Event-related potentials following gaps in noise: The effects of the intensity of preceding noise.

Auditory temporal resolution is critical for the perception of speech. It is often studied using gap detection methods in which a silent period (or "gap") is inserted in a long duration auditory stimulus. When the gap is inserted in a frequently occurring standard stimulus, it elicits a negative-going event-related potential, called the deviant-related negativity (DRN). A time-efficient multi-deviant paradigm was employed in which a standard 200 ms noise burst was presented on 50% of trials and a deviant stimulus, containing a gap, on the remaining 50% of trials. Seven different deviants were constructed by inserting a gap in the centre of the standard. The duration of the seven gaps ranged from 2 to 40 ms. In different conditions, the intensity of the noise burst was either 60 or 80 dB SPL. Ten adults watched a silent video while ignoring the auditory sequence. As expected, the amplitude of the DRN increased as gap duration became longer, regardless of the intensity of the noise in which the gap occurred. The intensity of the noise burst also affected the DRN measured peak-to-peak (DRN-to-following positivity). This was reduced when the gap occurred in the lower intensity noise burst. The time efficient multi-deviant paradigm can thus be employed to determine the effects of factors known to affect gap detection: the duration of the gap, and the intensity of the sound in which the gap is inserted.