Objective: To investigate the concurrent validity between the Action Research Arm Test (ARAT) and the Wolf Motor Function Test (WMFT) and to compare their reproducibility, internal consistency and floor and ceiling effects in the same sample of stroke patients.
Methods: Forty patients participated in this study. Concurrent validity was determined with Spearman's rank correlation coefficients. Reproducibility was assessed with intraclass correlation coefficients (ICCs) and Bland-Altman plots, internal consistency by means of Cronbach's alphas, and floor and ceiling effects were considered to be present if more than 20% of patients fell outside a preliminary set lower and upper boundary.
Results: Spearman's rank correlation coefficients ranged from 0.70 to 0.86. ICCs for inter-rater and intra-rater reliability ranged from 0.92 to 0.97. Bland-Altman plots showed a less stable way of scoring for the WMFT, compared with the ARAT. Cronbach's alpha was > 0.98 for both scales. No floor and ceiling effects were found.
Conclusion: The present study showed good clinimetric properties for both assessments. The high concurrent validity suggests that ARAT and WMFT have significant overlap with regard to the underlying construct that is being measured.