Does the 'P300' speller depend on eye gaze?
Does the 'P300' speller depend on eye gaze?
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DOI：
10.1088/1741-2560/7/5/056013
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发表时间：
2010-10
影响因子：
4
通讯作者：
Schalk G
中科院分区：
文献类型：
--
作者：
Brunner P;Joshi S;Briskin S;Wolpaw JR;Bischof H;Schalk G
许多受肌萎缩性侧索硬化症（ALS）、脑干中风或脊髓损伤等神经肌肉疾病影响的人，其交流能力受损，甚至无法交流。脑机接口（BCI）使用大脑信号而不是肌肉来重新建立与外部世界的通信。一种特殊的BCI方法是所谓的“P300矩阵拼写器”，它首先由。人们普遍认为这种方法不依赖于聚焦于所需特征的能力，因为人们认为它主要依赖于P300诱发电位，并且最小程度地依赖于其他EEG特征，如视觉诱发电位（VEP）。该问题与该BCI方法的临床应用高度相关，因为在相关用户群体中，眼球运动可能受损或丢失。这项研究调查了在多大程度上表现在“P300”拼写BCI取决于眼睛注视。我们评估了17名健康受试者在两种情况下使用“P300”矩阵拼写器的性能。在一种情况下（“字母”），受试者将他们的眼睛注视集中在预期的字母上，而在第二种情况下（“中心”），受试者将眼睛注视集中在位于矩阵中心的固定十字上。结果表明，正常人的“P300”矩阵拼写器的性能在很大程度上取决于注视方向。因此，他们推翻了BCI研究中的一个普遍假设，并建议BCI可能对保留一些眼球运动控制的人更有效地发挥作用。这些发现对严重神经肌肉残疾（特别是眼球运动）的人的适用性仍有待确定。
Many people affected by debilitating neuromuscular disorders such as amyotrophic lateral sclerosis (ALS), brainstem stroke, or spinal cord injury, are impaired in their ability to, or even unable to, communicate. A Brain-Computer Interface (BCI) uses brain signals, rather than muscles, to re-establish communication with the outside world. One particular BCI approach is the so-called “P300 matrix speller” that was first described by. It has been widely assumed that this method does not depend on the ability to focus on the desired character, because it was thought that it relies primarily on the P300 evoked potential and minimally if at all on other EEG features such as the visual evoked potential (VEP). This issue is highly relevant for clinical application of this BCI method, because eye movements may be impaired or lost in the relevant user population. This study investigated to what extent performance in a “P300” speller BCI depends on eye gaze. We evaluated the performance of 17 healthy subjects using a “P300” matrix speller during two conditions. In one condition (“letter”), the subjects focused their eye gaze on the intended letter, while in the second condition (“center”), subjects focused eye gaze on a fixation cross that was located in the center of the matrix. The results show that the performance of the “P300” matrix speller in normal subjects depends in considerable measure on gaze direction. They thereby disprove a widespread assumption in BCI research, and suggest that this BCI might function more effectively for people who retain some eye-movement control. The applicability of these findings to people with severe neuromuscular disabilities (particularly in eye-movements) remains to be determined.