Co-activation of upper limb muscles during reaching in post-stroke subjects: an analysis of the contralesional and ipsilesional limbs

Effects of Upper Limb Control on the Less-Affected Side on Upper Limb Function, Respiration, Balance, and Activities of Daily Living in Stroke

Background and Objectives: This study aimed to investigate the effects of upper limb control exercises on upper limb function, respiration, balance, and activities of daily living in patients with stroke. Materials and Methods: The 28 patients who met the selection criteria were randomly assigned to two groups of 14 patients each. Subsequently, upper limb control exercises using real-time feedback were applied. The same interventional exercise was applied to both the less-affected and affected limbs of the study participants, who were classified into a less-affected side upper limb control group and an affected side upper limb control exercise group. Interventional exercises, 30 min each, were performed five times weekly for 4 weeks, and follow-up examinations were performed 2 weeks after the end of exercise. Electronic muscle strength measurements and an electronic goniometer were used to evaluate upper limb function. A spirometer was used to measure respiration. Balance ability was evaluated using a force plate pressure distribution measuring system with a sensor that detects the movement of the body center on the ground. Daily life movements were evaluated using the Korean version of the modified Barthel index. Results: When examining the results, the upper limb function on the paralyzed side showed an increase in the electromyographic strength of shoulder joint depression and flexion angle. Improvements were also observed in respiration (forced vital capacity [L] and forced expiratory volume in 1 s [L]), balance (95% confidence ellipse area [mm2] and center of pressure displacement [mm]), and daily life activities, all of which showed statistically significant differences in the time × group interaction effect (p < 0.05). Conclusions: Thus, it was found that the upper limb control exercise on the less-affected side had a significant effect when the exercise was performed together with treatment on the affected side in patients with stroke. It is anticipated that this study will provide basic data for evaluating both the trunk and upper limbs of the less-affected and affected sides.

Surface-Electromyography-Based Co-Contraction Index for Monitoring Upper Limb Improvements in Post-Stroke Rehabilitation: A Pilot Randomized Controlled Trial Secondary Analysis

Persons post-stroke experience excessive muscle co-contraction, and consequently the arm functions are compromised during the activities of daily living. Therefore, identifying instrumental outcome measures able to detect the motor strategy adopted after a stroke is a primary clinical goal. Accordingly, this study aims at verifying whether the surface electromyography (sEMG)-based co-contraction index (CCI) could be a new clinically feasible approach for assessing and monitoring patients' motor performance. Thirty-four persons post-stroke underwent clinical assessment and upper extremity kinematic analysis, including sEMG recordings. The participants were randomized into two treatment groups (robot and usual care groups). Ten healthy subjects provided a normative reference (NR). Frost's CCI was used to quantify the muscle co-contraction of three different agonist/antagonist muscle pairs during an object-placing task. Persons post-stroke showed excessive muscle co-contraction (mean (95% CI): anterior/posterior deltoid CCI: 0.38 (0.34-0.41) p = 0.03; triceps/biceps CCI: 0.46 (0.41-0.50) p = 0.01) compared to NR (anterior/posterior deltoid CCI: 0.29 (0.21-0.36); triceps/biceps CCI: 0.34 (0.30-0.39)). After robot therapy, persons post-stroke exhibited a greater improvement (i.e., reduced CCI) in proximal motor control (anterior/posterior deltoid change score of CCI: -0.02 (-0.07-0.02) p = 0.05) compared to usual care therapy (0.04 (0.00-0.09)). Finally, the findings of the present study indicate that the sEMG-based CCI could be a valuable tool in clinical practice.

Electromyography study of six parts of the latissimus dorsi during reaching tasks while seated: A comparison between healthy subjects and stroke patients

PURPOSE

To compare the excitation of the six different segments of the latissimus dorsi (LD) while reaching different distances and in different directions in stroke patients and healthy controls.

METHOD

Surface electromyography was used to measure the excitation of the LD segments (LD1-LD6) in 12 chronic stroke patients and 11 healthy controls during reaching tasks. A target was placed in the sagittal and scapular planes at arm's length, 125% of arm's length, and maximum reaching distance. The clinical trial registration number is NCT04181151 (date of registration November 25, 2019).

