Perceptual and neural biomarkers of distraction from an external sound source are not associated with tinnitus severity

Individuals with chronic tinnitus perceive a phantom sound that imposes either a bothersome and irrepressible distraction throughout waking hours or a relatively mild nuisance that often fades into subliminal awareness. The difference in tinnitus salience may reflect a general difference in inhibitory control over any distracting sound, whether externally or internally generated. To test this hypothesis, we investigated neural and behavioral signatures of external auditory distraction suppression in participants with chronic tinnitus that had mild or bothersome tinnitus but were otherwise matched for age and hearing loss. Participants in both groups underwent behavioral and EEG testing that asked them to report on a target stream of amplitude modulated tones that switched from a random arrangement to a repeating sequence. Using additional sounds that imposed varying levels of distraction, we documented neural and perceptual suppression of auditory distractors. Behaviorally, participants with mild versus bothersome tinnitus showed comparable reductions in accuracy in the presence of varying distractor loads. Neural synchronization to the target stimulus change rate provided a useful proxy for distraction effects but did not differ between tinnitus groups. Likewise, no group differences were observed in the neural synchronization to modulation rates of the target or distractor stimuli. Our results build on work showing that individuals with tinnitus perform as well as individuals with normal hearing on listening tasks in noisy environments and expand this observation into the neural representation of sounds. Suppression of the internally generated phantom percept does not appear to be linked to general deficits in suppressing distractors.