Assessing the therapeutic potential of transcranial Direct Current Stimulation in the semantic variant of primary progressive aphasia (PPA sv): Preliminary analyses from an ongoing double blind, controlled clinical trial

Abstract Progressive primary aphasia (PPA) designates a group of neurodegenerative diseases affecting language processing for which no pharmacologically effective treatment exists. PPA presents in three different variants with distinct and brain damage areas: logopenic PPA, non-fluent/agrammatic semantic (PPA-sv). We here present an interim analysis sham-controlled randomized double-blind protocol STIM SD assessing the therapeutic effects direct current stimulation (tDCS) on cohort PPA-sv patients. This clinical condition affects system anterior temporal lobes (ATL) predominating left (dominant) hemisphere, leading to profound word finding comprehension impairments. To this end, n=27 patients was 2 week (10 day) regime anodal ATL, cathodal over right ATL (following interhemispheric inhibition principles) compared sham tDCS. Language tasks, including associations (SA) category fluency (FLU) were performed before onset (baseline), 3 days, weeks, 4 months thereafter. A matched healthy participants (n=20) assessed estimate normative task performance rate severity patient language/semantic deficits. The assessment baseline symptom revealed severe impairment AS FLU tasks controls. Regarding tDCS, intermediate (n=9 patients/group) failed show statistically significant any active conditions Nonetheless, individual improvement noted some treated stimulation. At stage, our observations confirm feasibility implemented experimental design patient’s tolerance protocol. Currently available datasets will be completed by recruiting planned number (n=20 condition) finally included. Research Category Technology Methods Clinical Research: 9. Transcranial Direct Current Stimulation Keywords: Noninvasive stimulation, Primary progressive aphasia, Semantic dementia, rehabilitation