Effects of gap onset time and gap duration on the deviant-related negativity in typically developing school-age...

This study examined whether automatic change detection to within-stimulus gaps, indexed by the deviant-related response (DRN), varies with gap duration and the temporal position of the gap within a long-duration sound, and whether these effects differ between children and adults.

Fifteen typically developing children (8-12 years) and fifteen adults (23-37 years) completed passive EEG recordings using a multi-deviant sequence in which standards and deviants alternated. All stimuli were 500-ms broadband-noise bursts. Deviants contained a silent gap of 10 or 30 ms inserted at 15, 50, 100, 200, 300, or 400 ms after stimulus onset. DRNs were derived from deviant-standard difference waves, and the presence of a DRN was evaluated using confidence interval (CI) procedures. In a separate behavioural task, participants performed active gap detection, and sensitivity was quantified using d'.

In both groups, DRN amplitude increased with gap duration and decreased as the gap onset time was delayed. Reliable DRNs were absent at the latest gap position (400 ms) in both groups. In adults, a small DRN was evident at 300 ms, whereas in children, CI testing showed that significant DRNs were limited to the 30-ms gaps occurring at 15 and 50 ms.. Behavioural sensitivity was high overall but lower in children than in adults, and did not correlate with DRN amplitude.

Automatic detection of within-stimulus gaps is constrained by the timing of the change, and this temporal constraint appears to be more pronounced in children. The dissociation between DRN outcomes and behavioural performance suggests that active detection may be supported by mechanisms beyond those indexed by the passive DRN.