BiSIPL, Department of Electrical Engineering, Sharif university of Technology, Tehran, Iran.
Department of Systems and Computer Engineering, Carleton University, Ottawa, Canada.
J Neurosci Methods. 2019 Dec 1;328:108420. doi: 10.1016/j.jneumeth.2019.108420. Epub 2019 Aug 31.
A speller system enables disabled people, specifically those with spinal cord injuries, to visually select and spell characters. A problem of primary speller systems is that they are gaze shift dependent. To overcome this problem, a single Rapid Serial Visual Presentation (RSVP) paradigm was initially introduced in which characters are displayed one-by-one at the center of a screen.
Two new protocols, Dual and Triple shifted RSVP paradigms, are introduced and compared against the single paradigm. In the Dual and Triple paradigms, two and three characters are displayed at the center of the screen simultaneously, holding the advantage of displaying the target character twice and three times respectively, compared to the one-time appearance in the single paradigm. To compare the named paradigms, three subjects participated in experiments using all three paradigms.
Offline results demonstrate an average character detection accuracy of 97% for the single and double protocols, and 80% for the Triple paradigm. In addition, average ITR is calculated to be 5.45, 7.62 and 7.90 bit/min for the single, Dual and Triple paradigms respectively. Results identify the Dual RSVP paradigm as the most suitable approach that provides the best balance between ITR and character detection accuracy.
The novel speller system (the Dual paradigm) suggested in this paper demonstrates improved performance compared to existing methods, and overcomes the gaze dependency issue.
Overall, our novel method is a reliable alternative that both removes limitations for users suffering from impaired oculomotor control and improves performance.
拼字系统使残疾人，特别是脊髓损伤患者，能够通过视觉选择和拼写字符。主要拼字系统的一个问题是它们依赖于眼球运动。为了克服这个问题，最初引入了一种单一的快速连续视觉呈现 (RSVP) 范式，其中字符一个一个地显示在屏幕中央。
引入了两种新协议，双和三重移位 RSVP 范式，并与单一范式进行了比较。在双和三重范式中，两个和三个字符同时显示在屏幕中央，与单一范式中字符一次出现相比，分别具有显示目标字符两次和三次的优势。为了比较命名范式，三名受试者参与了所有三种范式的实验。
离线结果表明，单一和双协议的平均字符检测准确率为 97%，三重范式的平均字符检测准确率为 80%。此外，单一、双和三重范式的平均 ITR 分别计算为 5.45、7.62 和 7.90 位/分钟。结果表明，双 RSVP 范式是最适合的方法，它在 ITR 和字符检测准确率之间提供了最佳平衡。
本文提出的新型拼字系统（双范式）与现有方法相比，性能得到了提高，并且克服了眼球依赖问题。
总的来说，我们的新方法是一种可靠的替代方案，既消除了患有眼球运动控制障碍的用户的限制，又提高了性能。
