Difference in somatosensory event-related potentials in the blind subjects leads to better performance in tactile P300 BCI

Abstract

In this study, we have created an 8-command P300 tactile BCI with two stimuli types, running on a minimally modified consumer Braille display and tested it on 10 blind subjects and 10 sighted controls. Blind subjects have demonstrated 27% higher median accuracy than sighted controls (p < 0.05), proving that the blind subjects are not only able to use tactile BCI but also can achieve superior results in comparison with sighted subjects. Median accuracy in the blind group with the best stimuli type has reached 95%. The difference in event-related potentials between groups is located in frontocentral sites before 300 ms post-stimulus and corresponds with early cognitive ERP components. The blind subjects have higher amplitude and lower latency of ERPs. This result is consistent through experimental conditions with different tactile stimuli. The classification performance for the blind subjects is correlated with Braille reading speed. This enables a discussion about mechanisms of plastic changes during sensory compensation after vision loss and its dependence on personal perceptual experience. Author summarySensory compensation following vision loss can be recognized as a unique model for neural plasticity. However, the magnitude of the effect and the specific tasks where it's manifested is still a subject for debate. In this study, we have created a tactile brain-computer interface game to study how somatosensory processing is different between the blind and the sighted people. The participants were required to attend to tactile stimuli, and the correct stimulus was selected using realtime EEG classification. We have shown, for the first time, that the blind subjects are significantly better than the sighted in tactile brain-computer interface tasks. We have also found, that individual performance is correlated with Braille proficiency. This result links personal perceptual abilities in two different sensory tasks. EEG analysis revealed that differences in performance can be attributed to early cognitive processing steps. Along with practical considerations in brain-computer interface development, the results also add to the data on cognitive processing in the blind and enable the discussion on the importance of Braille education.

Novel electrotactile brain-computer interface with somatosensory event-related potential based control

“…Signal from Fp1 location was used to register ocular artifacts. This subset of EEG channels have been selected based on the review of topography of sERP responses and the main sources of EEG activity which are expected in the contralateral somatosensory cortex ( Josiassen et al, 1990 ; Li et al, 2019 ; Grigoryan et al, 2020 ; Chu et al, 2021 ). The signals were digitized with a 1,200 Hz sampling rate and the amplifier was configured to use embedded notch filter at 50 Hz.…”