Spastic Elbow Research Articles

Acute effects of contrast bath on sympathetic skin response in patients with poststroke complex regional pain syndrome

Purpose Complex regional pain syndrome (CRPS) is one of the common complications in stroke patients. Sympathetic dysfunction is usually considered underlying pathology. The evidence for contrast bath (CB) used in the treatment of CRPS is limited. The aim of the study is to investigate the possible effects of CB on the sympathetic activity in poststroke CRPS. Materials and methods Stroke patients with CRPS (CRPS group) and without CRPS (control group) were included in the study. Age, gender, duration of stroke, aetiology, plegic side, dominant hand, spasticity level, Brunnstrom stages, and comorbidities were recorded. CB was performed for one session to the plegic side of the CRPS and control groups. Sympathetic skin responses (SSR) was recorded from the plegic and healthy hands of participants at pre-CB and post-CB. Results Each group consisted of 20 participants. No significant difference was detected in stroke duration, aetiology, and Brunnstrom stages between groups. Elbow spasticity level was significantly higher in CRPS group (p = .034). SSR amplitudes of plegic hands were significantly decreased after CB in CRPS and control groups (p = .0002, p = .013 respectively). Also, CB reduced the SSR amplitude of healty side in CRPS group (p = .003). There was no statistically significant change in SSR latency or percentage changes of SSR amplitude and latency after CB in both groups. Conclusion CB leads to a significant reduction in sympathetic activity of plegic side of stroke patients. Also, CB to the plegic side has an inhibitory effect on sympathetic activity of healty side in poststroke CRPS. ClinicalTrials.gov ID: NCT04198532

Analysis of Machine Learning-Based Assessment for Elbow Spasticity Using Inertial Sensors.

Spasticity is a frequently observed symptom in patients with neurological impairments. Spastic movements of their upper and lower limbs are periodically measured to evaluate functional outcomes of physical rehabilitation, and they are quantified by clinical outcome measures such as the modified Ashworth scale (MAS). This study proposes a method to determine the severity of elbow spasticity, by analyzing the acceleration and rotation attributes collected from the elbow of the affected side of patients and machine-learning algorithms to classify the degree of spastic movement; this approach is comparable to assigning an MAS score. We collected inertial data from participants using a wearable device incorporating inertial measurement units during a passive stretch test. Machine-learning algorithms—including decision tree, random forests (RFs), support vector machine, linear discriminant analysis, and multilayer perceptrons—were evaluated in combinations of two segmentation techniques and feature sets. A RF performed well, achieving up to 95.4% accuracy. This work not only successfully demonstrates how wearable technology and machine learning can be used to generate a clinically meaningful index but also offers rehabilitation patients an opportunity to monitor the degree of spasticity, even in nonhealthcare institutions where the help of clinical professionals is unavailable.

Effect of treating elbow flexor spasticity with botulinum toxin injection and adjunctive casting on hemiparetic gait parameters: A prospective case series.

To investigate changes in hemiparetic gait parameters after treatment of elbow flexor spasticity with botulinum neurotoxin (BoNT) injection and adjunctive casting. Prospective case series. Ten participants with spasticity secondary to acquired brain injury (8 stroke, 2 traumatic brain injury). Participants received BoNT injections for their spastic elbow flexors under ultrasound guid-ance. Two weeks post-injection, an elbow stretching cast was applied for 1 week. Assessments using the Modified Ashworth Scale (MAS), Tardieu scale V1 angle of arrest at slow speed and V3 angle of catch at fast speed, 2-min walk test (2MWT), Edinburgh Gait Score scale (EGS) and video gait analysis for step-length symmetry were conducted pre-BoNT injection (t0) and at cast removal (t1). Goal attainment scale (GAS) was used to assess changes in spasticity and gait 3 months post-injection (t2). At t1, participants showed a mean increase of 16.7° (p < 0.01) on the Tardieu Scale V3 and a mean reduction of 0.5 points on the MAS (p < 0.05). There was also a mean reduction on EGS of 2.7 points (p < 0.05), and a mean increase on 2MWT of 3.1 m (p < 0.05). On the GAS, all participants report-ed impro-ved gait at t2 and 80% reported a decrease in spasticity. Combining BoNT injection with casting for treatment of elbow flexor spasticity without treat-ing the lower limb may improve hemiparetic gait parameters.

