Katherine J. Sullivan

Body-weight-supported treadmill rehabilitation after stroke.

BACKGROUND Locomotor training, including the use of body-weight support in treadmill stepping, is a physical therapy intervention used to improve recovery of the ability to walk after stroke. The effectiveness and appropriate timing of this intervention have not been established. METHODS We stratified 408 participants who had had a stroke 2 months earlier according to the extent of walking impairment--moderate (able to walk 0.4 to <0.8 m per second) or severe (able to walk <0.4 m per second)--and randomly assigned them to one of three training groups. One group received training on a treadmill with the use of body-weight support 2 months after the stroke had occurred (early locomotor training), the second group received this training 6 months after the stroke had occurred (late locomotor training), and the third group participated in an exercise program at home managed by a physical therapist 2 months after the stroke (home-exercise program). Each intervention included 36 sessions of 90 minutes each for 12 to 16 weeks. The primary outcome was the proportion of participants in each group who had an improvement in functional walking ability 1 year after the stroke. RESULTS At 1 year, 52.0% of all participants had increased functional walking ability. No significant differences in improvement were found between early locomotor training and home exercise (adjusted odds ratio for the primary outcome, 0.83; 95% confidence interval [CI], 0.50 to 1.39) or between late locomotor training and home exercise (adjusted odds ratio, 1.19; 95% CI, 0.72 to 1.99). All groups had similar improvements in walking speed, motor recovery, balance, functional status, and quality of life. Neither the delay in initiating the late locomotor training nor the severity of the initial impairment affected the outcome at 1 year. Ten related serious adverse events were reported (occurring in 2.2% of participants undergoing early locomotor training, 3.5% of those undergoing late locomotor training, and 1.6% of those engaging in home exercise). As compared with the home-exercise group, each of the groups receiving locomotor training had a higher frequency of dizziness or faintness during treatment (P=0.008). Among patients with severe walking impairment, multiple falls were more common in the group receiving early locomotor training than in the other two groups (P=0.02). CONCLUSIONS Locomotor training, including the use of body-weight support in stepping on a treadmill, was not shown to be superior to progressive exercise at home managed by a physical therapist. (Funded by the National Institute of Neurological Disorders and Stroke and the National Center for Medical Rehabilitation Research; LEAPS ClinicalTrials.gov number, NCT00243919.).

Meaningful Gait Speed Improvement During the First 60 Days Poststroke: Minimal Clinically Important Difference

Background When people with stroke recover gait speed, they report improved function and reduced disability. However, the minimal amount of change in gait speed that is clinically meaningful and associated with an important difference in function for people poststroke has not been determined. Objective The purpose of this study was to determine the minimal clinically important difference (MCID) for comfortable gait speed (CGS) associated with an improvement in the modified Rankin Scale (mRS) score for people between 20 to 60 days poststroke. Design This was a prospective, longitudinal, cohort study. Methods The participants in this study were 283 people with first-time stroke prospectively enrolled in the ongoing Locomotor Experience Applied Post Stroke (LEAPS) multi-site randomized clinical trial. Comfortable gait speed was measured and mRS scores were obtained at 20 and 60 days poststroke. Improvement of ≥1 on the mRS was used to detect meaningful change in disability level. Results Mean (SD) CGS was 0.18 (0.16) m/s at 20 days and 0.39 (0.22) m/s at 60 days poststroke. Among all participants, 47.3% experienced an improvement in disability level ≥1. The MCID was estimated as an improvement in CGS of 0.16 m/s anchored to the mRS. Limitations Because the mRS is not a gait-specific measure of disability, the estimated MCID for CGS was only 73.9% sensitive and 57.0% specific for detecting improvement in mRS scores. Conclusions We estimate that the MCID for gait speed among patients with subacute stroke and severe gait speed impairments is 0.16 m/s. Patients with subacute stroke who increase gait speed ≥0.16 m/s are more likely to experience a meaningful improvement in disability level than those who do not. Clinicians can use this reference value to develop goals and interpret progress in patients with subacute stroke.

Motor learning after unilateral brain damage.

Forty adults, post-stroke from anterior circulation unilateral cerebrovascular accident (approximately 2 years post onset) and 40 age-matched controls (M = 57 years) practiced a rapid, spatially and temporally constrained programmed action under one of two augmented feedback practice conditions. Participants in the stroke group used the upper limb ipsilateral to the lesion. After an extended practice period (198 trials), acquisition, retention, and reacquisition performance was assessed for accuracy and consistency and compared over trials, between groups and feedback conditions. Both stroke and control groups demonstrated significant improvement in accuracy and consistency over practice with relative persistence of these changes during retention. There were no differences between groups (stroke vs control) in performance patterns across trials for acquisition, retention, or reacquisition phases. In addition, there were no differential effects of the two augmented feedback conditions on performance and no interactions of feedback condition with group. However, independent of feedback condition, the stroke group performed with more error than did the control group during all experimental phases (i.e., acquisition, retention, reacquisition). These results suggest that unilateral stroke-related damage in the sensorimotor areas primarily effects the processes underlying the control and execution of motor skills but not the learning of those skills. Implications of these findings for physical rehabilitation are discussed.

