Presbycusis

Overview
Presbycusis, or age-related hearing loss, is the cumulative effect of aging on hearing. Also known as presbyacusis, it is defined as a progressive bilateral symmetrical age-related sensorineural hearing loss. The hearing loss is confined to higher frequencies.

Presentation
Hearing loss usually begins gradually after the age of sixty, and is usually found more often in men than women. This can be miscontributed to men having a greater exposure to environmental noise. However, exposure to environmental noise can lead to Noise-induced hearing loss (NIHL), a hearing issue that is separate from presbycusis.

Over time, the detection of high-pitched sounds becomes more difficult and both ears tend to be affected.

Pathophysiology
Examples of microscopic changes seen in this condition are hair cell degeneration of the cochlea and giant stereociliary degeneration.

Causes
Factors responsible for presbycusis:
 * Hereditary: Features like early aging of the cochlea and susceptibility of the cochlea for drug insults are genetically determined.
 * Atherosclerosis: May diminish vascularity of the cochlea, thereby reducing its oxygen supply.
 * Dietary habits: Increased intake of fatty diet may accelerate atherosclerotic changes in old age.
 * Diabetes: May cause vasculitis and endothelial proliferation in the blood vessels of the cochlea, thereby reducing its blood supply.
 * Noise trauma: Exposure to loud noise on a continuing basis stresses the already hypoxic cochlea, hastening the presbycusis process.
 * Smoking: Is postulated to accentuate atherosclerotic changes in blood vessels aggravating presbycusis.
 * Hypertension: Causes potent vascular changes, like reduction in blood supply to the cochlea, thereby aggravating presbycusis.
 * Ototoxic drugs: Ingestion of ototoxic drugs like aspirin may hasten the process of presbycusis.

Cultural aspects
Recently, this condition has led to the development of technologies to stop younger people from loitering near British stores (The Mosquito), and the development of a cell phone ringtone, Teen Buzz, for students to use in school, that many older instructors are unable to hear. In September 2006 this technique was used to make a dance track called 'Buzzin'. The track had two melodies, one that everyone could hear and one that only younger people could hear.