Figure 2.

Stimulation strategies for tremor suppression. (A) Out-of-phase. The top panel shows the angular velocity of the joint when rest tremor occurred. The antagonist muscle was electrically stimulated when the agonist muscle was active (Maneski et al., 2011). (B) Co-contraction. The human joint impendence was modeled with the use of the stiffness and viscosity variables D_NP and K_NP determined by the stimulation parameters. Equal increments of D_NP and K_NP are shown as broken lines, larger increments of D_NP than K_NP are shown as red lines while larger increments of K_NP than D_NP are shown as yellow lines. The high frequency response of the joint can be attenuated so that the tremor was suppressed (Alvaro Gallego et al., 2013a).