Abstract: The landscape of modern warfare, significantly influenced by the Global War on Terror (GWOT, 2001-2021), has led soldiers to commonly experience blast-induced traumatic brain injury (bTBI) resulting from improvised explosive devices (IEDs). Between 2000 and 2024, over 515,000 service members deployed have sustained a traumatic brain injury (TBI) with 80% classified as mild TBI (i.e., concussion). Nonetheless, bTBI is not limited to service members as the rising incidence of terrorist attacks has also led to an increase of blast-related injuries in civilian populations (e.g., Oklahoma City, 1995; New York City, 2001; Boston Marathon, 2013; Paris, 2015; Gaza, 2023). Current diagnostics are non-objective and fail to detect important yet subtle structural and functional changes, often leading to misdiagnosis and delayed treatment. Hearing loss is commonly observed after sustaining bTBI due to the intense sound exposure and energy transferred from the blast source. Individuals who experience bTBI often complain of having difficulty hearing in complex auditory scenes despite having normal hearing thresholds. These hearing deficits have been suggested to originate from loss of sensory cells and peripheral innervation in the inner ear in addition to central damage along the auditory brainstem and cortex. However, it is still not fully understood how individual deficits at the peripheral and central levels contribute to the development of these hearing deficits. We hypothesize bTBI will affect hearing sensitivity, cochlear function, and temporal encoding followed by inflammation, astrocytosis, microglia activation in addition to loss of neurons, sensory cells, and afferent synapses. This proposal will assess the functional and structural changes in the peripheral and central auditory system following blast exposure using the chinchilla animal model. These findings will advance our understanding of how auditory deficits arise from complex peripheral and central injuries. Findings from this research are expected to contribute to the overall understanding of the pathophysiology of bTBI in addition to laying the groundwork for future objective auditory-based diagnostic frameworks of traumatic brain injury, not only for blast-related injuries, but potentially other TBI etiologies (e.g., motor vehicle accidents, sports, and falls). Future studies can use this auditory framework to assess hearing deficits across species—supported by an extensive repository of physiological and histological biomarkers. These auditory-based biomarkers have the potential to facilitate early diagnosis and intervention, particularly in mild-to-moderate traumatic brain injuries (e.g., concussions) where minimal yet significant damage occurs.

Location: Lyles-Porter Hall (715 Clinic Dr.) Room 1028 on Thursday, August 14th (1-3pm)