基于左右视野刺激范式的耳后SSVEP-BCI系统  

Retroauricular SSVEP-BCI system based on left and right visual field stimulation paradigm

作　　者：梁栗炎 李文宇 张倩 张利剑[3] 周洁 陈远方[3] 高小榕[2] LIANG Liyan;LI Wenyu;ZHANG Qian;ZHANG Lijian;ZHOU Jie;CHEN Yuanfang;GAO Xiaorong(China Academy of Information and Communications Technology,Beijing 100191;Department of Biomedical Engineering,School of Medicine,Tsinghua University,Beijing 100084;Beijing Institute of Mechanical Equipment,Beijing 100854)

机构地区：[1]中国信息通信研究院,北京100191 [2]清华大学医学院生物医学工程系,北京100084 [3]北京机械设备研究所,北京100854

出　　处：《北京生物医学工程》2023年第4期361-369,共9页Beijing Biomedical Engineering

基　　金：国家重点研发计划(2021YFF0601801);宁夏回族自治区重点研发计划(2022CMG02026)资助。

摘　　要：目的基于稳态视觉诱发电位(steady-state visual evoked potential,SSVEP)范式的脑机接口(brain-computer interface,BCI)主要信号响应位于枕叶区,因而通常需要使用者洗头、佩戴脑电帽并辅助使用导电膏,给实际应用带来不便。耳后区域虽然可直接通过电极贴的方式快速开展SSVEP-BCI应用,但由于SSVEP在耳后区域的响应信号较弱,最终的系统性能受限。为提升SSVEP-BCI的耳后应用性能,本研究引入左右视野刺激范式,设计耳机与凝胶电极结合的采集方式,开发了一套便携性的耳后SSVEP脑机接口应用系统。方法系统由刺激与反馈端、数据采集端、数据处理系统3部分构成,其中刺激与反馈端实时进行SSVEP刺激及结果显示;数据采集端可实时获取耳后区域8通道的脑电数据,分别支持贴片湿电极及凝胶电极方案;数据处理系统对采集到的信号实时处理识别,并将结果反馈至刺激与反馈端。最终,为验证系统性能,研究分别采用湿电极与凝胶电极的系统方案在开放环境进行了标准SSVEP刺激与左右视野SSVEP刺激的在线对照试验。结果在线验证试验中,凝胶电极的采集方式达到95.8%±5.3%的识别正确率及(22.9±3.0)bits/min的信息传输速率,与耳后湿电极方案效果接近。且左右视野刺激范式较标准范式的识别正确率提高了40.9%,信息传输速率提高了14.3 bits/min。结论以上结果表明,基于左右视野刺激范式的耳后SSVEP-BCI系统取得了很好的应用效果,使用者可快速开展脑机交互应用,有望将SSVEP-BCI推广至更广泛的应用场景。Objective The main response area of brain-computer interface(BCI)based on the steady-state visual evoked potential(SSVEP)is located in the occipital lobe.Therefore,users usually need to wash their hair,wear EEG cap and assist the use of conductive paste,which brings inconvenience to the practical application.Although the application of SSVEP-BCI in the region can be carried out quickly by means of electrode patch,the final system performance is limited due to weak response signal.In order to improve the application performance of SSVEP-BCI behind the ear,this study introduces the left-right visual field stimulation paradigm,designs a collection method combining headsets and gel electrodes,and develops a portable behind-ear SSVEP-BCI application system.Methods The system consists of stimulus and feedback terminal,data acquisition terminal and data processing system.Stimulus and feedback terminal is responsible for real-time SSVEP stimulation and results display.The data acquisition terminal can obtain the EEG data of 8 channels behind the ear in real time,respectively supporting the wet electrode and gel electrode schemes.The data processing system processes and recognizes the collected signals in real time and feeds back the results to the stimulus and feedback terminal.Finally,in order to verify the performance of the system,an online control experiment of classical SSVEP stimulation and left-right field SSVEP stimulation is conducted in an open environment with the system scheme of wet electrode and gel electrode respectively.Results In the online verification experiment,the gel electrode acquisition method achieves the average recognition accuracy of 95.8%±5.3%and an information transfer rate of(22.9±3.0)bits/min,which is close to that of the control scheme with wet electrode behind ear.Compared with the standard paradigm,the recognition accuracy of the left and right visual field stimulation paradigm increases by 40.9%,and ITR increases by 14.3 bits/min.Conclusions The above results illustrate that the SSVE

关 键 词：脑机接口 稳态视觉诱发电位 左右视野 耳后 凝胶电极 

分 类 号：R318.06[医药卫生—生物医学工程]