Abstract P206: Wearable Myoelectric Interface Training for Improving Arm Movement in Chronic Stroke

Abstract

Impaired arm movement after stroke is due not only to weakness and spasticity, but also to abnormal co-activation (a.k.a. abnormal synergies). Yet, few stroke therapies are aimed to reduce this co-activation. We designed a myoelectric computer interface (MyoCI) that provides feedback to stroke survivors to reduce this abnormal co-activation and associated arm impairment. Here, we describe a novel, wearable version of the MyoCI to control custom-designed computer games as a home-based therapy for chronic stroke survivors. This therapy, called the myoelectric interface for neurorehabilitation training (MINT), enables high-intensity, high-dose training using an inexpensive device at home. The MINT device records surface EMGs from 2-3 arm muscles and wirelessly controls games on a laptop or tablet. By mapping the muscle activities to orthogonal directions of cursor movements, the games operantly condition the participants to learn to reduce abnormal co-activation between the muscles. We are currently investigating this device in severely impaired stroke survivors (Fugl-Meyer score <30). Participants were asked to train 90 min per day, 6 days a week, for a total of 6 weeks, with different variants of the paradigm (2 or 3 muscles at a time) vs. a sham control group that trained on one muscle. We surveyed participants about their engagement with the game using a modified Intrinsic Motivation Inventory (IMI). Eighteen participants have completed the 6-week training to date. They averaged 75±19 min of daily training out of the 90 that were asked. Overall, 60% of participants surveyed enjoyed, and 90% were positively motivated by, the training. A few participants had significant difficulty with the laptops due to inexperience with computers. Participants’ performance on the game, measured by weighted time-to-target, improved steadily overall in the experimental group, while the sham control group stayed at high performance throughout. The MINT provides a motivating, enjoyable way to provide high-intensity therapy in the home to stroke survivors. This therapy is a new mechanism of action for stroke rehabilitation and we are evaluating its efficacy in an ongoing randomized controlled trial.