RESULTS

The excitation of the LD segments during the arm's length reaching task was similar between the groups (p greater than 0.05). The excitation of LD1, LD2, and LD5 in the sagittal plane and of LD1, LD2, LD3, and LD5 in the scapular plane was higher during the reaching 125% of arm's length task compared to the controls (p < 0.05). During the maximum reaching task, the excitation of LD1 was higher in the stroke patients in both the sagittal and scapular planes (p < 0.05).

CONCLUSION

The excitation of the LD segments was influenced by the direction and distance of the reaching in the stroke patients. The results of this study may help us to better understand how the LD behaves after stroke and to design rehabilitation approaches with a greater focus on the LD.

Exploring high-density corticomuscular networks after stroke to enable a hybrid Brain-Computer Interface for hand motor rehabilitation

BACKGROUND

Brain-Computer Interfaces (BCI) promote upper limb recovery in stroke patients reinforcing motor related brain activity (from electroencephalogaphy, EEG). Hybrid BCIs which include peripheral signals (electromyography, EMG) as control features could be employed to monitor post-stroke motor abnormalities. To ground the use of corticomuscular coherence (CMC) as a hybrid feature for a rehabilitative BCI, we analyzed high-density CMC networks (derived from multiple EEG and EMG channels) and their relation with upper limb motor deficit by comparing data from stroke patients with healthy participants during simple hand tasks.

METHODS

EEG (61 sensors) and EMG (8 muscles per arm) were simultaneously recorded from 12 stroke (EXP) and 12 healthy participants (CTRL) during simple hand movements performed with right/left (CTRL) and unaffected/affected hand (EXP, UH/AH). CMC networks were estimated for each movement and their properties were analyzed by means of indices derived ad-hoc from graph theory and compared among groups.

RESULTS

Between-group analysis showed that CMC weight of the whole brain network was significantly reduced in patients during AH movements. The network density was increased especially for those connections entailing bilateral non-target muscles. Such reduced muscle-specificity observed in patients was confirmed by muscle degree index (connections per muscle) which indicated a connections' distribution among non-target and contralateral muscles and revealed a higher involvement of proximal muscles in patients. CMC network properties correlated with upper-limb motor impairment as assessed by Fugl-Meyer Assessment and Manual Muscle Test in patients.

CONCLUSIONS

High-density CMC networks can capture motor abnormalities in stroke patients during simple hand movements. Correlations with upper limb motor impairment support their use in a BCI-based rehabilitative approach.

Cortico-muscular coupling to control a hybrid brain-computer interface for upper limb motor rehabilitation: A pseudo-online study on stroke patients

Brain-Computer Interface (BCI) systems for motor rehabilitation after stroke have proven their efficacy to enhance upper limb motor recovery by reinforcing motor related brain activity. Hybrid BCIs (h-BCIs) exploit both central and peripheral activation and are frequently used in assistive BCIs to improve classification performances. However, in a rehabilitative context, brain and muscular features should be extracted to promote a favorable motor outcome, reinforcing not only the volitional control in the central motor system, but also the effective projection of motor commands to target muscles, i.e., central-to-peripheral communication. For this reason, we considered cortico-muscular coupling (CMC) as a feature for a h-BCI devoted to post-stroke upper limb motor rehabilitation. In this study, we performed a pseudo-online analysis on 13 healthy participants (CTRL) and 12 stroke patients (EXP) during executed (CTRL, EXP unaffected arm) and attempted (EXP affected arm) hand grasping and extension to optimize the translation of CMC computation and CMC-based movement detection from offline to online. Results showed that updating the CMC computation every 125 ms (shift of the sliding window) and accumulating two predictions before a final classification decision were the best trade-off between accuracy and speed in movement classification, independently from the movement type. The pseudo-online analysis on stroke participants revealed that both attempted and executed grasping/extension can be classified through a CMC-based movement detection with high performances in terms of classification speed (mean delay between movement detection and EMG onset around 580 ms) and accuracy (hit rate around 85%). The results obtained by means of this analysis will ground the design of a novel non-invasive h-BCI in which the control feature is derived from a combined EEG and EMG connectivity pattern estimated during upper limb movement attempts.

