Deafness

Definition

Deafness means not having the full power of hearing. Lack or loss of the sense of hearing may be partial or complete. Moderate lack of hearing is often called hearing loss.

There are three primary types of hearing loss:
  • Conductive – hearing loss caused by 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, medications, or infections.
  • Mixed – hearing losses that are a combination of both conductive and sensorineural loss.

Causes

Causes of Deafness include:
  • Ear problems, such as:
    • Ear infections
    • Middle ear fluid
    • Earwax
    • Hole in the ear drum (tympanic membrane perforation)
  • 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
  • Ear disorders, such as:
    • Otosclerosis
    • Meniere’s disease
  • Infections, such as:
    • Viral infections
    • Mumps
  • Bacterial infections, such as:
    • Syphilis
    • Meningitis
  • Tumors involving the:
    • Ear
    • Brain
  • Neurological disorders, such as:
    • Multiple sclerosis
    • Stroke
  • Metabolic disorders such as:
    • Hypothyroidism (underactive thyroid)
    • Hyperlipidemia (high levels of fats in the blood)
  • Ototoxic drugs (medications that damage the ear), such as:
    • Aspirin
    • Quinine
    • Antibiotics: gentamycin, streptomycin, and neomycin

Risk Factors

A risk factor is something that increases your chances of getting a disease or condition. Risk factors for Deafness include:
  • Premature birth
  • Increasing age, for age-related hearing loss (presbycusis)
  • Exposure to loud noise on the job, such as:
    • Loud industrial noise
    • Use of heavy equipment
  • Exposure to loud noise recreationally, such as:
    • Guns (target practice)
    • Loud music

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
  • Feeling of ear fullness (as in earwax or fluid)
Symptoms of deafness in infants may be noted at these stages:
  • 1-4 months: Lack of response to sounds or voices
  • 4-8 months:
    • Disinterest in musical toys
    • Lack of verbalization, such as babbling, cooing, making sounds
  • 8-12 months: Lack of recognition of child’s own name
  • 12-16 months: Lack of speech

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 – this will be determined through testing.
  • Degree of loss – also determined through testing.
  • Cause – it is not always possible to identify the exact cause of hearing loss. If a cause can be found, 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, this helps to determine the type of hearing loss.
  • Audiogram – also called a hearing test,this measures the degree of hearing loss.
  • Tympanometry — a test to 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 – a test that 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.

Hearing aids – small devices that are worn in or behind the ear. They 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.