Clinical and therapeutic applications of neuromuscular stimulation: a review of current use and speculation into future developments.

In this paper we present an overview of current research into clinical and therapeutic applications of electrical neuromuscular stimulation (NMS). As this is now such a huge subject we have focused our attention on the therapeutic rather than orthotic uses of stimulation and limited the field almost exclusively to upper limb applications in hemiplegia. The evidence that NMS influences motor re-learning and how this may be measured is discussed. We have identified the following as the three most important unresolved issues: 1) an understanding of how NMS modifies the interactions within the nervous system, 2) clinical effectiveness of NMS, and 3) inexpensive, simple to insert and reliable controllable implanted systems. We discuss recent research aimed at resolving these issues and based on this we make some suggestions for future research. To resolve these issues we propose: 1) neurophysiologic research into the mechanism through which NMS interacts with the nervous system; 2) large multicenter randomized controlled trials using rigorous methodology that compare different applications of NMs; 3) continued technical development that is closely linked to clinical applications.