Upper Limbs Muscle Co-contraction Changes Correlated With the Impairment of the Corticospinal Tract in Stroke Survivors: Preliminary Evidence From Electromyography and Motor-Evoked Potential

Objective

Increased muscle co-contraction of the agonist and antagonist muscles during voluntary movement is commonly observed in the upper limbs of stroke survivors. Much remain to be understood about the underlying mechanism. The aim of the study is to investigate the correlation between increased muscle co-contraction and the function of the corticospinal tract (CST).

Methods

Nine stroke survivors and nine age-matched healthy individuals were recruited. All the participants were instructed to perform isometric maximal voluntary contraction (MVC) and horizontal task which consist of sponge grasp, horizontal transportation, and sponge release. We recorded electromyography (EMG) activities from four muscle groups during the MVC test and horizontal task in the upper limbs of stroke survivors. The muscle groups consist of extensor digitorum (ED), flexor digitorum (FD), triceps brachii (TRI), and biceps brachii (BIC). The root mean square (RMS) of EMG was applied to assess the muscle activation during horizontal task. We adopted a co-contraction index (CI) to evaluate the degree of muscle co-contraction. CST function was evaluated by the motor-evoked potential (MEP) parameters, including resting motor threshold, amplitude, latency, and central motor conduction time. We employed correlation analysis to probe the association between CI and MEP parameters.

Results

The RMS, CI, and MEP parameters on the affected side showed significant difference compared with the unaffected side of stroke survivors and the healthy group. The result of correlation analysis showed that CI was significantly correlated with MEP parameters in stroke survivors.

Conclusion

There existed increased muscle co-contraction and impairment in CST functionality on the affected side of stroke survivors. The increased muscle co-contraction was correlated with the impairment of the CST. Intervention that could improve the excitability of the CST may contribute to the recovery of muscle discoordination in the upper limbs of stroke survivors.

Usability of Functional Electrical Stimulation in Upper Limb Rehabilitation in Post-Stroke Patients: A Narrative Review

Stroke leads to significant impairment in upper limb (UL) function. The goal of rehabilitation is the reestablishment of pre-stroke motor stroke skills by stimulating neuroplasticity. Among several rehabilitation approaches, functional electrical stimulation (FES) is highlighted in stroke rehabilitation guidelines as a supplementary therapy alongside the standard care modalities. The aim of this study is to present a comprehensive review regarding the usability of FES in post-stroke UL rehabilitation. Specifically, the factors related to UL rehabilitation that should be considered in FES usability, as well a critical review of the outcomes used to assess FES usability, are presented. This review reinforces the FES as a promising tool to induce neuroplastic modifications in post-stroke rehabilitation by enabling the possibility of delivering intensive periods of treatment with comparatively less demand on human resources. However, the lack of studies evaluating FES usability through motor control outcomes, specifically movement quality indicators, combined with user satisfaction limits the definition of FES optimal therapeutical window for different UL functional tasks. FES systems capable of integrating postural control muscles involving other anatomic regions, such as the trunk, during reaching tasks are required to improve UL function in post-stroke patients.

Effectiveness of Contralaterally Controlled Functional Electrical Stimulation versus Neuromuscular Electrical Stimulation on Upper Limb Motor Functional Recovery in Subacute Stroke Patients: A Randomized Controlled Trial

Purpose

To compare the effectiveness of contralaterally controlled functional electrical stimulation (CCFES) versus neuromuscular electrical stimulation (NMES) on motor recovery of the upper limb in subacute stroke patients.

Materials and Methods

Fifty patients within six months poststroke were randomly assigned to the CCFES group (n = 25) and the NMES group (n = 25). Both groups underwent routine rehabilitation plus 20-minute stimulation on wrist extensors per day, five days a week, for 3 weeks. Fugl-Meyer Assessment of upper extremity (FMA-UE), action research arm test (ARAT), Barthel Index (BI), and surface electromyography (sEMG) were assessed at baseline and end of intervention.

