Auditory event related potentials in simulated tinnitus

It was previously demonstrated that noise induced tinnitus (NIT) patients have prolonged reaction times and event related potentials (ERPs) that are reduced in amplitude and prolonged in latency. This study considered whether these alterations occurred as a consequence of the competing auditory tinnitus sensation or as a result of a possible cognitive processing dysfunction in NIT patients. ERPs and reaction times (RTs) were recorded in response to a standard oddball auditory target detection paradigm, with and without simulated tinnitus. Tinnitus was simulated using a high tone narrow band noise presented at the forehead via a standard audiometric bone vibrator. The subjects consisted of 19 males suffering from noise induced hearing loss without tinnitus. The latencies and amplitudes of the ERP components N1, P2, N2, and P3, as recorded along the midline scalp sites (Fz, Cz, and Pz) and bilateral temporal sites (C3 and C4), did not differ significantly when recorded with and without simulated tinnitus. Similarly, the associated reaction times did not differ significantly. These findings suggest that the ERP alterations previously reported to exist for NIT patients cannot be explained simply as a consequence of increased task difficulty and cognitive loading due to the tinnitus sound.