Post-stroke Hemiparetic Subjects Research Articles

Sensory deficits of the paretic and non-paretic upper limbs relate with the motor recovery of the poststroke subjects

ABSTRACT Background Post stroke, motor paresis has usually been considered to be a crucial factor responsible for the disability; other impairments such as somatosensory deficits may also play a role. Objective To determine the relation between the sensory deficits (paretic and non-paretic upper limbs) and the motor recovery of the paretic upper limb and to predict the potential of motor recovery based on the sensory deficits among stroke subjects. Methods The study was a cross-sectional study conducted in a rehabilitation institute. Ninety-five poststroke hemiparetic subjects having sensory impairment in any of the modalities were considered for this study. Sensory deficits were assessed on both the upper limbs (paretic and non-paretic) primarily using Erasmus MC modification of the revised version of Nottingham Sensory Assessment (Em-NSA) and Nottingham Sensory Assessment (Stereognosis) (NSA-S). The motor recovery was assessed using the Fugl-Meyer assessment (FMA). Results The measures of sensory deficits exhibited weak but significant correlation [the paretic (Em-NSA and NSA; r = .38 to .58; p < .001) and the non-paretic (Em-NSA and NSA; r = .24 to .38; p = .03 to .001)] with the motor recovery of the paretic upper limb as measured by FMA. The potential of favorable recovery of the paretic upper limb may be predicted using the cutoff scores of Em-NSA (30, 21, and 24) and NSA-S (5, 8, and 5) of the paretic side. Conclusion In stroke, sensory deficits relate weakly with the recovery of the paretic upper limb and can predict recovery potential of the paretic upper limb.

Assessing Spatiotemporal and Quality Alterations in Paretic Upper Limb Movements after Stroke in Routine Care: Proposal and Validation of a Protocol Using IMUs versus MoCap.

Accurate assessment of upper-limb movement alterations is a key component of post-stroke follow-up. Motion capture (MoCap) is the gold standard for assessment even in clinical conditions, but it requires a laboratory setting with a relatively complex implementation. Alternatively, inertial measurement units (IMUs) are the subject of growing interest, but their accuracy remains to be challenged. This study aims to assess the minimal detectable change (MDC) between spatiotemporal and quality variables obtained from these IMUs and MoCap, based on a specific protocol of IMU calibration and measurement and on data processing using the dead reckoning method. We also studied the influence of each data processing step on the level of between-system MDC. Fifteen post-stroke hemiparetic subjects performed reach or grasp tasks. The MDC for the movement time, index of curvature, smoothness (studied through the number of submovements), and trunk contribution was equal to 10.83%, 3.62%, 39.62%, and 25.11%, respectively. All calibration and data processing steps played a significant role in increasing the agreement. The between-system MDC values were found to be lower or comparable to the between-session MDC values obtained with MoCap, meaning that our results provide strong evidence that using IMUs with the proposed calibration and processing steps can successfully and accurately assess upper-limb movement alterations after stroke in clinical routine care conditions.

The effect of virtual reality environment on spatial-temporal gait parameters during self-paced treadmill walking

A common measure of rehabilitation effectiveness post-stroke is self-selected walking speed, yet individuals may achieve the same speed using different coordination strategies. Asymmetry in the propulsion generated by each leg can provide insight into paretic leg coordination due to its relatively strong correlation with hemiparetic severity. Subjects walking at the same speed can exhibit different propulsion asymmetries, with some subjects relying more on the paretic leg and others on the nonparetic leg. The goal of this study was to assess whether analyzing propulsion asymmetry can help distinguish between improved paretic leg coordination versus nonparetic leg compensation.Three-dimensional forward dynamics simulations were developed for two post-stroke hemiparetic subjects walking at identical speeds before/after rehabilitation with opposite changes in propulsion asymmetry. Changes in the individual muscle contributions to forward propulsion were examined.The major source of increased forward propulsion in both subjects was from the ankle plantarflexors. How they were utilized differed and appears related to changes in propulsion asymmetry. Subject A increased propulsion generated from the paretic plantarflexors, while Subject B increased propulsion generated from the nonparetic plantarflexors. Each subject's strategy to increase speed also included differences in other muscle groups (e.g., hamstrings) that did not appear to be related to propulsion asymmetry.The results of this study highlight how speed cannot be used to elucidate underlying muscle coordination changes following rehabilitation. In contrast, propulsion asymmetry appears to provide insight into changes in plantarflexor output affecting propulsion generation and may be useful in monitoring rehabilitation outcomes.