Effects of radial extracorporeal shockwave therapy on spasticity of upper-limb agonist/antagonist muscles in patients affected by stroke: a randomized, single-blind clinical trial.

the effects of radial extracorporeal shock wave therapy (rESWT) were assessed on agonist/antagonist muscles in stroke patients with elbow spasticity, the duration of effects and influence on function. patients were randomly assigned into groups: control (A, n = 25), rESWT on agonist muscles (B, n = 27) and rESWT on antagonist muscles (C, n = 30) groups. Conventional physical therapy was given to three groups for 3weeks, six times a week, and besides, rESWT was given at 4-day intervals for five consecutive treatments, B received rESWT on agonist muscles and C received rESWT on antagonist muscles. The primary outcome was Modified Ashworth Scale (MAS) scores. Modified Tardieu Scale, Visual Analogue Scale (VAS), Fugl-Meyer Assessment and swelling scale (SS) scores were secondary outcomes. Indicators were assessed at baseline, after five treatments and after 4weeks follow-up. the rate of treatment was determined by changes in MAS, which was 16.0 (A), 70.4 (B) and 63.3% (C) after rESWT treatments, and was 24.0 (A), 74.1 (B) and 66.7% (C) after 4weeks follow-up. Improvements were achieved for R1 (P < 0.01), R2 (P < 0.01) and VAS (P < 0.01) after five rESWT interventions. At 4weeks, significant improvements were achieved for R1 (P < 0.01) and VAS (P < 0.01). rESWT is an effective therapy for spasticity after stroke, with lasting effects on both agonist and antagonist muscles after 4weeks. rESWT relieved pain but had no effect on active function or swelling of the upper limbs.

Application of upper-limb dynamic pseudoelastic splinting in the treatment of stroke chronic patient: a pilot assessment

Purpose The chronic sequelae of stroke are often a strong limitation to patient’s quality of life. New non-invasive elective treatments are required to support postural and functional improvements long after the primary insult. This study is an uncontrolled pilot evaluation of pseudoelastic orthotics for post-stroke upper-limb rehabilitation. Materials and methods Six chronic hemiplegic patients (3.8 ± 1.7 years since stroke) were evaluated with clinical scales, covering the ICF domains of body functions and structures (Modified Ashworth Score [MAS], Medical Research Council Scale for Muscle Strength, Fugl-Meyer [FM], Motricity Index [MI]), activities (Wolf Motor Function Test [WMF], Motor Activity Log [MAL]) and participation (quality of life questionnaires); sensors applied to the orthosis were used to assess changes in the articular and functional domains over a month’s treatment. Results Significant gains were achieved in elbow spasticity (MAS, p = .020), upper-limb motor function (FM, p = .005), reaching task (p = .035), and gait (p = .00046) speed. Most patients improved in functional tasks (WMF), but this did not reflect in daily-life activities as measured with MAL. Some patients reported an improved quality of life, especially the quality of sleep. Conclusions Pseudoelastic orthoses could be a comfortable and useful adjunct in the long-term management of stroke. Broader trials will have to confirm these preliminary observations. Implications for rehabilitation Use of new materials in neuromuscular rehabilitation. Customised and adjustable therapeutic action obtained with dynamic personalised orthoses. Non-invasive interventions could be of help for patients with chronic disability.