Results

After a 3-week intervention, FMA-UE and BI increased in both groups (p < 0.05). ARAT increased significantly only in the CCFES group (p < 0.05). The changes of FMA-UE, ARAT, and BI in the CCFES group were not greater than those in the NMES group. The improvement in sEMG response of extensor carpi radialis by CCFES was greater than that by NMES (p = 0.026). The cocontraction ratio (CCR) of flexor carpi radialis did not decrease in both groups.

Conclusions

CCFES improved upper limb motor function, but did not show better treatment effect than NMES. CCFES significantly enhanced the sEMG response of paretic extensor carpi radialis compared with NMES, but did not decrease the cocontraction of antagonist.

Reconstruction of paralyzed arm function in patients with hemiplegia through contralateral seventh cervical nerve cross transfer: a multicenter study and real-world practice guidance

BACKGROUND

A previous randomized controlled trial showed contralateral seventh cervical nerve (CC7) cross transfer to be safe and effective in restoring the arm function of spastic arm paralysis patients in a specified population. Guidance on indications, safety and expected long-term improvements of the surgery are needed for clinical practice.

METHODS

This is a retrospective, multicenter, propensity score-matched cohort study. All patients registered between 2013 and 2019 with unilateral spastic arm paralysis over 1 year who were registered at one of five centers in China and South Korea were included. Patients received CC7 cross transfer or rehabilitation treatment in each center. Primary outcome was the change in the upper-extremity Fugl-Meyer (UEFM) score from baseline to 2-year follow-up; larger increase indicated better functional improvements.

FINDINGS

The analysis included 425 eligible patients. After propensity score matching, 336 patients who were 1:1 matched into surgery and rehabilitation groups. Compared to previous trial, patient population was expanded on age (< 12 and > 45 years old), duration of disease (< 5 years) and severity of paralysis (severe disabled patients with UEFM < 20 points). In matched patients, the overall increases of UEFM score from preoperative evaluation to 2-year follow-up were 15.14 in the surgery group and 2.35 in the rehabilitation group (difference, 12.79; 95% CI: 12.02-13.56, p < 0.001). This increase was 16.58 at 3-year and 18.42 at 5-year follow-up compared with the surgery group baseline. Subgroup analysis revealed substantial increase on UEFM score in each subgroup of age, duration of disease, severity of paralysis and cause of injury. No severe complication or disabling sequela were reported in the surgery group.

INTERPRETATION

This study showed that CC7 cross transfer can provide effective, safe and stable functional improvements in long-term follow-up, and provided evidences for expanding the indications of the surgery to a wider population of patients with hemiplegia.

Corticomuscular and Intermuscular Coupling in Simple Hand Movements to Enable a Hybrid Brain-Computer Interface

Hybrid Brain-Computer Interfaces (BCIs) for upper limb rehabilitation after stroke should enable the reinforcement of "more normal" brain and muscular activity. Here, we propose the combination of corticomuscular coherence (CMC) and intermuscular coherence (IMC) as control features for a novel hybrid BCI for rehabilitation purposes. Multiple electroencephalographic (EEG) signals and surface electromyography (EMG) from 5 muscles per side were collected in 20 healthy participants performing finger extension (Ext) and grasping (Grasp) with both dominant and non-dominant hand. Grand average of CMC and IMC patterns showed a bilateral sensorimotor area as well as multiple muscles involvement. CMC and IMC values were used as features to classify each task versus rest and Ext versus Grasp. We demonstrated that a combination of CMC and IMC features allows for classification of both movements versus rest with better performance (Area Under the receiver operating characteristic Curve, AUC) for the Ext movement (0.97) with respect to Grasp (0.88). Classification of Ext versus Grasp also showed high performances (0.99). All in all, these preliminary findings indicate that the combination of CMC and IMC could provide for a comprehensive framework for simple hand movements to eventually be employed in a hybrid BCI system for post-stroke rehabilitation.

