Kojima Simon, Kanoh Shin'ichiro
Graduate School of Engineering and Science, Shibaura Institute of Technology, Tokyo, Japan.
College of Engineering, Shibaura Institute of Technology, Tokyo, Japan.
Front Hum Neurosci. 2024 Nov 26;18:1461960. doi: 10.3389/fnhum.2024.1461960. eCollection 2024.
The ASME (stands for Auditory Stream segregation Multiclass ERP) paradigm is proposed and used for an auditory brain-computer interface (BCI). In this paradigm, a sequence of sounds that are perceived as multiple auditory streams are presented simultaneously, and each stream is an oddball sequence. The users are requested to focus selectively on deviant stimuli in one of the streams, and the target of the user attention is detected by decoding event-related potentials (ERPs). To achieve multiclass ASME BCI, the number of streams must be increased. However, increasing the number of streams is not easy because of a person's limited audible frequency range. One method to achieve multiclass ASME with a limited number of streams is to increase the target stimuli in a single stream.
Two approaches for the ASME paradigm, ASME-4stream (four streams with a single target stimulus in each stream) and ASME-2stream (two streams with two target stimuli in each stream) were investigated. Fifteen healthy subjects with no neurological disorders participated in this study. An electroencephalogram was acquired, and ERPs were analyzed. The binary classification and BCI simulation (detecting the target class of the trial out of four) were conducted with the help of linear discriminant analysis, and its performance was evaluated offline. Its usability and workload were also evaluated using a questionnaire.
Discriminative ERPs were elicited in both paradigms. The average accuracies of the BCI simulations were 0.83 (ASME-4stream) and 0.86 (ASME-2stream). In the ASME-2stream paradigm, the latency and the amplitude of P300 were shorter and larger, the average binary classification accuracy was higher, and the average weighted workload was smaller.
Both four-class ASME paradigms achieved a sufficiently high accuracy (over 80%). The shorter latency and larger amplitude of P300 and the smaller workload indicated that subjects could perform the task confidently and had high usability in ASME-2stream compared to ASME-4stream paradigm. A paradigm with multiple target stimuli in a single stream could create a multiclass ASME BCI with limited streams while maintaining task difficulty. These findings expand the potential for an ASME BCI multiclass extension, offering practical auditory BCI choices for users.
提出了ASME（代表听觉流分离多类事件相关电位）范式并将其用于听觉脑机接口（BCI）。在该范式中，会同时呈现一系列被感知为多个听觉流的声音，且每个流都是一个异常球序列。要求用户选择性地关注其中一个流中的偏差刺激，并通过解码事件相关电位（ERP）来检测用户注意力的目标。为实现多类ASME BCI，必须增加流的数量。然而，由于人的可听频率范围有限，增加流的数量并不容易。一种在流数量有限的情况下实现多类ASME的方法是增加单个流中的目标刺激。
研究了ASME范式的两种方法，即ASME-4流（每个流中有一个目标刺激的四个流）和ASME-2流（每个流中有两个目标刺激的两个流）。15名无神经系统疾病的健康受试者参与了本研究。采集了脑电图并分析了ERP。借助线性判别分析进行了二分类和BCI模拟（从四个中检测试验的目标类别），并离线评估了其性能。还使用问卷评估了其可用性和工作量。
两种范式均诱发了可区分的ERP。BCI模拟的平均准确率分别为0.83（ASME-4流）和0.86（ASME-2流）。在ASME-2流范式中，P300的潜伏期和波幅更短、更大，平均二分类准确率更高，平均加权工作量更小。
两种四类ASME范式均实现了足够高的准确率（超过80%）。P300潜伏期更短、波幅更大以及工作量更小表明，与ASME-4流范式相比，受试者在ASME-2流中能够自信地执行任务且具有较高的可用性。单个流中具有多个目标刺激的范式可以在保持任务难度的同时，利用有限的流创建多类ASME BCI。这些发现扩展了ASME BCI多类扩展的潜力，为用户提供了实用的听觉BCI选择。
