Sburlea Andreea Ioana, Montesano Luis, Minguez Javier
University of Zaragoza (DIIS), Instituto de investigación en ingeniería de Aragón (I3A), Zaragoza, Spain. Bit&Brain Technologies S.L., Paseo Sagasta 19, 50001, Zaragoza, Spain.
J Neural Eng. 2017 Jun;14(3):036004. doi: 10.1088/1741-2552/aa5f2f. Epub 2017 Mar 14.
One use of EEG-based brain-computer interfaces (BCIs) in rehabilitation is the detection of movement intention. In this paper we investigate for the first time the instantaneous phase of movement related cortical potential (MRCP) and its application to the detection of gait intention.
We demonstrate the utility of MRCP phase in two independent datasets, in which 10 healthy subjects and 9 chronic stroke patients executed a self-initiated gait task in three sessions. Phase features were compared to more conventional amplitude and power features.
The neurophysiology analysis showed that phase features have higher signal-to-noise ratio than the other features. Also, BCI detectors of gait intention based on phase, amplitude, and their combination were evaluated under three conditions: session-specific calibration, intersession transfer, and intersubject transfer. Results show that the phase based detector is the most accurate for session-specific calibration (movement intention was correctly detected in 66.5% of trials in healthy subjects, and in 63.3% in stroke patients). However, in intersession and intersubject transfer, the detector that combines amplitude and phase features is the most accurate one and the only that retains its accuracy (62.5% in healthy subjects and 59% in stroke patients) w.r.t. session-specific calibration.
MRCP phase features improve the detection of gait intention and could be used in practice to remove time-consuming BCI recalibration.
基于脑电图的脑机接口（BCI）在康复中的一个用途是检测运动意图。在本文中，我们首次研究了运动相关皮层电位（MRCP）的瞬时相位及其在步态意图检测中的应用。
我们在两个独立的数据集中证明了MRCP相位的效用，其中10名健康受试者和9名慢性中风患者在三个阶段执行了自发步态任务。将相位特征与更传统的幅度和功率特征进行了比较。
神经生理学分析表明，相位特征比其他特征具有更高的信噪比。此外，基于相位、幅度及其组合的步态意图BCI检测器在三种条件下进行了评估：特定阶段校准、阶段间转移和受试者间转移。结果表明，基于相位的检测器在特定阶段校准方面最准确（健康受试者中66.5%的试验正确检测到运动意图，中风患者中为63.3%）。然而，在阶段间和受试者间转移中，结合幅度和相位特征的检测器是最准确的，并且是唯一相对于特定阶段校准保持其准确性的检测器（健康受试者中为62.5%，中风患者中为59%）。
MRCP相位特征改善了步态意图的检测，并且在实践中可用于消除耗时的BCI重新校准。
