Background noise can enhance cortical auditory evoked potentials under certain conditions

Objective: To use cortical auditory evoked potentials (CAEPs) to understand neural encoding in background noise and the conditions under which noise enhances CAEP responses. Methods: CAEPs from 16 normal-hearing listeners were recorded using the speech syllable/ba/presented in quiet and speech-shaped noise at signal-to-noise ratios of 10 and 30 dB. The syllable was presented binaurally and monaurally at two presentation rates. Results: The amplitudes of N1 and N2 peaks were often significantly enhanced in the presence of low-level background noise relative to quiet conditions, while P1 and P2 amplitudes were consistently reduced in noise. P1 and P2 amplitudes were significantly larger during binaural compared to monaural presentations, while N1 and N2 peaks were similar between binaural and monaural conditions. Conclusions: Methodological choices impact CAEP peaks in very different ways. Negative peaks can be enhanced by background noise in certain conditions, while positive peaks are generally enhanced by binaural presentations. Significance: Methodological choices significantly impact CAEPs acquired in quiet and in noise. If CAEPs are to be used as a tool to explore signal encoding in noise, scientists must be cognizant of how differences in acquisition and processing protocols selectively shape CAEP responses.