Sagar K. Naik

Bilateral movement training and stroke motor recovery progress: a structured review and meta-analysis.

The purpose was to conduct a structured review and meta-analysis to determine the cumulative effect of bilateral arm training on motor capabilities post stroke. Forty-eight stroke studies were selected from three databases with 25 comparisons qualifying for inclusion in our meta-analysis. We identified and coded four types of bilateral arm interventions with 366 stroke patients. A random effects model using the standardized mean difference technique determined a large and significant effect size (0.734; SE=0.125), high fail-safe N (532), and medium variability in the studies (I(2)=63%). Moderator variable analysis on the type of bilateral training revealed two large and significant effects: (a) BATRAC (0.842; SE=0.155) and (b) coupled bilateral and EMG-triggered neuromuscular stimulation (1.142; SE=0.176). These novel findings provide strong evidence supporting bilateral arm training with the caveat that two coupled protocols, rhythmic alternating movements and active stimulation, are most effective.

Force control and degree of motor impairments in chronic stroke

OBJECTIVE This study determined the variability and regularity of force production in impaired upper extremities of chronic stroke survivors. Two hypotheses included: (1) stroke will increase the variability and regularity of force output in comparison to age-matched controls and (2) degree of motor impairments will be positively correlated with the variability and regularity of force output. METHODS Nine chronic stroke and nine age-matched controls performed unimanual isometric wrist and finger extension movements for 20s to three different target force levels. Force output was indexed by magnitude, accuracy, variability, and regularity. Stroke motor impairment levels were determined by Fugl-Meyer upper extremity assessment. RESULTS The stroke group demonstrated increased variability and regularity of the force output. Further, motor impairments scaled with increase in variability and regularity of force output. CONCLUSIONS The variability and regularity of force differentiated isometric contractions performed by chronic stroke survivors from age-matched controls. Moreover, in clinical settings an objective assessment of force control on variability and regularity appears to be most meaningful at 25% of MVC. SIGNIFICANCE Increased variability contributes to reduced steadiness in force output. Increased regularity characterizes the adaptability losses in motor capabilities following stroke. This knowledge may facilitate planning and evaluating rehabilitation protocols.

Upper extremity improvements in chronic stroke: Coupled bilateral load training

BACKGROUND The current treatment intervention study determined the effect of coupled bilateral training (i.e., bilateral movements and EMG-triggered neuromuscular stimulation) and resistive load (mass) on upper extremity motor recovery in chronic stroke. METHODS Thirty chronic stroke subjects were randomly assigned to one of three behavioral treatment groups and completed 6 hours of rehabilitation in 4 days: (1) coupled bilateral training with a load on the unimpaired hand, (2) coupled bilateral training with no load on the unimpaired hand, and (3) control (no stimulation assistance or load). RESULTS Separate mixed design ANOVAs revealed improved motor capabilities by the coupled bilateral groups. From the pretest to the posttest, both the coupled bilateral no load and load groups moved a higher number of blocks and demonstrated more regularity in the sustained contraction task. Faster motor reaction times across test sessions for the coupled bilateral load group provided additional evidence for improved motor capabilities. CONCLUSIONS Together these behavioral findings lend support to the contribution of coupled bilateral training with a load on the unimpaired arm to improved motor capabilities on the impaired arm. This evidence supports a neural explanation in that simultaneously moving both limbs during stroke rehabilitation training appears to activate balanced interhemispheric interactions while an extra load on the unimpaired limb provides stability to the system.

Force control deficits in chronic stroke: grip formation and release phases

The aim of the study was to develop a novel approach for quantifying stair-stepping in a trajectory tracking task with the goal of understanding how age and stroke-related differences in motor control contribute to force control deficits. Nine stroke participants, nine age-matched controls, and nine young healthy adults performed an isometric gripping task while squeezing, holding, and releasing a cylindrical device. The visual tracking task involved three different rates of force production (5, 10, and 20% maximal force/s). Four outcome measures determined force control deficits: (a) root mean square error, (b) standard deviation, (c) step number, and (d) mean pause duration. Our findings indicate that step number, and especially mean pause duration, differentiated force control deficits in the three groups more effectively than the traditional root mean square error. Moreover, stroke participants showed the largest force control deficits during the grip release phase compared to age-matched and young healthy controls. Importantly, step number and mean pause duration quantified stair-stepping while measuring different constructs than root mean square error. Distinct step and duration interruptions in force modulation by persons post-stroke during the grip release phase provide new information with implications for motor recovery during rehabilitation.

Children with cerebral palsy: a systematic review and meta-analysis on gait and electrical stimulation

Objective: To conduct a systematic review and meta-analysis using the International Classification of Functioning to determine the summary effect of electrical stimulation on impairment and activity limitations relevant to gait problems of children with cerebral palsy. Methods: We identified 40 cerebral palsy and electrical stimulation studies, and 17 gait studies qualified for inclusion. Applying enablement classification methods to walking abnormalities created two subgroups: impairment (N = 14) and activity limitations (N = 15). Overall, 238 participants experienced electrical stimulation treatments and 224 served as a no stimulation control group. Calculations followed conventional data extraction and meta-analysis techniques: (a) individual standardized mean differences, (b) summary effect size, (c) I 2heterogeneity test, (d) fail-safe N analysis and (e) moderator variable analyses. Results: Common outcome measures associated with impairment (n = 3) and activity limitations (n = 6) were submitted to separate random effects models meta-analyses, and revealed significant cumulative effect sizes: (a) impairment = 0.616 (SE = 0.10) and (b) activity limitations = 0.635 (SE = 0.14). I 2indicated low and medium amounts of dispersion, whereas fail-safe analyses revealed high N-values for both disablement categories. Moderator variable analyses further confirmed the positive treatment effects from both functional and neuromuscular stimulation. Conclusions: The present systematic review and meta-analyses determined medium effect sizes for electrical stimulation on walking impairment and activity limitations of children with cerebral palsy.

Long-term rehabilitation for chronic stroke arm movements: a randomized controlled trial:

Objective: We investigated the effect of long-term practice on motor improvements in chronic stroke patients. Design: Randomized parallel group controlled study. Setting: Motor Behavior Laboratory, University of Florida. Subjects: Eighteen individuals who experienced a stroke more than nine months prior to enrolling. Interventions: The treatment interventions were bilateral arm movements coupled with active neuromuscular stimulation on the impaired arm for both practice duration groups. The short-term group received one treatment protocol, whereas, over 16 months, the long-term practice group completed 10 treatment protocols. All protocol sessions were 6 hours long (90 minutes 1 day/week/4 weeks) and were separated by 22 days. Main outcome measures: Repeated data collection on three primary outcome measures (i.e. Box and Block test, fractionated reaction times, and sustained force production) evaluated motor capabilities across rehabilitation times. Results: Mixed design ANOVAs (Group × Retention Test: 2 × 4; Group × Retention Test × Arm Condition: 2 × 4 × 2) revealed improved motor capabilities for the long-term practice duration group on each primary measure. At the 16-month delayed retention test, when compared to the short-term group, the long-term group demonstrated: (a) more blocks moved (43 v 32), (b) faster premotor reaction times (158 v 208 ms), and (c) higher force production (75 v 45 N). Conclusion: Sixty hours of rehabilitation over 16 months provided by various bilateral arm movements and coupled active stimulation improved motor capabilities in chronic stroke.