Assessment of Capacity for Myoelectric Control: Construct Validity and Rating Scale Structure

INTRODUCTION The Assessment of Capacity for Myoelectric Control (ACMC) is a 30-item standardized clinical assessment designed for the upper limb prosthesis group [1, 2]. It measures the quality of prosthetic hand movement performed by the prosthesis user during a self-chosen two-handed functional task. ACMC is suitable for prosthesis users of all ages and of all prosthetic sides/levels [2, 3] . Previously, repeated ACMC assessments of upper limb prosthesis users were used to evaluate the validity of the construct [1]. Since the strengths and weaknesses among these users were likely to be repeated several times in the data obtained, the abilities of the prosthesis users in that sample might not give the best picture of the functioning of the items. It was hypothesised that a wider range of ability across the sample might provide a better picture of the functioning of items. Therefore, a further validation of ACMC based on single measures was considered.