A randomised clinical trial comparing 35 Hz versus 50 Hz frequency stimulation effects on hand motor recovery in older adults after stroke

More solid data are needed regarding the application of neuromuscular electrical stimulation (NMES) in the paretic hand following a stroke. A randomised clinical trial was conducted to compare the effects of two NMES protocols with different stimulation frequencies on upper limb motor impairment and function in older adults with spastic hemiparesis after stroke. Sixty nine outpatients were randomly assigned to the control group or the experimental groups (NMES with 50 Hz or 35 Hz). Outcome measures included motor impairment tests and functional assessment. They were collected at baseline, after 4 and 8 weeks of treatment, and after a follow-up period. NMES groups showed significant changes (p < 0.05) with different effect sizes in range of motion, grip and pinch strength, the Modified Ashworth Scale, and the muscle electrical activity in the extensors of the wrist. The 35 Hz NMES intervention showed a significant effect on Barthel Index. Additionally, there were no significant differences between the groups in the Box and Block Test. Both NMES protocols proved evidence of improvements in measurements related to hand motor recovery in older adults following a stroke, nevertheless, these findings showed that the specific stimulation frequency had different effects depending on the clinical measures under study.

Effect of the Triceps Brachii Facilitation Technique on Scapulohumeral Muscle Activation during Reach and Point in a Healthy Population

Purpose: Neurodevelopmental techniques are commonly used in upper limb rehabilitation, but little evidence supports the facilitation techniques associated with this concept. This exploratory study determined whether a facilitation technique at the triceps muscle affected scapulothoracic muscle activity during reach in healthy participants compared with self-selected posture and reach. The secondary aim was to determine whether muscle activation levels differed between the facilitation technique and the optimized posture or guided movement. We also hypothesized that activity in the scapular stabilizers (lower trapezius [LT] and serratus anterior [SA]) would be increased during the facilitated movement than in the other conditions. Methods: The study included 17 healthy participants (aged 20-70 y). Surface electromyography recorded muscle activity in the upper trapezius (UT), middle trapezius (MT), and LT muscles and in the SA, middle deltoid (MD), and triceps during five performance conditions. We used Friedman's test to explore differences in muscle activity across conditions and Bonferroni's post hoc test to explore the differences between conditions. Results: The facilitation technique produced decreased activity in the SA, MD, and triceps muscles (p < 0.01) compared with the self-executed control condition. Compared with optimized posture with independent reach, facilitated movement again produced similar reductions in MD and triceps activity, with decreased LT activity also noted (p < 0.01). Lower activity levels were noted during facilitation than during manual guidance, with or without optimized posture, in the UT, MT, (p < 0.01), SA, and MD muscles (p < 0.05). Conclusions: Triceps facilitation did not increase scapular stability activity, but the activity levels in several other muscle groups (SA, MD, and triceps) were reduced during triceps facilitation compared with optimized posture or guided movement. Detailed analysis of this technique, including co-registered kinematic data and timing of muscle onset, is needed.

The Bobath concept - a model to illustrate clinical practice

Background and purpose: The model of Bobath clinical practice provides a framework identifying the unique aspects of the Bobath concept in terms of contemporary neurological rehabilitation. The utilisation of a framework to illustrate the clinical application of the Bobath concept provides the basis for a common understanding with respect to Bobath clinical practice, education, and research. The development process culminating in the model of Bobath clinical practice is described. Case description: The use of the model in clinical practice is illustrated using two cases: a client with a chronic incomplete spinal cord injury and a client with a stroke. Discussion: This article describes the clinical application of the Bobath concept in terms of the integration of posture and movement with respect to the quality of task performance, applying the Model of Bobath Clinical Practice. Facilitation, a key aspect of Bobath clinical practice, was utilised to positively affect motor control and perception in two clients with impairment-related movement problems due to neurological pathology and associated activity limitations and participation restrictions - the outcome measures used to reflect the individual clinical presentation. Implications for Rehabilitation The model of Bobath clinical practice provides a framework identifying the unique aspects of the Bobath-concept. The model of Bobath clinical practice provides the basis for a common understanding with respect to Bobath clinical practice, education, and research. The clinical application of the Bobath-concept highlights the integration of posture and movement with respect to the quality of task performance. Facilitation, a key aspect of Bobath clinical practice, positively affects motor control, and perception.

