RT info:eu-repo/semantics/article
T1 Enhancing user experience in c-VEP-based BCI: Effects of visual stimulus opacity on performance and visual fatigue
A1 Martín Fernández, Ana
A1 Martínez Cagigal, Víctor
A1 Moreno Calderón, Selene
A1 SantaMaría Vazquez, Eduardo
A1 Hornero Sánchez, Roberto
K1 Brain-computer interfaces (BCI)
K1 Code-modulated visual evoked potentials
K1 (c-VEP)
K1 Opacity
K1 Visual fatigue
K1 33 Ciencias Tecnológicas
K1 32 Ciencias Médicas
AB Brain-computer interfaces (BCI) based on code-modulated visual evoked potentials (c-VEP) enable users tocontrol devices through brain activity. These systems typically employ black and white flashes encodedvia pseudo-random binary sequences to synchronize brain responses with specific commands. However, thistraditional encoding often induces visual fatigue in users. Additionally, the sharp contrast of black andwhite commands can obscure the background on which they are displayed, complicating the integrationof this technology in dynamic environments. Using semi-transparent stimuli could address these issues byreducing eyestrain and enabling compatibility with diverse backgrounds. However, the impact of opacity inc-VEP stimuli remains unexplored. This study aims to assess how varying visual stimulus opacity influencessystem accuracy and user experience. Six different opacity and background combinations were tested with tenhealthy participants, who rated visual fatigue on a scale from 0 (none) to 10 (extreme) after each condition.Results showed that traditional encoding achieved 100% accuracy but induced high fatigue (6.4 points). Aconfiguration with 100% opacity for black and 50% for white maintained high accuracy (99.38%) whilereducing fatigue to 3.7 points. Brain responses were consistent when both black and white stimuli werepresent, but patterns changed when one color was omitted. Spatial filters revealed stable c-VEP decodingfrom the parieto-occipital cortex, with slightly higher activation in low-contrast conditions. The findings fromthis study suggest that adjusting the opacity of stimuli in c-VEP-based BCI can optimize the balance betweenperformance and user experience. Implementing a reduction in opacity not only improves visual fatigue butmay also facilitate the integration of c-VEP systems into lifelike environments.
PB Elsevier
SN 1746-8094
YR 2025
FD 2025
LK https://uvadoc.uva.es/handle/10324/76171
UL https://uvadoc.uva.es/handle/10324/76171
LA eng
NO Biomedical Signal Processing and Control, 2025, vol. 108, p. 107894
NO Producción Científica
DS UVaDOC
RD 04-jul-2025