Health Encyclopedia

Hearing loss

Definition

Hearing loss is the total or partial inability to hear sound in one or both ears.

Alternative Names

Decreased hearing; Deafness; Loss of hearing

Considerations

Minor decreases in hearing are normal after age 20. Hearing problems usually come on gradually, and rarely end in complete deafness.

There are many causes of hearing loss. They can be divided into two main categories:

Conductive hearing loss (CHL) occurs because of some mechanical problem in the external or middle ear. The three tiny bones of the ear (ossicles) may fail to conduct sound to the cochlea or the eardrum may fail to vibrate in response to sound. Fluid in the middle ear can cause CHL.
Sensorineural hearing loss (SNHL) results from a dysfunction of the inner ear. It most often occurs when the tiny hair cells (called cilia) that transmit sound through the ear are injured. This type of hearing loss is sometimes called "nerve damage," although this is not accurate.

CHL is often reversible -- SNHL is not. People who have both forms of hearing loss are said to have mixed hearing loss.

Screening for hearing loss is now recommended for all newborns. In children, hearing problems may cause speech to develop slowly.

Ear infections are the most common cause of temporary hearing loss in children. Fluid may linger in the ear following an ear infection. Although this fluid can go unnoticed, it can cause significant hearing problems in children. Any fluid that stays longer than 8 - 12 weeks is cause for concern.

Preventing hearing loss is more effective than treating it after "the damage is done."

Common Causes

Genetic:

Osteogenesis imperfecta
Leopard syndrome (multiple lentigines)
Otosclerosis
Robinson type ectodermal dysplasia
Cockayne syndrome
Bjorn pili torti and 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
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:

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

Age-related:

Age-related hearing loss (presbycusis)

Occupational:

Any occupation with 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 decreased the likelihood of work-related hearing loss. See occupational hearing loss.

Other:

Meniere's disease
Acoustic neuroma

Temporary hearing loss can be caused by:

The build-up of wax in the ear canal
Foreign body lodged in the ear canal
Injury to the head
Allergy
Blocked Eustachian tubes
Scarred or perforated eardrum
Ear infections (chronic otitis externa, chronic otitis media, malignant otitis externa)
Reaction to medication such as aminoglycosides, chloroquine, quinidine

Home Care

Wax build-up can frequently be flushed out of the ear (gently) with ear syringes (available in drug stores) and warm water. Wax softeners (like Cerumenex) may be needed if the wax is hard and impacted.

Care should be taken when removing foreign bodies. Unless it is easy to get to, have your health care provider remove the object. Don't use sharp instruments to remove foreign bodies.

Call your health care provider if

Call your health care provider if:

Hearing problems are persistent and unexplained
Hearing problems adversely affect lifestyle
Hearing problems go along with other symptoms such as ear pain

What to expect at your health care provider's office

The medical history will be obtained, and a physical examination performed.

Medical history questions documenting hearing loss in detail may include:

Is the hearing loss in both ears or one ear?
Is the hearing loss mild or severe?
Is all of the hearing lost (inability to hear any sound)?
Is there decreased hearing acuity (do words sound garbled)?
Is there decreased ability to understand speech?
Is there decreased ability to locate the source of a sound?
How long has the hearing loss been present?
Did it occur before age 30?
What other symptoms are also present?
Is there tinnitus (ringing or other sounds)?
Is there ear pain?

The physical examination will include a detailed examination of the ears.

Diagnostic tests that may be performed include:

Audiometry (an electronic hearing test )
Auditory response test
CT scan of the head (if a tumor or fracture is suspected)
X-ray of the head
Tympanometry
Caloric test
MRI of the ear (see MRI of the head)

A hearing aid or cochlear implant may be provided to improve hearing.

References

Rakel RE. Textbook of Family Practice. 6th ed. Philadelphia, PA: WB Saunders; 2005:443-444.

Review Date:10/24/2007
Reviewed By:James L. Demetroulakos, M.D., F.A.C.S., Department of Otolaryngology, North Shore Medical Center, Salem, MA. Clinical Instructor in Otology and Laryngology, Harvard Medical School. Review provided by VeriMed Healthcare Network.

ADAM Quality A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.