Right Hemisphere Contributions to Bilateral Force Control in Chronic Stroke: A Preliminary Report

Bilateral motor control deficits poststroke may be lateralized by hemisphere damage. This preliminary study investigated bilateral force control between left and right hemisphere-damaged groups at baseline and after coupled bilateral movement training with neuromuscular stimulation.

Stroke participants (8 left hemisphere and 6 right hemisphere cerebrovascular accidents) performed a bilateral isometric force control task at 3 submaximal force levels (5%, 25%, and 50% of maximum voluntary contraction [MVC]) before and after training. Force accuracy, force variability, and interlimb force coordination were analyzed in 3-way mixed design ANOVAs (2 × 2 × 3; Group × Test Session × Force Level) with repeated measures on test session and force level.

The findings indicated that force accuracy and variability at 50% of MVC in the right hemisphere-damaged group were more impaired than lower targeted force levels at baseline, and the impairment at the highest target level was improved after coupled bilateral movement training. However, these patterns were not observed in the left hemisphere-damaged group.

Current findings support a proposition that the right hemisphere presumably contributes to controlling bilateral force production.