Investigating Temporal Resolution in Children with Listening Difficulties Using a Novel Multi-Deviant Paradigm

Abstract

Auditory temporal resolution is the ability to detect rapid changes in sound. It is often measured using gap-detection tasks, in which a listener detects a brief silent interval within a continuous or long-duration sound. Gap detection is important for speech perception because many speech cues depend on fine temporal information. However, behavioural gap-detection tasks require attention, motivation, and active responses. These factors are especially important when testing children, including those with auditory processing disorder (APD), because poor behavioural performance may not always reflect a pure auditory temporal-processing deficit. The present thesis examined automatic auditory gap detection using event-related potentials (ERPs). The main focus was the deviant-related negativity (DRN), an electrophysiological response elicited by a gap deviant. The thesis investigated whether the temporal position of a gap affects the DRN and whether a time-efficient multi-deviant paradigm can be used to study multiple gap onset times within a single recording sequence. Behavioural and electrophysiological gap detection were examined in adults, typically developing (TD) children, and children with APD. Participants completed passive electroencephalography (EEG) recordings while watching a silent subtitled video and ignoring the auditory stimuli. The standard stimulus was a 500-ms broadband-noise burst. Deviants were created by inserting a silent gap of either 10 or 30 ms at different onset times, ranging from 15 to 400 ms after stimulus onset. In a separate behavioural task, participants actively detected the occurrence of the gap. There was no significant difference in DRN amplitude between the multi- and single deviant paradigms. Across groups, DRN amplitude was larger for 30-ms than for 10-ms gaps and decreased when the gap occurred later in the stimulus. In adults, the DRN was reduced for gaps occurring at 300 and 400 ms. In TD children, this temporal limitation was stronger, with reliable DRNs mainly observed for early-occurring gaps. Behavioural performance was generally high, but children performed more poorly than adults. Children with APD also showed poorer behavioural gap detection than TD children. However, their overall DRN amplitude was not consistently reduced, although less stable responses were observed in some conditions. Overall, this thesis showed that automatic neural detection of gaps is affected by both gap duration and gap onset time. The findings support the idea that auditory deviance detection is limited by a short temporal integration window. This limitation appears stronger in children than in adults. In children with APD, poorer behavioural performance may partly reflect task demands or attention rather than a consistent deficit in automatic auditory change detection. The multi-deviant gap paradigm may therefore be considered in future work as a time-efficient approach for studying auditory temporal processing in adults, children, and clinical populations.