Background

Brain-computer interface (BCI) spellers detect variations in brain waves to help subjects communicate with the world. This study introduces a P300-SSVEP hybrid BCI-based QWERTY speller.

Methods

The proposed hybrid speller, combines SSVEP and P300 features using a hybrid paradigm. P300 was used as time division multiplexing index which results in the use of lesser number of assumed frequencies for SSVEP elicitation. Each flickering frequency was also assigned a unique colour, to enhance system accuracy.

Results

On the basis of 20 subjects, an average accuracy of classification of 96.42% and a mean information transfer rate (ITR) of 131.0 bits per min. (BPM) was achieved during the free spelling trial (trial-F).

Comparison

The t test results revealed that the hybrid QWERTY speller performed significantly better (on the basis of mean classification accuracy and ITR) as compared to the traditional P300 speller) and the QWERTY SSVEP speller. Also, the amount of time taken to spell a word was significantly lesser in the case of hybrid QWERTY speller in contrast to traditional P300 speller while it was almost the same as compared to QWERTY SSVEP speller.

Conclusion

QWERTY speller outperformed the stereotypical P300 speller as well as QWERTY SSVEP speller.

Graphical abstract

中文翻译：

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具有高信息传输率的基于脑电图的混合 QWERTY 精神拼写器

背景

脑机接口 (BCI) 拼写器检测脑电波的变化，以帮助受试者与世界交流。本研究介绍了基于 P300-SSVEP 混合 BCI 的 QWERTY 拼写器。

方法

提议的混合拼写器使用混合范式结合了 SSVEP 和 P300 功能。P300 用作时分复用索引，这导致使用较少数量的假定频率进行 SSVEP 启发。每个闪烁频率也被分配了一种独特的颜色，以提高系统精度。

结果

在 20 名受试者的基础上，平均分类准确率为 96.42%，平均信息传输率 (ITR) 为 131.0 位/分钟。(BPM) 是在免费拼写试用 (trial-F) 期间实现的。

比较

所述吨试验结果表明，混合的QWERTY拼写进行显著更好相比传统P300拼写为）和QWERTY SSVEP拼写（平均分类精度和ITR的基础上）。此外，与传统 P300 拼写器相比，混合 QWERTY 拼写器的拼写时间显着减少，而与 QWERTY SSVEP 拼写器相比几乎相同。

结论

QWERTY 拼写器的表现优于刻板的 P300 拼写器以及 QWERTY SSVEP 拼写器。

图形概要