Presbyacusis, or age-related hearing loss, is the most frequent cause of sensory hearing loss and is progressive, predominantly high-frequency, and symmetrical Various etiologic factors (eg, prior noise trauma, drug exposure, genetic predisposition) may contribute to presbyacusis Most patients notice a loss of speech discrimination that is especially pronounced in noisy environments About 25% of people between the ages of 65 and 75 years and almost 50% of those over 75 experience hearing difficulties