Development Of Multi-mode Memory Consolidation Stimulation Equipment Based On EEG Feedback

Memory is the process of encoding,storing and reproducing the information of learning,and it is one of the most important functions of human brain.However,with the acceleration of the pace of modern life,the influx of a large number of information and the psychological problems caused by social pressure,more and more people are experiencing the phenomenon of memory decline.In addition,with the aggravation of China’s aging population,China has become the country with the largest number of elderly people in the world,and the memory of the elderly will decline with the aging of body organs.Serious cases can lead to mild cognitive impairment,and may develop into dementia,which has a great impact on the life of the elderly.Therefore,the decline of memory has become a serious problem in modern society.At present,the main methods for memory decline are training,medication and physiotherapy.The latest research showed that transcranial electrical stimulation and vagus nerve stimulation in sleep provide a new strategy for memory consolidation.Based on the latest research in neuroscience and the core mechanism theory that slow wave oscillation could promote memory consolidation during sleep,this paper developed a multimode memory consolidation stimulation device based on EEG feedback.The device collected eight channels of EEG signals during sleep and transmited them to the host computer.The host computer carried out real-time data processing to extract slow-wave signals.When the sleep state detected as slow wave sleep,a stimulation command would be sent to the lower computer stimulation device.There were two modes of stimulation device: transcranial electrical stimulation(tES)and vagus nerve stimulation(VNS).At the same time,in order to collect better EEG signals during sleep,this paper designs a pink noise generator to promote sleep effect,thus completing the development of a closed-loop device integrating acquisition and stimulation.The device was consisted of the following modules: EEG acquisition module,host computer processing module,transcranial electrical stimulation module,vagus nerve stimulation module and pink noise generator module.EEG acquisition module was composed of preprocessing circuit and high precision analog to digital conversion chip ADS1299.Preprocessing circuit included high-low pass filter circuit and power frequency notch circuit.The eight-channel EEG signal was filtered and amplified and transmitted to the host computer for data processing.The host computer processing module includes slow-wave sleep detection algorithm and graphical user interface(GUI)software,the collected EEG signal was processed in real time,and the stimulation command was sent to the lower computer when it was judged to be slow wave sleep state.At the same time,it is displayed on the GUI interface.The transcranial electrical stimulation module included ARM control unit,FPGA waveform generating unit and analog circuit.The host computer command was sent to the FPGA waveform generation unit via the ARM control unit to generate four stimulation signals,which would be performed through the analog circuit.The module of vagus nerve stimulation consisted of signal generating unit and boosting circuit,which could stimulate the human body by bilateral ear vagus nerve after receiving the command of the host computer.The module of pink noise generator mainly included the main control unit and audio unit,and the pink noise data generated by the main control unit was converted to audio signal through the audio unit and output through headphones.In order to promote sleep and improve the effect of sleep EEG acquisition.In view of the current status of people’s memory decline,this paper proposed to develop a multi-mode memory consolidation stimulation device based on EEG feedback.Data analysis was performed on the collected sleep EEG signals,and when it was judged to be a slow wave sleep state,transcranial electrical stimulation and vagus nerve stimulation were applied to achieve the purpose of memory consolidation.After system module testing and overall testing,the functions of all aspects of the equipment developed in this paper meet the expected requirements basically,meet the needs of scientific research experiments basically,and may lay the foundation for better equipment research and development in the future.