Bimanual force variability in chronic stroke: with and without visual information.

Visual information is critical to producing and controlling force output to achieve targeted levels. This study investigated bimanual force control in chronic stroke individuals while manipulating visual information. Nine chronic stroke individuals and nine age-matched controls executed bimanual wrist and finger extension at 5% of maximum voluntary contraction. Bimanual force control outcome measures included: (a) coefficient of variation, (b) approximate entropy, and (c) bimanual coordination. Without visual information, chronic stroke individuals displayed less force variability and more regular force production in comparison to age-matched controls. These findings suggest that chronic stroke individuals depended on visual information during bimanual force execution.