Communication Aid Based on Event Related Brain Potentials for Auditory Stimulus

作为开发用于残疾人交流辅助设备的人机界面的基础，我们对P300成分的行为进行了研究，以选择通过扬声器以随机序列呈现的单词之一。对于词汇选择实验的听觉刺激，使用了5个单词。目标词以20%的概率随机应用。受试者被指示保持目标词的数量的心理计数。P300成分是通过以下方法从目标反应中获得的：1）中心频率为3Hz的带通滤波，2）对每个刺激的单次试验反应进行30次平均，3）减去目标刺激和非目标刺激的ERP反应中的公共成分，4）使用梯形形式的时间窗口切割出P300。结果表明，P300成分可以用来检测没有任何物理动作的主题的注意。然而，正确的单词被选中的百分比约为60%。未来的工作将需要更多的实验来提高百分比。

As a basis to develop a human interface for communication aids for the handicapped, we conducted a study on the behavior of P300 components for selecting one of the words presented through a speaker in a random sequence. For the auditory stimulus of the word-selecting experiments, 5 words were used. The target word was randomly applied with a probability of 20 %. The subject was instructed to keep a mental count of the number of target words. The P300 components were obtained from the target responses by means of the following methods : 1) Band-pass filtering of the central frequency of 3 Hz, 2) Averaging the single-trial responses to each stimulus 30 times, 3) Subtracting the common components in ERP responses for both target stimuli and non-target stimuli, and 4) Cutting out the P300 using the time-window of the trapezoidal form. Results show that the P300 component can be used to detect the attention of the subject without any physical action. However, right words were selected in a percentage of about 60 %. More experiments will be needed for future work to improve the percentage.