Gait variability using waist- and ankle-worn inertial measurement units in healthy older adults

A common measure of rehabilitation effectiveness post-stroke is self-selected walking speed, yet individuals may achieve the same speed using different coordination strategies. Asymmetry in the propulsion generated by each leg can provide insight into paretic leg coordination due to its relatively strong correlation with hemiparetic severity. Subjects walking at the same speed can exhibit different propulsion asymmetries, with some subjects relying more on the paretic leg and others on the nonparetic leg. The goal of this study was to assess whether analyzing propulsion asymmetry can help distinguish between improved paretic leg coordination versus nonparetic leg compensation.Three-dimensional forward dynamics simulations were developed for two post-stroke hemiparetic subjects walking at identical speeds before/after rehabilitation with opposite changes in propulsion asymmetry. Changes in the individual muscle contributions to forward propulsion were examined.The major source of increased forward propulsion in both subjects was from the ankle plantarflexors. How they were utilized differed and appears related to changes in propulsion asymmetry. Subject A increased propulsion generated from the paretic plantarflexors, while Subject B increased propulsion generated from the nonparetic plantarflexors. Each subject's strategy to increase speed also included differences in other muscle groups (e.g., hamstrings) that did not appear to be related to propulsion asymmetry.The results of this study highlight how speed cannot be used to elucidate underlying muscle coordination changes following rehabilitation. In contrast, propulsion asymmetry appears to provide insight into changes in plantarflexor output affecting propulsion generation and may be useful in monitoring rehabilitation outcomes.

Interlimb coupling in poststroke rehabilitation: a pilot randomized controlled trial

ABSTRACTBackground: The interlimb coupling, coordination between the limbs, gets hampered in post-stroke hemiparesis. Most of the poststroke motor regimes primarily focus on the more affected limb.Objectives: To develop an interlimb coupling protocol and assess its feasibility and effect on motor recovery, gait and disability among post-stroke subjects.Design: A pilot randomized controlled, doubled blinded trialSetting: A rehabilitation instituteMethods: 50 post-stroke (> 6 months) hemiparetic subjects (Brunnstrom recovery stage ≥ 3) were randomly divided into experimental (n=26) and control (n=24) groups. The 8-week experimental intervention (3 sessions of 1 hour each, per week) comprised activities demanding coordinated, alternate, and rhythmic use of the affected as well as the less-affected limbs. The outcome measures were feasibility of activities, Fugl-Meyer assessment (FMA), Rivermead visual gait assessment (RVGA), Functional ambulation category (FAC) and modified Rankin scale (mRS).Results: The experimental protocol was found to be feasible by the participants. Post intervention, the experimental group exhibited highly significant difference for FMA (mean difference = 7.12, 95% CI = 5.71 – 8.53, p < 0.001), RVGA reduction (mean difference = - 6.32, 95% CI = 7.51 – 5.13, p < 0.001), and median FAC enhancement (p < 0.001) in comparison to the controls. However, the median mRS level of experimental group did not change significantly (p = 0.056) when compared with the controls.Conclusions: The interlimb coupling training, a feasible program may enhance recovery of the upper and lower limbs and gait in stroke. Further definitive randomized trials are warranted to validate the present findings.

