Proceedings #10: Transcranial Direct Current Stimulation Mediates Improvements in Verbal Fluency for Patients with Primary Progressive Aphasia

Primary Progressive Aphasia (PPA) refers to the syndrome of progressive language loss resulting from neurodegenerative dementias. This study explores the effects of left hemisphere transcranial direct current stimulation (tDCS) on language production deficits observed in the non-fluent/agrammatic and logopenic variants of PPAs. Six subjects participated in a randomized, sham-controlled full-crossover study in which they received 10 sessions of tDCS. Participants performed a battery of clinical language tests prior to receiving either real or sham tDCS, immediately after 10 days of stimulation, 6 weeks, and 12 weeks after stimulation. In the Category Fluency task (a measure of verbal fluency) subjects who received real tDCS showed a significant benefit in performance over time compared to subjects who received sham stimulation. When change from baseline was compared between groups, participants who received real tDCS showed significantly greater improvement than those who received sham tDCS. There was no significant difference between groups on measures of picture naming, understanding of grammar, or semantic processing. TDCS shows a promising potential to ameliorate verbal fluency deficits experienced by PPA patients who suffer from impairment in this domain.