Audiometry-Automated Hearing Tests

GENERAL AUDIOMETRY

Question 1. What is audiometry?

Deafness occurs in all ages but more common as we get older. We can walk around without knowing that we have deafness until tested by audiometry. Early diagnosis is very important in children as missed hearing problems can lead to speech problems, learning difficulties in school, behavioral difficulties and disobedience (difficulty child) if not diagnosed early and treated.

 Individuals working in noisy environments for example industries, airports and workshops with machinery noises all around them are higher risk of hearing loss if appropriate preventive measured are not taken.

 Question 2. How do I know if I have hearing problem?

You cannot tell if you are deaf in early stages until you are tested. In adult population 1 in 7 suffers have some degree of significant hearing impairment (over 20dB in the better ear). Hearing loss is classed as mild (soft spoken voice), moderate (normal voice), severe (shout), and profound (deaf).

You should have your hearing checked if you:

Are deaf

Have hearing difficulty

Talk very loud in normal environment

Work in noisy environment (see occupational audiometry)

Hear muffled sounds

Hear ringing &, buzzing sounds

Complaint about people mumbling

Habit of asking someone speak again repeatedly

Habit of turning radio or TV too high

Do not like attending gatherings & parties where lots of noise

In children

Child often does not follow instructions given

Disobedience

Learning problems at school

Delayed speech or pronunciation problems

Behavioural problems (e.g.,“hambak pikinini”)

Unable to pick up direction of sound

Recurrent ear infection.

Turning around to hear

Concentrates on lips of speaker

 Question 3. How is hearing tested?

Hearing is measured using latest specialized computer system called audiometry. Audiometry is also used in workplace/occupational testing for pre-employment screening and monitoring of employees working in noisy environments like airports and industrial centers. The test usually takes about an hour. No pre-test preparation is required except for prior booking for appointment.

You will be seated in a quiet room for the test. You will be given a pair of ear phones to wear and a cable with button to press. Both are connected to the computer or audiometer. Sounds of different frequencies and loudness are generated from the computer and you will press a button every time you can hear the sound. When the test is over, the result is displayed or printed out and the pattern generated will determine type or degrees of deafness you may have.

 Question 4. What exactly is an audiogram?

Along the horizontal line of the graph the numbers range from 125 to 8000Hz. These numbers refer to frequencies, or different pitches of sounds.

Frequency is expressed in terms of the number of cycles per second, or Hertz. The higher the number is the higher the pitch of the sound. For example, 250 Hertz (250 Hz) sounds like middle C on the piano, while the high-pitched ringing of the telephone is about 3000 Hz.

Normal, young, healthy human ears can actually hear frequencies as low as 20 Hz and as high as 20,000 Hz, but we only test hearing in the range of 250 Hz to 8000 Hz, as most sounds of speech occur in this frequency range.

Loudness or level of sounds is measured in units called decibels. Zero decibels (0 dB) do not mean ‘no sound’. It is just extremely soft sound. Conversational voice level is around 65db, and 120db is very, very loud—about as loud as a jet taking off when you are standing 25 meters away. The figures along the side of the graph are hearing levels in decibels.

 Question 5. What does the audiogram mean?

Your audiogram is a ‘picture’ of your hearing. It indicates how much your hearing varies from normal and, if there is a hearing loss, where the problem might be located in the hearing pathway. It helps doctors to detect degrees of deafness and whether you have conduction problem (example from wax impaction) or sensor neural deafness (nerve damage) or mixed deafness. The result is reported as:

Depending on the cause of your deafness you may or may need surgery or hearing aid to re-establish your hearing. For example, middle ear infection is a common cause of a conductive hearing loss in young children. Outer and middle ear blockages can often be corrected by medical or surgical treatment.

 Question 6. What other test are available?

While for most, audiometry with physical examination by your doctor provide bulk of information necessary for diagnosis of your deafness, other laboratory tests such as tympanometry, speech perception testing and MRI may be requested  to offer specific treatment. Check with your doctor to see what tests are available in PNG.

 Question 7. How does excessive noise cause deafness? 

Excessive noise is a leading cause of hearing loss, especially among young people.  The noise causes damage to the hair cells of the inner ear and is the largest single form of hearing loss. Noise Induced Hearing Loss (NIHL) is totally preventable, but once you have hearing loss, you’ll have it for life. NIHL can be caused by a one-time exposure to loud sound as well as by repeated exposure to sounds at various loudness levels over an extended period of time. We hear over various frequencies, NIHL will impact the higher frequencies first, resulting in difficulty with background noise, however, the loss will gradually progress into the lower speech frequencies, and once it has affected those, you will have problems understanding speech, and it will progress to a severe level in the high frequencies.

 Question 8. What kind of noise is too loud?

If you have to raise your voice to talk to someone who is only an arms-length away, chances are it is too loud. Sound is measured in decibels (dB). Prolonged exposure to noise over 85dB can cause hearing loss. Regular exposure to noise over 110dB or more for more than 1 minute can cause permanent hearing loss. Immediate ear damage will be caused by exposure to 150dB plus. For every 5dB increase in noise, the max exposure time is cut in half.

Question 9. What is the treatment?

Treatment varies depending on the cause of your hearing loss. You should see your doctor for more advice. You might need referral to ENT specialist.