Figure 5.

Frequency characteristics of PD tremor based on the EMG signals and inertial data. (A) Comparison of temporal and spectral features of EMG signal in the wrist extensor muscle between a PD patient (blue) and healthy person (black). The spectral-domain plot of PD patient's EMG exhibits an additional tremor frequency at 4.55 Hz (Castro et al., 2017). (B) Comparison of spectral features of wrist joint angular velocity between resting tremor (black) and voluntary movement (red) in a PD patient. Voluntary movement has a much lower frequency (0–2 Hz) compared to that of Parkinsonian tremor (Lambrecht et al., 2014).