established in 20 neurologically intact individuals. These changes in circuit function correlate with improvements in muscle hypertonia, spasms, and clonus. Our study opens the black box of the carryover effects of antispasticity TSCS and underpins a causal role of deficient post- and presynaptic inhibitory circuits in spinal spasticity.

Isokinetic and electromyographic characterization of ankle plantarflexors' hypertonia in people with multiple sclerosis

BACKGROUND

This study aimed at quantifying ankle plantarflexors' resistance to passive motion (RPM) by isokinetic dynamometry and muscle activity through surface electromyography (sEMG) in persons with multiple sclerosis (PwMS) with limb stiffness and spasticity.

METHODS

Slow and fast ankle dorsiflexions (from 5°/s to 210°/s) were imparted passively by an isokinetic dynamometer, and sEMG activity of plantarflexors was recorded at the same time as the square root of the moving average. Based on RPM evaluated at 5°/s, ankles were classified as more- and less-resistant as measured by average peak torque (APT).

RESULTS

Measurements were obtained bilaterally from 24 PwMS (median EDSS: 5.5) with median Modified Ashworth Scale (MAS) score of 1.75. Compared to the lowest velocity inducing EMG-evident responses (120°/s), RPM increased significantly at 180°/s (+137.8 %; p < 0.0005) and 210°/s (+85.3 %; p < 0.0005) in the less-resistant side, and only at 210°/s (+113.8 %; p < 0.0005) in the more-resistant side. sEMG activity increased significantly and similarly between limbs at increasing velocities. Significant velocity-dependent increases were detected in both limbs, with no difference by side, at 180°/s (+34.5 %; p = 0.005) and 210°/s (+48.4 %; p = 0.004). Regression analyses confirmed side (β=0.542; p < 0.0001) and speed (β=0.238; p < 0.0001) as significant predictors of APT change, but only speed for sEMG (speed: β=0.215; p = 0.019; side: β=0.012; p = 0.893). Bivariate correlations revealed that RPM was associated negatively with MAS and positively with sEMG.

CONCLUSION

Spasticity presented bilaterally in PwMS, with different mixed pictures of passive and reflex stiffness, both requiring attention. Combining isokinetics and sEMG allows detecting even subtle, subclinical alterations that can prompt and drive early tailored management.

A randomized, double-blind, placebo-controlled trial to evaluate the effect of nabiximols oromucosal spray on clinical measures of spasticity in patients with multiple sclerosis

BACKGROUND

Spasticity is a common and potentially debilitating symptom of multiple sclerosis (MS) with a highly variable presentation. Understanding, quantifying, and managing MS-associated spasticity (MSS) is a challenge for research and in clinical practice. The tetrahydrocannabinol:cannabidiol oromucosal spray nabiximols has demonstrated beneficial effects in the treatment of MSS in clinical studies as well as real-world observational studies, and is approved for the treatment of MSS in 29 countries globally. Most randomized studies evaluated the efficacy of nabiximols using the change in average daily spasticity scores reported by patients using the spasticity Numeric Rating Scale as a primary endpoint. This study, RELEASE MSS1 (NCT04657666), was conducted using a prespecified primary endpoint of change in spastic muscle tone (Modified Ashworth Scale Lower Limb Muscle Tone-6 [MAS LLMT-6]) to corroborate the efficacy of nabiximols as adjunctive therapy observed with the patient-measured spasticity Numeric Rating Scale primary endpoint in the previous pivotal studies.

METHODS

This was a phase 3, multicenter, randomized, double-blind, placebo-controlled, 2-treatment, 2-period, crossover trial. Because of the prevalence and functional impact of lower limb spasticity on the individual patient's overall experience of MS spasticity, the MAS LLMT-6 was derived from the clinician-rated MAS. The MAS LLMT-6 is the average transformed MAS score of 6 muscle groups (knee flexors, knee extensors, and ankle plantar flexors; all assessed bilaterally). Secondary measures included MAS LLMT-4 scores, defined as the average of the 4 individual MAS-transformed scores of knee flexors and knee extensors bilaterally. Patients had a diagnosis of MS and an untransformed MAS score of at least 2 in ≥2 of 6 LLMT-6 muscle groups despite current treatment with ≥1 of the following oral antispasticity agents: baclofen, tizanidine, or dantrolene. Eligible participants were randomly assigned to 1 of 2 treatment sequences. Each treatment sequence consisted of two treatment periods, each consisting of a 14-day dose titration phase followed by a 7-day dose maintenance phase.

RESULTS

Of 68 patients enrolled, 33 were assigned to nabiximols followed by placebo and 35 were assigned to placebo followed by nabiximols. Least squares mean changes in MAS LLMT-6 scores from baseline to day 21 were -0.23 for nabiximols and -0.26 for placebo; the least squares mean treatment difference in MAS LLMT-6 scores for nabiximols versus placebo was 0.04, which was not statistically significant (P = 0.7152). Mean changes in MAS LLMT-4 scores from baseline to day 21 also were not significantly different between the nabiximols and placebo groups. Safety results in this study were consistent with the known safety profile of nabiximols in patients with MSS.

CONCLUSION

Despite the established efficacy of nabiximols in MSS observed using patient-reported measures, the primary endpoint was not met in this study. The findings from this study reflect and emphasize some of the challenges in the evaluation and treatment of MS spasticity. CLINICAL TRIAL REGISTRATION NUMBER (CLINICALTRIALS.GOV): : NCT04657666.

The effect of robot-assisted versus standard training on motor function following subacute rehabilitation after ischemic stroke - protocol for a randomised controlled trial nested in a prospective cohort (RoboRehab)

BACKGROUND

Body weight unloaded treadmill training has shown limited efficacy in further improving functional capacity after subacute rehabilitation of ischemic stroke patients. Dynamic robot assisted bodyweight unloading is a novel technology that may provide superior training stimuli and continued functional improvements in individuals with residual impairments in the chronic phase after the ischemic insult. The aim of the present study is to investigate the effect of dynamic robot-assisted versus standard training, initiated 6 months post-stroke, on motor function, physical function, fatigue, and quality of life in stroke-affected individuals still suffering from moderate-to-severe disabilities after subacute rehabilitation.

METHODS

Stroke-affected individuals with moderate to severe disabilities will be recruited into a prospective cohort with measurements at 3-, 6-, 12- and 18-months post-stroke. A randomised controlled trial (RCT) will be nested in the prospective cohort with measurements pre-intervention (Pre), post-intervention (Post) and at follow-up 6 months following post-intervention testing. The present RCT will be conducted as a multicentre parallel-group superiority of intervention study with assessor-blinding and a stratified block randomisation design. Following pre-intervention testing, participants in the RCT study will be randomised into robot-assisted training (intervention) or standard training (active control). Participants in both groups will train 1:1 with a physiotherapist two times a week for 6 months (groups are matched for time allocated to training). The primary outcome is the between-group difference in change score of Fugl-Meyer Lower Extremity Assessment from pre-post intervention on the intention-to-treat population. A per-protocol analysis will be conducted analysing the differences in change scores of the participants demonstrating acceptable adherence. A priori sample size calculation allowing the detection of the minimally clinically important between-group difference of 6 points in the primary outcome (standard deviation 6 point, α = 5% and β = 80%) resulted in 34 study participants. Allowing for dropout the study will include 40 participants in total.

DISCUSSION

For stroke-affected individuals still suffering from moderate to severe disabilities following subacute standard rehabilitation, training interventions based on dynamic robot-assisted body weight unloading may facilitate an appropriate intensity, volume and task-specificity in training leading to superior functional recovery compared to training without the use of body weight unloading.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT06273475.

