causes of hearing loss

Presbycusis

This is the most common cause of hearing loss that is the result of the natural aging process. The condition involves degeneration of the inner ear (cochlea) over time which is progressive in nature, with loss of hearing for the high pitch sounds affected first. Some examples of high pitched sounds for speech are /s/, /f/, /th/, and /k/ which are the unvoiced consonants. The process of hearing loss begins after age 20; however, it is typically at ages 60 to 65 the high frequencies in the speech range begin to be affected.

Noise-Induced Hearing Loss

Prolonged exposure to loud noise damages the hair cells in the cochlea and results in permanent hearing loss that usually develops gradually and painlessly. Hearing loss can also occur as a result of an acoustic trauma due to a single exposure or few exposures to very loud sound.

Otitis Media

Otitis media is a middle-ear infection characterized by the accumulation of fluid in the middle ear. This can be caused by allergies, head colds, inflamed tonsils and adenoids, Eustachian tube dysfunction, sore throats and viruses.

Otosclerosis Media

This is a disease of the middle ear that specifically affects the movement of one of the three tiny bones (stapes) in the middle ear. Otosclerosis can cause a conductive hearing loss and patients with this problem may benefit from surgery or a hearing aid.

Cholesteatoma

Cholesteatoma is a type of skin cyst or sac located in the middle ear. People may be born with cholesteatoma or acquire it as a complication of repeated ear infections and Eustachian tube dysfunction. Cholesteatomas are benign but can erode the surrounding structures of the ear and cause hearing loss. The initial treatment for cholesteatoma is to stop the infection with antibiotics and ear drops; however, surgery is required in some cases.

Ménière’s Disease

Ménière’s disease affects the inner ear and is characterized by deafness, dizziness (vertigo), and ringing in the ear (tinnitus).

Drugs

Some drugs and antibiotics can cause damage to hair cells in the inner ear and the auditory nerve.

Some of these drugs known to be ototoxic are：

• Aminoglycoside antibiotics (such as streptomycin, neomycin, or kanamycin)
• Salicylates in large quantities (aspirin)
• Loop diuretics (Lasix or ethacrynic acid)
• Drugs used in chemotherapy regimens (cisplatin, carboplatin, or nitrogen mustard)

Acoustic Neuroma

An acoustic neuroma is an example of a benign tumor that arise in the eighth cranial nerve and causes hearing loss. One of the first symptoms is hearing loss in one ear accompanied by a feeling of fullness. Removing or reducing the tumor with microsurgery or stereotactic radiation therapy (radiosurgery) is the usual treatment.

Physical Trauma

A physical trauma can also result in hearing loss. Examples include skull fractures of the temporal bone—the area of the skull just behind the ear, puncture of the eardrum by foreign objects, and sudden changes in air pressure.