3. Comparison of Personalised Dosage Between HD-tDCS and Conventional tDCS

COEX 

The variability in the effects of transcranial Direct Current Stimulation (tDCS) is seen due to the inter-individual differences in brain anatomy causing variability in the current intensity reaching the Region of Interest (ROI). Evans et al. showed that variability in current intensity within the ROI can be reduced by varying the dose (amount of current applied to the scalp) from outside the brain [3]. It is known that current intensity at target ROI also depends on montage configurations like conventional (1x1) and high-definition (HD) tDCS (4x1) as HD-tDCS is thought to be more focal [1]. The present study investigates the variability in the personalised dose needed to obtain a constant intensity at the target ROI across individuals for both HD-tDCS and Conventional tDCS. This will be investigated in dementia patients, known to have severely atrophied brains, compared against a control major depressive disorder group expected to have relatively lesser brain atrophy.