Measurement properties and utility of performance-based outcome measures of physical functioning in individuals with facioscapulohumeral dystrophy - A systematic review and evidence synthesis.

Access to reliable, valid, accurate and responsive outcome measures is essential to ensure standards of care and clinical trial readiness in facioscapulohumeral dystrophy. Review aims: 1. identify and provide a descriptive summary of all outcome measures used to measure physical function. 2. systematically appraise the evidence on measurement properties (reliability, construct validity, measurement error and responsiveness) of performance-based outcome measures of physical function in individuals diagnosed with facioscapulohumeral dystrophy. Selected electronic health-related databases were searched from inception - Feb 2019. Two authors independently screened studies for eligibility and extracted data for psychometric evidence. The methodological quality of outcome measure studies was appraised using the consensus-based standards for the selection of health measurement instruments (COSMIN) checklist. Of 12 identified outcome measures, four required high-technology equipment. Only three were FSHD specific. The FSH-clinical score had 'moderate' quality positive evidence for reliability. The remaining measures had 'low' to 'very low' quality evidence supporting properties of reliability, validity, responsiveness and measurement error. Identified studies tended towards low recruitment in middle-aged, ambulant individuals making results hard to generalise across lifespan and levels of severity. There is a paucity of measurement evidence supporting the use of outcome measures in people with facioscapulohumeral dystrophy.