Causes of adult hearing loss

Hearing loss in adults has many causes. Factors that can contribute to hearing loss include the aging process, noise exposure, ototoxic drugs, diseases, tumors, and trauma.

Presbycusis: Presbycusis is the loss of hearing that gradually occurs in most individuals as they grow older. The process involves degeneration of the inner ear (cochlea). The hearing loss is progressive in nature with the high frequencies affected first. While the process begins after age 20, it is typically at ages 55 to 65 that the high frequencies in the speech range begin to be affected.

Noise Exposure: Prolonged exposure to noise causes damage to the hair cells in the cochlea and results in permanent hearing loss. Noise-induced hearing loss usually develops gradually and painlessly, however it can also occur as a result of a single exposure to a very high level of sound.

Ototoxic Drugs: Medications used to manage some diseases are damaging to the auditory system (ototoxic) and cause hearing loss. Some of the drugs known to be ototoxic include aminoglycoside antibiotics; salicylates in large quantities (aspirin), loop diuretics; and drugs used in chemotherapy regimens.

Diseases: Meniere’s disease affects the membranous inner ear and is characterized by deafness, dizziness (vertigo), and ringing in the ear (tinnitus). Otosclerosis is a disease that involves the middle ear capsule, specifically affecting the movement of the stapes (one of the three tiny bones in the middle ear).

Tumors: An acoustic neuroma is an example of a tumor that causes hearing loss. Acoustic neuromas arise in the eighth cranial nerve (acoustic nerve). The first symptom is reduction of hearing in one ear accompanied by a feeling of fullness.

Trauma: Trauma can also result in hearing loss. Examples include fractures of the temporal bone, puncture of the eardrum by foreign objects, and sudden changes in air pressure.