Cochlear Changes After Noise Trauma

Abstract

• Tinnitus, sound perception without an external source,occurs in 15% of the population and is the mostreported disability for soldiers after combat. Noiseoverexposure is the single most important known factor leading to tinnitus.• In addition, single exposures to blasts or acute harmingsounds, but also chronic expositions to moderate noisecan lead to long-term consequences to hearing, such uspermanent hearing threshold shifts as well as poorspeech discrimination in noisy environments. Almosthalf a billion people in the world have disabling hearing loss and 1.1 billion young people (aged between 12and 35 years old) are at risk of losing their hearing dueto recreational noise.• Thus, exposure to excessive noise is the most commonpreventable cause leading to hearing loss and tinnitus.• Noise overexposure leads to damage of mechanosensory hair cells and/or their stereocilia, synaptic ribbonreduction, and auditory nerve deterioration.• The clinical significance of noise-induced hearing loss(NIHL) and noise-induced tinnitus has driven effortsto understand the underlying molecular, physiological,and biochemical mechanisms in order to search fortherapeutic agents that act as otoprotectants.