[Presbyacusis: pathogenesis and treatment].

Although many adults retain good hearing as they age, hearing loss associated with ageing is common among elderly persons. There are a number of pathophysiological processes underlying age-related changes to functional components. Presbyacusis is especially caused by cochlear degeneration, most pronounced in the basal cochlear coil. Factors include physiological ageing processes as well as endogenous or exogenous causes. The common form of hardness of hearing seen in old age is not due to physiological age-related changes, but rather to a complex sensorineural pattern of injury. In the industrial countries, two main exogenous causes are exposure to loud noise and obesity. Pathomechanisms contributing to presbyacusis are hypoxia/ischemia, reactive species formation and oxidative stress, apoptotic and necrotic death of hair cells and spiral ganglion cells as well as inherited and acquired mutations in the mitochondrial DNA. Important for the successful treatment of presbyacusis is a timely fitting of hearing aids on both ears to improve communication, provide the auditory system with acoustic information, and potential prevention of social isolation. At present, several therapeutic interventions are under discussion. The application of antioxidants or caloric restriction is considered to prevent or reduce oxidative stress-induced damage. A further approach may be the overexpression or modulation of the superoxide dismutase 2 (SOD2) within the cochlea. Hair cell regeneration could also be a possible treatment of presbyacusis in the future.