Psychometric properties of outcome measures for freezing of gait in Parkinson’s disease: a systematic review and meta-analysis

This systematic review and meta-analysis aimed to evaluate validated tools for assessing FOG in individuals with PD, focusing on their psychometric properties, linguistic adaptations, and methodological quality. A systematic search was conducted across MEDLINE, CINHAL, SCOPUS, and Web of Science, following PRISMA-COSMIN guidelines. Studies assessing validity, reliability, and cross-cultural adaptation of FOG-specific tools were included. Psychometric properties, including internal consistency (Cronbach's alpha) and test-retest reliability (Intraclass Correlation Coefficient, ICC), were extracted. Methodological quality was assessed using the COSMIN Risk of Bias checklist, and meta-analyses were performed for comparable studies. Six validated tools were identified, with FOG-Q and NFOG-Q emerging as the most robust. Meta-analysis revealed high internal consistency (FOG-Q: α = 0.90; NFOG-Q: α = 0.87-0.89) and test-retest reliability (FOG-Q ICC = 0.87), but heterogeneity (I2 = 71.1-86.4%) was substantial. Emerging tools, including CFOG-Q, Ziegler test, and DYPAGS, addressed cognitive and dual-tasking dimensions but lacked sufficient linguistic validation. FOG-Q and NFOG-Q remain widely used tools for FOG assessment. However, recent findings suggest that the NFOG-Q may present limitations in detecting small clinical changes, highlighting the need for cautious interpretation in clinical trials.Broader linguistic and cultural adaptations are still requiredand emerging tools hold promise for addressing multidimensional aspects of FOG. Future research should focus on integrating subjective and objective measures for comprehensive and globally applicable assessments. PROSPERO (CRD42020173873).