Investigating the Efficacy Of Frequency and Pulse Width Modulation for Muscle Atrophy Rehabilitation

Muscle atrophy is a condition where the skeletal muscle loses mass resulting in a loss of muscle strength. This may eventually lead to the loss of functionality (fibrosis). For this reason, medical professionals utilize artificial stimulation of muscles by sending current pulses of short duration to the intended muscle group. This is done in the hopes of overcoming the effects of muscle atrophy. Stroke and spinal cord injury (SCI) are regarded as the main reasons of skeletal muscle atrophy. Stroke patients usually regain their motor ability of the lost function after the rehabilitation period; while SCI patients are expected to build up muscle mass in order to avoid atrophy. To study the effect of electrical stimulation on the amount of force produced by the muscle, a skeletal muscle model was utilized to investigate changes in fiber force by varying the pulse parameters (e.g. pulse width, pulse frequency). The simulation result indicated large amount of forces at high frequencies and wide pulse width. However, shortly after stimulation, muscle fatigue was observed, limiting the duration of contraction and ultimately prolonging rehabilitation period.