Heilinger Alexander, Ortner Rupert, La Bella Vincenzo, Lugo Zulay R, Chatelle Camille, Laureys Steven, Spataro Rossella, Guger Christoph
g.tec medical engineering GmbH, Schiedlberg, Austria.
g.tec medical engineering Spain SL, Barcelona, Spain.
Front Neurosci. 2018 Jul 31;12:514. doi: 10.3389/fnins.2018.00514. eCollection 2018.
Patients with locked-in syndrome (LIS) are typically unable to move or communicate and can be misdiagnosed as patients with disorders of consciousness (DOC). Behavioral assessment scales are limited in their ability to detect signs of consciousness in this population. Recent research has shown that brain-computer interface (BCI) technology could supplement behavioral scales and allows to establish communication with these severely disabled patients. In this study, we compared the vibro-tactile P300 based BCI performance in two groups of patients with LIS of different etiologies: stroke ( = 6) and amyotrophic lateral sclerosis (ALS) ( = 9). Two vibro-tactile paradigms were administered to the patients to assess conscious function and command following. The first paradigm is called vibrotactile evoked potentials (EPs) with two tactors (VT2), where two stimulators were placed on the patient's left and right wrist, respectively. The patients were asked to count the rare stimuli presented to one wrist to elicit a P300 complex to target stimuli only. In the second paradigm, namely vibrotactile EPs with three tactors (VT3), two stimulators were placed on the wrists as done in VT2, and one additional stimulator was placed on his/her back. The task was to count the rare stimuli presented to one wrist, to elicit the event-related potentials (ERPs). The VT3 paradigm could also be used for communication. For this purpose, the patient had to count the stimuli presented to the left hand to answer "yes" and to count the stimuli presented to the right hand to answer "no." All patients except one performed above chance level in at least one run in the VT2 paradigm. In the VT3 paradigm, all 6 stroke patients and 8/9 ALS patients showed at least one run above chance. Overall, patients achieved higher accuracies in VT2 than VT3. LIS patients due to ALS exhibited higher accuracies that LIS patients due to stroke, in both the VT2 and VT3 paradigms. These initial data suggest that controlling this type of BCI requires specific cognitive abilities that may be impaired in certain sub-groups of severely motor-impaired patients. Future studies on a larger cohort of patients are needed to better identify and understand the underlying cortical mechanisms of these differences.
闭锁综合征（LIS）患者通常无法移动或交流，可能会被误诊为意识障碍（DOC）患者。行为评估量表在检测该人群意识迹象方面能力有限。最近的研究表明，脑机接口（BCI）技术可以补充行为量表，并能够与这些严重残疾患者建立沟通。在本研究中，我们比较了基于振动触觉P300的BCI在两组不同病因的LIS患者中的表现：中风（n = 6）和肌萎缩侧索硬化症（ALS）（n = 9）。对患者应用了两种振动触觉范式来评估意识功能和听从指令情况。第一种范式称为双刺激振动触觉诱发电位（VT2），其中两个刺激器分别放置在患者的左手腕和右手腕上。要求患者对呈现给一只手腕的罕见刺激进行计数，以仅针对目标刺激引出P300复合波。在第二种范式中，即三刺激振动触觉诱发电位（VT3），如在VT2中一样在手腕上放置两个刺激器，并在患者背部额外放置一个刺激器。任务是对呈现给一只手腕的罕见刺激进行计数，以引出事件相关电位（ERP）。VT3范式也可用于交流。为此，患者必须对呈现给左手的刺激进行计数以回答“是”，对呈现给右手的刺激进行计数以回答“否”。除一名患者外，所有患者在VT2范式的至少一次测试中表现高于机遇水平。在VT3范式中，所有6名中风患者和8/9的ALS患者至少有一次测试高于机遇水平。总体而言，患者在VT2中的准确率高于VT3。在VT2和VT3范式中，由ALS导致的LIS患者比由中风导致的LIS患者表现出更高的准确率。这些初步数据表明，控制这种类型的BCI需要特定的认知能力，而这些能力在某些严重运动障碍患者亚组中可能受损。未来需要对更大规模的患者队列进行研究，以更好地识别和理解这些差异的潜在皮层机制。
