Myoelectric Computer Interface to Reduce Muscle Co-Activation after Stroke

Stroke remains the leading cause of disability in the U.S., and more than half of stroke survivors have persistent impairment of arm function despite receiving conventional therapy. In these stroke survivors, a significant cause of impaired arm movement is abnormal co-activation between muscles that normally do not activate together. The long-term goal of this research is to develop a new therapy for stroke using an inexpensive, easily portable device to improve motor function by decoupling abnormally co-activating muscles. This therapy, a myoelectric computer interface (MCI), maps electrical muscle activity onto movements of a cursor in a computer game. This provides direct, detailed feedback about the co-activation of a pair of muscles to the user. Our preliminary results suggest that training with the MCI allows stroke survivors to greatly reduce abnormal co-activation in the targeted arm muscle pair, and may also improve function. The objective of this proposal is to determine how best to enhance translation of the decoupled muscle activations into functional improvement. In this proposal, we will investigate the extent to which 1) training multiple muscle pairs, 2) movement-based training, and 3) increased training time can improve function over the isometric MCI training of a single muscle pair used in our preliminary studies. The specific aims of the proposal are to 1) determine the extent to which isometric MCI training of multiple muscle pairs improves function, and 2) determine the extent to which movement-based MCI training improves function. The proposed research is innovative because it applies fundamental insight about abnormal co-activation after stroke to develop a novel treatment modality that will be inexpensive and portable. This therapy will broadly impact the field since it can enable use by a wide range of stroke survivors. This includes those with severe motor impairments, who are those most in need of new therapies. Achieving our objective will be significant because we expect it to lead directly to development of an effective treatment for impaired movement after stroke, setting the stage for initial clinical trials of the therapy. We estimate that this therapy could benefit at least 1 million stroke survivors in the U.S. alone.