便携式柔性石墨烯电极脑电采集系统

Portable EEG acquisition system with flexible graphene electrode

脑电能反映人脑的健康及认知活动状况,是脑疾病诊治及认知神经科学的重要参数。基于头皮脑电的脑电信号监测也是脑机接口的重要手段。该文开发一种基于柔性石墨烯干式脑电(EEG)电极和便携式无线终端的脑电采集系统。利用真空抽滤的方法制备了柔性聚酯纤维(织物)基底石墨烯织物电极,基于ADS1299模拟前端和超低功耗单片机设计实现了便携式低功耗无线脑电采集系统,能够实现脑电信号的采集、处理、存储和无线传输。对石墨烯电极的导电特性、耐久性、稳定性进行了测试并和商用氯化银电极进行了对比。结果表明,文中开发的石墨烯电极能够实现脑电信号的高信噪比精确采集,并且满足长期佩戴所需的耐摩擦性。与皮肤连续摩擦接触的测试结果表明,随着时间的推移,石墨烯电极本征阻抗及采集的脑电信号质量并没有发生明显变化。基于石墨烯电极的便携式无线脑电采集系统数据采集准确可靠,设计合理,运行稳定,能够满足便携式脑电采集设备的需要。

EEG signal can reflect the health status and cognitive activity of the human brain,which is an important parameter in the brain disease diagnosis and treatment,as well as the cognitive neuroscience. The EEG signal monitoring based on scalp EEG is also an important mean of the brain-computer interface. An EEG acquisition system based on the flexible graphene dry EEG electrode and the portable wireless terminal is developed. The graphene fabric electrode with the flexible polyester(fabric)substrate is prepared by means of the vacuum filtration method. The portable low-power consumption wireless EEG acquisition system is designed and realized on the basis of ADS1299 analog front-end and ultra-low power consumption MCU,which can realize the acquisition,processing,storage and wireless transmission of EEG signal. The conductivity,durability and stability of the graphene electrode were tested and compared with those of the commercial silver chloride electrode. The results show that the developed graphene electrode can collect the EEG signals with high signal-to-noise ratio precisely,and meet the needs of the friction resistance for long-term wearing. The testing results of continuous frictional contact with skin indicate that,as times go on,the intrinsic impedance of the graphene electrode and the quality of the EEG signal collected by it do not change significantly. The data collected by the portable wireless collection system based on graphene electrode is accurate and reliable,its design is reasonable,and its operation is stable. It can satisfy the need of the portable EEG acquisition equipments.