Somatosensorische cross-modale Reorganisation bei Erwachsenen mit einseitiger Taubheit – eine EEG-Studie

Introduction

Somatosensory cross-modal reorganization of auditory cortices has been shown in unaided bilaterally deaf subjects and bilaterally deaf cochlear implant (CI) users. However, the literature on adults with postlingual single-sided deafness (SSD) is sparse. We therefore investigated the presence of somatosensory cross-modal reorganization in SSD adults.

Material and methods

High-density electroencephalography was used to record cortical somatosensory evoked potential (CSEP) responses to vibrotactile stimuli, administered to the right index finger of 15 postlingual SSD adults and 15 age- and sex-matched normal hearing (NH) controls. Global field power was calculated for the CSEP components P50, N70, P100 and N140 and compared between the NH and SSD groups. In both groups, current density reconstructions were conducted using Standardized Low Resolution Brain Electromagnetic Tomography to evaluate the extent of somatosensory cross-modal reorganization.

Results

In NH participants, CSEP and current density reconstructions followed expected patterns, with pre- and postcentral cortices activated contralaterally to the side of stimulation. SSD participants exhibited similar contralateral pre- and postcentral activation. However, they also demonstrated an additional significant activation of auditory cortical areas including the supramarginal gyrus and the superior and inferior temporal gyri. Additionally, the CSEP P100 appeared earlier in the SSD group than in the NH group, suggesting possible alterations in cortical timing.

Discussion

Our findings suggest that even in cases of postlingually acquired SSD, somatosensory cross-modal reorganisation occurs.

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