Operability of the Southampton Hand Assessment Procedure (SHAP) Tasks Using Voluntary Closing and Voluntary Opening Body-Powered Prosthesis Simulator

Abstract

ABSTRACT Introduction Body-powered prostheses are still essential in practice. There are two types of mechanisms to manipulate body-powered prostheses: voluntary closing (VC) and voluntary opening (VO). However, there are no studies investigating which is better suited for what type of movement in daily life. Materials and Methods The participants were eight right-handed, able-bodied adults. They were divided into two groups: a VC-to-VO group, in which the VC type was practiced first and then the VO type, and a VO-to-VC group, in which they practiced in the opposite order. VC/VO-type terminal device (EquiluxTM) was attached to a body-powered prosthesis simulator for the left hand, and the Southampton Hand Assessment Procedure (SHAP) tasks were practiced repeatedly. We compared the VC type and VO type for the number of practices to reach a plateau, Index of Functionality (IOF) score, the six prehensile pattern scores, and the time required for the 26 SHAP tasks. Scores were also compared before and after practice. In addition, changes in IOF and scores for each of the six patterns with proficiency were compared between VC type and VO type. Results Significant improvements were observed with manipulation practice for both types of devices. The mean SHAP scores at the plateau were 82.6 for VO type and 92.0 for VC type, with VC type significantly higher than VO type. In the six prehensile pattern scores, only two patterns, Tripod and Power, showed significant differences. When comparing the time required, Food Cutting task was an exception and significantly faster in the VC type, while there were no significant differences for the other tasks. Conclusions It was suggested that the VC type is more suitable for tasks requiring grip strength. Clinical Relevance We believe that this research will improve the daily lives of individuals with upper-limb amputation.