Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
J Neural Eng. 2012 Aug;9(4):045002. doi: 10.1088/1741-2560/9/4/045002. Epub 2012 Jul 25.
In this study, a tactile speller was developed and compared with existing visual speller paradigms in terms of classification performance and elicited event-related potentials (ERPs). The fingertips of healthy participants were stimulated with short mechanical taps while electroencephalographic activity was measured. The letters of the alphabet were allocated to different fingers and subjects could select one of the fingers by silently counting the number of taps on that finger. The offline and online performance of the tactile speller was compared to the overt and covert attention visual matrix speller and the covert attention Hex-o-Spell speller. For the tactile speller, binary target versus non-target classification accuracy was 67% on average. Classification and decoding accuracies of the tactile speller were lower than the overt matrix speller, but higher than the covert matrix speller, and similar to Hex-o-Spell. The average maximum information transfer rate of the tactile speller was 7.8 bits min(-1) (1.51 char min(-1)), with the best subject reaching a bit-rate of 27 bits min(-1) (5.22 char min(-1)). An increased amplitude of the P300 ERP component was found in response to attended stimuli versus unattended stimuli in all speller types. In addition, the tactile and overt matrix spellers also used the N2 component for discriminating between targets and non-targets. Overall, this study shows that it is possible to use a tactile speller for communication. The tactile speller provides a useful alternative to the visual speller, especially for people whose eye gaze is impaired.
在这项研究中，开发了一种触觉拼写器，并将其与现有的视觉拼写器范式在分类性能和诱发事件相关电位 (ERPs) 方面进行了比较。健康参与者的指尖受到短暂的机械敲击刺激，同时测量脑电图活动。字母表中的字母被分配到不同的手指上，参与者可以通过默数该手指上的敲击次数来选择其中一个手指。触觉拼写器的离线和在线性能与显性和隐性注意视觉矩阵拼写器以及隐性注意 Hex-o-Spell 拼写器进行了比较。对于触觉拼写器，平均目标与非目标分类准确率为 67%。触觉拼写器的分类和解码准确率低于显性矩阵拼写器，但高于隐性矩阵拼写器，与 Hex-o-Spell 相似。触觉拼写器的平均最大信息传输率为 7.8 位/分钟（1.51 个字符/分钟），最佳受试者的位率达到 27 位/分钟（5.22 个字符/分钟）。在所有拼写器类型中，与非目标相比，被注意到的刺激会引起 P300 ERP 成分的振幅增加。此外，触觉和显性矩阵拼写器还使用 N2 成分来区分目标和非目标。总体而言，这项研究表明，使用触觉拼写器进行交流是可行的。触觉拼写器为视觉拼写器提供了一个有用的替代方案，特别是对于那些目光受损的人。