Effects of Task-Specific Locomotor and Strength Training in Adults Who Were Ambulatory After Stroke: Results of the STEPS Randomized Clinical Trial

Background and Purpose: A phase II, single-blinded, randomized clinical trial was conducted to determine the effects of combined task-specific and lower-extremity (LE) strength training to improve walking ability after stroke. Subjects: The participants were 80 adults who were ambulatory 4 months to 5 years after a unilateral stroke. Method: The exercise interventions consisted of body-weight–supported treadmill training (BWSTT), limb-loaded resistive leg cycling (CYCLE), LE muscle-specific progressive-resistive exercise (LE-EX), and upper-extremity ergometry (UE-EX). After baseline assessments, participants were randomly assigned to a combined exercise program that included an exercise pair. The exercise pairs were: BWSTT/UE-EX, CYCLE/UE-EX, BWSTT/CYCLE, and BWSTT/LE-EX. Exercise sessions were 4 times per week for 6 weeks (total of 24 sessions), with exercise type completed on alternate days. Outcomes were self-selected walking speed, fast walking speed, and 6-minute walk distance measured before and after intervention and at a 6-month follow-up. Results: The BWSTT/UE-EX group had significantly greater walking speed increases compared with the CYCLE/UE-EX group; both groups improved in distance walked. All BWSTT groups increased walking speed and distance whether BWSTT was combined with LE strength training or not. Discussion and Conclusion: After chronic stroke, task-specific training during treadmill walking with body-weight support is more effective in improving walking speed and maintaining these gains at 6 months than resisted leg cycling alone. Consistent with the overtraining literature, LE strength training alternated daily with BWSTT walking did not provide an added benefit to walking outcomes.

Protocol for the Locomotor Experience Applied Post-stroke (LEAPS) trial: a randomized controlled trial

BackgroundLocomotor training using body weight support and a treadmill as a therapeutic modality for rehabilitation of walking post-stroke is being rapidly adopted into clinical practice. There is an urgent need for a well-designed trial to determine the effectiveness of this intervention.The objective of the Locomotor Experience Applied Post-Stroke (LEAPS) trial is to determine if there is a difference in the proportion of participants who recover walking ability at one year post-stroke when randomized to a specialized locomotor training program (LTP), conducted at 2- or 6-months post-stroke, or those randomized to a home based non-specific, low intensity exercise intervention (HEP) provided 2 months post-stroke. We will determine if the timing of LTP delivery affects gait speed at 1 year and whether initial impairment severity interacts with the timing of LTP. The effect of number of treatment sessions will be determined by changes in gait speed taken pre-treatment and post-12, -24, and -36 sessions.Methods/DesignWe will recruit 400 adults with moderate or severe walking limitations within 30 days of stroke onset. At two months post stroke, participants are stratified by locomotor impairment severity as determined by overground walking speed and randomly assigned to one of three groups: (a) LTP-Early; (b) LTP-Late or (c) Home Exercise Program -Early. The LTP program includes body weight support on a treadmill and overground training. The LTP and HEP interventions are delivered for 36 sessions over 12 weeks.Primary outcome measure include successful walking recovery defined as the achievement of a 0.4 m/s gait speed or greater by persons with initial severe gait impairment or the achievement of a 0.8 m/s gait speed or greater by persons with initial moderate gait impairment.LEAPS is powered to detect a 20% difference in the proportion of participants achieving successful locomotor recovery between the LTP groups and the HEP group, and a 0.1 m/s mean difference in gait speed change between the two LTP groups.DiscussionThe goal of this single-blinded, phase III randomized clinical trial is to provide evidence to guide post-stroke walking recovery programs.Trial registrationNCT00243919.

Neural substrates of motor memory consolidation depend on practice structure

Motor-skill practice drives subsequent offline activity in functionally related resting human brain networks. We investigated the manner in which offline neural networks are modulated by practice structures that affect motor-skill retention. Interference to dorsolateral-prefrontal cortex (DLPFC), but not to primary motor cortex (M1), after variable practice attenuated motor-skill retention, whereas interference to M1, but not to DLPFC, after constant practice attenuated motor-skill retention. We conclude that neural substrates of motor-memory consolidation are modulated by practice structure.