Merged plantarflexor muscle activity is predictive of poor walking performance in post-stroke hemiparetic subjects

Stroke is the leading cause of long-term disability and individuals post-stroke often experience impaired walking ability. The plantarflexor (PF) muscles are critical to walking through their contributions to the ground reaction forces and body segment energetics. Previous studies have shown muscle activity during walking can be grouped into co-excited muscle sets, or modules. Improper co-activation, or merging of modules, is a common impairment in individuals post-stroke. The purpose of this study was to determine the influence of merged PF modules on walking performance in individuals post stroke by examining balance control, body support and propulsion, and walking symmetry. Muscle modules were identified using non-negative matrix factorization to classify subjects as having an independent or merged PF module. The merged group had decreased balance control with a significantly higher frontal plane whole-body angular momentum than both the independent and control groups, while the independent and control groups were not significantly different. The merged group also had higher paretic braking and nonparetic propulsion than both the independent and control groups. These results remained when comparisons were limited to subjects who had the same number of modules, indicating this was not a general effect due to subjects with merged PF having fewer modules. It is likely that a merged PF module is indicative of general PF dysfunction even when some activation occurs at the appropriate time. These results suggest an independent PF module is critical to walking performance, and thus obtaining an independent PF module should be a crucial aim of stroke rehabilitation.

The Effect of the Lumbar Vibratory Belt on Static and Dynamic Postural Stability in Post Stroke Hemiplegic Subjects

Background: Loss of postural control has been recognized as a major health problem in post-stroke hemiplegic patients. Vibratory somatosensory stimulation (VSS) is a novel method with considerable promises for improving postural stability in these subjects. Objective: The aim of this study was to evaluate the effects and feasibility of local vibration through a lumbar belt on static and dynamic postural stability in post-stroke hemiparetic subjects. Methods: Eighteen stroke subjects participated in this study. Subjects were checked by Berg balance scale and then were asked to wear the vibratory belt which applies mechanical vibration on both sides of the posterior lumbar region. Balance control of the patients was tested in static and dynamic modes with open and closed eyes, in separate sets with and without vibration. Results: There was statistically significant stability improvement in overall stability index during applying vibratory belt ON. No significant evidence was shown the preferential balance improvement of the vibratory belt in either dynamic vs. static state or open vs. closed eye condition. Conclusions: Localized vibratory stimulation can improve the postural stability in patients with post-stroke hemiplegia.

Effect of activity-based mirror therapy on lower limb motor-recovery and gait in stroke: A randomised controlled trial

ABSTRACTObjective: To determine the effect of activity-based mirror therapy (MT) on motor recovery and gait in chronic poststroke hemiparetic subjects.Design: A randomised, controlled, assessor-blinded trial.Setting: Rehabilitation institute.Participants: Thirty-six chronic poststroke (15.89 ± 9.01 months) hemiparetic subjects (age: 46.44 ± 7.89 years, 30 men and functional ambulation classification of median level 3).Interventions: Activity-based MT comprised movements such as ball-rolling, rocker-board, and pedalling. The activities were provided on the less-affected side in front of the mirror while hiding the affected limb. The movement of the less-affected lower limb was projected as over the affected limb. Conventional motor therapy based on neurophysiological approaches was also provided to the experimental group. The control group received only conventional management.Main outcome measures: Brunnstrom recovery stages (BRS), Fugl-Meyer assessment lower extremity (FMA-LE), Rivermead visual gait assessment (RVGA), and 10-metre walk test (10-MWT).Results: Postintervention, the experimental group exhibited significant and favourable changes for FMA-LE (mean difference = 3.29, 95% CI = 1.23–5.35, p = .003) and RVGA (mean difference = 5.41, 95% CI = 1.12–9.71, p = .015) in comparison to the control group. No considerable changes were observed on 10-MWT.Conclusions: Activity-based MT facilitates motor recovery of the lower limb as well as reduces gait deviations among chronic poststroke hemiparetic subjects.

Walking speed intention model using soleus electromyogram signal of nondisabled and post-stroke hemiparetic patients.