Getting a kinematic handle on reach-to-grasp: a meta-analysis

BACKGROUND AND OBJECTIVES

Reach-to-grasp is an essential everyday activity that is often impaired after stroke. The objectives of this review are: (1) identify differences in the kinematic characteristics of reach-to-grasp between individuals with and without stroke, and (2) determine the influence of object location on kinematics.

DATA SOURCES

MEDLINE, AMED, and Embase databases.

ELIGIBILITY CRITERIA

Studies investigating individuals with stroke and neurologically intact control participants completing reach-to-grasp (paretic upper limb) of an object assessed via kinematic assessment (motion analysis).

REVIEW METHODS

Following Cochrane Collaboration guidelines a meta-analysis comparing kinematic characteristics of reach-to-grasp between individuals with and without stroke. Potential risk of bias was assessed using the Down's and Black Tool. Data were synthesised by calculating the standardised mean difference (SMD) in kinematic characteristics between adults with and without stroke.

RESULTS

Twenty-nine studies met the review criteria, mainly of observational design; 460 individuals with stroke and 324 control participants. Kinematic differences in reach-to-grasp were identified in the central and ipsilateral workspace for example, individuals with stroke exhibited significantly lower peak velocity SMD -1.48 (95% CI -1.94, -1.02), and greater trunk displacement SMD 1.55 (95% CI 0.85, 2.25) than control participants. Included studies were assessed as demonstrating unclear or high potential risk-of-bias.

CONCLUSIONS

Differences in kinematic characteristics between individuals with and without stroke were identified which may be different reaching in the ipsilateral and central workspace. Suggesting, that object location may influence some kinematic characteristics and not others which may be pertinent when re-training reach-to-grasp.

PROSPERO

CRD42014009479.

Behavioral and neurophysiological mechanisms underlying motor skill learning in patients with post-stroke hemiparesis

OBJECTIVE

Given the presence of execution deficits after stroke, it is difficult to determine if patients with stroke have deficits in motor skill learning with the paretic arm. Here, we controlled for execution deficits while testing practice effects of the paretic arm on motor skill learning, long-term retention, and corticospinal excitability.

METHODS

Ten patients with unilateral stroke and ten age-matched controls practiced a kinematic arm skill for two days and returned for retention testing one-day and one-month post-practice. Motor skill learning was quantified as a change in speed-accuracy tradeoff from baseline to retention tests. Transcranial magnetic stimulation (TMS) was used to generate an input-output curve of the ipsilesional motor cortex (M1), and measure transcallosal inhibition from contralesional to ipsilesional M1.

RESULTS

While the control group had greater overall accuracy than the stroke group, both groups showed comparable immediate and long-term improvements with practice. Skill improvements were accompanied by greater excitability of the ipsilesional corticospinal system and reduced transcallosal inhibition from contralesional to ipsilesional M1.

CONCLUSIONS

When execution deficits are accounted for, patients with stroke demonstrate relatively intact motor skill learning with the paretic arm. Paretic arm learning is accompanied by modulations in corticospinal and transcallosal mechanisms.

SIGNIFICANCE

Functional recovery after stroke relies on ability for skill learning and the underlying mechanisms.

FUNCTION AND BIOMECHANICS OF UPPER LIMB IN POST-STROKE PATIENTS — A SYSTEMATIC REVIEW

Current clinical services are struggling to provide the most favorable rehabilitation treatment for patients with stroke, which inspired researchers to investigate and explore the use of rehabilitation devices suitable for the patients and rehabilitation therapy. This review paper addresses the importance of biomechanical features in patients who experienced stroke to the upper limb. First and foremost, a review was done on general biomechanical description associated with motor control, shoulder, elbow, wrist and fingers joint. This included the ability of the patients to move their affected arm and the affect on peak joint torque, range of motion, joint forces, grip strength and muscle activities during the activities of daily living. In addition, we also reviewed the material properties and geometrical condition of tissue in stroke patient. The repercussions of post-stroke patient regarding the bone density, stiffness of muscle as well as the thickness of cartilage are described in this review. Based on the findings, the movement of affected stroke hand is associated with the motor control and material properties of tissue. To strengthen the motor control and maintaining tissue properties, early physical training on patients should be conducted in two to four weeks after stroke. In conclusion, this report suggests a new approach for future biomechanical studies in order to enhance the quality of physiotherapy rehabilitation peculiarly for post-stroke patients.