Cryoneurotomy as a novel adjunct to botulinum toxin treatment for the spastic elbow: A case study

Cryoneurotomy as a novel adjunct to botulinum toxin treatment for the spastic elbow: A case study

Motor Overflow and Spasticity in Chronic Stroke Share a Common Pathophysiological Process: Analysis of Within-Limb and Between-Limb EMG-EMG Coherence

The phenomenon of exaggerated motor overflow is well documented in stroke survivors with spasticity. However, the mechanism underlying the abnormal motor overflow remains unclear. In this study, we aimed to investigate the possible mechanisms behind abnormal motor overflow and its possible relations with post-stroke spasticity. 11 stroke patients (63.6 ± 6.4 yrs; 4 women) and 11 healthy subjects (31.18 ± 6.18 yrs; 2 women) were recruited. All of them were asked to perform unilateral isometric elbow flexion at submaximal levels (10, 30, and 60% of maximum voluntary contraction). Electromyogram (EMG) was measured from the contracting biceps (iBiceps) muscle and resting contralateral biceps (cBiceps), ipsilateral flexor digitorum superficialis (iFDS), and contralateral FDS (cFDS) muscles. Motor overflow was quantified as the normalized EMG of the resting muscles. The severity of motor impairment was quantified through reflex torque (spasticity) and weakness. EMG-EMG coherence was calculated between the contracting muscle and each of the resting muscles. During elbow flexion on the impaired side, stroke subjects exhibited significant higher motor overflow to the iFDS muscle compared with healthy subjects (ipsilateral or intralimb motor overflow). Stroke subjects exhibited significantly higher motor overflow to the contralateral spastic muscles (cBiceps and cFDS) during elbow flexion on the non-impaired side (contralateral or interlimb motor overflow), compared with healthy subjects. Moreover, there was significantly high EMG-EMG coherence in the alpha band (6–12 Hz) between the contracting muscle and all other resting muscles during elbow flexion on the non-impaired side. Our results of diffuse ipsilateral and contralateral motor overflow with EMG-EMG coherence in the alpha band suggest subcortical origins of motor overflow. Furthermore, correlation between contralateral motor overflow to contralateral spastic elbow and finger flexors and their spasticity was consistently at moderate to high levels. A high correlation suggests that diffuse motor overflow to the impaired side and spasticity likely share a common pathophysiological process. Possible mechanisms are discussed.

Assessment of post-stroke elbow flexor spasticity in different forearm positions

Purpose/Aim: There have been conflicting results regarding which muscle contribute most to the elbow spastic flexion deformity. This study aimed to investigate whether flexor spasticity of the elbow changed according to the position of the forearm, and to determine the muscle or muscles that contributed most to the elbow spastic flexion deformity by clinical examination.Methods: This study is a single group, observational and cross-sectional study. Sixty patients were assessed for elbow flexor spasticity in different forearm positions (pronation, neutral and supination) with Modified Tardieu Scale. The primary outcome measure was a domain of the Modified Tardieu Scale, the dynamic component of spasticity (spasticity angle).Results: In general, there was a significant difference between forearm positions regarding spasticity angle (p < .001). In pairwise comparisons, median spasticity angles in pronation (70 degrees) and neutral position (60 degrees) were significantly higher than those in supination (57.5 degrees) (adjusted p < .001 and adjusted p = .003, respectively). However, median spasticity angle in pronation did not differ significantly from those in neutral position in favour of pronation (adjusted p = .274).Conclusions: The severity of spasticity changes according to the elbow position which suggests that the magnitude of contribution of each elbow flexor muscle to spastic elbow deformity is different. Reduction of spasticity from pronation to supination leads us to consider brachialis as the most spastic muscle. Since biceps was suggested to be the least spastic muscle in this study, and also to avoid spastic pronation deformity of the forearm, it should be rethought before performing chemodenervation into biceps muscle.

