Functional Electrical Stimulation (FES) of Long-Term Dener- vated Muscles in Humans: Clinical Observations and Laboratory Findings

High intensity stimulation is a feasible clinical method for preventing effects of early denervation, however in long-term denervation exponential currents could not elicit tetanic contractions of denervated-degenerated muscles (DDM) powerful enough to sustain motility functions. In our earlier clinical work, we demonstrated that electrical stimulation with exponential current could slow down atrophy of the DDM in human. Here we show that a modulated long-term training program restore function up to supported standing. To elicit single muscle twitches of the DDM we use biphasic electric impulses with durations of 120-150 ms at the beginning of muscle training. Contractions of whole thigh muscles are elicited by using anatomically shaped large-size electrodes. In the progress of training, sustained contractions are achieved with the following parameters: pulse duration of 30-50 ms, frequency of 16-25 Hz, amplitudes of up to 250 mA. This stimulation protocol effectively improves the structural and metabolic characteristics of the denervateddegenerated human muscles. Following these procedures trophism and power of DDM improve even if denervation lasts up to 20 years. Effectiveness of electrical stimulation protocols of DDM is demonstrated by measuring contraction force. Measurements by CT-scans reveal high variation in the increase of thigh muscle cross-sectional area during the first years of functional electrical stimulation (FES). At present we are conducting a co-operative European research project with the goal to strengthen the scientific bases of this innovative rehabilitation procedure for people with permanent chronic denervation of skeletal muscles. Our working hypothesis is based on sound knowledge of regeneration capabilities of satellite cells in long-term denervated skeletal muscles and on the expected additional contribution of myoblast replication activated by the above-described FES training of degenerated-denervated muscles. All patients with complete conus cauda lesion are welcome to join the European partners in the effort to develop this new rehabilitation procedure. We are confident that the goal will be scored and the quality of life of this specific group of patients will improve during the four-year period of the EU research project “RISE”.