A Longitudinal Electromyography Study of Complex Movements in Poststroke Therapy. 1: Heterogeneous Changes Despite Consistent Improvements in Clinical Assessments

Poststroke weakness on the more-affected side may arise from reduced corticospinal drive, disuse muscle atrophy, spasticity, and abnormal coordination. This study investigated changes in muscle activation patterns to understand therapy-induced improvements in motor-function in chronic stroke compared to clinical assessments and to identify the effect of motor-function level on muscle activation changes. Electromyography (EMG) was recorded from five upper limb muscles on the more-affected side of 24 patients during early and late therapy sessions of an intensive 14-day program of Wii-based Movement Therapy (WMT) and for a subset of 13 patients at 6-month follow-up. Patients were classified according to residual voluntary motor capacity with low, moderate, or high motor-function levels. The area under the curve was calculated from EMG amplitude and movement duration. Clinical assessments of upper limb motor-function pre- and post-therapy included the Wolf Motor Function Test, Fugl-Meyer Assessment and Motor Activity Log Quality of Movement scale. Clinical assessments improved over time (p < 0.01) with an effect of motor-function level (p < 0.001). The pattern of EMG change by late therapy was complex and variable, with differences between patients with low compared to moderate or high motor-function levels. The area under the curve (p = 0.028) and peak amplitude (p = 0.043) during Wii-tennis backhand increased for patients with low motor-function, whereas EMG decreased for patients with moderate and high motor-function levels. The reductions included movement duration during Wii-golf (p = 0.048, moderate; p = 0.026, high) and Wii-tennis backhand (p = 0.046, moderate; p = 0.023, high) and forehand (p = 0.009, high) and the area under the curve during Wii-golf (p = 0.018, moderate) and Wii-baseball (p = 0.036, moderate). For the pooled data over time, there was an effect of motor-function (p = 0.016) and an interaction between time and motor-function (p = 0.009) for Wii-golf movement duration. Wii-baseball movement duration decreased as a function of time (p = 0.022). There was an effect on Wii-tennis forehand duration for time (p = 0.002), an interaction of time and motor-function (p = 0.005) and an effect of motor-function level on the area under the curve (p = 0.034) for Wii-golf. This study demonstrated different patterns of EMG changes according to residual voluntary motor-function levels, despite heterogeneity within each level that was not evident following clinical assessments alone. Thus, rehabilitation efficacy might be underestimated by analyses of pooled data.

Flexion synergy overshadows flexor spasticity during reaching in chronic moderate to severe hemiparetic stroke

OBJECTIVE

Pharmaceutical intervention targets arm flexor spasticity with an often-unsuccessful goal of improving function. Flexion synergy is a related motor impairment that may be inadvertently neglected. Here, flexor spasticity and flexion synergy are disentangled to determine their contributions to reaching dysfunction.

METHODS

Twenty-six individuals participated. A robotic device systematically modulated shoulder abduction loading during ballistic reaching. Elbow muscle electromyography data were partitioned into windows delineated by elbow joint velocity allowing for the separation of synergy- and spasticity-related activation.

RESULTS

Reaching velocity decreased with abduction loading (p<0.001) such that velocity was 30% slower when lifting the arm at 50% of abduction strength compared to when arm weight was supported. Abnormal flexion synergy increased with abduction loading (p<0.001) such that normalized activation ranged from a median (interquartile range) of 0.07 (0.03-0.12) when arm weight was supported to 0.19 (0.12-0.40) when actively lifting (large effect size, d=0.59). Flexor spasticity was detected during reaching (p=0.016) but only when arm weight was supported (intermediate effect size, d=0.33).

