Zhang Dan, Gao Xiaorong, Gao Shangkai, Engel Andreas K, Maye Alexander
Department of Biomedical Engineering at Tsinghua University, Beijing 100084, China.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:539-42. doi: 10.1109/IEMBS.2009.5333740.
Modulation of steady-state visual evoked potential (SSVEP) by directing gaze to targets flickering at different frequencies has been utilized in many brain-computer interface (BCI) studies. However, this paradigm may not work with patients suffering from complete locked-in syndrome or other severe motor disabilities that do not allow conscious control of gaze direction. In this paper, we present a novel, independent BCI paradigm based on covert shift of non-spatial visual selective attention. Subjects viewed a display consisting of two spatially overlapping sets of randomly positioned dots. The two dot sets differed in color, motion and flickering frequency. Two types of motion, rotation and linear motion, were investigated. Both, the SSVEP amplitude and phase response were modulated by selectively attending to one of the two dot sets. Offline analysis revealed a predicted online classification accuracy of 69.3+/-10.2% for the rotating dots, and 80.7+/-10.4% for the linearly moving dots.
通过将目光指向以不同频率闪烁的目标来调节稳态视觉诱发电位（SSVEP），这一方法已在许多脑机接口（BCI）研究中得到应用。然而，对于患有完全闭锁综合征或其他严重运动障碍、无法有意识地控制目光方向的患者而言，这种范式可能并不适用。在本文中，我们提出了一种基于非空间视觉选择性注意的隐蔽转移的新型独立BCI范式。受试者观看一个由两组随机分布的点组成的显示器，这两组点在空间上相互重叠。这两组点在颜色、运动和闪烁频率上有所不同。我们研究了旋转和直线运动这两种运动类型。通过选择性地关注两组点中的一组，SSVEP的幅度和相位响应均受到了调制。离线分析显示，对于旋转的点，预测的在线分类准确率为69.3±10.2%；对于直线运动的点，预测的在线分类准确率为80.7±10.4%。
