Neural Responses to Visuo-Tactile Stimulation in Early Deaf
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Authors
Harlan De Crescenzo, Angelo
Issue Date
2021
Type
Thesis
Language
Keywords
Alternative Title
Abstract
Multi-sensory integration (MI) of cross-modal stimuli is pivotal to navigate our everyday activities. Sensory stimuli from different modalities are integrated to create a more complete perception. Early deafness (ED) allows us to study cortical re-organization and multisensory processing following sensory deprivation, when compared to the normal hearing (NH) population. The goal of this study was to investigate the neural mechanisms of multi-sensory processing and its temporal attributes in early deaf using EEG and fast periodic visual stimulation (FPVS). We presented tactile (point-like vibration on right index fingertip) and visual (circular flash) stimuli at the frequency of 1 Hz, with varying stimulus onset asynchronies (SOAs) between tactile and visual stimuli. We analyzed the amplitude of the frequency-domain response in various regions of interest: a frontal-central (FrCen), an occipital (Occ), two bilateral temporal (rTemp and lTemp), and one region-free, all scalp assessment. We did not find differences in amplitude response when comparing ED vs NH. However, analysis of the amplitude as a function of SOA revealed that tactile leading stimuli elicited significantly greater amplitudes than visual leading conditions. Also, the unisensory visual stimulation resulted in higher amplitudes than the unisensory tactile one.These findings, taken together, point towards a difference in neural processing of multisensory, visuo-tactile stimuli, as a function of the presentation order (visual vs tactile first). However, there seems to be no change in neural responses based on hearing capabilities (NH vs ED).