Treating Primary Progressive Aphasia (PPA) Using High-definition tDCS

This is a double-blind, sham-controlled, crossover study in which subjects with the non-fluent/agrammatic and logopenic variants of primary progressive aphasia (naPPA and lvPPA, respectively) will undergo language testing and structural and functional brain imaging before and after receiving 10 semi-consecutive daily sessions of real or sham high-definition transcranial direct current stimulation (HD-tDCS) paired with modified constraint-induced language therapy (mCILT). Language testing and brain imaging will be repeated immediately after completion of and 3 months following completion of treatment. The 3-month follow-up will be the primary endpoint. The investigators will examine changes in language performance induced by HD-tDCS + mCILT compared to sham HD-tDCS + mCILT. The investigators will also use network science to analyze brain imaging (fMRI) data to identify network properties associated with baseline PPA severity and tDCS-induced changes in performance. This study will combine knowledge gained from our behavioral, imaging, and network data in order to determine the relative degrees to which these properties predict whether persons with PPA will respond to intervention.

Inclusion Criteria: 1. Presence of aphasia attributable to nonfluent agrammatic PPA (naPPA) or logopenic variant PPA (lvPPA) 2. High school education (or more) 3. Must be able to understand the nature of the study, and give informed consent 4. Native English speaker Exclusion Criteria: * Presence of additional neurological illness such as stroke or traumatic brain injury * Diagnosis of epilepsy or reoccurening seizures * Pacemaker or ICDs * Craniotomy or skull breech * Small vessel disease