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Hearing Loss and Causes

There are many types of hearing loss and many different causes. An audiologist's testing is designed to help determine the type of hearing loss you have and what next steps may be helpful. Because of the complexity of the hearing mechanism and the seriousness of some of the causes of hearing loss, it is particularly important that you have your hearing checked by an audiologist. Audiologists are trained to help determine the causes of loss and will refer you for further evaluation if medical treatment is indicated.

Learn how sound travels from the outer ear to the brain» (Turn up the volume on your speakers.)


The major types of hearing loss are:

  • Conductive Hearing Loss
    This means the cause of the hearing loss is in the outer or middle ear. Most conductive hearing losses can be medically treated. Some common causes of conductive hearing loss include cerumen (ear wax) in the ear canal, middle ear infection, and otosclerosis (a disease of the bones of the middle ear, similar to arthritis). For conductive hearing loss, we refer clientst to a physician to evaluate any medically treatable middle ear issues. 

  • Sensorineural Hearing Loss
    This is the most common type of hearing loss and the type most often addressed with hearing aids.This means that the cause of the hearing loss is in the inner ear or the neurological portion the hearing mechanism. The sensory receptors of the ear are damaged or not optimally functioning. Some people used to refer to this as "nerve deafness." Most sensorineural hearing losses cannot presently be medically treated. Sensorineural hearing loss can be genetic or caused by problems during pregnancy or birth. Excessive noise exposure can also cause sensorineural hearing loss, as do a variety of drugs.

  • Retrocochlear Hearing Loss and Central Hearing Loss
    This means that the hearing loss lies in the lower or central portions of the brain, where sensory messages are interpreted. These are best treated by a physician and/or ENT.

  • Mixed Hearing Loss
    Some people have hearing loss from more than one cause, for example, wax in their ears and inner ear losses from noise exposure.

Audiological Assessment

A thorough audiological assessment may include the following:

  1. Background history
  2. Examination of the ear canals
  3. Tympanometry, which looks at middle ear function
  4. Acoustic reflex testing
  5. Testing of pure tones under headphones in a sound booth
  6. Testing of the individual's ability to understand words
  7. Bone conducted testing
  8. And other testing the audiologist may consider necessary

An audiogram is a graph that many audiologists use to record pure tone and other test results. The audiogram shows how much intensity was required before that individual could hear sounds of different frequencies (pitch) in each ear.

Degrees Of Hearing Loss

  • Mild loss is when someone may hear well in a quiet environment where the speaker is close and speaks distinctly, but will have trouble when the speaker turns away, or when there is competing noise.
  • Moderate loss means that many speech sounds are not audible. Ability to understand speech will be greatly affected in many settings.
  • Severe loss will only hear loud sounds and loud voices. Understanding will be very poor.
  • Profound loss is the equivalent of the word "deaf." People with profound loss will only hear very loud sounds and may rely on visual information and vibrations.
  • Unilateral loss means hearing loss in only one ear. Unilateral loss can affect people's ability to hear and understand in many situations. Also, people with unilateral loss cannot tell where sounds are coming from.

Sound Decibel Abuse

mp3 player

The link between the usage of some popular technology devices that provide audio through ear buds or earphones-like Apple's iPod, other MP3 players, and portable DVD players-and hearing loss. Read more»

When to Protect Your Hearing

Protect Your Hearing
The best way to protect against hearing loss in the future is to protect your hearing today and every day.Find out how loud sounds are that you may encounter in your daily activities.

Sound Decibel Abuse

Since mid-December 2005, ASHA (American Speech Language Hearing Association) has mounted an aggressive public awareness campaign on the potential link between the usage of some popular technology devices that provide audio through ear buds or earphones (like Apple's iPod, other MP3 players, portable DVD players) and hearing loss.

ASHA was the only organization mentioned when CNN reported Apple's recent decision to introduce sound-limiting software for its iPod. ASHA called Apple's decision "a step in the right direction." However, ASHA continues to educate the public about safe listening and considers public education the long-tem answer to the risk of hearing loss posed by popular technology.

In addition to the problems due to the degree of hearing loss, it is important to know that hearing loss also causes problems in terms of the quality of sounds received by the brain. This is particularly true in presbycusis. The inner ear may receive the speech signal, but because it is not functioning well, the sounds are not processed clearly. The inner ear does not transmit the sounds accurately. It may sound like a radio that is out of tune. This aspect of hearing loss is tested by repeating a list of words. In a sense, sensorineural hearing loss is more similar to macular degeneration than it is to near-sightedness or far-sightedness. It is this factor that can make hearing loss such a frustrating problem for so many.

American Speech Language Hearing Association

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