Design Of Multi-mode And Multi-channel Transcranial Direct Current Stimulation Device

Transcranial direct current stimulation(tDCS)is a non-invasive neuromodulation technique.It uses electrodes fixed on the scalp to input a weak current to stimulate the brain area,adjust the excitability of cerebral cortex neurons,and improve the function of stimulating the brain area.In recent years,this technology has been widely used in the fields of cognition,psychological science,rehabilitation medicine and other mental and neurological diseases,and has become a kind of electrical stimulation technology with great development prospects.The widely used tDCS equipment is mainly developed and produced by companies in Germany and the United States.No professional tDCS equipment has been developed in China,and the performance parameters,focus and safety of domestic products have yet to be verified.The current mainstream tDCS products are mainly single-channel or single-mode stimulation,and the spatial focus is not ideal.Therefore,a tDCS device with adjustable parameters,multi-channel and multi-stimulation modes is developed in this paper,which improves the spatial focus while ensuring safety.The tDCS device designed and developed in this paper includes two parts: a lower computer and a human-computer interaction interface.The lower computer is based on a microcontroller.The hardware circuit includes stimulation mode and channel selection circuit,current and impedance real-time monitoring circuit,current source circuit,power management circuit and human-computer interaction circuit.The human-computer interaction interface completes stimulation parameter control and data display.The current source circuit is the core part of the whole design.It can output a weak current of 0-2m A,the current output error is within 2.5%,and when the impedance remains unchanged,the current output error variation range is up to 2% when the current setting value is changed.The overcurrent protection circuit and the impedance detection circuit can monitor the current intensity flowing through the channel and the contact impedance between the electrode and the scalp in real time.The tested electrode impedance has a maximum error of 4.4%,which verifies the real-time detection reliability of the device.The load capacity of the device is within 5.1k?.During this range,the output current of the device changes little,and the constant current characteristics are good.The prototype in this article can output multiple stimulation modes such as direct current stimulation,current sinusoidal stimulation,current pulse stimulation,pseudo stimulation,etc.,and the current intensity,waveform frequency,duty cycle and stimulation duration of the stimulation mode can be adjusted;multiple channel stimulation The combination method improves the focus of stimulation and makes the stimulation effect better.In addition,a comparative analysis with existing laboratory equipment shows that the device designed in this paper meets the industry’s electrical standards.