It is well known that the activation of plantar flexors have a strong influence on the walking speed. If the gait speed can be predicted using this relationship, a post-stroke hemiparetic patient could control a gait rehabilitation robot according to his or her gait intention, and the robotic gait rehabilitation effect could be further improved. To find out this relationship, 9 nondisabled subjects and 4 chronic post-stroke hemiparetic subjects performed overground level walking at a comfortable pace, a slow pace, a fast pace, and an increasing pace with electromyogram sensors attached on plantar flexors. Soleus among plantar flexors showed the most stable relationship with walking speed. The relationship between maximum activation level of soleus electromyogram during stance phase before toe-off and walking speed during swing phase after the same toe-off was modeled by a polynomial regression model. The model outputs were then compared to the measured walking speeds using coefficients of determination (R2). The average R2 values are 0.594 and 0.692 for 1st· and 2nd order models respectively in the nondisabled subjects. The average R2 values are 0.598 and 0.623 for the unaffected side and 0.388 and 0.394 for the affected side in the chronic subjects. The results show the feasibility of applying the soleus-walking speed relationship to control the robot gait speed at will. A walking speed estimation method is proposed using only a walking step in real time.

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

To examine the effect of Mirror therapy (MT) on dexterity, coordination, and muscle strength of the less-affected upper limb in stroke. Pre-test post-test, single group, experimental design. Rehabilitation institute. Post-stroke hemiparetic chronic subjects (N=21). 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. 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. 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). 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.

Minimal clinically important difference of the lower-extremity fugl–meyer assessment in chronic-stroke

Background: The Minimal Clinically Important Difference (MCID), the smallest difference in the treatment outcome, augments both clinical and research practice. The MCID of the Fugl–Meyer assessment: Lower extremity (FMA-LE), an important motor measure in stroke, is not known.Objective: To estimate MCID score of FMA-LE using an anchor-based approach in chronic poststroke hemiparetic (>6 months) stroke subjects.Methods: Design: A prospective, observational study. Setting: Occupational therapy department of a rehabilitation institute. Participants: Sixty-five poststroke hemiparetic subjects (Mean age = 44.22 years, 42 men, Mean poststroke duration = 16.42 months). Intervention: The conventional motor therapy based on neurophysiological approaches was provided for the affected lower extremity (30 sessions, 45 min each, 3/week). Outcome Measures: FMA-LE, Functional ambulation classification (FAC), and global rating of patient-perceived changes (GRPPC). Result: The estimated MCID of FMA-LE was found to be a score of 6 using both FAC (sensitivity 90, specificity 94) and GRPPC (sensitivity 87, specificity 91). Conclusion: In chronic poststroke hemiparetic subjects, the computed MCID of FMA-LE is a score of 6. The subjects who achieve a change in a score of 6 on FMA-LE would perceive a meaningful recovery of lower-extremity function than those who do not. The reference value may be utilized in stroke rehabilitation.

Task-Based Mirror Therapy Augmenting Motor Recovery in Poststroke Hemiparesis: A Randomized Controlled Trial

To establish the effect of the task-based mirror therapy (TBMT) on the upper limb recovery in stroke. A pilot, randomized, controlled, assessor-blinded trial was conducted in a rehabilitation institute. A convenience sample of 33 poststroke (mean duration, 12.5 months) hemiparetic subjects was randomized into 2 groups (experimental, 17; control, 16). The subjects were allocated to receive either TBMT or standard motor rehabilitation-40 sessions (5/week) for a period of 8 weeks. The TBMT group received movements using various goal-directed tasks and a mirror box. The movements were performed by the less-affected side superimposed on the affected side. The main outcome measures were Brunnstrom recovery stage (BRS) and Fugl-Meyer assessment (FMA)-FMA of upper extremity (FMA-UE), including upper arm (FMA-UA) and wrist-hand (FMA-WH). The TBMT group exhibited highly significant improvement on mean scores of FMA-WH (P < .001) and FMA-UE (P < .001) at postassessment in comparison to the control group. Furthermore, there was a 12% increase in the number of subjects at BRS stage 5 (out of synergy movement) in the experimental group as compared to a 0% rise at the same stage in the control group. This pilot trial confirmed the role of TBMT in improving the wrist-hand motor recovery in poststroke hemiparesis. MT using tasks may be used as an adjunct in stroke rehabilitation.

