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

Introduction: This systematic review and meta-analysis evaluated validated tools for assessing FOG in PD, focusing on their psychometric properties, linguistic adaptations, and methodological quality.

Methods: A systematic search was conducted in MEDLINE, CINAHL, SCOPUS, and Web of Science, following PRISMA-COSMIN guidelines. Studies assessing validity, reliability, and cross-cultural adaptation of FOG-specific tools were included. Key psychometric properties, such as internal consistency (Cronbach's alpha) and test-retest reliability (Intraclass Correlation Coefficient, ICC), were extracted. The COSMIN Risk of Bias checklist was used to assess methodological quality, and meta-analyses were performed for comparable studies.

Results: Six validated tools were identified, with FOG-Q and NFOG-Q emerging as the most robust. Meta-analysis showed high internal consistency (FOG-Q: α = 0.90; NFOG-Q: α = 0.87-0.89) and test-retest reliability (FOG-Q ICC = 0.87), though substantial heterogeneity was noted (I² = 71.1-86.4%). Emerging tools, including CFOG-Q, Ziegler test, and DYPAGS, addressed cognitive and dual-tasking aspects but lacked linguistic validation.

Conclusion: FOG-Q and NFOG-Q remain widely used, yet NFOG-Q may have limitations in detecting small clinical changes. Broader linguistic adaptations are needed, and emerging tools hold promise for multidimensional assessment. Future research should integrate subjective and objective measures for comprehensive evaluations.

Registration: PROSPERO (CRD42020173873).