University of Texas at Austin
Auditory gating in tinnitus
Tinnitus is the perception of sound, such as ringing or buzzing, without an external source. Though tinnitus likely arises, in part, from hearing loss in the inner ear, research has determined that the ongoing perception of tinnitus occurs in the brain. It has been suggested that auditory gating, a function carried out by the brain in filtering out unimportant auditory information, may be abnormal in individuals with tinnitus and contribute to the conscious perception of the phantom sound.
Auditory gating can be measured noninvasively through the brain’s cortical response to sound during recording of brainwave activity, known as EEG (electroencephalography). In typical auditory gating function, cortical auditory evoked potentials (CAEPs) recorded during EEG show a decrease in amplitude when sounds (e.g., tone pairs) are presented close together in time. This decrease in amplitude reflects the brain’s ability to filter out repetitive auditory input. In atypical gating function, CAEP amplitude remains the same across sound presentation or shows little change, again suggestive of the brain’s inability to filter out irrelevant input.
This study aims to evaluate auditory gating processes in tinnitus, including cortical sources of active gating networks as observed through source localization analyses. These results will be correlated with subject reports of tinnitus severity.