Effect of motor training involving the less-affected side (MTLA) in post-stroke subjects: a pilot randomized controlled trial

Introduction:Poststroke, less-severe motor impairment occurs on the ipsilesional side of body. The objective of the present study was to evaluate the effectiveness of the motor training involving the less-affected side (MTLA) in stroke.Methods:This was a randomized, controlled, double-blinded pilot study conducted in the occupational therapy unit of a rehabilitation Institute. A convenience sample of 35 stroke subjects (mean poststroke duration, 28.76 weeks) was randomized into two groups (the experimental group: 17 and control group: 18). Thirty-two participants completed the entire study protocol. The experimental group and control group were provided MTLA and neurophysiological-based conventional therapy respectively. Both the groups received 24 treatment sessions (60 minutes each) over the period of two months. The Affected side was assessed using Brunnstrom recovery stage (BRS) and Fugl-Meyer assessment (FMA) whereas the less-affected side was evaluated by Minnesota manual dexterity test (MMDT), Purdue peg board test (PPBT) and Manual Muscle Testing (MMT).Results:Postintervention, the less-affected side of experimental group demonstrated significant improvement for MMDT (P = 0.003), PPBT (P = 0.01) and MMT (P < 0.001 to 0.043) in comparison to the control group. Further, as compared to the control group, the experimental group exhibited positive significant change for the measure of affected side [BRS (P < 0.001) and FMA (P < 0.001 to 0.03)] at post assessment.Conclusion:MTLA enhanced the muscle strength, dexterity and coordination of the less-affected side as well as the motor recovery of the affected side in poststroke hemiparetic subjects.

Forward propulsion asymmetry is indicative of changes in plantarflexor coordination during walking in individuals with post-stroke hemiparesis

BackgroundA common measure of rehabilitation effectiveness post-stroke is self-selected walking speed, yet individuals may achieve the same speed using different coordination strategies. Asymmetry in the propulsion generated by each leg can provide insight into paretic leg coordination due to its relatively strong correlation with hemiparetic severity. Subjects walking at the same speed can exhibit different propulsion asymmetries, with some subjects relying more on the paretic leg and others on the nonparetic leg. The goal of this study was to assess whether analyzing propulsion asymmetry can help distinguish between improved paretic leg coordination versus nonparetic leg compensation. MethodsThree-dimensional forward dynamics simulations were developed for two post-stroke hemiparetic subjects walking at identical speeds before/after rehabilitation with opposite changes in propulsion asymmetry. Changes in the individual muscle contributions to forward propulsion were examined. FindingsThe major source of increased forward propulsion in both subjects was from the ankle plantarflexors. How they were utilized differed and appears related to changes in propulsion asymmetry. Subject A increased propulsion generated from the paretic plantarflexors, while Subject B increased propulsion generated from the nonparetic plantarflexors. Each subject's strategy to increase speed also included differences in other muscle groups (e.g., hamstrings) that did not appear to be related to propulsion asymmetry. InterpretationThe results of this study highlight how speed cannot be used to elucidate underlying muscle coordination changes following rehabilitation. In contrast, propulsion asymmetry appears to provide insight into changes in plantarflexor output affecting propulsion generation and may be useful in monitoring rehabilitation outcomes.

The influence of solid ankle-foot-orthoses on forward propulsion and dynamic balance in healthy adults during walking

