UBC Theses and Dissertations
Cortical auditory evoked potentials to estimate gap-detection thresholds in adults Angel, Rebecca
Temporal resolution is the ability of the auditory system to detect small changes over time and is an important component for the detection and decoding of speech by the central auditory nervous system. Temporal resolution is most often measured by asking a person to detect small gaps between sounds, known as behavioural gap-detection tests. However, certain populations may be unable or unwilling to respond reliably due to perceptual or cognitive deficits, or in medico-legal compensation cases. There are limitations to behavioural gap-detection measures because they cannot separate cognitive from perceptual deficits. The present study utilized electrophysiological gap-detection measures as a means of objectively estimating behavioural gap-detection thresholds. Cortical auditory evoked potentials (CAEPs) are neural responses to changes in sound, duration, and frequency that can be measured from the scalp. The specific aim of this study was to collect adult normative data for CAEP gap-detection thresholds to examine if CAEPs could accurately estimate behavioural gap-detection thresholds. Gap-evoked CAEPs could be recorded in participants who were awake and passively listening and could estimate temporal resolution without the need for a participant’s cooperation or attention. The results showed that there was a significant N1-P2 response to gaps at ≥ 4 ms, with 85% of participants having a response to a 10 ms gap. Additionally, the electrophysiological mean gap-detection threshold was within 1 ms of behavioral mean gap-detection threshold. This demonstrated that gap-evoked CAEPs can accurately estimate behavioural gap-detection thresholds in a normal hearing adult population.
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