RecruitingDevice studyStimulating the Aging Brain Using Brain and Sensory StimulationThe goal of this project is to investigate whether transcranial electrical stimulation and sensory stimulation affect language outcomes in individuals with primary progressive aphasia (PPA). The main questions it aims to answer are: Does transcranial alternating current stimulation (tACS) affect verbal short-term memory (STM) in individuals with PPA? Does a single session of multisensory stimulation affect verbal STM in individuals with PPA? Researchers will compare active tACS to sham tACS (a fake stimulation condition) to see if active tACS improves verbal STM. Researchers will compare pre-multisensory stimulation to post-stimulation performance to see if multisensory stimulation improves verbal STM. Participants will: Undergo EEG, MRI (anatomical and functional) May complete a cognitive exam Undergo tACS over 3 separate sessions Undergo multisensory stimulation Complete language tasks before, during and/or after stimulation