Definition

Deafness means a lack or loss of the sense of hearing, which may be partial or complete. Partial loss of hearing is often called hearing loss rather than deafness. Deafness can occur in one or both ears.

There are three primary types of hearing loss:

• Conductive—hearing loss caused by the inability of the sound to reach the inner ear. This can result from outer or middle ear problems, such as ear infection, excess wax, or swelling. This type of hearing loss is most likely to respond to medical or surgical treatment.
• Sensorineural—hearing loss caused by disorders of the inner ear or auditory nerve. This type of loss is usually permanent. It can be caused by heredity or congenital problems, excess noise, old age, medications, infections such as ear infections and meningitis , or from tumors compressing the nerve of hearing such as an acoustic neuroma .
• Mixed—hearing losses that are a combination of both conductive and sensorineural loss.

The Ear

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Causes

Deafness may occur at any age, from birth through old age.

The conditions that can cause or be associated with hearing loss include the following:

• Ear infections
• Middle ear fluid
• Earwax
• Hole in the ear drum (tympanic membrane perforation)
• Trauma may cause rupture of the tympanic membrane and disruption of the middle ear ossicles, or concussion of the inner ear
• Nose or throat problems, such as:
  • Nasal allergies
  • Sinus problems
  • Blockage of the eustachian tubes (tubes leading from the ears to the throat)
• Hereditary factors
• Birth defects
  • Trauma, injury, or fracture
• Noise
• Ear disorders, such as:
  • Otosclerosis
  • Meniere’s disease
• Infections, such as:
  • Viral infections
  • Mumps
• Bacterial infections, such as:
  • Syphilis
  • Meningitis
  • Otitis media
• Tumors involving the:
  • Ear
  • Brain
• Neurological disorders, such as:
  • Multiple sclerosis
  • Stroke
• Hypothyroidism (underactive thyroid)
• Ototoxic drugs (medications that damage the ear), such as:
  • Aspirin (usually reverses when aspirin is stopped)
  • Quinine (usually reverses when quinine is stopped)
  • Antibiotics: gentamicin, streptomycin, and neomycin (usually is not reversible after stopping drug)

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. Risk factors for deafness include:

• Premature birth
• Increasing age, for age-related hearing loss ( presbycusis )
• Taking ototoxic medications
• Exposure to loud noise on the job, such as:
  • Loud industrial noise
  • Use of heavy equipment
  • Being a musician
• Exposure to recreational loud noise, such as:
  • Guns (target practice)
  • Loud music
  • Family history of deafness

Symptoms

Hearing loss usually comes on gradually, but may come on suddenly. Symptoms may include:

• Difficulty hearing
• Ringing in the ears ( tinnitus )
• Dizziness
• Ear pain in case of an infection
• Feeling of ear fullness (as in earwax or fluid)

Symptoms of deafness in infants may be noted at these stages:

• 1 to 4 months: lack of response to sounds or voices
• 4 to 8 months:
  • Disinterest in musical toys
  • Lack of verbalization, such as babbling, cooing, making sounds
• 8 to 12 months: lack of recognition of child’s own name
• 12 to 16 months: lack of speech

According to the American Academy of Pediatrics, all children (including newborns) should be screened for hearing loss so that hearing loss occurring before birth can be uniformly detected prior to three months of age.

Diagnosis

Your doctor will ask about your symptoms and medical history, and perform a physical exam. As part of the diagnosis, your doctor may try to determine the following:

• Location of the problem
• Degree of loss
• Cause—not always possible to identify the exact cause of hearing loss; this information can help guide treatment

Depending on the type of hearing loss you have, the doctor may order tests to confirm your diagnosis. Tests may include:

• Otoscopy—examination of the structures inside the ear
• Bone vibrator (also called a tuning fork test)—helps to determine the type of hearing loss
• Audiogram (also called a hearing test)—measures the degree of hearing loss
• Tympanometry—measure middle ear fluid and pressures
• Brainstem auditory evoked response—measures electrical response in the brain to sounds in order to help determine the exact location of certain hearing problems
• CT scan —a type of x-ray that uses a computer to make pictures of the inside of the body, in this case the head
• MRI scan —uses magnetic waves to make pictures of the inside of the body, in this case the head

Treatment

Treatment for deafness depends on the type of hearing loss. Options may include:

• Medical treatment—for example, removal of earwax or use of antibiotics to treat an ear infection
• In selected cases of sudden hearing loss, medical treatment with Intratympanic steroids may be effective.
• Hearing aids—small devices that are worn in or behind the ear to help amplify sounds
• Surgery—in some cases, surgery may be recommended to help improve hearing; types of surgery include:
  • Stapedectomy—for treatment of otosclerosis
  • Tympanoplasty —for a perforated eardrum
  • Tympanoplasty tubes—for persistent middle ear infections or fluid
• Cochlear implant —a surgically implanted electronic device that helps provide sound to a person with severe sensorineural hearing loss (although the devices do not completely restore hearing, improvements in implant technology continue to be made)

Prevention

To help prevent deafness, avoid loud noise. In cases when loud noise cannot be avoided, you can reduce exposure to loud noises by wearing earplugs, earmuffs, or ear protectors. Also, taking steps to reduce injuries or disease may prevent certain types of deafness.

There is currently no effective way to prevent congenital or genetic deafness. Hearing screening for newborns can help insure that hearing loss in young babies is detected and treated at the earliest possible stage.