Enhancing Language Function in Primary Progressive Aphasia

Primary Progressive Aphasia (PPA) is a neurodegenerative disorder that selectively affects language comprehension and/or production, with initial preservation of other cognitive domains. As tDCS has not been extensively studied in PPA, the investigators will measure both short- and long-term effects of stimulation in patients with this neurodegenerative disorder that affects specific language regions. Previous research suggests that neurostimulation with tDCS can safely induce changes in neural plasticity that can lead to long-term restoration of synaptic function. Thus, individually targeted stimulation to structurally preserved but dysfunctional regions may be able to produce behavioral improvements in primary progressive aphasia (PPA). TDCS is a method of stimulating the brain that does not require any sedation or surgery. TDCS is a technique that sends a weak electrical current through the scalp to stimulate the brain areas below. The information gained from this research study will aid in the development of therapies to improve language in people with neurological conditions that affect language use. TDCS will be applied over the activated area identified with the functional magnetic resonance imaging (fMRI) fMRI-localizer task. This approach will allow for individually optimized tDCS electrode placement. It will also account for potential inter-participant variability in the brain atrophy and language organization Summary of study sequence and procedures: Week 1: Baseline screening, language testing, one event-related brain potential (EEG-ERP) session Weeks 2: fMRI session to determine most effective treatment Weeks 3-4: tDCS with Language Treatment Part 1 Weeks 5 and 6: rest-period, post-treatment assessment Weeks 7 to 8: TDCS with Language Treatment Part 2 Weeks 9 and 10: rest period, post-treatment assessment 2-month follow-up, language assessment, one MRI scan, one EEG-ERP session