A Preliminary Study on Non-Invasive Detection of Electrical Stimulation Current Based on Magneto-Acoustic Effect

Electrical stimulation is widely used in nerve regulation and treatment. The detection of the distribution of stimulation current in tissues is of great significance to improve the accuracy of electrical stimulation, but the current technical means are still difficult to achieve the non-invasive detection of stimulation current. This study proposes a non-invasive detection method of electrical stimulation current based on the magneto-acoustic (MA) effect, which has the advantages of high spatial resolution and high spatial contrast. In this study, continuous sine waves with the frequency of 20kHz are used to stimulate samples. The MA signal generated by the stimulation current in the samples in a stable magnetic field is detected by lock-in amplifier, and the two-dimensional distribution of sound source is extracted. The current density distribution of samples is simulated by the method of finite element analysis, and the simulation results are verified by experiments. The results show that under the electrical stimulation of the order of 0.01A, the location measurement of two-dimensional surface sound source with millimeter accuracy can be achieved non-invasively in isolated pork and pig brain, and the measurement accuracy of weak MA signal can reach 10^-7Pa. In short, the stimulation current detection method based on MA effect can achieve the non-invasive and high-precision detection of electrical stimulation current distribution, which is of great significance to improve the stimulation accuracy and study the neural regulation mechanism of electrical stimulation.