Cao Yong, An Xingwei, Ke Yufeng, Jiang Jin, Yang Hanjun, Chen Yuqian, Jiao Xuejun, Qi Hongzhi, Ming Dong
National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing, China.
Department of Biomedical Engineering, Tianjin University, Tianjin, China.
Biomed Eng Online. 2017 Jul 25;16(1):91. doi: 10.1186/s12938-017-0381-4.
Over the past few decades, there have been many studies of aspects of brain-computer interface (BCI). Of particular interests are event-related potential (ERP)-based BCI spellers that aim at helping mental typewriting. Nowadays, audiovisual unimodal stimuli based BCI systems have attracted much attention from researchers, and most of the existing studies of audiovisual BCIs were based on semantic incongruent stimuli paradigm. However, no related studies had reported that whether there is difference of system performance or participant comfort between BCI based on semantic congruent paradigm and that based on semantic incongruent paradigm.
The goal of this study was to investigate the effects of semantic congruency in system performance and participant comfort in audiovisual BCI. Two audiovisual paradigms (semantic congruent and incongruent) were adopted, and 11 healthy subjects participated in the experiment. High-density electrical mapping of ERPs and behavioral data were measured for the two stimuli paradigms.
The behavioral data indicated no significant difference between congruent and incongruent paradigms for offline classification accuracy. Nevertheless, eight of the 11 participants reported their priority to semantic congruent experiment, two reported no difference between the two conditions, and only one preferred the semantic incongruent paradigm. Besides, the result indicted that higher amplitude of ERP was found in incongruent stimuli based paradigm.
In a word, semantic congruent paradigm had a better participant comfort, and maintained the same recognition rate as incongruent paradigm. Furthermore, our study suggested that the paradigm design of spellers must take both system performance and user experience into consideration rather than merely pursuing a larger ERP response.
在过去几十年里，对脑机接口（BCI）的各个方面进行了许多研究。特别令人感兴趣的是基于事件相关电位（ERP）的BCI拼写器，其旨在帮助进行心理打字。如今，基于视听单峰刺激的BCI系统已引起研究人员的广泛关注，并且现有的大多数视听BCI研究都是基于语义不一致刺激范式。然而，尚无相关研究报道基于语义一致范式的BCI与基于语义不一致范式的BCI在系统性能或参与者舒适度方面是否存在差异。
本研究的目的是调查语义一致性对视听BCI系统性能和参与者舒适度的影响。采用了两种视听范式（语义一致和不一致），11名健康受试者参与了实验。针对这两种刺激范式测量了ERP的高密度电图和行为数据。
行为数据表明，对于离线分类准确率，一致范式和不一致范式之间没有显著差异。然而，11名参与者中有8人表示他们优先选择语义一致的实验，2人表示两种条件之间没有差异，只有1人更喜欢语义不一致范式。此外，结果表明在基于不一致刺激的范式中发现ERP的幅度更高。
总之，语义一致范式具有更好的参与者舒适度，并且与不一致范式保持相同的识别率。此外，我们的研究表明，拼写器的范式设计必须同时考虑系统性能和用户体验，而不是仅仅追求更大的ERP反应。
