Effects of background noise and tonal target stimulus on human auditory evoked potential

Abstract

The effect of background noise on the central auditory processing of stimuli with or without tonal target was examined by using mismatch negativity (MMN) response in this study. Subjects were presented with broadband noise stimuli either in the presence or in the absence of tonal target. Experimental results of MMN response showed that the presence of tonal target and the intensity level of background noise had an interaction effect on the cortical auditory encoding process. Test sequences containing tonal target did not show significant difference in their MMN responses at two noise levels of 65 and 55 dB SPL. However, the lower noise level elicited a shorter MMN latency in the absence of pure-tone stimulus. The results in this work provided evidence that the background noise level and the presence of tonal target jointly affected auditory cortical neural encoding.