A high-performance SSVEP-based BCI using imperceptible flickers

Gege Ming; Weihua Pei; Xiaorong Gao; Yijun Wang

doi:10.1088/1741-2552/acb50e

A high-performance SSVEP-based BCI using imperceptible flickers

J Neural Eng. 2023 Feb 2;20(1). doi: 10.1088/1741-2552/acb50e.

Authors

Gege Ming^{1

2}, Weihua Pei^{1

2}, Xiaorong Gao³, Yijun Wang^{1

2

4}

Affiliations

¹ State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, People's Republic of China.
² School of Future Technology, University of Chinese Academy of Sciences, Beijing, People's Republic of China.
³ Department of Biomedical Engineering, Tsinghua University, Beijing, People's Republic of China.
⁴ Chinese Institute for Brain Research, Beijing, People's Republic of China.

PMID: 36669202
DOI: 10.1088/1741-2552/acb50e

Abstract

Objective.Existing steady-state visual evoked potential (SSVEP)-based brain-computer interfaces (BCIs) struggle to balance user experience and system performance. This study proposed an individualized space and phase modulation method to code imperceptible flickers at 60 Hz towards a user-friendly SSVEP-based BCI with high performance.Approach.The individualized customization of visual stimulation took the subject-to-subject variability in cortex geometry into account. An annulus global-stimulation was divided into local-stimulations of eight annular sectors and presented to subjects separately. The local-stimulation SSVEPs were superimposed to simulate global-stimulation SSVEPs with 4⁷space and phase coding combinations. A four-class phase-coded BCI diagram was used to evaluate the simulated classification performance. The performance ranking of all simulated global-stimulation SSVEPs were obtained and three performance levels (optimal, medium, worst) of individualized modulation groups were searched for each subject. The standard-modulation group conforming to the V1 'cruciform' geometry and the non-modulation group were involved as controls. A four-target phase-coded BCI system with SSVEPs at 60 Hz was implemented with the five modulation groups and questionnaires were used to evaluate user experience.Main results.The proposed individualized space and phase modulation method effectively modulated the SSVEP intensity without affecting the user experience. The online BCI system using the 60 Hz stimuli achieved mean information transfer rates of 52.8 ± 1.9 bits min^-1, 16.8 ± 2.4 bits min^-1, and 42.4 ± 3.0 bits min^-1with individualized optimal-modulation, individualized worst-modulation, and non-modulation groups, respectively.Significance.Structural and functional characteristics of the human visual cortex were exploited to enhance the response intensity of SSVEPs at 60 Hz, resulting in a high-performance BCI system with good user experience. This study has important theoretical significance and application value for promoting the development of the visual BCI technology.

Keywords: brain-computer interfaces; electroencephalography; imperceptible flickers; steady-state visual evoked potentials; task-related component analysis.

Publication types

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

MeSH terms

Brain-Computer Interfaces*
Electroencephalography / methods
Evoked Potentials, Visual
Humans
Photic Stimulation / methods
Visual Cortex*