Severens M, Van der Waal M, Farquhar J, Desain P
Sint Maartenskliniek Nijmegen, Research Department, The Netherlands; Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, The Netherlands.
Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, The Netherlands.
Clin Neurophysiol. 2014 Nov;125(11):2297-2304. doi: 10.1016/j.clinph.2014.03.005. Epub 2014 Mar 14.
Brain-computer interfaces (BCI) tested in patients often are gaze-dependent, while these intended users could possibly lose the ability to focus their gaze. Therefore, a visual and a tactile gaze-independent spelling system were investigated.
Five patients with amyotrophic lateral sclerosis (ALS) tested a visual Hex-o-Spell and a tactile speller. Six healthy participants were also included, mainly to evaluate the tactile stimulators.
A significant attentional modulation was seen in the P300 for the Hex-o-Spell and in the N2 for the tactile speller. Average on-line classification performance for selecting a step in the speller was above chance level (17%) for both spellers. However, average performance was higher for the Hex-o-Spell (88% and 85% for healthy participants and patients, respectively) than for the tactile speller (56% and 53%, respectively). Likewise, bitrates were higher for the Hex-o-Spell compared with the tactile speller, and in the subjective usability a preference for the Hex-o-Spell was found.
The Hex-o-Spell outperformed the tactile speller in classification performance, bit rate and subjective usability.
This is the first study showing the possible use of tactile and visual gaze-independent BCI spelling systems by ALS patients with mild to moderate disabilities.
在患者身上测试的脑机接口（BCI）通常依赖于注视，而这些目标用户可能会失去集中注视的能力。因此，研究了一种视觉和一种触觉的非注视依赖拼写系统。
五名肌萎缩侧索硬化症（ALS）患者测试了视觉Hex-o-Spell和触觉拼写器。还纳入了六名健康参与者，主要用于评估触觉刺激器。
对于Hex-o-Spell，在P300中观察到显著的注意力调制；对于触觉拼写器，在N2中观察到显著的注意力调制。两种拼写器在选择拼写步骤时的平均在线分类性能均高于机遇水平（17%）。然而，Hex-o-Spell的平均性能（健康参与者和患者分别为88%和85%）高于触觉拼写器（分别为56%和53%）。同样地，Hex-o-Spell的比特率高于触觉拼写器，并且在主观可用性方面，发现用户更倾向于Hex-o-Spell。
Hex-o-Spell在分类性能、比特率和主观可用性方面优于触觉拼写器。
这是第一项表明轻度至中度残疾的ALS患者可能使用触觉和视觉非注视依赖BCI拼写系统的研究。
