Reorganization of auditory cortex in tinnitus with a normal audiogram

<p>Hui Wang</p>

Reorganization of auditory cortex in tinnitus with a normal audiogram

Hui Wang

Shanghai Sixth People's Hospital, China

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Abstract

High-density electroencephalogram (EEG) source analysis is used to determine whether there is reorganization of auditory cortex in tinnitus with a normal audiogram. Brain responses from 45 healthy right-handed tinnitus patients and 20 matched controls with normal audiometry (pure tone threshold below 25 dB HL at all frequencies from 0.125 to 8 kHz) were recorded with a 256-channel high-density electroencephalogram (HD-EEG) and auditory brainstem responses. We reported that in human subjects with tinnitus and a normal audiogram, auditory brainstem responses show significantly reduced amplitude of the wave I potential but normal amplitudes of wave V. A marked shift of the cortical representation of the tinnitus frequency into an area adjacent to the expected tonotopic location was observed after source analysis. This provides evidence of hidden hearing loss that manifests as reduced neural output from the cochlea in the absence of elevated hearing thresholds, and consequent cortical reorganization.