Author(s): Chen, XG (Chen, Xiaogang); Liu, BC (Liu, Bingchuan); Wang, YJ (Wang, Yijun); Gao, XR (Gao, Xiaorong)

Source: IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING Volume: 30 Pages: 2764-2772 DOI: 10.1109/TNSRE.2022.3208717 Published: 2022

Abstract: The practical functionality of a brain-computer interface (BCI) is critically affected by the number of stimuli, especially for steady-state visual evoked potential based BCI (SSVEP-BCI), which shows promise for the implementation of a multi-target system for real-world applications. Joint frequency-phase modulation (JFPM) is an effective and widely used method in modulating SSVEPs. However, the ability of JFPM to implement an SSVEP-BCI system with a large number of stimuli, e.g., over 100 stimuli, remains unclear. To address this issue, a spectrally-dense JPFM (sJFPM) method is proposed to encode a broad array of stimuli, which modulates the low- and medium-frequency SSVEPs with a frequency interval of 0.1 Hz and triples the number of stimuli in conventional SSVEP-BCI to 120. To validate the effectiveness of the proposed 120-target BCI system, an offline experiment and a subsequent online experiment testing 18 healthy subjects in total were conducted. The offline experiment verified the feasibility of using sJFPM in designing an SSVEP-BCI system with 120 stimuli. Furthermore, the online experiment demonstrated that the proposed system achieved an average performance of 92.47 +/- 1.83 in online accuracy and 213.23 +/- 6.60 bits/min in online information transfer rate (ITR), where more than 75% of the subjects attained the accuracy above 90% and the ITR above 200 bits/min. This present study demonstrates the effectiveness of sJFPM in elevating the number of stimuli to more than 100 and extends our understanding of encoding a large number of stimuli by means of finer frequency division.

Accession Number: WOS:000862372500005

PubMed ID: 36136927

Author Identifiers:

Author        Web of Science ResearcherID        ORCID Number

Chen, Xiaogang                  0000-0002-5334-1728

Liu, Bingchuan                  0000-0001-5988-6051

ISSN: 1534-4320

eISSN: 1558-0210

Full Text: https://ieeexplore.ieee.org/document/9899472/