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Hearing loss and deafness

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Introductio to hearing loss and deafness 

Hearing impairment, which means that there is either a partial loss in hearing or complete deafness, and it can be permanent or temporary. Sound is measured by its loudness or intensity (measured in units called decibels) and its frequency is measured in units called hertz. Hearing loss is described, depending on the slight, mild, moderate or severe levels of hearing intensities or frequencies and is associated with speech. Those whose hearing loss is more than 90 decibels are considered deaf.1

Hearing loss can occur at any age. Hence, the child is also unable to speak. With age, the chance of developing hearing loss is increased. Many people who are above 60 years of age could experience hearing impairment. A child with hearing loss does not have the ability to respond to auditory stimuli like speech. Hearing impairment affects the children’s learning process adversely.


Types of Hearing loss

Hearing loss could be of three types as described below.

1. Conductive Hearing Loss: This kind of hearing loss is caused when something interferes with the conduction of sound from outer ear to the middle ear.

 

2. Sensorineural Hearing Loss: This kind of hearing loss is caused when there is damage to the pathway, which carries the sound impulses from the inner ear to the auditory nerve and the brain.

 

3. Mixed Hearing Loss: This kind of hearing loss is a combination of both conductive and sensorineural hearing loss.


Causes of hearing loss and deafness
 

Hearing loss is caused owing to a number of factors.2

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Causes of Conductive Hearing Loss

  • Infections of the middle ear

  • Accumulation of fluid in the middle ear

  • Ear wax blocking the outer ear

  • Otosclerosis, a condition where the ossicles of the middle ear harden and become immobile

  • Untreated ear infections, head injury, hard blow to the ears causes perforation of the ears leading to hearing loss

  • Severe infection or head injury damaging the ossicles of the middle ear thereby causing hearing loss


Causes of Sensorineural Hearing Loss

  • Presbyacusis, a condition of hearing loss caused owing to increase in age and occurs owing to loss of hair cells in the cochlea.

  • Injury caused by loud noise.

  • Some viral and bacterial infections can damage the auditory nerve.

  • Some powerful antibiotics can cause hearing loss.

  • High doses of aspirin can cause constant ringing in the ears.

  • Non-cancerous tumors like acoustics neuroma can also affect the auditory nerve leading to hearing loss.

  • Neurological conditions like multiple sclerosis, stroke or brain tumor can cause hearing loss.

     

Diagnosis of hearing loss and deafness 

Diagnosis is based on the clinical presentation, examination and diagnostic tests. The specialist may discuss the causes, which might be helpful in the treatment. A thorough physical examination is conducted. Some electronic devices and equipments are used to find out the degree of hearing loss.

The following are some of the hearing tests conducted to measure the degree of hearing loss.3

  • Whispered speech test

  • Tuning fork test 

  • Pure tone audiometry

  • Otoacoustic emissions

  • Auditory brainstem response

If the hearing loss is caused owing to brain abnormality, then magnetic resonance imaging (MRI) scan of the head may be helpful in diagnosis.

 

Treatment of hearing loss and deafness

Treatment of hearing loss is based on the cause. The following are some of the treatments suggested.

  • Hearing loss caused owing to bacterial infection is treated with antibiotics.

  • Hearing loss caused owing to blockage with ear wax is treated with over-the-counter drops to dissolve the wax or the person can get the ear canal cleaned by a doctor.

  • Hearing loss caused owing to accumulation of fluid in the middle ear can get a tympanostomy performed, where a small tube is placed in the eardrum, which prevents the fluid from getting accumulated.

  • Sudden hearing loss or hearing loss caused owing to autoimmune disorders is treated with corticosteroids.

  • Hearing loss caused owing to damage of the eardrum or bones of the middle ear is treated through a reconstructive surgery.

Most cases of hearing loss cannot be cured, but can be compensated using the following.

  • Hearing Aids: These aids help people suffering from conductive or sensorineural hearing loss, but do not help in restoring normal hearing.
  • Cochlear Implants: This is very useful to persons who cannot hear even with the help of hearing aids. These implants help in providing electrical signals to the auditory nerve with the assistance of several electrodes inserted into the cochlea.1
 

Prevention of hearing loss and deafness 

Hearing loss can be prevented by:

  • Avoiding exposure to loud sounds.

  • Using hearing protectors like plastic or rubber plugs in the ear canal during occupational or firearm exposure.

Written by: Healthplus24 team
Date last updated: April 15, 2012