Ethnoracial and Linguistic Diversity in Treatment Research for Primary Progressive Aphasia: A Systematic Review

Purpose: This systematic review sought to characterize the ethnoracial and linguistic representation of participants in the nonpharmacological intervention literature for primary progressive aphasia (PPA) and primary progressive apraxia of speech (PPAOS). In addition, we aimed to identify which social determinants of health (SDOH) factors are most frequently reported across studies. Method: We performed a comprehensive search across six electronic databases: OVID Medline, OVID PsycINFO, EBSCO Medline, EBSCO CINAHL Plus, Embase, and Web of Science, as well as unpublished literature. We identified 149 original studies that administered neuromodulation and/or speech-language interventions to individuals with PPA or PPAOS and reported communication outcomes relative to a baseline or control group. From these studies, we extracted data on participants’ race, ethnicity, spoken languages, occupation, years of education, and other relevant sociodemographic variables. Results: Ethnoracial and linguistic diversity in the current PPA literature remains limited. Among studies that reported the extracted variables, the majority of participants were identified as non-Hispanic White, and most studies were conducted in the United States. English was the most commonly reported spoken language and was frequently used as an inclusion criterion. Regarding SDOH, participants tend to have medium-high education and hold higher skill-level occupations. Very few studies reported retirement status and whether retirement was due to symptom onset. Conclusions: Current intervention research for PPA and PPAOS lacks ethnoracial and linguistic diversity. Underrepresentation is exacerbated by not reporting factors concerning SDOH. The concentration of research in homogenous populations limits the generalizability of current findings and restricts their relevance for managing PPA and PPAOS across diverse demographic, cultural, linguistic, and socioeconomic contexts. Future research on treatment should not only ensure comprehensive reporting of participant characteristics but also actively expand the inclusivity of recruitment practices.