BackgroundIn post-stroke hemiparetic subjects, solid polypropylene ankle-foot-orthoses are commonly prescribed to assist in foot clearance during swing while bracing the ankle during stance. Mobility demands, such as changing walking speed and direction, are accomplished by accelerating or decelerating the body and maintaining dynamic balance. Previous studies have shown that the ankle plantarflexors are primary contributors to these essential biomechanical functions. Thus, with ankle-foot-orthoses limiting ankle motion and plantarflexor output during stance, execution of these walking subtasks may be compromised. This study examined the influence of a solid polypropylene ankle-foot-orthosis on forward propulsion and dynamic balance in healthy adults. MethodsKinematic and kinetic data were recorded from 10 healthy adults walking with and without a unilateral ankle-foot-orthosis at steady-state slow (0.6m/s) and moderate (1.2m/s) speeds, and during accelerated (0–1.8m/s at 0.06m/s2) and decelerated (1.8–0m/s at −0.06m/s2) walking. Propulsion was quantified by propulsive and braking impulses (i.e., time integral of the anterior–posterior ground reaction force) while dynamic balance was quantified by the peak-to-peak range of whole-body angular momentum. FindingsThe propulsive impulses decreased in the leg with ankle-foot-orthosis compared to the contralateral leg and no ankle-foot-orthosis condition. Further, the ankle-foot-orthosis resulted in a greater range of angular momentum in both the frontal and sagittal planes, which were correlated with the reduced peak hip abduction and reduced ankle plantarflexor moments, respectively. InterpretationSolid ankle-foot-orthoses limit the successful execution of important mobility subtasks in healthy adults and that the prescription of ankle-foot-orthosis should be carefully considered.

Does motor training of the nonparetic side influences balance and function in chronic stroke? A pilot RCT.

Background. Balance and functional abilities are controlled by both sides of the body. The role of nonparetic side has never been explored for such skills. Objective. The objective of the present study was to examine the effect of a motor therapy program primarily involving the nonparetic side on balance and function in chronic stroke. Method. A randomized controlled, double blinded trial was conducted on 39 poststroke hemiparetic subjects (21, men; mean age, 42 years; mean poststroke duration, 13 months). They were randomly divided into the experimental group (n = 20) and control group (n = 19). The participants received either motor therapy focusing on the nonparetic side along with the conventional program or conventional program alone for 8 weeks (3 session/week, 60 minutes each). The balance ability was assessed using Berg Balance Scale (BBS) and Functional Reach Test (FRT) while the functional performance was measured by Barthel Index (BI). Result. After intervention, the experimental group exhibited significant (P < 0.05) change on BBS (5.65 versus 2.52) and BI (12.75 versus 2.16) scores in comparison to the control group. Conclusion. The motor therapy program incorporating the nonparetic side along with the affected side was found to be effective in enhancing balance and function in stroke.

The influence of merged muscle excitation modules on post-stroke hemiparetic walking performance

BackgroundPost-stroke subjects with hemiparesis typically utilize a reduced number of modules or co-excited muscles compared to non-impaired controls, with at least one module resembling the merging of two or more non-impaired modules. In non-impaired walking, each module has distinct contributions to important biomechanical functions, and thus different merged module combinations post-stroke may result in different functional consequences. MethodsThree-dimensional forward dynamics simulations were developed for non-impaired controls and two groups of post-stroke hemiparetic subjects with different merged module combinations to analyze how paretic leg muscle contributions to body support, forward propulsion, mediolateral control and leg swing are altered. FindingsThe potential of the plantarflexors to generate propulsion was impaired in both hemiparetic groups while the remaining functional consequences differed depending on which modules were merged. Paretic leg swing was impaired during pre-swing when Modules 1 (hip abductors and knee extensors during early stance), and 2 (plantarflexors during late stance) were merged and during late swing when Modules 1 and 4 (hamstrings during late swing into early stance) were merged. When Modules 1 and 4 were merged, body support during early stance was also impaired. InterpretationThese results suggest that improving plantarflexor ability to generate propulsion is critical during rehabilitation regardless of module composition. If Modules 1 and 2 are merged, then rehabilitation should also focus on improving paretic leg pre-swing whereas if Modules 1 and 4 are merged, then rehabilitation should also focus on improving early stance body support and late paretic leg swing.

