Guided Training with Visual Feedback can Improve Direct Electromyography Control of Prosthetic Ankles and Sit-to-Stand Performance: A Case Study

Direct electromyography (EMG)-controlled prostheses can allow people with amputation (PWA) to directly control their prosthetic ankle. This versatile control can assist with a variety of activities of daily life (ADL), including rising from and sitting down into a chair (i.e., sit-to-stand (S2S)). However, direct EMG control may be limited by a PWA's ability to activate their residual muscles. Physical therapy training with visual feedback may allow PWA to better utilize direct EMGcontrolled prostheses. One PWA (transtibial) completed four training sessions with physical therapy guidance and visual feedback of their dorsiflexor and plantarflexor EMG during S2S tasks using a direct EMG-controlled prosthesis. They returned two weeks after the fourth training session and repeated S2S tasks without physical therapist guidance or visual feedback. We found that as the training progressed, residual EMG activation became more similar to the intact limb and was retained when feedback was removed. We also found that S2S movement was smoother (less jerk) during the retention session compared to the first training session. Our results demonstrate the potential of physical therapy with visual feedback to improve PWA's utilization of direct EMG-controlled ankle prostheses and performance in tasks related to ADL.