Abstract:  Noise-induced hearing loss (NIHL) is a prevalent issue among military personnel, primarily attributed to environmental auditory stressors in their environment, notably firearm noise, which consists of repeated, high-intensity bursts of sound. While previous research has investigated the impact of firearm noise on the peripheral auditory system, its influence on the central auditory system (CAS) is still unknown. Therefore, our study aims to identify how firearm-like sounds affects cochlear and CAS structures and processes, specifically within the thalamocortical region. Our hypothesis posits that firearm induced NIHL will elevate auditory thresholds and lead to an overall reduction in middle latency response (MLR) component amplitudes, indicated compromised functionality within the inferior colliculus and medial geniculate body. We exposed subjects to a simulated small arms fire (SAF) noise, and subsequently employed a modified click train to assess the effects of noise exposure on thalamocortical processing over a 56-day period. Our preliminary findings reveal a reduction in all MLR component amplitudes and a loss of peak distinctiveness. Intriguingly, we observed a non-monotonic progression of thalamocortical dysfunction, characterized by phases of initial damage, temporary recovery, and chronic degradation. Future analyses will enable us to compare the progression of thalamocortical processing in response to both NIHL and metabolic-induced hearing loss as we examine the effects of SAF exposure relative to D-galactose exposure.

This year’s SHRP schedule is available here: https://purdue.edu/TPAN/hearing/shrp_schedule 

Titles and abstracts of all SHRP talks are here: https://purdue.edu/TPAN/hearing/shrp_abstracts