TRIAL STATUS

Recruiting. Trial identifier: NCT06273475. Registry name: ClinicalTrials.gov. Date of registration on ClinicalTrials.gov: 22/02/2024.

A portable system to measure knee extensor spasticity after spinal cord injury

BACKGROUND

The pendulum test is a quantitative method used to assess knee extensor spasticity in humans with spinal cord injury (SCI). Yet, the clinical implementation of this method remains limited. The goal of our study was to develop an objective and portable system to assess knee extensor spasticity during the pendulum test using inertial measurement units (IMU).

METHODS

Spasticity was quantified by measuring the first swing angle (FSA) using a 3-dimensional optical tracking system (with external markers over the iliotibial band, lateral knee epicondyle, and lateral malleolus) and two wireless IMUs (positioned over the iliotibial band and mid-part of the lower leg) as well as a clinical exam (Modified Ashworth Scale, MAS).

RESULTS

Measurements were taken on separate days to assess test-retest reliability and device agreement in humans with and without SCI. We found no differences between FSA values obtained with the optical tracking system and the IMU-based system in control subjects and individuals with SCI. FSA values from the IMU-based system showed excellent agreement with the optical tracking system in individuals with SCI (ICC > 0.98) and good agreement in controls (ICC > 0.82), excellent test-retest reliability across days in SCI (ICC = 0.93) and good in controls (ICC = 0.87). Notably, FSA values measured by both systems showed a strong association with MAS scores ( ρ  ~ -0.8) being decreased in individuals with SCI with higher MAS scores, reflecting the presence of spasticity.

CONCLUSIONS

These findings suggest that our new portable IMU-based system provides a robust and flexible alternative to a camera-based optical tracking system to quantify knee extensor spasticity following SCI.

Acute suppression of lower limb spasm by sacral afferent stimulation for people with spinal cord injury: A pilot study

Lower limb spasm and spasticity may develop following spinal cord injury (SCI), causing hyper-excitability and increased tone, which can impact function and quality of life. Pharmaceutical interventions for spasticity may cause unwanted side effects such as drowsiness and weakness. Invasive and non-invasive electrical stimulation has been shown to reduce spasticity without these side effects. The aim of this study was to investigate the effect of sacral afferent stimulation (SAS), through surface electrical stimulation of the dorsal genital nerve (N = 7), and through implanted electrodes on the sacral afferent nerve roots, on lower limb spasm and spasticity (N = 2). Provoked spasms were interrupted with conditional SAS, where stimulation commenced following a provoked spasm, or unconditional stimulation, which was applied continuously. Conditionally and unconditionally applied SAS was shown to suppress acute provoked spasms in people with SCI. There was a statistically significant reduction in area under the curve of quadriceps electromyography during acute spasm with SAS compared to a control spasm. These results show that SAS may provide a safe, low-cost method of reducing acute spasm and spasticity in people living with SCI. SAS through implanted electrodes may also provide an additional function to sacral nerve stimulation devices.

Knockdown of calpain1 in lumbar motoneurons reduces spasticity after spinal cord injury in adult rats

Spasticity, affecting ∼75% of patients with spinal cord injury (SCI), leads to hyperreflexia, muscle spasms, and cocontractions of antagonist muscles, greatly affecting their quality of life. Spasticity primarily stems from the hyperexcitability of motoneurons below the lesion, driven by an upregulation of the persistent sodium current and a downregulation of chloride extrusion. This imbalance results from the post-SCI activation of calpain1, which cleaves Nav1.6 channels and KCC2 cotransporters. Our study was focused on mitigating spasticity by specifically targeting calpain1 in spinal motoneurons. We successfully transduced lumbar motoneurons in adult rats with SCI using intrathecal administration of adeno-associated virus vector serotype 6, carrying a shRNA sequence against calpain1. This approach significantly reduced calpain1 expression in transduced motoneurons, leading to a noticeable decrease in spasticity symptoms, including hyperreflexia, muscle spasms, and cocontractions in hindlimb muscles, which are particularly evident in the second month post-SCI. In addition, this decrease, which prevented the escalation of spasticity to a severe grade, paralleled the restoration of KCC2 levels in transduced motoneurons, suggesting a reduced proteolytic activity of calpain1. These findings demonstrate that inhibiting calpain1 in motoneurons is a promising strategy for alleviating spasticity in SCI patients.

Epidural Spinal Cord Stimulation for Spasticity: a Systematic Review of the Literature

OBJECTIVE

Spasticity is a form of muscle hypertonia secondary to various diseases, including traumatic brain injury, spinal cord injury, cerebral palsy, and multiple sclerosis. Medical treatments are available; however, these often result in insufficient clinical response. This review evaluates the role of epidural spinal cord stimulation (SCS) in the treatment of spasticity and associated functional outcomes.

METHODS

A systematic review of the literature was performed using the Embase, CENTRAL, and MEDLINE databases. We included studies that used epidural SCS to treat spasticity. Studies investigating functional electric stimulation, transcutaneous SCS, and animal models of spasticity were excluded. We also excluded studies that used SCS to treat other symptoms such as pain.

RESULTS

Thirty-four studies were included in the final analysis. The pooled rate of subjective improvement in spasticity was 78% (95% confidence interval, 64%-91%; I2 = 77%), 40% (95% confidence interval, 7%-73%; I2 = 88%) for increased H-reflex threshold or decreased Hoffman reflex/muscle response wave ratio, and 73% (65%-80%; I2 = 50%) for improved ambulation. Patients with spinal causes had better outcomes compared with patients with cerebral causes. Up to 10% of patients experienced complications including infections and hardware malfunction.

CONCLUSIONS

Our review of the literature suggests that SCS may be a safe and useful tool for the management of spasticity; however, there is significant heterogeneity among studies. The quality of studies is also low. Further studies are needed to fully evaluate the usefulness of this technology, including various stimulation paradigms across different causes of spasticity.

A scoping review on muscle cramps and spasms in upper motor neuron disorder-two sides of the same coin?

Background

Muscle cramps are typically regarded as benign muscle overactivity in healthy individuals, whereas spasms are linked to spasticity resulting from central motor lesions. However, their striking similarities made us hypothesize that cramping is an under-recognized and potentially misidentified aspect of spasticity.

Methods

A systematic search on spasms and cramps in patients with Upper Motor Neuron Disorder (spinal cord injury, cerebral palsy, traumatic brain injury, and stroke) was carried out in Embase/Medline, aiming to describe the definitions, characteristics, and measures of spasms and cramps that are used in the scientific literature.

Results

The search identified 4,202 studies, of which 253 were reviewed: 217 studies documented only muscle spasms, 7 studies reported only cramps, and 29 encompassed both. Most studies (n = 216) lacked explicit definitions for either term. One-half omitted any description and when present, the clinical resemblance was significant. Various methods quantified cramp/spasm frequency, with self-reports being the most common approach.

Conclusion

Muscle cramps and spasms probably represent related symptoms with a shared pathophysiological component. When considering future treatment strategies, it is important to recognize that part of the patient's spasms may be attributed to cramps.

Case report: Intrathecal baclofen therapy improved gait pattern in a stroke patient with spastic dystonia

Background

Intrathecal baclofen (ITB) therapy, a viable alternative for unsuitable candidates of conventional spasticity medications, is a preferred method of administration over the oral route. Owing to its enhanced bioavailability, ITB ensures a more effective delivery at the target site.

Objective

There is a lack of conclusive evidence regarding the use of ITB treatment in managing ambulatory patients with spastic dystonia. Before ITB pump implantation, patients commonly undergo an ITB bolus injection trial to rule out potential adverse reactions and verify the therapeutic effects on hypertonic issues. In this report, we highlight a case of spastic dystonia, particularly focusing on an ambulatory patient who demonstrated significant improvement in both the modified Ashworth scale (MAS) score and gait pattern following the ITB injection trial.

