Implementation Of A Temporally Interfering Transcranial Electrical Stimulator

In recent years,the global population is aging significantly,and functional brain diseases such as Alzheimer’s,Parkinson’s,epilepsy and depression not only seriously affect the daily life of patients,but also bring a certain economic burden to the country.In contrast to a series of side effects after drug treatment,the physiotherapy method of neuroelectric stimulation has emerged.Temporal interferential electrical stimulation not only solves some of the morbidities associated with the use of traditional implanted electrodes,but also improves the lack of focus and penetration depth of non-invasive transcranial electrical stimulation.In this paper,a complementary output type voltage controlled current source for temporal interferometric electrical stimulation is proposed to investigate the current generation site and the distribution problem of interference when the current sources with different topological models are applied to temporal interferometric electrical stimulation,as follows:(1)The theoretical analysis of the circuit models of two conventional voltage controlled current sources suggests that their output ports have asymmetric impedance to ground,and when they are applied to temporal interferometric electrical stimulation,there is an unreasonable spatial distribution of interference intensity and unwanted interference effects near some electrodes.The topological model of the voltage controlled current source with complementary symmetric output is proposed,and the spatial distribution of the interference intensity of the new current source and two conventional current sources in the application of temporal phase interference is simulated and analyzed,and the results show that the interference region of the new current source is relatively concentrated and suitable for the application of temporal phase interference electrical stimulation.(2)According to the proposed topology of the voltage controlled current source,the actual circuit of the complementary output type voltage controlled current source with good symmetry is realized by reasonably using the existing passive devices and circuit connections of the integrated instrumentation amplifier chip,reducing the use of peripheral devices and connection complexity,and avoiding errors caused by device inconsistencies.On the basis of this,the control circuit composed of the microcontroller CY8C5888,the digital frequency synthesizer AD9959,and the touch screen is further designed to realize a time-phase interferometric electrical stimulator with adjustable frequency and intensity for multi-channel stimulation.(3)The results show that the developed electrical stimulator can produce a stable output signal and stimulation effect in the central target area without unnecessary stimulation effect near the electrode.The system provides an effective tool to complete deep nerve stimulation by applying two differential frequency currents generated by the action of constant lowintensity kilohertz alternating current on the human epidermis to precisely and deeply stimulate deep nerves in a non-invasive manner,thereby regulating neuronal activity.