Wang Yu-Te, Wang Yijun, Cheng Chung-Kuan, Jung Tzyy-Ping
Computer Science and Engineering Department, University of California San Diego (UCSD), San Diego, CA, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2012;2012:1806-9. doi: 10.1109/EMBC.2012.6346301.
Steady-State Visual Evoked Potential (SSVEP)-based Brain-Computer Interface (BCI) applications have been widely applied in laboratories around the world in the recent years. Many studies have shown that the best locations to acquire SSVEPs were from the occipital areas of the scalp. However, for some BCI users such as quadriparetic patients lying face up during ventilation, it is difficult to access the occipital sites. Even for the healthy BCI users, acquiring good-quality EEG signals from the hair-covered occipital sites is inevitably more difficult because it requires skin preparation by a skilled technician and conductive gel usage. Therefore, finding an alternative approach to effectively extract high-quality SSVEPs for BCI practice is highly desirable. Since the non-hair-bearing scalp regions are more accessible by all different types of EEG sensors, this study systematically and quantitatively investigated the feasibility of measuring SSVEPs from non-hair-bearing regions, compared to those measured from the occipital areas. Empirical results showed that the signal quality of the SSVEPs from non-hair-bearing areas was comparable with, if not better than, that measured from hair-covered occipital areas. These results may significantly improve the practicality of a BCI system in real-life applications; especially used in conjunction with newly available dry EEG sensors.
近年来，基于稳态视觉诱发电位（SSVEP）的脑机接口（BCI）应用已在世界各地的实验室中得到广泛应用。许多研究表明，获取SSVEP的最佳位置是头皮的枕叶区域。然而，对于一些BCI用户，如在通气过程中仰卧的四肢瘫痪患者，很难触及枕叶部位。即使对于健康的BCI用户，从覆盖头发的枕叶部位获取高质量的脑电图信号也不可避免地更加困难，因为这需要技术熟练的技术人员进行皮肤准备并使用导电凝胶。因此，找到一种替代方法来有效地提取用于BCI实践的高质量SSVEP是非常可取的。由于所有不同类型的脑电图传感器都更容易触及无毛发的头皮区域，本研究系统地、定量地研究了从无毛发区域测量SSVEP的可行性，并与从枕叶区域测量的结果进行了比较。实证结果表明，无毛发区域的SSVEP信号质量即使不比覆盖头发的枕叶区域测量的信号质量更好，也与之相当。这些结果可能会显著提高BCI系统在实际应用中的实用性；特别是与新出现的干式脑电图传感器结合使用时。
