The use of an adjustable electrode housing unit to compare electrode alignment and contact variation with myoelectric prosthesis functionality: A pilot study

Abstract

Background: Usable myoelectric control relies on secure and intimate contact at all times between the electrode, the socket and the residual limb. At present, there is little post-fitting socket adjustment available to prosthetists with respect to electrode contact security or alignment. Failure to provide secure electrode contact could result in the development of motion artefacts, poor prehensor response and subsequent prosthesis non-usage.

Objectives: To establish the effect of alteration to electrode contract security and alignment on prosthesis functionality using a bespoke electrode housing unit.

Study design: This study investigated the effect of electrode contact security and alignment on upper limb myoelectric prosthesis functionality.

Methods: Four different electrode housing arrangements were assessed within prosthetic sockets fitted to six transradial prosthesis subjects using the Southampton Hand Assessment Procedure, which is a reliable and validated prosthesis functionality assessment tool.

Results: Significantly higher functionality scores were achieved with the bespoke housing unit compared to when using conventional electrode housings.

Conclusion: Myoelectric prosthesis functionality is closely linked to electrode contact security and to electrode alignment with respect to the residual limb. Both of these factors can be improved locally using an adjustable electrode housing unit.

Clinical relevance: Provision of an electrode housing system that enables adjustments to be made to electrode orientation can improve prosthesis functionality, particularly in cases where tight-fitting sockets are not possible, and/or where the prosthetist may be inexperienced with regard to myoelectric prosthesis fitting.

Keywords: Upper limb prosthetics; education; prosthetics; testing of prosthetic and orthotic components.