Case report

This case report outlines the medical history of a 67-year-old male diagnosed with left-side hemiplegia and spastic dystonia, resulting from his second episode of intracranial hemorrhage in the right thalamus. An ITB injection trial was initiated because the patient was not suitable for continued botulinum toxin injections and oral medications. This was due to the persistent occurrence of spastic dystonia in both the upper and lower extremities. The patient underwent a four-day ITB injection trial with progressively increasing doses, resulting in improved MAS scores and gait parameters, including cadence, step length, step time, stride length, and stride time were increased. Particularly, kinematic gait analysis demonstrates a substantial improvement of increased knee flexion in the swing phase in stiff knee gait pattern. These findings indicated a gradual reduction in spasticity-related symptoms, signifying the positive effect of the ITB injection trial. The patient eventually received an ITB pump implantation.

Conclusion

In this post-stroke patient with spastic dystonia, ITB therapy has demonstrated effective and substantial management of spasticity, along with improvement in gait patterns.

Validating the measurement of passive Musculo-articular wrist stiffness without intentional or reactive contraction using axillary plexus block

BACKGROUND

Passive stiffness describes how easily a joint may move passively. To accurately measure wrist stiffness, an electro-oscillation device was developed. The objectives were to 1) ensuring that the measurement are free from intentional or reflex contraction, 2) analyzing how forearm anatomy affects the passive stiffness of the wrist and 3) determining the clinical practical relevance of the device.

METHODS

In this prospective study, the device generated low amplitude sinusoidal motions in flexion and extension on the wrist to quantify elastic and viscous passive stiffness in voluntary orthopaedic patients. The first series of measurements was carried out in the state of voluntary relaxation, the second series of measurements was carried out after an axillary plexus anesthetic block. A matched group of healthy subjects were use for control.

FINDINGS

The Electromechanical Oscillation methods effectively enable the measurement of passive joint stiffness since the stiffness values obtained show no statistically significant difference pre-post the anesthesia. The stiffness values are comparable to those of healthy subjects. The effect of forearm passive structure, estimated by the perimeter of the forearm, influences the passive stiffness of the wrist, mainly the viscous component.

INTERPRETATION

The use of sinusoidal oscillation was well accepted by the participants, demonstrating its usefulness and applicability in a clinical setting. This work serves as a foundation for future investigations of orthopaedic and/or neurological pathological conditions characterized by abnormal passive joint stiffness of the wrist. It paves the way for its use as a diagnostic, prognostic, and monitoring tool in these pathologies.

Upper limb assessment with inertial measurement units according to the international classification of functioning in stroke: a systematic review and correlation meta-analysis

OBJECTIVE

To investigate the usefulness of inertial measurement units (IMUs) in the assessment of motor function of the upper limb (UL) in accordance with the international classification of functioning (ICF).

DATA SOURCES

PubMed; Scopus; Embase; WoS and PEDro databases were searched from inception to 1 February 2022.

METHODS

The current systematic review follows PRISMA recommendations. Articles including IMU assessment of UL in stroke individuals have been included and divided into four ICF categories (b710, b735, b760, d445). We used correlation meta-analysis to pool the Fisher Z-score of each correlation between kinematics and clinical assessment.

RESULTS

A total of 35 articles, involving 475 patients, met the inclusion criteria. In the included studies, IMUs have been employed to assess the mobility of joint functions (n = 6), muscle tone functions (n = 4), control of voluntary movement functions (n = 15), and hand and arm use (n = 15). A significant correlation was found in overall meta-analysis based on 10 studies, involving 213 subjects: (r = 0.69) (95% CI: 0.69/0.98; p < 0.001) as in the d445 (r = 0.71) and b760 (r = 0.64) ICF domains, with no heterogeneity across the studies.

CONCLUSION

The literature supports the integration of IMUs and conventional clinical assessment in functional evaluation of the UL after a stroke. The use of a limited number of wearable sensors can provide additional kinematic features of UL in all investigated ICF domains, especially in the ADL tasks when a strong correlation with clinical evaluation was found.

Testing spasticity mechanisms in chronic stroke before and after intervention with contralesional motor cortex 1 Hz rTMS and physiotherapy

BACKGROUND

Previous studies showed that repetitive transcranial magnetic stimulation (rTMS) reduces spasticity after stroke. However, clinical assessments like the modified Ashworth scale, cannot discriminate stretch reflex-mediated stiffness (spasticity) from passive stiffness components of resistance to muscle stretch. The mechanisms through which rTMS might influence spasticity are also not understood.

METHODS

We measured the effects of contralesional motor cortex 1 Hz rTMS (1200 pulses + 50 min physiotherapy: 3×/week, for 4-6 weeks) on spasticity of the wrist flexor muscles in 54 chronic stroke patients using a hand-held dynamometer for objective quantification of the stretch reflex response. In addition, we measured the excitability of three spinal mechanisms thought to be related to post-stroke spasticity: post-activation depression, presynaptic inhibition and reciprocal inhibition before and after the intervention. Effects on motor impairment and function were also assessed using standardized stroke-specific clinical scales.

RESULTS

The stretch reflex-mediated torque in the wrist flexors was significantly reduced after the intervention, while no change was detected in the passive stiffness. Additionally, there was a significant improvement in the clinical tests of motor impairment and function. There were no significant changes in the excitability of any of the measured spinal mechanisms.

CONCLUSIONS

We demonstrated that contralesional motor cortex 1 Hz rTMS and physiotherapy can reduce the stretch reflex-mediated component of resistance to muscle stretch without affecting passive stiffness in chronic stroke. The specific physiological mechanisms driving this spasticity reduction remain unresolved, as no changes were observed in the excitability of the investigated spinal mechanisms.

Common modelling assumptions affect the joint moments measured during passive joint mobilizations

Joint resistance to passive mobilization has already been estimated in-vivo in several studies by measuring the applied forces and moments while manipulating the joint. Nevertheless, in most of the studies, simplified modelling approaches are used to calculate this joint resistance. The impact of these simplifications is still unknown. We propose a protocol that enables a reference 3D inverse dynamics approach to be implemented and compared to common simplified approaches. Eight typically developed children and eight children with cerebral palsy were recruited and underwent a passive testing protocol, while applied forces and moments were measured through a 3D handheld dynamometer, simultaneously to its 3D kinematics and the 3D kinematics of the different segments. Then, passive joint resistance was estimated using the reference 3D inverse dynamics approach and according to 5 simplified approaches found in the literature, i.e. ignoring either the dynamometer kinematics, the measured moments alone or together with the measured tangential forces, the gravity and the inertia of the different segments, or the distal segments kinematics. These simplifications lead to non-negligible differences with respect to the reference 3D inverse dynamics, from 3 to 32% for the ankle, 4 to 34% for the knee and 1 to 58% for the hip depending of the different simplifications. Finally, we recommend a complete 3D kinematics and dynamics modelling to estimate the joint resistance to passive mobilization.

