Clinical practice of functional electrical stimulation: from "Yesterday" to "Today"

Functional electrical stimulation (FES) is an accepted treatment method for paresis or paralysis after spinal cord and head injury as well as stroke and other neurological upper motor neuron disorders. At the beginning, FES worked like an electrophysiological brace for the correction of drop foot of patients after a stroke. When analyzing early accomplishments, it becomes evident that FES was influenced rather by technological and biomedical engineering development than by contemporary knowledge on neurocontrol of movement in individuals with upper motor neuron paralysis. Nevertheless, with better understanding of pathophysiology of spasticity and neurocontrol of impaired movement, FES advanced from an electrophysiological brace to a treatment modality for the improvement of muscle control, neuroaugmentation of residual movements, and supportive procedure for "spontaneous recovery" of motor control. In the present article we shall illustrate barriers which delayed FES to be applied in clinical practice of neuron rehabilitation from "Yesterday" to "Today." We shall discuss the importance to apply FES early after the onset of neurological conditions to prevent disuse of noninjured portions of the CNS. Moreover, FES can play a significant role in the supporting processes of neuroplasticity in the subacute phase of upper motor neuron dysfunction. Therefore, the electrophysiological brace of "Yesterday" provides "Today" a correction of missing neuromuscular function. At the same time, it is an active external device for the correction of motor deficits interacting with the somatosensory-motor integration. Thus, "Yesterday" and "Today" of the same technological approach can be very different, thanks to a different understanding and assessment of "external" and "internal" components of human motor control.