Impaired brain processing in noise-induced tinnitus patients as measured by auditory and visual event-related potentials

Objectives: This study aimed to confirm that the brain processing of auditory stimuli in tinnitus patients is impaired (Attias, Urbach, Gold, & Shemesh, 1993). In addition, possible brain processing dysfunction in response to visual stimuli was assessed. Design: Auditory and visual event-related potentials (ERPs) and reaction times were recorded in response to a standard oddball target detection paradigm. The subjects consisted of 21 noise-induced chronic tinnitus patients and 21 age- and hearing-matched control subjects without tinnitus. Results: The tinnitus patients had significantly prolonged latencies for the auditory nontarget ERP components N1, N2, and P3 and for the auditory target ERP P3 component. The auditory P3 component was also significantly reduced in amplitude for both target and nontarget stimuli for the tinnitus patients. The visual P3 target and nontarget components were similarly significantly prolonged in latency for the tinnitus patients. Reaction times to both target and nontarget stimuli were significantly delayed for the tinnitus patients for both stimulus modalities. Conclusions: These findings point to a cortical information processing dysfunction in chronic tinnitus patients associated primarily with auditory stimuli. ERPs may provide an objective electrophysiologic tinnitus measure.