Effect of gravity on robot-assisted motor training after chronic stroke: a randomized trial

Abstract

Objectives: To determine the efficacy of 2 distinct 6-week robot-assisted reaching programs compared with an intensive conventional arm exercise program (ICAE) for chronic, stroke-related upper-extremity (UE) impairment. To examine whether the addition of robot-assisted training out of the horizontal plane leads to improved outcomes.

Design: Randomized controlled trial, single-blinded, with 12-week follow-up.

Setting: Research setting in a large medical center.

Participants: Adults (N=62) with chronic, stroke-related arm weakness stratified by impairment severity using baseline UE motor assessments.

Interventions: Sixty minutes, 3 times a week for 6 weeks of robot-assisted planar reaching (gravity compensated), combined planar with vertical robot-assisted reaching, or intensive conventional arm exercise program.

Main outcome measure: UE Fugl-Meyer Assessment (FMA) mean change from baseline to final training.

Results: All groups showed modest gains in the FMA from baseline to final with no significant between group differences. Most change occurred in the planar robot group (mean change ± SD, 2.94 ± 0.77; 95% confidence interval [CI], 1.40-4.47). Participants with greater motor impairment (n=41) demonstrated a larger difference in response (mean change ± SD, 2.29 ± 0.72; 95% CI, 0.85-3.72) for planar robot-assisted exercise compared with the intensive conventional arm exercise program (mean change ± SD, 0.43 ± 0.72; 95% CI, -1.00 to 1.86).

Conclusions: Chronic UE deficits because of stroke are responsive to intensive motor task training. However, training outside the horizontal plane in a gravity present environment using a combination of vertical with planar robots was not superior to training with the planar robot alone.

Trial registration: ClinicalTrials.gov NCT00333983.

Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Figures

Fig 1

Enrollment. Abbreviation: F/u, follow-up.

Fig 2

This figure of FMA change scores shows the sample means and SDs at each baseline evaluation and each posttraining time point by intervention groups. P was based on paired t tests. Scores at the baseline demonstrate stability and were without significant between group differences. The within group change from baseline to final showed a significant benefit for both robotic groups: planar 2.79±3.82 (P=.005) and planar with vertical 1.69±2.19 (P=.005). This benefit was also seen from baseline to follow-up: planar 3.27±3.27 (P=.002) and planar with vertical 2.51±3.33 (P=.007).