Upper limb motor function in hemiparesis: Concurrent validity of the Arm Motor Ability Test

Abstract

Objective: To evaluate the concurrent validity of the Arm Motor Ability Test (AMAT) using the Fugl-Meyer Assessment (FMA) as the criterion measure of poststroke upper limb motor impairment. Design: Upper limb motor impairment and arm ability of 30 chronic stroke survivors were assessed with the FMA and AMAT, respectively. Spearman's correlation coefficients were generated relating the components of FMA and AMAT. Scatterplots were generated to provide qualitative assessments of the relationship between FMA and AMAT. Bar graphs of FMA and AMAT normalized to their maximum scores were generated to compare the levels of motor status measured by each instrument. Results: All components of AMAT correlated highly with FMA total (r = 0.92-0.94; P < 0.001). AMAT functional ability and AMAT quality of movement were linearly related with FMA total. However, AMAT time of performance exhibited significant ceiling and floor effects with respect to FMA. Normalized AMAT scores were generally lower than normalized FMA scores (P < 0.001), with the greatest difference in scores observed in subjects with more severe motor impairments. Conclusion: This study demonstrates a high degree of concurrent criterion validity of the AMAT. However, AMAT tends to underestimate the arm motor status of those with more severe motor impairments.