Development of a Brain-Computer Interface Toggle Switch with Low False-Positive Rate Using Respiration-Modulated Photoplethysmography
Development of a Brain-Computer Interface Toggle Switch with Low False-Positive Rate Using Respiration-Modulated Photoplethysmography
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DOI：
10.3390/s20020348
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发表时间：
2020-01-01
期刊：
影响因子：
3.9
通讯作者：
Im, Chang-Hwan
中科院分区：
文献类型：
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作者：
Han, Chang-Hee;Kim, Euijin;Im, Chang-Hwan
基于脑电的异步脑机接口在分类准确率和假阳性率方面性能较差。因此，开发了基于眼电图（EOG）信号的BCI拨动开关以切换开/关同步BCI系统。传统的BCI拨动开关表现出快速响应和高精度;然而，它们具有高FPR或不能应用于具有眼部损伤的患者。为了解决这些问题，我们开发了一种新颖的BCI切换开关，用户可以通过屏住呼吸几秒钟来打开或关闭同步BCI。两种状态-正常呼吸和屏气-使用线性判别分析从呼吸调制光电容积描记（PPG）信号中提取的特征进行分类。实时BCI切换开关的实施与校准数据训练只有1分钟PPG数据。我们通过将其与基于稳态视觉诱发电位的BCI系统相结合来评估我们的PPG开关的性能，该系统旨在控制四个外部设备，关于真阳性率和FPR。PPG开关的参数进行了优化，通过离线实验与五个主题，和开关系统的性能进行了评估，在一个在线实验与七个主题。所有参与者通过屏住呼吸约10 s（100%准确度）成功打开BCI，开关系统表现出非常低的FPR，每分钟0.02次错误操作，这是迄今为止报告的最低FPR。所有参与者都可以在同步BCI模式下成功控制外部设备。我们的研究结果表明，所提出的基于PPG的BCI拨动开关可以用来实现实际的BCI。
Asynchronous brain-computer interfaces (BCIs) based on electroencephalography (EEG) generally suffer from poor performance in terms of classification accuracy and false-positive rate (FPR). Thus, BCI toggle switches based on electrooculogram (EOG) signals were developed to toggle on/off synchronous BCI systems. The conventional BCI toggle switches exhibit fast responses with high accuracy; however, they have a high FPR or cannot be applied to patients with oculomotor impairments. To circumvent these issues, we developed a novel BCI toggle switch that users can employ to toggle on or off synchronous BCIs by holding their breath for a few seconds. Two states-normal breath and breath holding-were classified using a linear discriminant analysis with features extracted from the respiration-modulated photoplethysmography (PPG) signals. A real-time BCI toggle switch was implemented with calibration data trained with only 1-min PPG data. We evaluated the performance of our PPG switch by combining it with a steady-state visual evoked potential-based BCI system that was designed to control four external devices, with regard to the true-positive rate and FPR. The parameters of the PPG switch were optimized through an offline experiment with five subjects, and the performance of the switch system was evaluated in an online experiment with seven subjects. All the participants successfully turned on the BCI by holding their breath for approximately 10 s (100% accuracy), and the switch system exhibited a very low FPR of 0.02 false operations per minute, which is the lowest FPR reported thus far. All participants could successfully control external devices in the synchronous BCI mode. Our results demonstrated that the proposed PPG-based BCI toggle switch can be used to implement practical BCIs.