Test-retest and alternate forms reliability of the assisting hand assessment.

OBJECTIVE The Assisting Hand Assessment (AHA) has earlier demonstrated excellent validity and rater reliability. This study aimed to evaluate test-retest reliability of the AHA and alternate forms reliability between Small kids vs School kids AHA and the 2 board games in School kids AHA. DESIGN Test-retest and alternate forms reliability was evaluated by repeated testing with 2 weeks interval. SUBJECTS Fifty-five children with unilateral cerebral palsy, age range 2 years and 3 months to 11 years and 2 months. METHODS Intraclass correlation coefficients and smallest detectable difference were calculated. Common item and common person linking plots using Rasch analysis and Bland-Altman plots were created. RESULTS Intraclass correlation coefficients for test-retest was 0.99. Alternate forms intraclass correlation coefficients were 0.99 between Small kids and School kids AHA and 0.98 between board games. Smallest detectable difference was 3.89 points (sum scores). Items in common item linking plots and persons in common person linking plots were within 95% confidence intervals, indicating equivalence across test forms. CONCLUSION The AHA has excellent test-retest and alternate forms reliability. A change of 4 points or more between test occasions represents a significant change. Different forms of the AHA give equivalent results.