Pendulum test parameters are useful for detecting knee muscle hypertonia and quantifying response to an intrathecal baclofen bolus injection

Our objective was to determine which pendulum test parameters are useful for detecting hypertonia in the knee muscles and assessing the group and individual responses to intrathecal baclofen (ITB) bolus injection among prospective pump recipients. We included 15 neurological patients with lower limb hypertonia (mainly spinal cord injury, n  = 7) and collected data the day before (baseline), and 2.5 and 5.0 h after the 50-µg ITB bolus injection. For comparison, data were collected in 15 healthy controls. The average over six test repetitions was obtained for the number of oscillations, swing time (SwingT), amplitudes of the first flexion and extension, maximum angular velocities of the first flexion (F1V) and extension (E1V), relaxation index, and damping coefficient (DampC). Across the patient group, all pendulum parameters indicated a significant decrease in hypertonia from baseline to postinjection (analysis of variance P  ≤ 0.004), except DampC. On the basis of the cutoffs from the receiver operating characteristic curve, all parameters were good or excellent discriminators of hypertonia in patients from normotonia in controls (area under the curve ≥0.85), with the highest sensitivity for SwingT and E1V (≥93%). Furthermore, all parameters except F1V revealed a significant shift from preinjection hypertonia to postinjection normotonia among patients (McNamar test P  ≤ 0.002, DampC excluded due to missing data), with the greatest responsiveness for E1V and relaxation index (≥73%). The results confirm the overall usefulness of pendulum test parameters in this patient population and indicate that some parameters are better at detecting hypertonia (SwingT, E1V) whereas others (E1V, relaxation index) are more responsive to the ITB injection.

Child Neurology: KMT2B-Related Dystonia in a Young Child With Worsening Gait Abnormality

KMT2B gene-related dystonia (DYT-KMT2B) is a primarily childhood-onset movement disorder that usually starts with lower limb dystonia progressing into generalized dystonia. Our patient described in this study experienced difficulty gaining weight, laryngomalacia, and feeding difficulties during infancy and later developed gait difficulties, frequent falls, and toe walking. Gait assessment revealed prominent bilateral intoeing, intermittent ankle inversion, and extension of left leg. At times, the gait seemed to be spastic. Whole-exome sequencing revealed a novel de novo heterozygous likely pathogenic variant, c.7913 T > A (p.V2638E), in the KMT2B gene located in chromosome 19. This variant, which has not been previously published as pathogenic or benign in the literature, can be added to the repertoire of KMT2B variants causing inherited dystonias.

Quantitative assessment of spasticity: a narrative review of novel approaches and technologies

Spasticity is a complex neurological disorder, causing significant physical disabilities and affecting patients' independence and quality of daily lives. Current spasticity assessment methods are questioned for their non-standardized measurement protocols, limited reliabilities, and capabilities in distinguishing neuron or non-neuron factors in upper motor neuron lesion. A series of new approaches are developed for improving the effectiveness of current clinical used spasticity assessment methods with the developing technology in biosensors, robotics, medical imaging, biomechanics, telemedicine, and artificial intelligence. We investigated the reliabilities and effectiveness of current spasticity measures employed in clinical environments and the newly developed approaches, published from 2016 to date, which have the potential to be used in clinical environments. The new spasticity scales, taking advantage of quantified information such as torque, or echo intensity, the velocity-dependent feature and patients' self-reported information, grade spasticity semi-quantitatively, have competitive or better reliability than previous spasticity scales. Medical imaging technologies, including near-infrared spectroscopy, magnetic resonance imaging, ultrasound and thermography, can measure muscle hemodynamics and metabolism, muscle tissue properties, or temperature of tissue. Medical imaging-based methods are feasible to provide quantitative information in assessing and monitoring muscle spasticity. Portable devices, robotic based equipment or myotonometry, using information from angular, inertial, torque or surface EMG sensors, can quantify spasticity with the help of machine learning algorithms. However, spasticity measures using those devices are normally not physiological sound. Repetitive peripheral magnetic stimulation can assess patients with severe spasticity, which lost voluntary contractions. Neuromusculoskeletal modeling evaluates the neural and non-neural properties and may gain insights into the underlying pathology of spasticity muscles. Telemedicine technology enables outpatient spasticity assessment. The newly developed spasticity methods aim to standardize experimental protocols and outcome measures and enable quantified, accurate, and intelligent assessment. However, more work is needed to investigate and improve the effectiveness and accuracy of spasticity assessment.

Validity of Accelerometer-Based Sensor System for Muscle Tightness Estimation through Vibration on the Upper Limb

Spasticity is a condition that profoundly impacts the ability to perform everyday tasks. However, its diagnosis requires trained physicians and subjective evaluations that may vary depending on the evaluator. Focal vibration of spastic muscles has been proposed as a non-invasive, pain-free alternative for spasticity modulation. We propose a system to estimate muscular tightness based on the propagation of elastic waves in the skin generated by focal vibration of the upper limb. The developed system generates focalized displacements on the biceps muscle at frequencies from 50 to 200 Hz, measures the vibration acceleration on the vibration source (input) and the distant location (output), and extracts features of ratios between input and output. The system was tested on 5 healthy volunteers while lifting 1.25 - 11.25 kg weights to increase muscle tone resembling spastic conditions, where the vibration frequency and weight were selected as explanatory variables. An increase in the ratio of the root mean squares proportional to the weight was found, validating the feasibility of the current approach to estimating muscle tightness.Clinical Relevance- This work presents the feasibility of a vibration-based system as an alternative method to objectively diagnose the degree of spasticity.

Spasticity assessment with muscle coactivation of elbow flexors during passive stretch in Post-stroke Hemiplegia

the assessment of muscle properties is an essential prerequisite in the treatment of post-stroke muscle spasticity. Previous studies have shown that muscle coactivation, which reflects the simultaneous activation of agonist and antagonist muscle groups, is associated with muscle spasticity during voluntary contraction. However, current spasticity assessment approaches do not often consider muscle coactivation for passive contraction measured with surface electromyography (sEMG). The purpose here is to evaluate the validity and reliability of muscle co-activation based on sEMG for assessing spasticity of post-stroke patients. This study was conducted on 39 chronic hemiplegia post-stroke patients with varying degrees of elbow flexor spasticity. The severity of spasticity was assessed with Modified Ashworth Scale (MAS). The patients produced elbow flexion passively on affected arm. Two-channel surface sEMG recordings were acquired simultaneously for the biceps and triceps muscles. The effectiveness and reliability of the EMG-based spasticity assessment method were evaluated using Spearman's correlation analysis and intra class correlation coefficients (ICCs). The results showed that there was a statistically significant positive relationship between the level of activity and the coactivation index (R=0.710, P=0.003), while the ICCs for intra trial measures ranged between 0.928 and 0.976. Muscle coactivation is a promising tool for continuously quantifying muscle spasticity in post-stroke patients, suggesting that the EMG-based muscle coactivation index could be useful for assessing motor function.

Measuring resistance to externally induced movement of the wrist joint in chronic stroke patients using an objective hand-held dynamometer

Objective

We evaluated the resistance to externally induced wrist extension in chronic stroke patients. We aimed to objectively measure and distinguish passive (muscle and soft tissue stiffness) and active (spasticity and spastic dystonia) components of the resistance.

Methods

We used a hand-held dynamometer, which measures torque, joint movement and electromyography (EMG) simultaneously, to assess the resistance to externally induced wrist extension. Slow and fast stretches were applied to the affected and unaffected wrists in 57 chronic stroke patients (57 ± 11 years). We extracted from the data parameters that represent passive and muscle activity components and assessed the validity, test-retest reliability and the clinical utility of the measurement.

Results

The analysis showed (1) a significant difference in the passive and muscle activity components between the affected and unaffected sides; (2) a significant correlation between passive and muscle activity components and the modified Ashworth scale (MAS); (3) a significant difference between the subgroups of patients stratified by the MAS; (4) an excellent intra-rater reliability on each of the passive and muscle activity components with intra-class coefficients between 0.92 and 0.99; (5) and small measurement error.

