Speech, language, social communication, and communication assessments in Rett syndrome: A systematic review.

AIM: To provide a systematic overview of speech, language, and social abilities of people with Rett syndrome (RTT), and identify the most frequently used communication assessments in the literature. METHOD: A systematic search of PubMed, CINAHL, ScienceDirect, ERIC, and speechBITE databases was conducted using terms synonymous with RTT, speech, language, social, and clinical assessment. Two independent reviewers screened abstracts; one reviewer conducted full-text screening, communication-related data extraction, and quality appraisal, with verification by a senior author of a subset of full-text articles. RESULTS: A total of 3091 papers were identified after removal of duplicates, of which 59 met inclusion criteria. Severe communication impairment emerged as a core feature of RTT, across classic and atypical variants, to differing degrees. Expressive language and speech production were most severely affected. Atypicality in all communication domains was reported both pre- and post-regression. Genetic (e.g. MECP2 variant) and developmental (e.g. age) factors modulated ability; poorer outcomes often linked to early truncations and large deletions. Most assessments relied on caregiver report. INTERPRETATION: Speech-language difficulties are ubiquitous in RTT, ranging from mild to profound. Objective assessment is limited by severe motor-speech impairment and a reliance on caregiver report; flexible and/or more granular tools are necessary. The use of both objective (e.g. acoustic analysis) and subjective (e.g. caregiver recall) measures is warranted for characterizing speech-language ability.