Impact of Altered Sensory Feedback on Adaptation of Hand Muscle Coordination of Stroke Survivors

The following experiment will be conducted with 15 chronic stroke survivors and 15 control subjects. Subjects will perform hand movements in the virtual reality environment using a head-mounted display. Quest's onboard cameras allow real-time tracking of hand motion, estimating joint angles of the finger and the thumb. For each feedback manipulation condition (i.e., movement amplification or reduction), the estimated joint angles will be multiplied by a factor greater than 1 (amplification) or a factor smaller than 1 (reduction). Then the newly-estimated hand posture will be displayed in the VR environment. Subjects will be randomly assigned into two groups (A and B), who will receive the assistance in a different order. Subjects will perform finger extension under three conditions: no sensory modulation, movement visual feedback (VF) amplification, and movement VF reduction (error augmentation), while their movement muscle activation patterns are recorded.