Fugl-Meyer Assessment of Sensorimotor Function After Stroke Standardized Training Procedure for Clinical Practice and Clinical Trials

Background and Purpose— Outcome measurement fidelity within and between sites of multi-site, randomized, clinical trials is an essential element to meaningful trial outcomes. As important are the methods developed for randomized, clinical trials that can have practical utility for clinical practice. A standardized measurement method and rater training program were developed for the total Fugl-Meyer motor and sensory assessments; inter-rater reliability was used to test program effectiveness. Methods— Fifteen individuals with hemiparetic stroke, 17 trained physical therapists across 5 regional clinical sites, and an expert rater participated in an inter-rater reliability study of the Fugl-Meyer motor (total, upper extremity, and lower extremity subscores) and sensory (total, light touch, and proprioception subscores) assessments. Results— Intra-rater reliability for the expert rater was high for the motor and sensory scores (range, 0.95–1.0). Inter-rater agreement (intraclass correlation coefficient, 2, 1) between expert and therapist raters was high for the motor scores (total, 0.98; upper extremity, 0.99; lower extremity, 0.91) and sensory scores (total, 0.93; light touch, 0.87; proprioception, 0.96). Conclusions— Standardized measurement methods and training of therapist assessors for a multi-site, rehabilitation, randomized, clinical trial resulted in high inter-rater reliability for the Fugl-Meyer motor and sensory assessments. Poststroke sensorimotor impairment severity can be reliably assessed for clinical practice or rehabilitation research with these methods.

Endurance and gait in children with cerebral palsy after intensive body weight-supported treadmill training.

Purpose: This study was designed to investigate changes in endurance, functional gait, and balance after intensive body weight-supported treadmill training in children with CP who were ambulatory. Methods: Six school-aged children with CP (four boys, two girls; age range: six to 14 years) participated in an intensive program of body weight-supported treadmill training 30 minutes twice daily for two weeks. Results: Statistically significant improvement in walking velocity and energy expenditure were observed. Variability of individual outcomes was observed with some children showing positive changes, and others no change or a decline in performance. Four children showed minimal detectable changes in a positive direction on both an endurance measure and a functional gait measure. Each endurance and functional gait measure included at least one child with a positive minimal detectable change. Conclusion: Intensive body weight-supported treadmill training may be an effective intervention for some children with CP who are ambulatory.

Activity-dependent factors affecting poststroke functional outcomes.

Abstract Over the last several years, there has been increasing recognition of the potential for central nervous system (CNS) recovery after brain damage. One commonality across the recovery and brain plasticity literature is that practice induces plastic, dynamic changes in the CNS. However, more than simply repetition, it is the manipulation of specific practice variables that appears to drive these dynamic processes in the CNS. The experimental manipulations used in the studies on neuroplasticity largely derive from the concept that in the undamaged or healthy brain neuronal connections and cortical maps are continuously remodeled by experience and by the performance of specific, intensive, and complex movements used to solve motor problems and attain goals. Intervention designed to promote recovery rather than compensation after stroke would then manipulate these same practice variables that have consistently promoted behavioral recovery and neuroplasticity in laboratory settings. Three current intervention strategies that incorporate these practice variables are reviewed. Preliminary results provide evidence that manipulation of task intensity and specificity and the sensorimotor experience of the task training are the necessary ingredients for maximizing the tremendous potential for recovery in patients with stroke.

Motor Learning in Children: Feedback Effects on Skill Acquisition

Background and Purpose: Reduced feedback during motor skill practice benefits motor learning. However, it is unknown whether these findings can be applied to motor learning in children, given that children have different information-processing capabilities than adults. The purpose of this study was to determine the effect of different relative frequencies of feedback on skill acquisition in children compared with young adults. Subjects: The participants were 20 young adults and 20 children. Methods: All participants practiced 200 trials of a discrete arm movement with specific spatiotemporal parameters. Participants from each group (adults and children) were randomly assigned to either a 100% feedback group or a reduced (62% faded) feedback group. Learning was inferred from the performance on the delayed (24-hour) retention and reacquisition tests. Results: All participants improved accuracy and consistency across practice trials. During practice, the adults performed with significantly less error than the children. Adults who practiced with reduced feedback performed with increased consistency during the retention test compared with those who practiced with 100% feedback. In contrast, children who received reduced feedback during practice performed with less accuracy and consistency during the retention test than those who received 100% feedback. However, when feedback was reintroduced during the reacquisition test, the children in the reduced feedback group were able to improve their performance comparable to those in the 100% feedback group. Discussion and Conclusions: During motor learning, children use feedback in a manner different from that of adults. To optimize motor learning, children may require longer periods of practice, with feedback reduced more gradually, compared with young adults.