Evaluation of a toolkit for standardizing clinical measures of muscle tone

Objective: To evaluate a new portable toolkit for quantifying upper and lower extremity muscle tone in patients with upper motor neuron syndrome (UMNS). Approach: Cross-sectional, multi-site, observational trial to test and validate a new technology. Setting: Neurorehabilitation clinics at tertiary care hospitals. Participants: Four cohorts UMNS patient, >6 mo post acquired brain injury, spinal cord injury, multiple sclerosis and cerebral palsy, and a sample of healthy age-matched adult controls. Measures: Strength: grip, elbow flexor and extensor, and knee extensor; range of motion (ROM): passive ROM (contracture) and passive-active ROM (paresis); objective spasticity: stretch-reflex test for elbow, and pendulum test for knee; subjective spasticity: modified Ashworth scale scores for elbow and knee flexors and extensors. Results: Measures were acquired for 103 patients from three rehabilitation clinics. Results for patient cohorts were consistent with the literature. Grip strength correlated significantly with elbow muscle strength and all patient populations were significantly weaker in upper- and lower-extremity compared to controls. Strength and paresis were correlated for elbow and knee but neither correlated with contracture. Elbow spasticity correlated with strength and paresis but not contracture. Knee spasticity correlated with strength, and subjective spasticity correlated with contracture. Significance: The BioTone™ toolkit provided comprehensive objective measures for assessing muscle tone in patients with UMNS. The toolkit could be useful for standardizing outcomes measures in clinical trials and for routine practice.

Normalization factor for the assessment of elbow spasticity with passive stretch measurement: maximum torque VS. body weight.

Spasticity of the elbow was generally assessed by repeated passive stretch movement, including the modified Ashworth Scale (MAS) from physiotherapist, and biomechanics analysis of the movement. The MAS-based method depends on the subjective evaluations and the performance of biomechanics analysis assessment is affected by the individual difference. Therefore, the normalization to reduce the individual difference for the assessment of spasticity is very important. In this study, the elbow spasticity was assessed with MAS by one skillful physiotherapist and biomechanics measurements during repetitive passive isokinetic movements at velocity of 60 degree$/$second. 20 post-stroke patients with elbow spasticity caused by hemorrhagic cerebral damage were divided into three groups according to the MAS grades (MAS $=1, 1+$, 2). The torque and position were recorded when the patients extension their elbows passively. The mean stiffness and the mean torque features of the passive isokinetic were calculated. Two normalization factors for biomechanics analysis assessment were investigated: body weight normalization factor and maximum isometrics volunteer contraction normalization factor. Spearman correlation analysis was used to investigate the relationship between the features and spasticity grades. The results showed that the correlation between MAS and two biomechanics features (mean stiffness, mean torque) were significant improved. For mean stiffness feature, the correlation coefficients were $-0.313, -0.563$ and -0.603 individually for non-normalization, body weight normalization and maximum isometrics volunteer contraction normalization. For mean torque feature, the correlation coefficients were $-0.260, -0.523$ and -0.691, respectively. These results suggest that the normalization methods would be helpful for the assessment of spasticity in biomechanics and will be a necessary way of spasticity estimation in clinical methods.

Possibility of Gait Improvement after Reduction of Spastic Elbow

Possibility of Gait Improvement after Reduction of Spastic Elbow

Improving the test-retest and inter-rater reliability for stretch reflex measurements using an isokinetic device in stroke patients with mild to moderate elbow spasticity

The conventional tools to measure spasticity exhibited insufficient test-retest or inter-rater reliability. Therefore, the spasticity measurement using an isokinetic device has been proposed to improve these reliabilities of the angle of catch (AoC) measurements; however, this proposal has not been investigated in a standardized manner.In this study, the comparison of the AoC measurement was performed using two modes (isokinetic and manual motion) to investigate whether the standardized isokinetic motion could increase the reliabilities. Motion consistency was calculated using a newly developed index. To analyze the effect of the motion standardization, AoC were estimated using EMG data for both modes, and to compare the measurement reliability, AoC for isokinetic mode was estimated using both EMG and torque data.Although the test-retest reliability for manual motion was excellent, the use of isokinetic motion improved it to the level of extremely excellent. Intraclass correlation coefficient (ICC) for the inter-rater reliability of manual motion was 0.788, which was near the lower limit of the excellent. Isokinetic motion improved it to the ICC of 0.890 and 0.931 based on the EMG and torque, respectively.These improvements in reliabilities reduced the measurement errors, sample size, and need for the same rater in clinical trials.

