Liselotte M. Hermansson ^{A1, A2}, Anne G. Fisher ^A3, Birgitta Bernspång ^A3, Ann‐Christin Eliasson ^A2
A1 Limb Deficiency and Arm Prosthesis Centre, Örebro University Hospital, Örebro
^A2 Department of Woman and Child Health, Karolinska Institute, Stockholm
^A3 Division of Occupational Therapy, Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden
DOI: 10.1080/16501970410024280

Objective: To report the results from a Rasch rating scale analysis of the Assessment of Capacity for Myoelectric Control (ACMC) implemented to evaluate internal scale validity, person response validity, separation reliability, targeting and responsiveness of the measures over time. Design: Longitudinal data (18 months) from a prospective study of development of capacity for myoelectric control in children and adults were used for the analysis. Patients: A consecutive sample of 75 subjects (43 males, 32 females) with upper limb reduction deficiency or amputation and myoelectric prosthetic hands referred for occupational therapy from September 2000 to March 2002. Participants' ages ranged from 2 to 57 years. Methods: Outcome measure was the ACMC. Occupational therapists completed 210 assessments at an arm prosthesis centre in Sweden. A two-faceted rating scale analysis of the data was performed. Results: All 30 ACMC items and 96. 2% of participants demonstrated goodness-of-fit to the rating scale model for the ACMC. Separation and SE values suggested adequate reliability of the item and person estimates. Conclusion: The items demonstrated internal scale validity and the participants demonstrated person response validity. The ACMC was well targeted and sensitive enough to detect expected change in ability.