Dose-response relationship during motor learning with bimanual-to-unimanual training

Abstract

Few options exist for training arm movements in patients with little active movement in their affected arm after a stroke. The purpose of this study was to test the efficacy of bimanual-to-unimanual training in reducing upper limb motor impairment and active movement in the affected arm, and to examine the effect of training dose on motor learning. Twenty subjects with chronic post-stroke hemiparesis underwent 6 weeks of usual care. They then received 12 one-hour sessions of bimanual-to-unimanual training using the Bimanual Arm Trainer (BAT, Mirrored Motion Works, Inc.). The training consisted of bimanual training of both arms followed by unimanual training of the affected arm alone. Some patients received the 12 sessions over 4 weeks, whereas others received it within 6 weeks. Extent of motor impairment on the Fugl-Meyer scale and active movement at upper limb joints was examined at baseline and pre- and post-training. The degree of improvement in the affected arm was computed both within and between training sessions as well as pre- and post-training. Repeated measures ANOVA was performed on the variables of interest. Bimanual-to-unimanual training led to a significant improvement in upper limb Fugl-Meyer scores and active movement compared with usual care ( P < 0.05). The difference was significantly greater in patients who underwent 12 sessions of training within 4 weeks compared with those who underwent training over 6 weeks. Changes in within and between session learning curves enable characterization of patterns of motor learning across individuals that can facilitate the development of algorithms for precision rehabilitation for post-stroke motor learning and recovery. Bimanual-to-unimanual arm training can reduce motor impairment in patients with chronic post-stroke hemiparesis. Higher frequency of training leads to greater improvements despite the same total dose. The study provides a means for understanding dosing of treatment for motor learning post-stroke.