Presbycusis is the medical term for age-related hearing loss. Most people suffer some degree of hearing loss as they age. According to the National Institutes of Health, approximately 30 to 35 percent of adults between 65 and 75 years old will lose some hearing. Approximately half of all people over 75 have some noticeable hearing loss, too.
There are many factors that can contribute to presbycusis. As a person ages the cumulative effects of noises in the environment can cause some hearing loss, as can the aging process itself. Hair cells, which are the receptors in the inner ear, tend to fall out and degrade as a person ages, which also affects their ability to hear. Damage to the nerves that carry sound to the brain can also cause hearing loss, as can medical conditions that effect blood flow. High blood pressure, diabetes, circulatory problems and many vascular conditions can all contribute to hearing loss.
Some people with these conditions will never develop hearing loss, and not all elderly individuals will lose their hearing as they age. It is not clear why some people are more prone to presbycusis than others, although some scientists suspect that it may be a genetic condition.
Presbycusis normally affects a person's hearing range. Usually the higher frequencies are the first to go, making it difficult to hear high-pitched sounds like birds chirping, sirens or a telephone ringing. Additionally, specific sounds in speech may no longer be audible. The "s" and "th" sounds are especially high in pitch, so a person with age-relating hearing loss may have difficulty telling the two apart.
Conversations as a whole may be hard to understand, especially in crowds or in areas with a lot of background noise. Voices can become muddled and it may sound like people are not speaking clearly. In some cases tinnitus, or a constant ringing in the ears, may occur as well.
If a person suspects they might be suffering from presbycusis or any other form of hearing loss they will usually take a hearing test. These tests determine a person's absolute threshold of hearing, the minimum sounds and frequencies that a person can hear. The more frequencies a person cannot hear, the worse the hearing damage is. Treatment options for age-related hearing loss are limited. There is no way to repair hearing that has degraded over time. Instead the only option is typically a hearing aid. Preventative measures can sometimes be taken to stop further loss, including the use of ear plugs to limit hearing damage from loud noises.