Stimulation frequency is set similar to that of the tremor and the amplitude is set up to 2 mA peak amplitude (reduced if not uncomfortable). One 5*5 cm2 square patch electrodes are placed over the Motor cortex and the Prefrontal cortex respectively and a common return electrode of 10*10 cm2 over the ankle. Each subject follows three sessions of 12 min length each. During each session the tremor is measured while interleaving between Motor cortex stimulation, Prefrontal cortex stimulation and No stimulation. By the end of each session we get 4 min of Motor Cortex stimulation, 4 min of Prefrontal Cortex stimulation and 4 min of No stimulation.

Stimulation frequency is set similar to that of the tremor and the amplitude is set up to 5 mA peak amplitude (with the help of local anesthetic cream and amplitude is reduced if not uncomfortable). A set of 4*1 gel-filled cup-electrodes is placed over each of motor cortex and the occipital cortex respectively. Each subject follows three sessions of 12 min length each. During each session the tremor is measured while interleaving between Motor cortex stimulation, Occipital cortex stimulation and No stimulation. By the end of each session we get 3 min of Motor Cortex stimulation, 3 min of occipital Cortex stimulation and 6 min of No stimulation.

tACS applied between the stimulation electrodes at tremor frequency

phase locking value was calculated between the tremor signal measured using accelerometer and the stimulation signal

The subject is asked to rate the phosphene intensity during the stimulation using a visual analog scale from 0 to 10. Zero means no phosphene is perceived and the number starts to increase as the phosphene perception intensity increases to reach 10 if the subject observe only a white view