Eliseyev Andrey, Aksenova Tatiana
Clinatec/LETI/CEA, Grenoble, France.
J Neural Eng. 2014 Dec;11(6):066005. doi: 10.1088/1741-2560/11/6/066005. Epub 2014 Oct 23.
The key criterion for reliability of brain-computer interface (BCI) devices is their stability and robustness in natural environments in the presence of spurious signals and artifacts.
To improve stability and robustness, a generalized additive model (GAM) is proposed for BCI decoder identification. Together with partial least squares (PLS), GAM can be applied to treat high-dimensional data and it is compatible with real-time applications. For evaluation of prediction quality, along with standard criteria such as Pearson correlation, root mean square error (RMSE), mean absolute error (MAE), additional criteria, mean absolute differential error (MADE) and dynamic time warping (DTW) distance, are chosen. These criteria reflect the smoothness and dissimilarity of the predicted and observed signals in the presence of phase desynchronization.
The efficiency of the GAM-PLS model is tested on the publicly available database of simultaneous recordings of the continuous three-dimensional hand trajectories and epidural electrocorticogram signals of the Japanese macaque. GAM-PLS outperforms the generic PLS and improves the evaluation criteria: 22% (Pearson correlation), 8% (RMSE), 13% (MAE), 31% (MADE), 20% (DTW).
Motor-related BCIs are systems to improve the quality of life of individuals with severe motor disabilities. The improvement of the reliability of the BCI decoder is an important step toward real-life applications of BCI technologies.
脑机接口（BCI）设备可靠性的关键标准是其在存在伪信号和伪迹的自然环境中的稳定性和鲁棒性。
为提高稳定性和鲁棒性，提出了一种广义相加模型（GAM）用于BCI解码器识别。GAM与偏最小二乘法（PLS）一起，可用于处理高维数据且与实时应用兼容。为评估预测质量，除了诸如皮尔逊相关系数、均方根误差（RMSE）、平均绝对误差（MAE）等标准准则外，还选择了额外的准则，即平均绝对差分误差（MADE）和动态时间规整（DTW）距离。这些准则反映了在存在相位失同步情况下预测信号与观测信号的平滑度和差异度。
在公开可用的关于日本猕猴连续三维手部轨迹与硬膜外皮层脑电图信号同步记录的数据库上测试了GAM - PLS模型的效率。GAM - PLS优于通用的PLS并改善了评估标准：皮尔逊相关系数提高22%、RMSE提高8%、MAE提高13%、MADE提高31%、DTW提高20%。
与运动相关的BCI是用于改善严重运动障碍个体生活质量的系统。提高BCI解码器的可靠性是迈向BCI技术实际应用的重要一步。
