Electrophysiological auditory measures to identify potential cortical markers of tinnitus

• Published in: Brain research Vol. 1842; p. 149100
• Main Authors: Caldwell, Joshua, Gopal, Kamakshi, Ortu, Daniele, Miller, Sharon
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2024
• Subjects: Auditory late response; Linear mixed analysis; Mismatch negativity; P300; Tinnitus; Mismatch negativity; Tinnitus; Linear mixed analysis; P300; Auditory late response
• ISSN: 0006-8993; 1872-6240; 1872-6240
• DOI: 10.1016/j.brainres.2024.149100

[Display omitted] •Individuals with tinnitus exhibit differences in cortical auditory evoked potentials generated with stimuli close to the tinnitus frequency compared to those without tinnitus.•P2 latency of the ALR may be a good assessor of efficacy of tinnitus treatments given its correlation with tinnitus questionnaires.•GFP analysis, combined with topographic maps, of tinnitus electrophysiological data suggests differences in neural activation at higher level cortical processes in tinnitus when the tinnitus frequency is involved, indicating involvement of attentional networks. Tinnitus, or the perception of a sound in the absence of an external acoustic stimulus, is a common condition that cannot yet be objectively diagnosed. Current diagnostic tests of tinnitus consist of case history and behavioral measures that rely on subjective responses. This study examined electrophysiological measures, specifically the auditory late response (ALR), mismatch negativity (MMN), and P300 as potential neural biomarkers of tinnitus in both a tinnitus and non-tinnitus control group while utilizing the pitch-matched tinnitus frequencies as the test stimuli. Results of this study found differences in MMN amplitudes and area under the curve, and in P300 topographic maps between tinnitus and control subjects. The differences in MMN responses across groups suggest that dysfunctional processing of acoustic stimuli located near the tinnitus frequency in individuals with tinnitus manifests as soon as 200 ms after initial onset of the stimulus. In addition, results from a global field power analysis and differences in spatial distributions on topographical maps indicate that deficits persist through higher levels of cortical processing. A secondary goal of this study was to determine if electrophysiological measures correlated with reported tinnitus severity on questionnaires. This analysis indicated that P2 latency was a significant predictor of Tinnitus Reaction Questionnaire, Tinnitus Handicap Inventory, and percent of the time participant’s tinnitus was considered bothersome, suggesting that this measure could potentially be used to assess the efficacy of treatment programs for tinnitus.