Interlimb interactions during bilateral voluntary elbow flexion tasks in chronic hemiparetic stroke

The purpose was to systematically investigate interlimb interactions in chronic hemiparetic stroke. Fourteen poststroke hemiparetic subjects (>1 year) performed maximum voluntary contraction (MVC) elbow flexion tasks without visual feedback with one (unilateral) and two limbs simultaneously (bilateral). At submaximal levels, subjects produced force to a visual target reflecting 20%, 40%, 60%, and 80% of corresponding MVC in unilateral tasks, and of summated unilateral MVCs in bilateral tasks. Elbow flexion force and biceps surface electromyogram (EMG) were measured bilaterally. Proportionally increased EMG activity on the contralateral limb (motor overflow) was observed during unilateral tasks of the nonimpaired limb but not of the impaired limb. During bilateral tasks at submaximal levels, the impaired limb produced less force (i.e., force deficit [FD]) as compared to expected forces based upon its unilateral MVC. Force deficit on the impaired limb was compensated by greater force production on the nonimpaired limb such that the visual target was reached. However, force contribution to the total force progressively decreased from the nonimpaired side, when the level of submaximal contractions increased. During bilateral MVC tasks, there was no FD on the impaired limb, but FD was observed on the nonimpaired limb. A net result of a small bilateral deficit in force with parallel changes in EMG was observed. These novel findings of activation level–dependent interactions and asymmetrical contralateral motor overflow provide new insights that, among other compensatory mechanisms, ipsilateral corticospinal projections from the nonlesioned hemisphere play an important role in interlimb interactions in chronic stroke, in addition to unbalanced interhemispheric inhibition.

The influence of locomotor rehabilitation on module quality and post-stroke hemiparetic walking performance

Recent studies have suggested the biomechanical subtasks of walking can be produced by a reduced set of co-excited muscles or modules. Individuals post-stroke often exhibit poor inter-muscular coordination characterized by poor timing and merging of modules that are normally independent in healthy individuals. However, whether locomotor therapy can influence module composition and timing and whether these improvements lead to improved walking performance is unclear. The goal of this study was to examine the influence of a locomotor rehabilitation therapy on module composition and timing and post-stroke hemiparetic walking performance.Twenty-seven post-stroke hemiparetic subjects participated in a 12-week locomotor intervention incorporating treadmill training with body weight support and manual trainers accompanied by training overground walking. Electromyography (EMG), kinematic and ground reaction force data were collected from subjects both pre- and post-therapy and from 19 age-matched healthy controls walking on an instrumented treadmill at their self-selected speed. Non-negative matrix factorization was used to identify the module composition and timing from the EMG data. Module timing and composition, and various measures of walking performance were compared pre- and post-therapy.In subjects with four modules pre- and post-therapy, locomotor training resulted in improved timing of the ankle plantarflexor module and a more extended paretic leg angle that allowed the subjects to walk faster and with more symmetrical propulsion. In addition, subjects with three modules pre-therapy increased their number of modules and improved walking performance post-therapy. Thus, locomotor training has the potential to influence module composition and timing, which can lead to improvements walking performance.

Myoelectrically driven functional electrical stimulation may increase motor recovery of upper limb in poststroke subjects: A randomized controlled pilot study

The objective of this randomized controlled pilot study was to assess the feasibility and effectiveness of myoelectrically controlled functional electrical stimulation (MeCFES) for rehabilitation of the upper limb in poststroke subjects. Eleven poststroke hemiparetic subjects with residual proximal control of the arm, but impaired volitional opening of the paretic hand, were enrolled and randomized into a treated and a control group. Subjects received 3 to 5 treatment sessions per week until totaling 25 sessions. In the experimental group, myoelectric activity from wrist and finger extensors was used to control stimulation of the same muscles. Patients treated with MeCFES (n = 5) had a significant (p = 0.04) and clinically important improvement in Action Research Arm Test score (median change 9 points), confirmed by an Individually Prioritized Problem Assessment self-evaluation score. This improvement was maintained at follow-up. The control group did not show a significant improvement (p = 0.13). The reduced sample size of participants, together with confounding factors such as spontaneous recovery, calls for larger studies to draw definite conclusions. However, the large and persistent treatment effect seen in our results indicate that MeCFES could play an important role as a clinical tool for stroke rehabilitation.