Home-based tDCS in Frontotemporal Dementia or Alzheimer's Disease

The primary objective of this research is to evaluate the effects of non-invasive brain stimulation and computerized cognitive training on executive functioning in individuals with Primary Progressive Aphasia (PPA), mild cognitive impairment (MCI), or dementia. In this study, investigators will use transcranial direct current stimulation (tDCS) to stimulate the left dorsolateral prefrontal cortex (DLPFC). Previous studies have demonstrated that tDCS over the DLPFC led to improvements in attention deficit caused by stroke, Parkinson's Disease, and major depression as well as language deficits caused by neurodegenerative conditions such as primary progressive aphasia or mild cognitive impairment. The investigators seek to expand on this literature by investigating how anodal tDCS paired with and without cognitive training will impact executive functioning in PPA with Frontotemporal Dementia or Alzheimer's Disease pathology and Mild Cognitive Impairment/Alzheimer's Disease (e.g. shifting, updating, monitoring, and manipulation).

In this within-subject cross-over protocol, all participants will receive both, cognitive training and brain stimulation tDCS. Participants will be randomly assigned to begin with either cognitive training and brain stimulation (dual therapy) or just brain stimulation (monotherapy) and will receive the complementary therapy program in the second round of treatment. During each period of therapy, participants will receive 50 treatment sessions over the course of approximately 10 weeks. The computerized cognitive training and brain stimulation will both be preprogrammed to be done at home by the participant.