Presbycusis is a type of sensorineural hearing loss that occurs gradually as people age. In some cases, there may be a loss of ability to discriminate sounds. That is, a person may be able to hear sounds, but may not be able to make words out of them. The cause is that tiny inner-ear hair cells (sensory neuroreceptor cells) degenerate, leading to a gradual loss of hearing. These cells send electrical sound impulses to the brain where sounds are received and processed.
Presbycusis generally begins to affect people between ages 55 and 65, but may not occur until much later.