Conclusions

Using a hand-held dynamometer, we were able to objectively measure the resistance to muscle stretch in the wrist joint in chronic stroke patients and discriminate muscle overactivity components from muscle and soft tissue stiffness. We demonstrated validity, test-retest reliability and the clinical utility of the measurement.

Significance

Quantification of the different components of resistance to externally induced movement enables the objective evaluation of neurorehabilitation effects in chronic stroke patients.

Bumetanide increases postsynaptic inhibition after chronic SCI and decreases presynaptic inhibition with step-training

Current anti-spastic medication significantly compromises motor recovery after spinal cord injury (SCI), indicating a critical need for alternative interventions. Because a shift in chloride homeostasis decreases spinal inhibition and contributes to hyperreflexia after SCI, we investigated the effect of bumetanide, an FDA-approved sodium-potassium-chloride intruder (NKCC1) antagonist, on presynaptic and postsynaptic inhibition. We compared its effect with step-training as it is known to improve spinal inhibition by restoring chloride homeostasis. In SCI rats, a prolonged bumetanide treatment increased postynaptic inhibition but not presynaptic inhibition of the plantar H-reflex evoked by posterior biceps and semitendinosus (PBSt) group I afferents. By using in vivo intracellular recordings of motoneurons, we further show that a prolonged bumetanide increased postsynaptic inhibition by hyperpolarizing the reversal potential for inhibitory postsynaptic potentials (IPSPs) after SCI. However, in step-trained SCI rats an acute delivery of bumetanide decreased presynaptic inhibition of the H-reflex, but not postsynaptic inhibition. These results suggest that bumetanide might be a viable option to improve postsynaptic inhibition after SCI, but it also decreases the recovery of presynaptic inhibition with step-training. We discuss whether the effects of bumetanide are mediated by NKCC1 or by off-target effects. KEY POINTS: After spinal cord injury (SCI), chloride homeostasis is dysregulated over time in parallel with the decrease in presynaptic inhibition of Ia afferents and postsynaptic inhibition of motoneurons, and the development of spasticity. While step-training counteracts these effects, it cannot always be implemented in the clinic because of comorbidities. An alternative intervention is to use pharmacological strategies to decrease spasticity without hindering the recovery of motor function with step-training. Here we found that, after SCI, a prolonged bumetanide (an FDA-approved antagonist of the sodium-potassium-chloride intruder, NKCC1) treatment increases postsynaptic inhibition of the H-reflex, and it hyperpolarizes the reversal potential for inhibitory postsynaptic potentials in motoneurons. However, in step-trained SCI, an acute delivery of bumetanide decreases presynaptic inhibition of the H-reflex, but not postsynaptic inhibition. Our results suggest that bumetanide has the potential to decrease spastic symptoms related to a decrease in postsynaptic but not presynaptic inhibition after SCI.

Neural bases characterizing chronic and severe upper-limb motor deficits after brain lesion

Chronic and severe upper-limb motor deficits can result from damage to the corticospinal tract. However, it remains unclear what their characteristics are and whether only corticospinal tract damage determines their characteristics. This study aimed to investigate the clinical characteristics and neural bases of chronic and severe upper-limb motor deficits. Motor deficits, including spasticity, of 45 patients with brain lesions were assessed using clinical scales. Regarding their scores, we conducted a principal component analysis that statistically extracted the clinical characteristics as two principal components. Using these principal components, we investigated the neural bases underlying their characteristics through lesion analyses of lesion volume, lesion sites, corticospinal tract, or other regional white-matter integrity. Principal component analysis showed that the clinical characteristics of chronic and severe upper-limb motor deficits could be described as a comprehensive severity and a trade-off relationship between proximal motor functions and wrist/finger spasticity. Lesion analyses revealed that the comprehensive severity was correlated with corticospinal tract integrity, and the trade-off relationship was associated with the integrity of other regional white matter located anterior to the posterior internal capsule, such as the anterior internal capsule. This study indicates that the severity of chronic and severe upper-limb motor deficits can be determined according to the corticospinal tract integrity, and such motor deficits may be further characterized by the integrity of other white matter, where the corticoreticular pathway can pass through, by forming a trade-off relationship where patients have higher proximal motor functions but more severe wrist/finger spasticity, and vice versa.

Riluzole for treating spasticity in patients with chronic traumatic spinal cord injury: Study protocol in the phase ib/iib adaptive multicenter randomized controlled RILUSCI trial

BACKGROUND

Satisfactory treatment is often lacking for spasticity, a highly prevalent motor disorder in patients with spinal cord injury (SCI). Low concentrations of riluzole potently reduce the persistent sodium current, the post-SCI increase in which contributes to spasticity. The repurposing of this drug may therefore constitute a useful potential therapeutic option for relieving SCI patients suffering from chronic traumatic spasticity.

OBJECTIVE

RILUSCI is a phase 1b-2b trial designed to assess whether riluzole is a safe and biologically effective means of managing spasticity in adult patients with traumatic chronic SCI.

METHODS

In this multicenter double-blind trial, adults (aged 18-65 years) suffering from spasticity after SCI (target enrollment: 90 participants) will be randomly assigned to be given either a placebo or a recommended daily oral dose of riluzole for two weeks. The latter dose will be previously determined in phase 1b of the study by performing double-blind dose-finding tests using a Bayesian continuous reassessment method. The primary endpoint of the trial will be an improvement in the Modified Ashworth Score (MAS) or the Numerical Rating Score (NRS) quantifying spasticity. The secondary outcomes will be based on the safety and pharmacokinetics of riluzole as well as its impact on muscle spasms, pain, bladder dysfunction and quality of life. Analyses will be performed before, during and after the treatment and the placebo-controlled period.

CONCLUSION

To the best of our knowledge, this clinical trial will be the first to document the safety and efficacy of riluzole as a means of reducing spasticity in patients with chronic SCI.

TRIAL REGISTRATION

The clinical trial, which is already in progress, was registered on the ClinicalTrials.gov website on August 9, 2016 under the registration number NCT02859792.

TRIAL SPONSOR

Assistance Publique-Hôpitaux de Marseille.

Clinical efficacy of botulinum toxin type A in patients with traumatic brain injury, spinal cord injury, or multiple sclerosis: An observational longitudinal study

Botulinum toxin type A (BoNT-A) is the treatment of choice for focal spasticity, with a concomitant effect on pain reduction and improvement of quality of life (QoL). Current evidence of its efficacy is based mainly on post stroke spasticity. This study aims to clarify the role of BoNT-A in the context of non-stroke spasticity (NSS). We enrolled 86 patients affected by multiple sclerosis, spinal cord injury, and traumatic brain injury with clinical indication to perform BoNT-A treatment. Subjects were evaluated before injection and after 1, 3, and 6 months. At every visit, spasticity severity using the modified Ashworth scale, pain using the numeric rating scale, QoL using the Euro Qol Group EQ-5D-5L, and the perceived treatment effect using the Global Assessment of Efficacy scale were recorded. In our population BoNT-A demonstrated to have a significant effect in improving all the outcome variables, with different effect persistence over time in relation to the diagnosis and the number of treated sites. Our results support BoNT-A as a modifier of the disability condition and suggest its implementation in the treatment of NSS, delivering a possible starting point to generate diagnosis-specific follow-up programs.

Clinical trial identifier

NCT04673240.

Paving the way for a better management of pain in patients with spinal cord injury: An exploratory study on the use of Functional Electric Stimulation(FES)-cycling

CONTEXT/OBJECTIVE

Chronic pain is common in patients with spinal cord injury (SCI), for whom it negatively affects quality of life, and its treatment requires an integrated approach. To this end, lower limb functional electrical stimulation (FES) cycling holds promise.

