Neuromuscular stimulation after stroke: from technology to clinical deployment.

Since the early 1960s, electrical or neuromuscular electrical stimulation (NMES) has been used to support the rehabilitation of stroke patients. One of the earliest applications of NMES included the use of external muscle stimulation to correct drop-foot after stroke. During the last few decades various clinical applications have been used for the upper and lower limb. Despite a growing body of literature on the use of NMES, its application in stroke is still limited to a few clinical groups that provide dedicated clinical services. Some explanations for the limited use are the sometimes conflicting clinical evidence, the size of the effects or the complicated use of the technology itself. This review points out three directions for future research. First, we need to expand our knowledge on brain plasticity and the use of different electrical stimulation strategies to modulate the neural system. Second, we foresee an increase in therapies combining different training principles, for example, the combination of NMES and robotics or neuromodulating drugs. Finally, with the ever-increasing pressure on healthcare budgets, it is expected that clinical and economic evidence will become more relevant in transferring these interventions to a wider community.