AI Graduate School, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
J Neural Eng. 2024 Aug 5;21(4). doi: 10.1088/1741-2552/ad6187.
Although motor imagery-based brain-computer interface (MI-BCI) holds significant potential, its practical application faces challenges such as BCI-illiteracy. To mitigate this issue, researchers have attempted to predict BCI-illiteracy by using the resting state, as this was found to be associated with BCI performance. As connectivity's significance in neuroscience has grown, BCI researchers have applied connectivity to it. However, the issues of connectivity have not been considered fully. First, although various connectivity metrics exist, only some have been used to predict BCI-illiteracy. This is problematic because each metric has a distinct hypothesis and perspective to estimate connectivity, resulting in different outcomes according to the metric. Second, the frequency range affects the connectivity estimation. In addition, it is still unknown whether each metric has its own optimal frequency range. Third, the way that estimating connectivity may vary depending upon the dataset has not been investigated. Meanwhile, we still do not know a great deal about how the resting state electroencephalography (EEG) network differs between BCI-literacy and -illiteracy.To address the issues above, we analyzed three large public EEG datasets using three functional connectivity and three effective connectivity metrics by employing diverse graph theory measures. Our analysis revealed that the appropriate frequency range to predict BCI-illiteracy varies depending upon the metric. The alpha range was found to be suitable for the metrics of the frequency domain, while alpha + theta were found to be appropriate for multivariate Granger causality. The difference in network efficiency between BCI-literate and -illiterate groups was constant regardless of the metrics and datasets used. Although we observed that BCI-literacy had stronger connectivity, no other significant constructional differences were found.Based upon our findings, we predicted MI-BCI performance for the entire dataset. We discovered that combining several graph features could improve the prediction's accuracy.
虽然基于运动想象的脑机接口 (MI-BCI) 具有重要的潜力,但它的实际应用面临着 BCI 文盲等挑战。为了缓解这个问题,研究人员试图通过使用静息态来预测 BCI 文盲,因为静息态与 BCI 性能有关。随着连通性在神经科学中的重要性不断增加,BCI 研究人员已经将连通性应用于其中。然而,连通性的问题尚未得到充分考虑。首先,尽管存在各种连通性指标,但只有一些被用于预测 BCI 文盲。这是有问题的,因为每个指标都有一个独特的假设和视角来估计连通性,因此根据指标的不同,结果也会有所不同。其次,频率范围会影响连通性的估计。此外,尚不清楚每个指标是否都有其自己的最佳频率范围。第三,基于数据集的不同,估计连通性的方式也可能不同,但目前尚未对此进行研究。同时,我们仍然不太了解 BCI 识字者和文盲者之间静息态脑电图 (EEG) 网络的差异。为了解决上述问题,我们使用三种功能连通性和三种有效连通性指标,通过采用多种图论度量方法,对三个大型公共 EEG 数据集进行了分析。我们的分析表明,预测 BCI 文盲的适当频率范围取决于指标。发现频域指标适合使用 alpha 范围,而多元 Granger 因果关系则适合使用 alpha + theta 范围。无论使用的指标和数据集如何,BCI 识字者和文盲者之间网络效率的差异都是恒定的。虽然我们观察到 BCI 识字者的连通性更强,但没有发现其他显著的结构性差异。基于我们的发现,我们对整个数据集进行了 MI-BCI 性能预测。我们发现,结合几个图特征可以提高预测的准确性。