January 24, 2021

Neurophysiological correlates of residual inhibition in tinnitus: Hints for trait-like EEG power spectra

Objective: To investigate oscillatory brain activity changes specific for short-term acoustic tinnitus suppression (residual inhibition) and whether these changes can be associated with behavioral measures of tinnitus loudness. Further, contrasts between acoustic stimulation responders and non-responders provide profound insights in spontaneous brain activity related to residual inhibition. Methods: Three different types of noise stimuli were administered for acoustic stimulation in 45 tinnitus patients. Subjects resting state EEG activity was recorded before and during tinnitus suppression alongside with subjective measurements of tinnitus loudness. Results: On the whole-group level, tinnitus-unspecific changes were observed which fit established knowledge about basic neural responses after acoustic stimulation. Responder non-responder contrasts revealed differences in alpha and gamma band activity in line with the proposed neural models for oscillatory brain activity in tinnitus. Sample characteristic analysis demonstrated divergences between responders and non-responders notably for tinnitus duration. Neither correlations of behavioral tinnitus measures nor differences for stimulus-induced changes in ongoing brain activity were detected. Conclusions: Taken together, our observations might be indicative of trait-specific forms of oscillatory signatures in different subsets and chronification grades of the tinnitus population possibly related to acoustic tinnitus suppression. Results and insights are not only useful to understand basic neural mechanisms behind residual inhibition but are also valuable for general neural models of tinnitus. Significance: This is the first EEG experiment in tinnitus which compares acoustic stimulation responders and non-responders.

 bioRxiv Subject Collection: Neuroscience

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