Psychological and cognitive assessment A research staff will conduct Beck Depression Inventory (BDI), Fatigue Severity Scale, forward and backward digit span. Digit Span is neuropsychological test widely used to assess executive abilities following stroke and is sensitive to brain damage (Tamez et al., 2011). The Beck's Depression Inventory will be used to screen for major depression. As tDCS has been investigated for use in the treatment of depression and cognitive impairment, we added the digit span to control for confounding effect of cognitive improvement in this study.For subjects who screen positive for major depression or suicidal ideation, the investigator performing the screening will inform a physician investigator who will assess and make the necessary referral for psychiatric assessment and management.