RT info:eu-repo/semantics/article
T1 Reevaluating performance in c-VEP BCIs: The impact of calibration time
A1 Martínez Cagigal, Víctor
A1 SantaMaría Vazquez, Eduardo
A1 Pérez Velasco, Sergio
A1 Martín Fernández, Ana
A1 Hornero Sánchez, Roberto
K1 Calibration
K1 Code-modulated visual evoked potentials (c-VEP)
K1 Brain-computer interfaces (BCI)
K1 Neurotechnology
K1 Electroencephalography (EEG)
K1 3314 Tecnología Médica
AB Code-modulated visual evoked potentials (c-VEP) have demonstrated high performance in non-invasive brain-computer interfaces (BCIs). Recently, research has begun to consider practical aspects such as visual comfort,where non-binary sequences and variations in the spatial frequency of stimuli play significant roles. However,calibration requirements remain underexplored in performance comparisons. This study aims to analyze a multi-variable tradeoff crucial to the practical application of c-VEP-based BCIs: decoding accuracy, decoding speed, andcalibration time. Visual comfort is retrospectively evaluated using two pre-recorded datasets. Models were trainedwith increasing calibration cycles and tested across varying decoding times, depicting learning and decodingcurves. The datasets comprised 32 healthy subjects, and featured different stimulus paradigms: plain non-binarystimuli and checkerboard-like binary stimuli with spatial frequency variations. Results showed that all conditionsachieved over 97 % grand-averaged accuracy with sufficient calibration. However, a clear tradeoff emergedbetween calibration duration and performance. Achieving 95 % average accuracy within a 2 s decoding windowrequired mean calibration durations of 28.7±19.0 s for binary stimuli, or 148.7±72.3 s for non-binary stimuli.The binary checkerboard-based condition with a spatial frequency of 1.2 c/º (C016) proved to be particularlyeffective, achieving over 95 % accuracy within 2 s decoding window using only 7.3 s of calibration, and reportinga significant improvement in visual comfort. A minimum calibration time of 1 min was considered essentialto adequately estimate the brain response, critical in template-matching paradigms. In conclusion, achievingoptimal c-VEP performance requires balancing calibration duration, decoding speed and accuracy, and visualcomfort.
PB Elsevier
SN 0208-5216
YR 2025
FD 2025
LK https://uvadoc.uva.es/handle/10324/80692
UL https://uvadoc.uva.es/handle/10324/80692
LA eng
NO Biocybernetics and Biomedical Engineering, 2025, vol. 45, n. 4, p. 685-696
NO Producción Científica
DS UVaDOC
RD 17-dic-2025