Mismatch negativity and psychoacoustic measures of gap detection in normally hearing subjects

Temporal auditory processing deficits are thought to play an important role in some pathologies of speech understanding difficulties. The purposes of the present study were to determine whether short silent gaps within a pure tone can be used to elicit mismatch negativity (MMN) as an objective measu re of temporal resolution, and to investigate the relation between MMN and performance on a behavioral gap-detection task. The stimuli used for both t asks were 1-kHz sinusoids presented in a low-pass masking noise. Behavioral gap-detection thresholds were determined using an adaptive three-alternati ve forced-choice procedure. To elicit MMN, a series of deviant stimuli with varying gap durations was generated and presented in an oddball paradigm a mong standard stimuli without a gap. Only the gaps than the mean behavioral gap-detection threshold evoked a clear MMN. There was no clear relation be tween psychoacoustic and MMN thresholds.