OBJECTIVE

To investigate pain reduction in a sample of patients with SCI by means of lower limb rehabilitation using FES cycling.

DESIGN, SETTING AND PARTICIPANTS

Sixteen patients with incomplete and complete SCIs, attending the Neurorobotic Unit of our research institute and reporting pain at or below the level of their SCI were recruited to this exploratory study.

INTERVENTIONS

Patients undertook two daily sessions of FES cycling, six times weekly, for 6 weeks.

OUTCOME MEASURES

Pain outcomes were measured using the 0-10 numerical rating scale (NRS), the Multidimensional Pain Inventory for SCI (MPI-SCI), and the 36-Item Short Form Survey (SF-36). Finally, we assessed the features of dorsal laser-evoked potentials (LEPs) to objectively evaluate Aδ fiber pathways.

RESULTS

All participants tolerated the intervention well, and completed the training without side effects. Statistically significant changes were found in pain-NRS, MPI-SCI, and SF-36 scores, and LEP amplitudes. Following treatment, we found that three patients experienced high pain relief (an NRS decrease of at least 80%), six individuals achieved moderate pain relief (an NRS decrease of about 30-70%), and five participants had mild pain relief (an NRS decrease of less than 30%).

CONCLUSION

Our preliminary results suggest that FES cycling training is capable of reducing the pain reported by patients with SCI, regardless of American Spinal Injury Association scoring, pain level, or the neurological level of injury. The neurophysiological mechanisms underlying such effects are likely to be both spinal and supraspinal.

Intrathecal and Oral Baclofen Use in Adults With Spinal Cord Injury: A Systematic Review of Efficacy in Spasticity Reduction, Functional Changes, Dosing, and Adverse Events

OBJECTIVE

To examine the efficacy, dosing, and safety profiles of intrathecal and oral baclofen in treating spasticity after spinal cord injury (SCI).

DATA SOURCES

PubMed and Cochrane Databases were searched from 1970-2018 with keywords baclofen, spinal cord injury, and efficacy.

STUDY SELECTION

The database search yielded 588 sources and 10 additional relevant publications. After removal of duplicates, 398 publications were screened.

DATA EXTRACTION

Data were extracted using the following population, intervention, comparator, outcomes, and study designs criteria: studies including adult patients with SCI with spasticity; the intervention could be oral or intrathecal administration of baclofen; selection was inclusive for control groups, surgical management, rehabilitation, and alternative pharmaceutical agents; outcomes were efficacy, dosing, and adverse events. Randomized controlled trials, observational studies, and case reports were included. Meta-analyses and systematic reviews were excluded.

DATA SYNTHESIS

A total of 98 studies were included with 1943 patients. Only 4 randomized, double-blinded, and placebo-controlled trials were reported. Thirty-nine studies examined changes in the Modified Ashworth Scale (MAS; 34 studies) and Penn Spasm scores (Penn Spasm Frequency; 19 studies), with average reductions of 1.7±1.3 and 1.6±1.4 in individuals with SCI, respectively. Of these data, a total of 6 of the 34 studies (MAS) and 2 of the 19 studies (Penn Spasm Frequency) analyzed oral baclofen. Forty-three studies addressed adverse events with muscle weakness and fatigue frequently reported.

CONCLUSIONS

Baclofen is the most commonly-prescribed antispasmodic after SCI. Surprisingly, there remains a significant lack of large, placebo-controlled, double-blinded clinical trials, with most efficacy data arising from small studies examining treatment across different etiologies. In the studies reviewed, baclofen effectively improved spasticity outcome measures, with increased efficacy through intrathecal administration. Few studies assessed how reduced neural excitability affected residual motor function and activities of daily living. A host of adverse events were reported that may negatively affect quality of life. Comparative randomized controlled trials of baclofen and alternative treatments are warranted because these have demonstrated promise in relieving spasticity with reduced adverse events and without negatively affecting residual motor function.

Is There a Relation between Brain and Muscle Activity after Virtual Reality Training in Individuals with Stroke? A Cross-Sectional Study

Objective-The aim was to verify the correlation between cerebral and muscular electrical activity in subjects trained in virtual reality after a stroke. Method-The trial design was a cross-sectional study. Fourteen volunteers who were diagnosed with a stroke participated in the study. The intervention protocol was to perform functional activity with an upper limb using virtual reality. The functional protocol consisted of four one-minute series with a two-minute interval between series in a single session. Results-We observed, at initial rest, a positive correlation between brachii biceps and the frontal canal medial region (F7/F8) (r = 0.59; p = 0.03) and frontal canal lateral region (F3/F4) (r = 0.71; p = 0.006). During the activity, we observed a positive correlation between the anterior deltoid and frontal anterior channel (AF3/AF4) (r = 0.73; p = 0.004). At final rest, we observed a positive correlation between the anterior deltoid and temporal region channel (T7/T8) (r = 0.70; p = 0.005). Conclusions-We conclude that there was no correlation between brain and muscle activity for the biceps brachii muscle in subjects trained with virtual reality. However, there was a positive correlation for the deltoid anterior muscle.

Effect of Dry Needling Treatment on Tibial Musculature in Combination with Neurorehabilitation Treatment in Stroke Patients: Randomized Clinical Study

(1) Background: Introducing ultrasound-guided dry needling to neurorehabilitation treatments increases the beneficial effects of therapy. The aim of this study was to compare the effects of including an ultrasound-guided dry needling session in neurorehabilitation treatment on spasticity and gait-balance quality versus neurorehabilitation treatment in subjects who had suffered a stroke. (2) Methods: A single-blind, randomized clinical trial was conducted. Thirty-six patients who had suffered a stroke in the right middle cerebral artery signed the informed consent for participation in the study. Twenty patients finally participated and were randomly assigned to the control group (neurorehabilitation treatment) or experimental group (neurorehabilitation treatment plus ultrasound-guided dry needling). Pre-treatment and post-treatment data were collected on the same day. The experimental group (n = 10) first underwent an ultrasound-guided dry needling intervention on the tibialis anterior and tibialis posterior musculature, followed by neurorehabilitation treatment; the control group (n = 10) underwent their corresponding neurorehabilitation without the invasive technique. Pre-treatment and post-treatment measurements were taken on the same day, assessing the quality of balance-gait using the "Up and Go" test and the degree of spasticity using the Modified Modified Ashworth Scale. (3) Results: The patients who received neurorehabilitation treatment plus ultrasound-guided dry needling showed a greater decrease in spasticity in the tibial musculature after the neurorehabilitation treatment session (p < 0.001), improving balance and gait (p < 0.001). (4) Conclusions: An ultrasound-guided dry needling session combined with neurorehabilitation treatment reduced spasticity and improved balance and gait in stroke patients.

Development of a simple mechanical measurement method to measure spasticity based on an analysis of a clinical maneuver and its concurrent validity with the modified Ashworth scale

Background: Despite recent developments in the methodology for measuring spasticity, the discriminative capacity of clinically diagnosed spasticity has not been well established. This study aimed to develop a simple device for measuring velocity-dependent spasticity with improved discriminative capacity based on an analysis of clinical maneuver and to examine its reliability and validity.

Methods: This study consisted of three experiments. First, to determine the appropriate motion of a mechanical device for the measurement of velocity-dependent spasticity, the movement pattern and the angular velocity used by clinicians to evaluate velocity-dependent spasticity were investigated. Analysis of the procedures performed by six physical therapists to evaluate spasticity were conducted using an electrogoniometer. Second, a device for measuring the resistance force against ankle dorsiflexion was developed based on the results of the first experiment. Additionally, preliminary testing of validity, as compared to that of the Modified Ashworth Scale (MAS), was conducted on 17 healthy participants and 10 patients who had stroke with spasticity. Third, the reliability of the measurement and the concurrent validity of mechanical measurement in the best ankle velocity setting were further tested in a larger sample comprising 24 healthy participants and 32 patients with stroke.

