Reviewed by Dr. Clement J. Cheng
More than 28 million people have hearing impairments. The most common form of hearing loss is sensorineural damage, otherwise known as nerve deafness. Hearing aids can correct hearing loss for approximately 95 percent of those who have hearing impairment.
Although 30 percent of people over the age of 65 have some type of hearing loss, 14 percent of those between 45 and 64 have hearing loss. Nearly 8 million people between the ages of 18 and 44 and 7 million children have hearing loss.
The most common hearing disorders are:
- Otitis media (ear infection): This form is the most common cause of temporary hearing loss, which affects 70 percent of all infants and young children wirh treatment that annually exceeds $1 billion.
- Presbycusis: This high-frequency hearing loss occurs with advancing age, it is the most prevalent, but least studied, handicapping hearing condition.
- Tinnitus: Characterized by ringing in the ears, this condition affects 50 million people, with those over the age of 59 twice as likely to have it. For 12 million, tinnitus is so severe that they are incapacitated. Almost 70 percent of those who have tinnitus also have hearing loss.
Hearing loss may also account for some children’s impaired speech development. Although minor decreases in hearing—especially of higher frequencies—is normal after the age of 20, it usually comes on gadually. Some nerve deafness, or loss of hearing affects one out of five people by age 55, it rarely ends in complete deafness.
Numerous causes exist for hearing loss. They fall into several groups. One group divides into two categories: conductive loss and nerve loss. Conductive loss occurs when the three tiny bones of the ear (ossicles) fail to conduct sound to the cochlea, or when the eardrum fails to vibrate in response to sound because of some mechanical problem, such as fluid in the ear or disruption of the ossicles. Nerve loss occurs when the nerve is injured by physical or other means. Conductive loss is often potentially reversible; nerve loss is not.
Common causes of hearing loss include:
- Genetic:
- osteogenesis imperfecta
- Leopard syndrome (multiple lentigines)
- otosclerosis
- Robinson type ectodermal dysplasia
- Cockayne syndrome
- Bjorn pili torti & deafness syndrome
- Multiple synostosis syndrome
- Hunter syndrome
- Taybi oto-palato-digital syndrome
- hereditary nephritis
- Mohr syndrome
- Hurler syndrome
- Waardenburg syndrome
- Kartagener syndrome
- Fronto-metaphyseal dysplasia syndrome
- Morquio syndrome
- Trisomy 13 S
- Multiple lentigines syndrome
- Treacher Collins syndrome
- Stickler syndrome
- Congenital:
- Rubella syndrome
- congenital atresia of the external auditory canal
- congenital cytomegalovirus
- congenital perilymphatic fistula
- fetal methyl mercury effects
- fetal iodine deficiency effects
- Infectious:
- meningitis
- mumps
- measles
- otitis media
- scarlet fever
- ossicular discontinuity
- adhesive otitis
- Occupational:
- Any occupation with chronic exposure to loud noises on a continuous day-to-day basis can result in hearing loss due to nerve end damage. Increased attention to conditions in the work environment has markedly decrease the likelihood of work-related hearing loss.
- Traumatic:
- traumatic perforation of the eardrum
skull fracture (temporal bone)
- acoustic trauma such as from explosions, fireworks, gunfire, rock concerts, and earphones
- barotrauma (differences in pressure)
- Toxic:
- aminoglycoside antibiotics
- ethacrynic acid - oral
- aspirin
- chloroquine
- quinidine
- Aging:
- age-related hearing loss (presbycusis)
- Other:
- Meniere's disease
- acoustic neuroma
- temporary, or sometimes permanent, hearing loss
- the build-up of wax in the ear canal(s)
- foreign body lodged in the ear canal
- injury to the head
- allergy
- blocked eustachian tubes
- scarred or perforated eardrum
- ear infections (otitis externa - chronic, otitis media - chronic, otitis externa; malignant)
- reaction to medication such as aminoglycosides, chloroquine, quinidine
