A preliminary protocol for prescribing upper limb prostheses

Abstract

Selecting an appropriate prosthesis is a complex process. To the best of our knowledge, to date there is no standard prescription protocol for upper limb prostheses. Thus, the primary objective of this study was to propose a prescription protocol for upper limb prostheses. To understand more about the properties of the prosthetic terminal device; frictional properties of the contact surfaces between terminal devices and the grasped object, and the effect of loading rates on the frictional properties of the terminal devices were evaluated. The results showed that metal is better gripped by the body-powered hook than by the myoelectric hand; whereas plastic and wood are better gripped by the myoelectric hand than by the body-powered hook. In addition, as loading rate increases, the friction coefficient decreases. With regard to the prescription protocol for upper limb prostheses, this study proposed a prescription protocol that not only contains comprehensive information, but also proposed a scoring system to assist in selecting an appropriate prosthesis. The scoring system was developed by factorial survey approach. Five factors affecting the type of upper limb prosthetic device were selected for vignette constructions. Twenty upper limb prosthetic experts were involved in this study. Each participant was asked to rate 20 vignettes regarding the appropriateness in selecting a myoelectric prosthesis for an individual with upper limb amputation. The findings from the factorial survey analysis suggested that “work condition” is the most critical factor that influences the judgments of the upper limb prosthetic experts in making the selection of prosthetic devices for both trans-radial and trans-humeral amputation. The proposed scoring system was also evaluated for its effectiveness. The study suggests that the proposed scoring system may be improved as a tool to assist in the selection of an appropriate prosthetic device. In conclusion, this study suggested that the frictional coefficients of the terminal devices and the grasped objects are dependent on the material and the loading rate. “Work condition” is a key factor in selecting an appropriate prosthesis for the upper limb amputee, and a systematic evaluation of an amputee’s condition is useful in selecting an appropriate prosthetic device.