Results: The average angular velocity used by physical therapists to assess spasticity was 268 ± 77°/s. A device that enabled the measurement of resistance force at velocities of 300°/s, 150°/s, 100°/s, and 5°/s was developed. In the measurement, an angular velocity of 300°/s was found to best distinguish patients with spasticity (MAS of 1+ and 2) from healthy individuals. A measurement of 300°/s in the larger sample differentiated the control group from the MAS 1, 1+, and 2 subgroups (p < 0.01), as well as the MAS 1 and 2 subgroups (p < 0.05). No fixed or proportional bias was observed in repeated measurements.

Conclusion: A simple mechanical measurement methodology was developed based on the analysis of the clinical maneuver for measuring spasticity and was shown to be valid in differentiating the existence and extent of spasticity. This study suggest possible requirements to improve the quality of the mechanical measurement of spasticity.

Neural data-driven model of spinal excitability changes induced by transcutaneous electrical stimulation in spinal cord injury subjects

The efficacy of trans-spinal direct current stimulation (tsDCS) as neurorehabilitation technology remains sub-optimal, partly due to the variability introduced by subject-specific neurophysiological features and stimulation conditions (e.g. electrode placement, stimulating amplitude, polarity, etc.) Hence, current therapies apply tsDCS in an open-loop fashion, resulting in a lack of standardized protocols for controlling elicited neuronal adaptations in closed-loop. Through the combination of high-density electromyogram (HD-EMG) decomposition, biophysical neuronal modelling and metaheuristic optimization, this work presents a novel neural data-driven framework for estimating subject-specific features and quantifying acute neuronal adaptations elicited by tsDCS on incomplete spinal cord injury subjects. This approach consists of calibrating the anatomical parameters (e.g. soma diameter) of in silico $\alpha-$motoneuron (MN) models for firing similarly to in vivo MNs decoded from HD-EMG. Assuming that cathodal-tsDCS elicits excitability changes in the MN pool, while preserving their anatomical parameters, optimization of an excitability gain common to the entire pool was performed to minimize discrepancies in firing rate and recruitment time between in vivo and in silico MNs after cathodal-tsDCS. This quantification of excitability changes on MN models calibrated in a person specific way enables closing the loop with neuro-modulation devices to tailor neurorehabilitation therapies. Clinical Relevance - This framework addresses a key limitation in non-invasive neuro-modulative technologies via a novel model-assisted framework that enables quantifying acute excitability changes induced on a person-specific in silico MN pool calibrated using in vivo neural data. This will enable the development of advanced controllers for modulating targeted neuronal adaptations in closed-loop.

The effects of cycling using lower limb active passive trainers in people with neurological conditions: a systematic review

Background Active passive trainers are frequently used as a safe, feasible way for people with neurological disabilities to exercise. However, evidence regarding their efficacy is limited. The aim of this study was to review the literature investigating the effects of lower limb active passive trainer cycling, with or without functional electrical stimulation, on spasticity, cardiovascular fitness, function and quality of life in people with neurological conditions

Methods Five electronic databases were searched from inception to June 2021. Studies included: randomised controlled trials using lower limb active passive trainers as a cycling intervention; participants with neurological conditions, such as multiple sclerosis, spinal cord injury, stroke and Parkinson's disease; and at least one outcome related to spasticity, cardiovascular fitness, physical function or quality of life.

Results A total of 12 articles were included (n=423 participants, 52% male). Of these, six used functional electrical stimulation-assisted active passive trainer interventions, and the remaining six used active passive trainer interventions alone. A meta-analysis demonstrated statistically significant improvement in walking endurance; however, this only included stroke studies (6-Minute Walk Test performance, P<0.00001). No statistically significant improvement in walking speed was found (P=0.31). A significant improvement in spasticity was reported by three studies (two using the active passive trainer intervention alone, one using the active passive trainer with functional electrical stimulation). One study reported improvement in quality of life. Few studies considered cardiovascular fitness.

Conclusions The included studies featured heterogeneous designs, outcome measures, exercise prescriptions and participant disability levels, which made comparison difficult. Active passive trainer interventions appear to improve walking endurance in people with stroke; however, the effect on other outcomes and in other conditions remains unclear. It also remains uncertain as to whether functional electrical stimulation-assisted cycling is more beneficial than active passive trainer cycling alone.

The Efficacy of Cannabis on Multiple Sclerosis-Related Symptoms

Multiple sclerosis (MS) is known as an autoimmune disease that damages the neurons in the central nervous system. MS is characterized by its most common symptoms of spasticity, muscle spasms, neuropathic pain, tremors, bladder dysfunction, dysarthria, and some intellectual problems, including memory disturbances. Several clinical studies have been conducted to investigate the effects of cannabis on the relief of these symptoms in MS patients. The efficacy of Cannabis sativa (C. Sativa) in the management of MS outcomes such as spasticity, pain, tremors, ataxia, bladder functions, sleep, quality of life, and adverse effects were assessed in this review. Most clinical studies showed the positive effects of cannabinoids with their different routes of administration, such as oromucosal spray and oral form, in reducing most MS symptoms. The oromucosal spray Nabiximols demonstrated an improvement in reducing MS spasticity, pain, and quality of life with a tolerated adverse effect. Oral cannabinoids are significantly effective for treating MS pain and spasticity, while the other symptoms indicate slight improvement and the evidence is quite inconsistent. Oromucosal spray and oral cannabis are mainly used for treating patients with MS and have positive effects on treating the most common symptoms of MS, such as pain and spasticity, whereas the other MS symptoms indicated slight improvement, for which further studies are needed.

Recent State of Wearable IMU Sensors Use in People Living with Spasticity: A Systematic Review

Spasticity is a disabling characteristic of neurological disorders, described by a velocity-dependent increase in muscle tone during passive stretch. During the last few years, many studies have been carried out to assess spasticity using wearable IMU (inertial measurements unit) sensors. This review aims to provide an updated framework of the current research on IMUs wearable sensors in people living with spasticity in recent studies published between 2017 and 2021. A total of 322 articles were screened, then finally 10 articles were selected. Results show the lack of homogenization of study procedures and missing apparatus information in some studies. Still, most studies performed adequately on measures of reporting and found that IMUs wearable data was successful in their respective purposes and goals. As IMUs estimate translational and rotational body motions, we believe there is a strong potential for these applications to estimate velocity-dependent exaggeration of stretch reflexes and spasticity-related characteristics in spasticity. This review also proposes new directions of research that should be challenged by larger study groups and could be of interest to both researchers as well as clinicians. The use of IMUs to evaluate spasticity is a promising avenue to provide an objective measurement as compared to non-instrumented traditional assessments.

Evidence of treating spasticity before it develops: a systematic review of spasticity outcomes in acute spinal cord injury interventional trials

Introduction: Spasticity is a common consequence of spinal cord injury (SCI), estimated to affect up to 93% of people living with SCI in the community. Problematic spasticity affects around 35% people with SCI spasticity. The early period after injury is believed to be the most opportune time for neural plasticity after SCI. We hypothesize that clinical interventions in the early period could reduce the incidence of spasticity. To address this, we evaluated the spasticity outcomes of clinical trials with interventions early after SCI.Methods: We performed a systematic review of the literature between January 2000 and May 2021 to identify control trials, in humans and animals, that were performed early after SCI that included measures of spasticity in accordance with PRISMA guidelines.Results: Our search yielded 1,463 records of which we reviewed 852 abstracts and included 8 human trial peer-reviewed publications and 9 animal studies. The 9 animal trials largely supported the hypothesis that early intervention can reduce spasticity, including evidence from electrophysiological, behavioral, and histologic measures. Of the 8 human trials, only one study measured spasticity as a primary outcome with a sample size sufficient to test the hypothesis. In this study, neuromodulation of the spinal cord using electric stimulation of the common peroneal nerve reduced spasticity in the lower extremities compared to controls.Conclusion: Given the prevalence of problematic spasticity, there is surprisingly little research being performed in the early period of SCI that includes spasticity measures, and even fewer studies that directly address spasticity. More research on the potential for early interventions to mitigate spasticity is needed.

