Psychometric properties of the Action Research Arm Test using decision rules for skipping items in hemiparetic patients after stroke: a retrospective study

Important properties have been studied using the Action Research Arm Test (ARAT) in patients with stroke. However, whether the ARAT subtests constitute a Guttman scale (i.e., items hierarchically ordered according to difficulty) remains unclear. Guttman scales can define decision rules for skipping items in patients with low endurance. This study investigated the psychometric properties of the ARAT when applying decision rules for post-stroke hemiparetic patients.A retrospective, single-institution study was conducted between 2020 and 2021. Datasets of 30 patients with stroke-induced hemiparesis were collected from a previous study which employed the ARAT without decision rules, Fugl-Meyer assessment (FMA), Box and Block Test (BBT), and Motor Activity Log (MAL). The ARAT was rescored with decision rules for this study, and inter-rater reliability/agreement, parallel forms reliability, and construct validity were assessed.Parallel forms reliability (Spearman's rho) was 0.99 (95% CI, 0.99-0.99) for both raters. The lower 95% CI limits of the sum and individual item scores in the reliability analysis exceeded the planned value (0.8). Construct validity values exceeded the planned value (0.8) for FMA, BBT, and MAL.Decision rules can be used to skip ARAT items when assessing upper extremity motor function in stroke patients.IMPLICATIONS FOR REHABILITATIONThe Action Research Arm Test with decision rules for skipping items was valid and reliable for measuring upper extremity motor function in hemiparetic patients after stroke.The decision rules may reduce the burden of both patients and evaluators by decreasing the number of Action Research Arm Test items to be administrated.