Personalized upper limb training combined with anodal-tDCS for sensorimotor recovery in spastic hemiparesis: study protocol for a randomized controlled trial

BackgroundRecovery of voluntary movement is a main rehabilitation goal. Efforts to identify effective upper limb (UL) interventions after stroke have been unsatisfactory. This study includes personalized impairment-based UL reaching training in virtual reality (VR) combined with non-invasive brain stimulation to enhance motor learning. The approach is guided by limiting reaching training to the angular zone in which active control is preserved (“active control zone”) after identification of a “spasticity zone”. Anodal transcranial direct current stimulation (a-tDCS) is used to facilitate activation of the affected hemisphere and enhance inter-hemispheric balance. The purpose of the study is to investigate the effectiveness of personalized reaching training, with and without a-tDCS, to increase the range of active elbow control and improve UL function.MethodsThis single-blind randomized controlled trial will take place at four academic rehabilitation centers in Canada, India and Israel. The intervention involves 10 days of personalized VR reaching training with both groups receiving the same intensity of treatment. Participants with sub-acute stroke aged 25 to 80 years with elbow spasticity will be randomized to one of three groups: personalized training (reaching within individually determined active control zones) with a-tDCS (group 1) or sham-tDCS (group 2), or non-personalized training (reaching regardless of active control zones) with a-tDCS (group 3). A baseline assessment will be performed at randomization and two follow-up assessments will occur at the end of the intervention and at 1 month post intervention. Main outcomes are elbow-flexor spatial threshold and ratio of spasticity zone to full elbow-extension range. Secondary outcomes include the Modified Ashworth Scale, Fugl-Meyer Assessment, Streamlined Wolf Motor Function Test and UL kinematics during a standardized reach-to-grasp task.DiscussionThis study will provide evidence on the effectiveness of personalized treatment on spasticity and UL motor ability and feasibility of using low-cost interventions in low-to-middle-income countries.Trial registrationClinicalTrials.gov, ID: NCT02725853. Initially registered on 12 January 2016.

Technologically-advanced assessment of upper-limb spasticity: a pilot study.

Spasticity is a muscle disorder associated with upper motor neuron syndrome occurring in neurological disorders, such as stroke, multiple sclerosis, spinal cord injury and others. It influences the patient's rehabilitation, interfering with function, limiting independence, causing pain and producing secondary impairments, such as contractures or other complications. Due to the heterogeneity of clinical signs of spasticity, there is no agreement on the most appropriate assessment and measurement modality for the evaluation of treatment outcomes. The aim of this article is to propose the use of new robotic devices for upper-limb spasticity assessment and describe the most relevant measures of spasticity which could be automatically assessed by using a technologically advanced device. Observational pilot study. The treatment was provided in a Rehabilitation Centre where the device was located and the subjects were treated in an outpatients setting. Five post-stroke patients, age range 19-79 years (mean age 61, standard deviation [SD]±25) in their chronic phase. A new robotic device able to automatically assess upper-limb spasticity during passive and active mobilization has been developed. The elbow spasticity of five post stroke patients has been assessed by using the new device and by means of the Modified Ashworth Scale (MAS). After the first assessment, subjects were treated with botulin toxin injections, and then underwent 10 sessions of robotic treatments. After the treatment, subjects spasticity was assessed by using the robotic device and the MAS Score. In four out of five patients, the botulin toxin injection and robotic treatment resulted in the improvement of the MAS Score; in three patients the robotic measures were able to detect the MAS changes. In one subject botulin toxin was not effective and the robotic device was able to detect the lack of effectiveness. By using the robotic device some spasticity parameters can be continuously recorded during the rehabilitation treatment in order to objectively measure the effectiveness of the interventions provided. The standardized evaluation parameters recorded using robotic devices may provide several advantages: 1) the measures for spasticity assessment can be monitored during every rehabilitation session (even during each movement); 2) these measurements are able to highlight even small changes; 3) the recovery plateau can be detected early thus avoiding further rehabilitation sessions; and 4) these measurements can reduce the assessment bias in multicenter studies.

A new EMG-based index towards the assessment of elbow spasticity for post-stroke patients.

