Role of Electrolyte Gels in Signal Transmission Across the Interface Between Skin and Surface Electrodes in Hand Exoprosthesis

Abstract

A key component of a successful external myoprosthesis is not a part of the prosthesis, but an area: the interface between the prosthesis and the amputation stump. This is because in this area takes place a critical exchange of information, in the form of a myoelectrical signal being transferred from the muscles, through the fascia, fat and skin, to the surface EMG sensors, that in turn transfer this information to a part of the prosthesis that is responsible with the analysis, augmentation and use of this signal in order to control the movements of the electromechanical parts of the prosthesis. Any condition that leads to an impaired transmission of information from the skin to the EMG sensors inevitably leads to an underperformance of what may otherwise be a highly developed model of exoprosthesis, thus potentially rendering it no more useful than a basic mechanical model. We aim to review the possible difficulties that may arise in this area, and that may lead to a faulty transfer of signal, with a loss in quantity or quality. For this purpose, we will review the current literature for this subject, including reference books and articles, and complete this information with our personal experience. In doing this, we hope to provide a guide to practitioners, bioengineers and patients alike, in order to be able to anticipate and correct any potential problem as they may arise.