Variations in neuromuscular electrical stimulation's ability to increase reach and hand opening during voluntary effort after stroke

Functional Electrical Stimulation (FES) has shown potential as a mechanism to augment functional arm and hand movement after stroke. However, neuroprostheses that combine voluntary effort and FES must account for co-activation patterns (synergies) that limit movement. The goal of this study is to explore the conditions under which voluntary effort and FES can be combined to achieve useful reach and hand opening in different subjects. Subjects performed a reach and hand opening task where different levels of voluntary effort and FES were applied to produce reach and hand opening while measuring the resulting hand opening and distance from a target. Initial results indicate that there are significant variations between participants and how much effort can be exerted while still eliciting effective reach and hand opening.