The commonly used method for grading spasticity in clinical applications is Modified Ashworth Scale (MAS). The MAS-based method depends on the subjective evaluations and the experience of physicians, which may lead to imprecise and inconsistent evaluations. In this study, we propose a novel index (A-ApA, which was calculated with the root mean square (RMS) of agonist muscle activity by the mean between the RMS of agonistic and antagonistic muscle activations extracted from surface electromyography (sEMG) signals to quantitatively assess elbow spasticity. 39 post-stroke patients with elbow spasticity caused by hemiplegia participated in the experiments, and their elbow spasticity was assessed with MAS by one experienced physiotherapist. Patients were thereafter divided into four groups according to the MAS scales. The sEMG signals were recorded simultaneously on the patients' biceps and triceps when they extended or bended their elbows passively. The correlations between MAS and RMS of sEMG signals as well as the newly proposed index were calculated. The results demonstrated that the correlation between the MAS and the sEMG-based index in the assessment of elbow spasticity was significant. This suggests that the EMG-based index would be helpful for the assessment of spasticity..

Development of elbow spasticity model for objective training of spasticity assessment of patients post stroke.

Reliable assessment is essential for the management of spasticity, one of the most frequent complication of various neurological diseases. For the spasticity assessment, several clinical tools have been developed and widely used in clinics. The most popular one is modified Ashworth scale (MAS). It has a simple protocol, but is subjective and qualitative. To improve its reliability, quantitative measurement and consistent training would be needed. This study presents an elbow spasticity simulator which mimics spastic response of adult post stroke survivors. First, spastic responses (i.e. resistance and joint motion) from patients with a stroke were measured during conventional MAS assessment. Each grade of MAS was quantified by using three parameters representing three characteristics of the spasticity. Based on the parameters, haptic models of MAS were developed for implementing repeatable and consistent haptic training of novice clinicians. Two experienced clinicians participated in preliminary evaluation of the models.

Assessment of elbow spasticity with surface electromyography and mechanomyography based on support vector machine.

The Modified Ashworth Scale (MAS) is the gold standard in clinical for grading spasticity. However, its results greatly depend on the physician evaluations and are subjective. In this study, we investigated the feasibility of using support vector machine (SVM) to objectively assess elbow spasticity based on both surface electromyography (sEMG) and mechanomyography (MMG). sEMG signals and tri-axial accelerometer mechanomyography (ACC-MMG) signals were recorded simultaneously on patients' biceps and triceps when they extended or bended elbow passively. 39 post-stroke patients participated in the study, and were divided into four groups regarding MAS level (MAS=0, 1, 1+ or 2). The three types of features, root mean square (RMS), mean power frequency (MPF), and median frequency (MF), were calculated from sEMG and MMG signal recordings. Spearman correlation analysis was used to investigate the relationship between the features and spasticity grades. The results showed that the correlation between MAS and each of the five features (MMG-RMS of the biceps, MMG-RMS of the triceps, the EMG-RMS of the biceps, EMG-RMS of the triceps, EMG-MPF of the triceps) was significant (p<;0.05). The four spasticity grades were identified with SVM, and the classification accuracy of SVM with sEMG, MMG, sEMG-MMG were 70.9%, 83.3%, 91.7%, respectively. Our results suggest that using the SVM-based method with sEMG and MMG to assess elbow spasticity would be suitable for clinical management of spasticity.

KAPS (kinematic assessment of passive stretch): a tool to assess elbow flexor and extensor spasticity after stroke using a robotic exoskeleton

BackgroundSpasticity is a common sequela of stroke. Traditional assessment methods include relatively coarse scales that may not capture all characteristics of elevated muscle tone. Thus, the aim of this study was to develop a tool to quantitatively assess post-stroke spasticity in the upper extremity.MethodsNinety-six healthy individuals and 46 individuals with stroke participated in this study. The kinematic assessment of passive stretch (KAPS) protocol consisted of passive elbow stretch in flexion and extension across an 80° range in 5 movement durations. Seven parameters were identified and assessed to characterize spasticity (peak velocity, final angle, creep (or release), between-arm peak velocity difference, between-arm final angle, between-arm creep, and between-arm catch angle).ResultsThe fastest movement duration (600 ms) was most effective at identifying impairment in each parameter associated with spasticity. A decrease in peak velocity during passive stretch between the affected and unaffected limb was most effective at identifying individuals as impaired. Spasticity was also associated with a decreased passive range (final angle) and a classic ‘catch and release’ as seen through between-arm catch and creep metrics.ConclusionsThe KAPS protocol and robotic technology can provide a sensitive and quantitative assessment of post-stroke elbow spasticity not currently attainable through traditional measures.