CONCLUSION

Flexion synergy is the predominant contributor to reaching dysfunction while flexor spasticity appears only relevant during unnaturally occurring passively supported movement.

SIGNIFICANCE

Interventions targeting flexion synergy should be leveraged in future stroke recovery trials.

The Use of Functional Electrical Stimulation on the Upper Limb and Interscapular Muscles of Patients with Stroke for the Improvement of Reaching Movements: A Feasibility Study

Introduction

Reaching movements in stroke patients are characterized by decreased amplitudes at the shoulder and elbow joints and greater displacements of the trunk, compared to healthy subjects. The importance of an appropriate and specific contraction of the interscapular and upper limb (UL) muscles is crucial to achieving proper reaching movements. Functional electrical stimulation (FES) is used to activate the paretic muscles using short-duration electrical pulses.

Objective

To evaluate whether the application of FES in the UL and interscapular muscles of stroke patients with motor impairments of the UL modifies patients’ reaching patterns, measured using instrumental movement analysis systems.

Design

A cross-sectional study was carried out.

Setting

The VICON Motion System^® was used to conduct motion analysis.

Participants

Twenty-one patients with chronic stroke.

Intervention

The Compex^® electric stimulator was used to provide muscle stimulation during two conditions: a placebo condition and a FES condition.

Main outcome measures

We analyzed the joint kinematics (trunk, shoulder, and elbow) from the starting position until the affected hand reached the glass.

Results

Participants receiving FES carried out the movement with less trunk flexion, while shoulder flexion elbow extension was increased, compared to placebo conditions.

Conclusion

The application of FES to the UL and interscapular muscles of stroke patients with motor impairment of the UL has improved reaching movements.

Effects of upper extremity training in a standing position on trunk alignment in stroke patients

[Purpose] This study aimed to examine the effect of upper extremity training in the standing position on trunk alignment of patients with stroke. [Subjects and Methods] Twelve stroke patients were enrolled in the study and divided into two groups: a group of six patients in a sitting position and a group of six patients in a standing position. Upper extremity training for 30 min per day, five times a week for six weeks was given to subjects in both groups. In order to assess trunk alignment, lumbar lordosis and thoracic kyphosis were examined before and after upper extremity training using Formetric 4D. [Results] After training the standing position group had no significant change in lumbar lordosis but a significant change in thoracic kyphosis. The sitting position group showed no significant changes in either lumbar lordosis or thoracic kyphosis. The comparison between groups showed there was no significant difference in the change in lumbar lordosis but there was a significant difference in the change in thoracic kyphosis. [Conclusion] Examination of trunk alignment showed that upper extremity training conducted in a standing position reduced thoracic kyphosis more than in a sitting position.

Task-based mirror therapy enhances ipsilesional motor functions in stroke: A pilot study

OBJECTIVE

To examine the effect of Mirror therapy (MT) on dexterity, coordination, and muscle strength of the less-affected upper limb in stroke.

DESIGN

Pre-test post-test, single group, experimental design.

SETTING

Rehabilitation institute.

PARTICIPANTS

Post-stroke hemiparetic chronic subjects (N = 21).

INTERVENTIONS

Forty sessions of MT using various tasks in addition to the conventional rehabilitation. Tasks such as lifting a glass, ball-squeezing, and picking-up objects were performed by the less-affected side in front of the mirror-box creating an illusion for the affected side.

MAIN OUTCOME MEASURES

Minnesota Manual Dexterity Test (MMDT), Purdue Peg Board Test (PPBT), and Manual Muscle Testing (MMT) were used to measure the deficits of the less-affected side.

RESULT

Post-intervention, the less-affected side of the participants exhibited significant improvement on MMDT (p < 0.001), PPBT (p < 0.001), and MMT (shoulder flexors, wrist extensors and deviators, and finger flexors-extensors; p = 0.005-0.046).

CONCLUSION

In post-stroke hemiparesis, MT also led to the improvement in dexterity, coordination, and strength of the less-affected side. In addition to the affected side, the technique may augment the subtle motor deficits of the less-affected side.