Auditory cortical processing in noise in normal-hearing young adults

Objective: The ability to hear in background noise is related to the processing of the incoming acoustic signal in the peripheral auditory system as well as the central auditory nervous system (CANS). Electrophysiological tests have the ability to demonstrate the underlying neural integrity of the CANS, but to date a lack of literature exists demonstrating the effects of background noise on auditory cortical potentials. Therefore, the purpose of this investigation was to systematically investigate the effects of white noise on tone burst-evoked late auditory evoked potentials (N1, P2, and P3) in normal hearing young adults. Study Design: Twenty young-adult normal-hearing individuals served as subjects. A comparison of the late auditory evoked potentials (N1, P2, and P3) was made at multiple signal-to-noise ratios (SNRs) (quiet, + 20, + 10, 0). N1, P2, and P3 were elicited and both amplitude and latency were measured for each of the potentials. A standard oddball paradigm with binaural stimulation was used to evoke the potentials. Repeated Measures Analyses of Variance (ANOVA) were conducted for both the experimental factors of amplitude and latency with within subjects factors of condition (quiet, + 20, + 10, 0). Results: Results indicated no significant differences in N1, P2, or P3 amplitude or latency between the quiet and + 20 SNR condition; however, at poorer SNRs significant N1, P2, and P3 amplitude and/or latency differences were observed. Conclusion: The results indicate a change in higher-order neural function related to the presence of increased noise in the environment.