Alteration of muscle recruitment in Parkinson's disease assessed by EMG-based occurrence frequency

Gait analysis has been widely adopted to describe Parkinson's disease (PD) dysfunctions. Nevertheless, only few efforts were made to investigate the role of muscle activity by surface-electromyography (sEMG). The current study aims to provide a quantification of muscle recruitment during walking in people with PD through the assessment of the sEMG-based occurrence frequency (OF). To this aim, sEMG signals from Tibialis Anterior (TA), Gastrocnemius Lateralis (GL), Rectus Femoris (RF), and Biceps Femoris (BF) of 20 people with PD and 10 age-matched healthy controls (HC) were acquired during walking. sEMG signals were processed to assess muscle-activation intervals and then the associate OF, i.e., the percentage of strides of each specific muscle activation occurrence. This OF-based analysis allowed to detect in people with PD an over-recruitment of proximal-leg muscles in the first half of stance. An impairment in muscle recruitment of proximal leg in the preparation of the transition between stance and of distal leg throughout the swing phase is also observed. The current approach provides a compact and synthetic representation of muscle recruitment alteration in PD which could turn out to be particularly suitable for application in clinics and rehabilitation.