Multi-session Anodal Cerebellar Transcranial Direct Current Stimulation (tDCS) vs Anodal Cerebral tDCS

Anodal transcranial direct current stimulation was given using a portable battery-driven brain stimulator (The Brain Stimulator v3.0 Deluxe tDCS Kit, using Professional 3x3 inches Amrex Sponge Electrodes). Skin was prepared before application of electrodes by cleaning the skin surface using alcohol swabs. In cerebellar stimulation group (CbSG) a stimulation intensity of 2mA for duration of 20 minutes. In order to avoid sudden initiation and termination of the stimulation the first and last 10 seconds of anodal tDCS application, current will gradually fade in/fade out to avoid any sudden starting or stopping of the stimulation. For the CbSG active anodal electrode was placed over the cerebellum with about 1-2 cm below inion occipital protuberance, whereas the returning cathodal electrode was placed on right buccinator muscle.

In the M1 Stimulation Group (MSG) a similar intensity of current with 2mA was applied for a period of 20 minutes. Skin was cleaned with alcohol swab ahead of placing the electrodes. The anode was positioned over the lesioned M1 motor cortex area (C3, International 10-20 system) while the cathode was placed over the contra-lateral supraorbital area. Due to the large size of electrodes, the active electrode covered the area of M1 for the hand, arm, trunk, and the LL. Ten sessions of anodal tDCS were applied over a duration of 2 weeks. The stimulation was applied during active participation of patients in Biodex balance training.

In Sham Stimulation group (SSG) Ten sessions of anodal tDCS were applied over a duration of 2 weeks having same intensity i.e., 2 mA stimulation was used for a period of 30 seconds and then gradually ramped-down and turned off for the rest of the treatment time of 20 minutes. The same procedure for skin preparation was used as in the other two groups. Electrode placement for SSG was same as in MSG for half of the patients i.e. 8 participants; anode will be placed over the left (dominant) lesioned M1 whereas the cathode will be positioned over the right (contralateral) supraorbital area. For the other 8 participants the stimulation montages were similar to cerebellar stimulation group. The active anodal electrode was placed over the cerebellum with about 1-2 cm below inion occipital protuberance, whereas the returning cathodal electrode was placed on right Buccinator Muscle.