The Assessment of Capacity for Myoelectric Control (ACMC) is an observation-based tool that evaluates ability to control a myoelectric prosthetic hand. Validity evidence led to ACMC version 2.0, but the test-retest reliability and minimal detectable change (MDC) of the ACMC have never been evaluated. Investigation of rater agreements in this version was also needed because it has new definitions in certain rating categories and items. Upper-limb prosthesis users (n = 25, 15 congenital, 10 acquired; mean age 27.5 yr) performed one standardized activity twice, 2 to 5 wk apart. Activity performances were videorecorded and assessed by two ACMC raters. Data were analyzed by weighted kappa, intraclass correlation coefficient (ICC), and Bland-Altman method. For test-retest reliability, weighted kappa agreements were fair to excellent (0.52 to 1.00), ICC2,1 was 0.94, and one user was located outside the limits of agreement in the Bland-Altman plot. MDC95 was less than or equal to 0.55 logits (1 rater) and 0.69 logits (2 raters). For interrater reliability, weighted kappa agreements were fair to excellent in both sessions (0.44 to 1.00), and ICC2,1 was 0.95 (test) and 0.92 (retest). Intrarater agreement (rater 1) was also excellent (ICC3,1 0.98). Evidence regarding the reliability of the ACMC is satisfactory and MDC95 can be used to indicate change.
Keywords: ACMC; assessment; capacity; myoelectric control; myoelectric prosthetic hand; prosthesis; prosthetic hand control; rater agreement; test-retest; upper limb.