Guger Christoph, Spataro Rossella, Pellas Frederic, Allison Brendan Z, Heilinger Alexander, Ortner Rupert, Cho Woosang, Xu Ren, La Bella Vincenzo, Edlinger Günter, Annen Jitka, Mandalá Giorgio, Chatelle Camille, Laureys Steven
Guger Technologies OG, Graz, Austria.
g.tec Medical Engineering GmbH, Schiedlberg, Austria.
Front Neurosci. 2018 Jun 29;12:423. doi: 10.3389/fnins.2018.00423. eCollection 2018.
Persons diagnosed with disorders of consciousness (DOC) typically suffer from motor disablities, and thus assessing their spared cognitive abilities can be difficult. Recent research from several groups has shown that non-invasive brain-computer interface (BCI) technology can provide assessments of these patients' cognitive function that can supplement information provided through conventional behavioral assessment methods. In rare cases, BCIs may provide a binary communication mechanism. Here, we present results from a vibrotactile BCI assessment aiming at detecting command-following and communication in 12 unresponsive wakefulness syndrome (UWS) patients. Two different paradigms were administered at least once for every patient: (i) VT2 with two vibro-tactile stimulators fixed on the patient's left and right wrists and (ii) VT3 with three vibro-tactile stimulators fixed on both wrists and on the back. The patients were instructed to mentally count either the stimuli on the left or right wrist, which may elicit a robust P300 for the target wrist only. The EEG data from -100 to +600 ms around each stimulus were extracted and sub-divided into 8 data segments. This data was classified with linear discriminant analysis (using a 10 × 10 cross validation) and used to calibrate a BCI to assess command following and YES/NO communication abilities. The grand average VT2 accuracy across all patients was 38.3%, and the VT3 accuracy was 26.3%. Two patients achieved VT3 accuracy ≥80% and went through communication testing. One of these patients answered 4 out of 5 questions correctly in session 1, whereas the other patient answered 6/10 and 7/10 questions correctly in sessions 2 and 4. In 6 other patients, the VT2 or VT3 accuracy was above the significance threshold of 23% for at least one run, while in 4 patients, the accuracy was always below this threshold. The study highlights the importance of repeating EEG assessments to increase the chance of detecting command-following in patients with severe brain injury. Furthermore, the study shows that BCI technology can test command following in chronic UWS patients and can allow some of these patients to answer YES/NO questions.
被诊断患有意识障碍（DOC）的患者通常存在运动障碍，因此评估他们残留的认知能力可能会很困难。几个研究小组最近的研究表明，非侵入性脑机接口（BCI）技术可以对这些患者的认知功能进行评估，从而补充通过传统行为评估方法获得的信息。在极少数情况下，脑机接口可以提供一种二元通信机制。在此，我们展示了一项旨在检测12名无反应觉醒综合征（UWS）患者的指令跟随和通信能力的振动触觉脑机接口评估结果。为每位患者至少进行一次两种不同的范式：（i）VT2，在患者的左手腕和右手腕固定两个振动触觉刺激器；（ii）VT3，在双腕和背部固定三个振动触觉刺激器。患者被要求在心里数左手腕或右手腕上的刺激，这可能只会在目标手腕上引发强烈的P300。提取每个刺激周围从 -100到 +600毫秒的脑电图数据，并将其细分为8个数据段。使用线性判别分析（采用10×10交叉验证）对这些数据进行分类，并用于校准脑机接口以评估指令跟随和是/否通信能力。所有患者的VT2总体平均准确率为38.3%，VT3准确率为26.3%。两名患者的VT3准确率≥80%，并进行了通信测试。其中一名患者在第1次测试中5个问题答对了4个，而另一名患者在第2次和第4次测试中分别答对了6/10和7/10个问题。在其他6名患者中，VT2或VT3准确率在至少一次测试中高于23%的显著性阈值，而在4名患者中，准确率始终低于该阈值。该研究强调了重复脑电图评估对于增加检测重度脑损伤患者指令跟随能力机会的重要性。此外，该研究表明，脑机接口技术可以测试慢性UWS患者的指令跟随能力，并使其中一些患者能够回答是/否问题。
