Clinical Gaps-in-Noise Measures in Blast-Exposed Veterans: Associations with Electrophysiological and Behavioral Responses.

It has been established that blast exposure and brain injury can result in self-reported and measured auditory processing deficits in individuals with normal or near-normal hearing sensitivity. However, the impaired sensory and/or cognitive mechanisms underlying these auditory difficulties are largely unknown. This work used a combination of behavioral and electrophysiological measures to explore how neural stimulus discrimination and processing speed contribute to impaired temporal processing in blast-exposed Veterans measured using the behavioral Gaps-in-Noise (GIN) Test. Results confirm previous findings that blast exposure can impact performance on the GIN and effect neural auditory discrimination, as measured using the P3 auditory event-related potential. Furthermore, analyses revealed correlations between GIN thresholds, P3 responses, and a measure of behavioral reaction time. Overall, this work illustrates that behavioral responses to the GIN are dependent on both auditory-specific bottom-up processing beginning with the neural activation of the cochlea and auditory brainstem as well as contributions from complex neural networks involved in processing speed and task-dependent target detection.