Estimulação elétrica funcional aplicada em cadeia aberta - Um estudo de caso com monitoração mecanomiográfica

Abstract

Mechanomyography (MMG) can indicate the strength changes and fatigue of contracting muscles. Functional electrical stimulation (FES) causes artificial movements in spinal cord injury (SCI) persons. Since triaxial MMG has not been widely investigated in FES elicited contractions, this paper aims to monitor MMG responses of the rectus femoris muscle of a SCI volunteer during FES application. An accelerometer-based MMG sensor and FES electrodes were placed on the thigh. An electrogoniometer was positioned laterally to the knee. Controlled FES amplitude maintained the knee at full extension. As the muscle fatigued, knee angle decreased. Temporal (root mean square - RMS) and spectral (mean frequency - FM) features are assessed. During open-chain stimulation, RMS showed lower values during isometric contractions than dynamic ones. FM decreased during near isometric contractions, probably due to muscle fatigue or motoneuron adaptation. When wider angle variations were observed, FM tended to reduce the decreasing rate and increase again. © 2013 Springer.