Acquisition Protocol and Comparison of Myoelectric Signals of the Muscles Innervated by the Ulnar, Radial and Medial Nerves for a Hand Orthoses

Abstract

This paper proposes a protocol for obtaining surface myoelectric signals in muscles of the upper limb for characterization of hand movement patterns. To characterize the movement patterns, the magnitude of the signal from each muscle is compared, for eight movements: (i) flexion, (ii) extension, (iii) ulnar and (iv) radial deviation of the hand, (v) metacarpophalangeal flexion, (vi) metacarpophalangeal extension, (vii) opposition and (viii) adduction thumb. Specific points were considered to acquire the signals from muscles innervated by the radial, medial and ulnar nerve, following the recommendations of the SENIAM project, in six intact people, using a myoelectric signal acquisition system. Seven protocols with recommendations for the location of sensors in the muscles were obtained, intended to establish combinations to reduce the number of sensors for future designs of assistive technologies, such as active orthoses. The suitable characteristic patterns for the hand movements studied allows the identification of a reduced set of sensors, considering the same eight movements. In this way, the functionality and rehabilitation processes of hand injuries are improved, facilitating the execution of activities of daily living.