Intensive Neurorehabilitation and Gait Improvement in Progressive Multiple Sclerosis: Clinical, Kinematic and Electromyographic Analysis

Background: Gait deficit is a hallmark of multiple sclerosis and the walking capacity can be improved with neurorehabilitation. Technological advances in biomechanics offer opportunities to assess the effects of rehabilitation objectively. Objective: Combining wireless surface electromyography and wearable inertial sensors to assess and monitor the gait pattern before and after an intensive multidisciplinary neurorehabilitation program (44 h/4weeks) to evaluate rehabilitation efficiency. Methods: Forty people with progressive multiple sclerosis were enrolled. Wireless wearable devices were used to evaluate the gait. Instrumental gait analysis, clinical assessment, and patient report outcome measures were acquired before and after the neurorehabilitation. Spatiotemporal gait parameters, the co-activation index of lower limb muscles, and clinical assessments were compared pre- and post-treatment. Results: Significant improvements after intensive neurorehabilitation were found in most of the clinical assessments, cadence, and velocity of the instrumental gait analysis, paralleled by amelioration of thigh co-activation on the less-affected side. Subjects with better balance performance and higher independence at baseline benefit more from the neurorehabilitation course. Conclusions: Significant improvements in gait performance were found in our cohort after an intensive neurorehabilitation course, for both quantitative and qualitative measures. Integrating kinematic and muscle activity measurements offers opportunities to objectively evaluate and interpret treatment effects.

Successful long-term management of spasticity in people with multiple sclerosis using a software application: Results from a randomized-controlled, multicenter study

BACKGROUND

Successful long-term treatment of spasticity in people with multiple sclerosis (pwMS) is challenging. We investigated the effects of multidisciplinary inpatient rehabilitation (MIR) and an individualized self-training program delivered by an App on spasticity in pwMS.

METHODS

First we assessed the efficacy of 4-weeks MIR in ambulatory pwMS (EDSS<7.0) with moderate to severe lower limb spasticity (defined by ≥4 points on the Numeric Rating Scale for spasticity (NRSs)) in a cohort of 115 pwMS in 7 rehabilitation centers in Austria. In case of a clinically relevant improvement in spasticity of ≥20% on the NRSs following MIR (n=94), pwMS were randomly allocated in a 1:1 ratio to either a newly designed "MS-spasticity App" or to a paper-based self-training program for 12 weeks. The primary outcome was change in NRSs (DRKS00023960).

RESULTS

MIR led to a significant reduction of 2.0 points on the NRSs (95% Confidence Interval (CI) 2.5 to 2.0; p<0.000). MIR was further associated with a statistically significant improvement in spasticity on the modified Ashworth scale, strength and all mobility outcomes. Following MIR, self-training with "MS-spasticity App" was associated with a sustained positive effect on the NRSs, while paper-based self-training led to a worsening in spasticity (median NRSs difference 1.0; 95% CI 1.7 to 0.3; p=0.009). "MS-spasticity App" was also associated with a significantly better adherence to self-training (95% versus 72% completion rate; p<0.001).

CONCLUSION

In pwMS, MIR is able to significantly improve lower-limb spasticity, strength and mobility. Following MIR, an individually tailored anti-spasticity program delivered by an App leads to sustained positive long-term management.

The cost-effectiveness of abobotulinumtoxinA (Dysport) and onabotulinumtoxinA (Botox) for managing spasticity of the upper and lower limbs, and cervical dystonia

OBJECTIVE

To evaluate the costs and benefits associated with the use of abobotulinumtoxinA (aboBoNT-A) and onabotulinumtoxinA (onaBoNT-A) for lower limb spasticity in children, upper and lower limb spasticity in adults, and cervical dystonia in adults.

METHODS

This pharmacoeconomic analysis compared aboBoNT-A with onaBoNT-A. A decision tree model with a 1-year time horizon was conducted from a UK National Health Service (NHS) perspective using data from a variety of sources: randomized controlled trials (RCTs), network meta-analyses (NMAs), observational studies, and a physician survey investigating treatment patterns and resource utilization. Four patient populations were included: pediatric patients with lower limb spasticity (PLL), and adults with upper limb spasticity (AUL), lower limb spasticity (ALL), and cervical dystonia (CD). Outcomes included costs, quality-adjusted life years (QALYs) gained, cost per responder, and incremental cost per QALY gained. The effectiveness of each treatment was evaluated as a response to treatment. The base case assumption was that all patients in the model continued to receive botulinum toxin type A (BoNT-A) treatments at regular intervals regardless of treatment response status. Scenario analysis evaluated the impact of discontinuing BoNT-A for patients without a response to the first injection.

RESULTS

The model found that aboBoNT-A resulted in greater quality-of-life and lower costs compared with onaBoNT-A for the management of spasticity and CD in all included indications. Across populations, cost savings ranged from £304 to £3,963 and QALYs gained ranged from 0.010 to 0.02 over a 1-year time horizon. Results were robust to scenario analyses and were driven by the impact of treatment response on health-related quality-of-life.

CONCLUSIONS

AboBoNT-A was associated with higher treatment response, improved quality-of-life, and reduced costs in spasticity and CD versus onaBoNT-A. These findings could help deliver more effective and efficient healthcare in the NHS.

The Assessment of Upper-Limb Spasticity Based on a Multi-Layer Process Using a Portable Measurement System

Spasticity is a common disabling complication caused by the upper motor neurons dysfunction following neurological diseases such as stroke. Currently, the assessment of the spastic hypertonia triggered by stretch reflexes is manually performed by clinicians using perception-based clinical scales, however, their reliability is still questionable due to the inter-rater and intra-rater variability. In order to objectively quantify the complex spasticity phenomenon in post-stroke patients, this study proposed a multi-layer assessment system based on a novel measurement device. The exoskeletal device was developed to synchronously record the kinematic, biomechanical and electrophysiological information in sixteen spastic patients and ten age-matched healthy subjects, while the spastic limb was stretched at low, moderate and high velocities. The mechanical impedance of the elbow joint was identified using a modified genetic algorithm to quantify the alterations in viscoelastic properties underlying pathological resistance. Simultaneously, the time-frequency features were extracted from the surface electromyography (sEMG) signals to reveal the neurophysiological mechanisms of the spastic muscles. By concatenating these single-layer decisions, a support vector regression (SVR)-based fusion model was developed to generate a more comprehensive quantification of spasticity severity. Experimental results demonstrated that the stiffness and damping components of the spastic arm significantly deviated from the nonspastic baseline, and strong correlations were observed between the proposed spasticity assessment and the severity level measured by clinical scales ( R = 0.86, P = 1.67e - 5 ), as well as the tonic stretch reflex threshold (TSRT) value ( R = - 0.89, P = 3.54e - 6 ). These promising results suggest that the proposed assessment system holds great potential to support the clinical diagnosis of motor abnormalities in spastic patients, and ultimately enables optimal adjustment of treatment protocols.