Measurement of an acousto-electric interaction signal: An experimental setup

Abstract

Muscles suffering from denervation will weaken and degenerate since no contraction of the muscles occur. In order to prevent degeneration of denervated muscle, electrical stimulation treatment is used, where each fibre is depolarized. It is necessary to monitor this therapy for an effective usage. The most common monitoring method now used is to place a finger on the tendon and sense if there is a movement. But this method does not inform which muscles are involved in the contraction nor which muscle fibers are being stimulated. A new monitoring method is proposed in this work that is based on acousto-electric effect. As a pressure wave propagates through medium, it changes locally the conductivity of the medium. If electrical current is existent simultaneously at this location, a change in voltage is sensed. This voltage change is called acousto-electric interaction (AEI) signal. Recording the AEI signal over certain volume, an ultrasound current source density imaging (UCSDI) can be registered. By reconstruction method, the electrical current in the muscle will be mapped. In this paper, an experimental setup for investigating the AEI signal is developed. The AEI signal and the Debye effect are measured. Debye effect is a voltage change due to variation in pressure only. Finally, the signals are compared to calculated values of the AEI signal. The results are that the signals were detected with reasonable resolution and of measurable magnitude that corresponds to calculated value of the AEI signal.