The effect of stimulus number on the recognition accuracy and information transfer rate of SSVEP-BCI in augmented reality

Rui Zhang; Zongxin Xu; Lipeng Zhang; Lijun Cao; Yuxia Hu; Beihan Lu; Li Shi; Dezhong Yao; Xincan Zhao

doi:10.1088/1741-2552/ac6ae5

The effect of stimulus number on the recognition accuracy and information transfer rate of SSVEP-BCI in augmented reality

J Neural Eng. 2022 May 13;19(3). doi: 10.1088/1741-2552/ac6ae5.

Authors

Rui Zhang¹, Zongxin Xu¹, Lipeng Zhang¹, Lijun Cao¹, Yuxia Hu¹, Beihan Lu², Li Shi³, Dezhong Yao^{1

4

5}, Xincan Zhao⁶

Affiliations

¹ Henan Key Laboratory of Brain Science and Brain-Computer Interface Technology, School of Electrical Engineering, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
² International College, Zhengzhou University, Zhengzhou, 450001, People's Republic of China.
³ Department of Automation, Tsinghua University, Beijing 100084, People's Republic of China.
⁴ The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Laboratory for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, People's Republic of China.
⁵ School of Life Science and Technology, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, People's Republic of China.
⁶ School of Information Engineering, Zhengzhou University, Zhengzhou, 450001, People's Republic of China.

PMID: 35477130
DOI: 10.1088/1741-2552/ac6ae5

Abstract

Objective. The biggest advantage of steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) lies in its large command set and high information transfer rate (ITR). Almost all current SSVEP-BCIs use a computer screen (CS) to present flickering visual stimuli, which limits its flexible use in actual scenes. Augmented reality (AR) technology provides the ability to superimpose visual stimuli on the real world, and it considerably expands the application scenarios of SSVEP-BCI. However, whether the advantages of SSVEP-BCI can be maintained when moving the visual stimuli to AR glasses is not known. This study investigated the effects of the stimulus number for SSVEP-BCI in an AR context.Approach.We designed SSVEP flickering stimulation interfaces with four different numbers of stimulus targets and put them in AR glasses and a CS to display. Three common recognition algorithms were used to analyze the influence of the stimulus number and stimulation time on the recognition accuracy and ITR of AR-SSVEP and CS-SSVEP.Main results.The amplitude spectrum and signal-to-noise ratio of AR-SSVEP were not significantly different from CS-SSVEP at the fundamental frequency but were significantly lower than CS-SSVEP at the second harmonic. SSVEP recognition accuracy decreased as the stimulus number increased in AR-SSVEP but not in CS-SSVEP. When the stimulus number increased, the maximum ITR of CS-SSVEP also increased, but not for AR-SSVEP. When the stimulus number was 25, the maximum ITR (142.05 bits min^-1) was reached at 400 ms. The importance of stimulation time in SSVEP was confirmed. When the stimulation time became longer, the recognition accuracy of both AR-SSVEP and CS-SSVEP increased. The peak value was reached at 3 s. The ITR increased first and then slowly decreased after reaching the peak value.Significance. Our study indicates that the conclusions based on CS-SSVEP cannot be simply applied to AR-SSVEP, and it is not advisable to set too many stimulus targets in the AR display device.

Keywords: augmented reality (AR); brain–computer interface (BCI); computer screen (CS); information transfer rate (ITR); steady-state visually evoked potential (SSVEP).

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Algorithms
Augmented Reality*
Brain-Computer Interfaces*
Electroencephalography / methods
Evoked Potentials, Visual
Humans
Photic Stimulation / methods
Retinal Diseases*