Effects of hand dominance on lateralized tactile processing

Objective of the study: The study aimed to examine how the manipulation of static interstimulus intervals (ISI) influences cortical somatosensory responses to non-painful tactile stimuli when applied to the dominant and non-dominant hands. Methods: Nineteen healthy, right-handed volunteers participated in the EEG study.non-painful tactile stimuli were delivered to the right and left fingertips in separate sessions. The ISI was set at a short 2-second interval (ISI2) and a long 8-second interval (ISI8) in separate sessions. The primary measure was the Peak-to-Peak Maximum (PPMax) amplitude, calculated between the late cortical N2 (200 ms) and P2 (around 300 ms) components. A three-way repeated-measures ANOVA (ISI x Electrode x Hand) was used for statistical analysis. Results: A significant main effect of ISI was found (p < .001), with PPMax amplitudes significantly higher in the ISI8 session compared to ISI2. Crucially, there was no significant main effect of the hand. Conclusion(s): The increased amplitude at ISI8 supports the concept that longer intervals facilitate recovery from habituation. The absence of a significant difference between the dominant and non-dominant hands, contrary to typical lateralized findings, suggests a weakening of this lateralized pattern under static ISI conditions.