Effect of Cerebellar Transcranial Direct Current Stimulation on Balance and Sensory System of the Elderly

Postural and balance control is essential for almost all daily activities. The purpose of the present study was to investigate the effect of cerebellar transcranial direct current stimulation (tDCS) on balance and somatosensory, vision, and vestibular systems function of the elderly.
An experimental, pre- and posttest design study was carried out on 20 elderlies (60-75 year olds) of both sexes who referred to Tehran Rehabilitation Center of Red Crescent Society in the summer of 1396. They were selected based on inclusion criteria and available and targeted sampling method, and were randomly assigned to two “Intervention” (real) and “control” (Placebo) groups (n=10). After a preliminary assessment of equilibrium parameters using Computerized Dynamic Posturorghraphy, “Intervention” group received direct current stimulation over the cerebellum at 2mA and “Placebo” group received sham stimulation, for 20 minutes in five sessions. At each session, immediately after stimulation, participants performed half-hour equilibrium exercises on the Huber apparatus. After completing five sessions, the variables were re-measured. Shapiro–Wilk, Levene's Test for Equality of Error Variances, the homogeneity of slope regression, and covariance analysis (MANCOVA and ANCOVA) were used to analyze the data.
The results of the current study showed that direct electric stimulation of the cerebellum has significant effects on the postural control equilibrium variables in the first sensory condition absent vision and fixed support (P = 0.036), and the fifth sensory condition with absent vision and sway support (P = 0.034). Also, the electrical stimulation of the cerebellum increased the ability of the elderly group to use vestibular system input to maintain balance (P = 0.014), but did not have a significant effect on the ability to use the somatosensory, vision, and vestibular systems inputs (P>0/05).
The results of the present study showed that cerebellar TDCS with balance has beneficial effects on postural control and balance of elderly people probably by improving the processing of vestibular inputs and can improve motor adaptation and facilitate motor skills learning.