A cross-sectional study of the event-related potential of tactile stimulus recognition and brain activity in individuals with early- and late-onset visual impairment

People with visual impairment (VI) may have improved tactile recognition skills due to enhanced cognitive processing. However, whether this enhancement varies depending on whether VI is acquired early or late is unclear. This study aimed to determine the differences in behavioral performance during tactile stimulus detection and P300 wave latency between three groups: early-onset VI group (EVI), late-onset VI group (LVI), and sighted control group (CG). Brain cortical activity was also analyzed. Participants' hands were passively stimulated with a vibrotactile device, and participants were asked to identify the stimulus while electroencephalography and P300 event-related potentials were recorded. Behavioral performance, P300 latency, and bioelectrical brain activity were assessed. EVI (n = 13) and LVI (n = 12) groups showed better tactile recognition performance with shorter reaction times than CG (n = 14) (p < 0.05). This may be due to the tactile experience that people with VI may have. No differences were found among the three groups for P300 latency (p > 0.05). Both EVI and CG groups exhibited significant activity in the superior and middle frontal regions, which may be related to attention and working memory processes. EVI group also exhibited greater activity in bilateral parietal structures, which may be linked to multimodal information processing and the dorsal pathway, involved in spatial processing (the "where" of things). By contrast, the LVI group showed significantly higher activity in the superior temporal areas, which may be related to the ventral pathway responsible for object identification (the "what" of things).