Traumatic brain injury impact on normal hearing.

Traumatic brain injury (TBI) incidents bring drastic health adversities in multiple systems of the body. The immediate impact on the head and central nervous system is promptly accelerated to the autonomous and peripheral nervous system. It causes an instant variability in intracranial pressure, heart rate, blood pressure, normal function of chemo/baro receptors, and sudden failure in normal communication. These effects promote long-term secondary health adversity, such as nerve schwannoma, gliosis, Wallerian degeneration, mitochondrial dysfunction, change in blood-brain barrier pathology, and impaired drainage of cerebrospinal fluid. The focal and diffuse character of TBI has a primary effect on the auditory system in terms of outer, middle, and inner ear damage. Auditory nerve dysfunction, central auditory miscommunication with the brain, intracanalicular vestibular schwannomas, lesions in cortical regions, hair cell damage, and spiral ganglion injury cause long-term secondary consequences on normal hearing function associated with TBI. In this present work, normal hearing impairment due to TBI-induced nerve damage, central-peripheral auditory dysfunction, long-term hearing loss, and associated other health impacts are highlighted.