幅度调制稳态听觉刺激脑电信号响应及选择性注意力分析

闭锁症患者不能自主控制眼球运动，无法使用视觉刺激脑-机接口（BCI）技术实现意识交流，听觉刺激脑-机接口技术不受视觉限制，可实现这类患者的意识交流，具有重要意义。首先，对不同受试者在幅度调制频率变化的听觉诱发刺激下的响应特征进行研究，获得人体大脑听觉通频带的幅频特性。然后，基于受试者的听觉通频带频率特征，设计了全新的听觉选择注意力实验范式，选择响应幅值较强的刺激频率作为受试者的刺激频率，并提出了改进的空间相干脑电（EEG）信号解算方法，提高了算法的鲁棒性，获得了相对更高的准确率，受试者通过注意力选择实现脑-机接口的二分类控制。实验获得了不同受试者的大脑听觉通频带频率特征，得到了人体大脑在35~94 Hz调制频率范围内的听觉幅频特性曲线，发现了响应幅值在35~44 Hz调制频率范围最强。利用改进的空间相干算法，将提出的基于通频带特征的实验范式和固定频率组合的实验范式进行比较，由3名受试者的对比实验表明，所提实验范式和改进的空间相干算法获得了更高的准确率。 

EEG based amplitude-modulated auditory steady-state response and auditory selective attention analysis

Patients with atresia cannot control eye movement independently, and cannot use visual Brain-Computer Interface (BCI) to realize consciousness communication. The technology of auditory BCI is not restricted by vision. It is of great significance to realize the consciousness communication of such patients. Firstly, the response characteristics of different subjects to auditory evoked stimuli with amplitude modulation frequency change were studied to obtain the amplitude-frequency characteristics of auditory passband. Based on the auditory passband frequency characteristics of subjects, a new auditory selective attention paradigm was designed. The stimulus frequency with stronger response amplitude was selected as the stimulus frequency of subjects. An improved spatial coherence Electroencephalogram (EEG) signal resolution method was proposed, which improves algorithm robustness and achieves higher classification accuracy. The two-class classification was realized through attention selection. In this paper, the frequency characteristics of the auditory passband of different subjects were accessed, and the auditory amplitude-frequency characteristic curves of the human brain in the frequency range of 35-94 Hz are obtained. It was found that the response amplitude is the strongest in the frequency range of 35-44 Hz. By using the improved spatial coherence algorithm, the proposed experimental paradigm based on the passband characteristics and the fixed frequencies experimental paradigm for three subjects were compared and tested. The results show that the proposed experimental paradigm and the improved spatial coherence algorithm achieve higher accuracy.