Biomechanical Reactions of Exoskeleton Neurorehabilitation Robots in Spastic Elbows and Wrists.

Spasticity is an important factor in designing wearable and lightweight exoskeleton neurorehabilitation robots. The proposed study evaluates biomechanical reactions of an exoskeleton robot to spasticity and establishes relevant guidelines for robot design. A two-axis exoskeleton robot is used to evaluate a group of 20 patients post-stroke with spastic elbow and/or wrist joints. All subjects are given isokinetic movements at various angular velocities within the capable range of motion for both joints. The resistance torque and corresponding angular position at each joint are recorded continuously. Maximal resistance torques caused by low (modified Ashworth scale (MAS) 0, 1), intermediate (MAS 1+), and high (MAS 2 and 3) grade spasticity were 3.68 ± 2.42, 5.94 ± 2.55, and 8.25 ± 3.35 Nm for the elbow flexor ( , between each grades) and 4.23 ± 1.75, 5.68 ± 1.96, and 5.44 ± 2.02 Nm for the wrist flexor ( , for low versus intermediate, low versus high grade spasticity). The angular velocity did not significantly influence maximal resistance torque in either joint. The catch occurred more quickly at higher velocities for low and intermediate elbow flexor spasticity ( ). Spasticity caused considerable resistance to the robots during mechanically actuated movements. The resistance range according to the degree of spasticity should be considered when designing practical neurorehabilitation robots.

Phase-II Clinical Validation of a Powered Exoskeleton for the Treatment of Elbow Spasticity.

Introduction: Spasticity is a typical motor disorder in patients affected by stroke. Typically post-stroke rehabilitation consists of repetition of mobilization exercises on impaired limbs, aimed to reduce muscle hypertonia and mitigate spastic reflexes. It is currently strongly debated if the treatment's effectiveness improves with the timeliness of its adoption; in particular, starting intensive rehabilitation as close as possible to the stroke event may counteract the growth and postpone the onset of spasticity. In this paper we present a phase-II clinical validation of a robotic exoskeleton in treating subacute post-stroke patients.Methods: Seventeen post-stroke patients participated in 10 daily rehabilitation sessions using the NEUROExos Elbow Module exoskeleton, each one lasting 45 min: the exercises consisted of isokinetic passive mobilization of the elbow, with torque threshold to detect excessive user's resistance to the movement. We investigated the safety by reporting possible adverse events, such as mechanical, electrical or software failures of the device or injuries or pain experienced by the patient. As regards the efficacy, the Modified Ashworth Scale, was identified as primary outcome measure and the NEEM metrics describing elbow joint resistance to passive extension (i.e., maximum extension torque and zero-torque angle) as secondary outcomes.Results: During the entire duration of the treatments no failures or adverse events for the patients were reported. No statistically significant differences were found in the Modified Ashworth Scale scores, between pre-treatment and post-treatment and between post-treatment and follow-up sessions, indicating the absence of spasticity increase throughout (14 days) and after (3–4 months follow-up) the treatment. Exoskeleton metrics confirmed the absence of significant difference in between pre- and post-treatment data, whereas intra-session data highlighted significant differences in the secondary outcomes, toward a decrease of the subject's joint resistance.Conclusions: The results show that our robotic exoskeleton can be safely used for prolonged sessions in post-stroke and suggest that intensive early rehabilitation treatment may prevent the occurrence of spasticity at a later stage. Moreover, the NEEM metrics were found to be reliable compared to the Modified Ashworth Scale and sensitive to revealing intra-session changes of elbow resistance to passive extension, in agreement with clinical evidences.