Baseline Performance Predicts tDCS-mediated Improvements in Language Symptoms in Primary Progressive Aphasia

Primary Progressive Aphasia (PPA) is a neurodegenerative condition characterized by insidious irreversible loss of language abilities. Prior studies suggest that transcranial direct current stimulation (tDCS) directed toward language areas of the brain may help to ameliorate symptoms of PPA. In the current study, the investigators are examining whether tDCS could be used to enhance language abilities (e.g., picture naming) in individuals with PPA variants primarily characterized by difficulties with speech production (non-fluent and logopenic). Participants are being recruited from the Penn Frontotemporal Dementia Center to receive 10 days of both real and sham tDCS (counter-balanced, full-crossover design; participants are naïve to stimulation condition). A battery of language tests are being administered at baseline, immediately post-tDCS (real and sham), and six weeks and twelve weeks following stimulation. Real tDCS may improve language performance in some individuals with PPA. Specifically, the investigators expect that tDCS will be more effective in people whose baseline performance is worse based on previous research. Severity of deficits at baseline may be an important factor in predicting which patients will respond positively to language-targeted tDCS therapies.