Psychometric Properties of the Wolf Motor Function Test (WMFT) and Its Modified Versions: A Systematic Review With Meta-Analysis

Background: The Wolf Motor Function Test (WMFT) and its modified versions are widely used to assess upper limb (UL) function in stroke survivors. However, comprehensive evaluations of its psychometric properties are lacking. Objective: To perform a systematic review with meta-analysis on the psychometric properties (following the COnsensus-based Standards for the selection of health Measurement INstruments [COSMIN] taxonomy) of the WMFT and modified versions in stroke survivors. Methods: Six databases were searched until May 2024 for studies examining at least one WMFT measurement property in stroke patients. Two independent reviewers conducted study selection, data extraction, and quality assessment using the COSMIN Risk of Bias checklist and quality of evidence (QoE) with the Grading of Recommendations Assessment, Development, and Evaluation approach. Meta-analyses synthesized psychometric properties reported in at least two studies. Results: Twenty-five studies (N = 2044) were included. Regarding the WMFT Functional Ability Scale (FAS) and TIME scales, internal consistency (alpha ≥.88), intra-rater (intraclass correlation coefficient [ICC] ≥.97) and inter-rater (ICC ≥.92) reliability, measurement error for TIME, construct validity (strong correlations [r ≥|.64|] with Fugl-Meyer Assessment and Action Research Arm Test), and responsiveness (ES ≥ 0.48) were rated sufficiently with QoE from very low to high. Measurement error for FAS was assessed as inconsistent with moderate QoE, and cross-cultural validity was rated as indeterminate with very low QoE. Content validity was not assessed. Few studies investigated the psychometric properties of the modified versions. Conclusions: WMFT demonstrates robust psychometric properties in assessing UL function in stroke survivors. While the WMFT-modified versions showed promising properties, further research is needed to use them. Future studies should focus on WMFT measurement error, content, and cross-cultural validity. Trial Review Registration: PROSPERO: CRD42021237425.