Definition of Tremor

Tremor is generally defined as a rhythmic shaking of a body part (Deuschl et al. 1998; Findley and Capildeo 1984). Tremor is a nonlinear and nonstationary phenomenon, often made of a roughly sinusoidal oscillatory movement, usually nonvoluntary. Tremor is readily apparent in most cases. The oscillation is composed of a back-and-forth movement (McAuley and Marsden 2000), where “back-and-forth” means that there is a relatively symmetric velocity profile in both directions about a midpoint of the movement, with the velocity profile of oscillations appearing sinusoidal (Sanger et al. 2010).