Understanding Right-Hemisphere Language Disorders Through a Half-Century of Research: A Systematic Review

PURPOSE: Language deficits affecting multiple domains (e.g., semantics, pragmatics) have been reported after right-hemisphere (RH) stroke. The goal of the current study was to summarize the existing knowledge within the apragmatism framework. METHOD: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided systematic review of 55 years of research was conducted. Data were extracted to describe study characteristics, along with linguistic and extralinguistic apragmatism components. RESULTS: After content and quality reviews, 233 articles were included. Data were reported for over 4,300 participants with RH stroke. Methodological weaknesses included poor participant descriptions and use of experimental versus standardized/published assessments. Linguistic comprehension deficits were apparent at the word, sentence, and discourse levels, primarily in figurative language, inferencing, use of context, and humor. Linguistic production deficits at all three levels occurred particularly with less-structured elicitation tasks. Specifically for discourse, deficits affected coherence, cohesion, intended meaning, and emotional processing. Extralinguistic deficits consistently affected comprehension and production of facial expression; few studies examined other nonverbal communication cues. CONCLUSIONS: Language deficits at the word, sentence, and discourse levels can occur after RH stroke: Linguistic and extralinguistic apragmatism predominantly affect figurative language, inferencing, emotion, and intended meaning. Weaknesses in research methodology impede clear understanding of the language challenges experienced by this population.