Spatial filters to detect steady-state visual evoked potentials elicited by high frequency stimulation: BCI application
Spatial filters to detect steady-state visual evoked potentials elicited by high frequency stimulation: BCI application
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DOI：
10.1515/bmt.2010.013
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发表时间：
2010-06-01
期刊：
影响因子：
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通讯作者：
Mihajlovic, Vojkan
中科院分区：
文献类型：
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作者：
Molina, Gary Garcia;Mihajlovic, Vojkan
基于稳态视觉诱发电位（SSVEP）的脑机接口（BCI）需要最少的用户培训，与其他BCI模式相比，可以提供更高的信息吞吐量。我们专注于高频刺激（> 30 Hz）引起的SSVEP，因为它们引起的疲劳/烦恼最小，并降低了诱导光癫痫发作的风险。本文提出了一种方法，分析脑电活动，自动获得最佳的空间滤波器，用于检测SSVEP在一个给定的刺激频率从一个短的信号，其中的刺激是在间歇期间穿插休息。定义了由刺激频率和谐波处的正弦信号生成的矢量空间。空间滤波器系数是通过使空间滤波信号的能量与其关于向量空间的正交分量的能量之间的比率最大化而产生的。空间滤波器通过考虑个体特异性的简短校准程序为每个BCI用户定制。我们对六个应用空间滤波器的受试者进行的实验导致平均传输速率范围从20.9到22.7比特/分钟。
Brain-computer interfaces (BCIs) based on steady-state visual evoked potentials (SSVEPs) require minimal user training and can offer higher information throughput compared to other BCI modalities. We focused on SSVEPs elicited by high-frequency stimuli (> 30 Hz) because they cause minimal fatigue/annoyance and reduce the risk of inducing photoepileptic seizures. This paper presents an approach that analyzes electroencephalographic activity to automatically obtain the optimum spatial filter for detecting the SSVEP at a given stimulation frequency from a short signal where the stimulation is presented at intermittent periods interspersed with breaks. A vector space generated by sinusoidal signals at the stimulation frequency and harmonics is defined. The spatial filter coefficients result from maximizing the ratio between the energy of the spatially filtered signal and that of its orthogonal component with regard to the vector space. The spatial filters are customized for each BCI user through a short calibration procedure taking into account individual specificity. Our experiments on six subjects applying the spatial filters resulted in an average transfer rate ranging from 20.9 to 22.7 bits/min.