Treatment Methods of Language and Transcranial Direct Current Stimulation on Naming Impairment Resulted from the Primary Progressive Aphasia: A Systematic Review

Context: Primary progressive aphasia (PPA) is a neurological condition characterized by the gradual and progressive deterioration of language abilities, typically occurring before the age of 65. Naming impairments are a primary and consistent issue in PPA. In light of the absence of effective pharmacological treatments, numerous studies over the past few decades have explored the efficacy of language therapy and transcranial direct current stimulation (tDCS) in reducing the functional impacts of word-finding difficulties in everyday life. Objectives: This study aimed to identify the language therapy methods and tDCS techniques used to address naming impairments in PPA. Data Sources: The research involved searching the Cochrane Library, PubMed, Scopus, Web of Science, Science Direct, and ProQuest databases using keywords relevant to studies conducted from January 1, 2010, to December 31, 2022. This review focused on case reports, case series, cross-sectional, cohort, and case-control studies (observational studies) published in English, following the PICO criteria. Data Extraction: The initial search yielded 349 articles. Results: After a thorough review, 43 studies were selected for inclusion in this research. Among these, 27 studies focused on language therapy methods, three studies examined tDCS, and 13 articles investigated a combination of language therapy methods and tDCS. The JBR guidelines were adhered to throughout the review process. Conclusions: The findings from these studies indicate that language therapy methods, tDCS, and their combination are effective in treating naming deficiencies in patients with primary progressive aphasia.