Recent research indicates that up to 22 per cent of adults have a significant level of hearing loss. Hearing loss refers to reduced hearing, which can be caused by a variety of factors. It is different from deafness which is normally present from birth and may be caused by genetic factors or rubella infection during pregnancy.

Check yourself to see if you have hearing loss

1. Do you have a problem hearing over the telephone?
2. Do you have trouble following the conversation when two or more people are talking at the same time?
3. Do people complain that you turn the TV volume up too high?
4. Do you have to strain to understand conversation?
5. Do you have trouble hearing in a noisy background?
6. Do you find yourself asking people to repeat themselves?
7. Do many people you talk to seem to mumble (or not speak clearly)?
8. Do you misunderstand what others are saying and respond inappropriately?
9. Do you have trouble understanding the speech of women and children?
10. Do people get annoyed because you misunderstand what they say?
11. Does your partner have to keep repeating your name during intercourse?

If you answered "Yes" to more than two of the above, it is likely you are working for an equipment supplier (wholesaler) or you have simply got a bit of hearing loss.

There are two main types of hearing loss
'Conductive' hearing loss is caused by obstructions or malfunctions in the outer or middle ear. It can be caused by:

• Middle ear infections and malfunctions
• A damaged ear drum
• Impacted ear wax.

• Exposure to loud noise
• Disease, such as Meningitis
• Ageing.

Air Conduction Testing (normal hearing test)
Normal hearing tests in their most simple form are just pure tone audiometry, whereby a bunch of pure tones are presented to the listener at predefined levels and the listener indicates the level of the softest sound they can hear. This process is repeated for a series of frequencies so that a picture of the hearing ability of a range of frequencies is seen. Normally they just check you for the main octave frequencies 250Hz, 500 Hz, 1000Hz, 2000Hz and 4000 Hz. Sometimes (if they are being thorough) intermediate frequencies such as 750Hz, 1500 Hz and 3000 hz are also measured, and on the rare occasion (when they are really scratching for clues), the extremes at 125 Hz and 8000 are also measured.

We all hear differently because our gain structure at different frequencies is always unique but over all, it pans out to be reasonably consistent. Our hearing is at it's best when we are children and just deteriorates as we get older (doesn't everything). Audiometric zero dB was established by using a bunch of healthy twenty year olds as the reference.

If you ever bother to have your hearing tested in this way, they most likely will give you a chart showing the results. It's fairly basic.

A mark is placed on the audiogram to represent the level of hearing ability. They normally tend to use an 'X' for the left ear and an "O" for the right ear.

If you are getting on in years, the chart will often show a nice even roll off in the top end. Bit like a top end filter on an EQ. The effect on your hearing will be a smooth, predictable loss of high frequency. Not such a major problem to hearing unless you are in a crowded room or having the spoilt rotten grand children over.

But if, on your chart, you can see any sudden dips and dives, it is normally noise induced hearing loss. Any dramatic drop above 1K normally indicates hearing loss in the inner ear (hairs and nerve cells) and is accompanied by the words "Bad luck old chum, there's nothing we can do". But if you have sudden dips below 1K then further tests will be in order because there could be a chance the problem is physical and repairable.

Our suggestion (for what it's worth), avoid operations if possible. They can often create symptoms that are worse that the condition they are trying to fix.

Tympanograms
On the same page as your audiogram, you will probably have a small section that says Tympanograms. It will be marked RE (Right ear) and LE (left ear) and contain a single number for each.

It's simply a measure of how well sound is transmitted by the eardrum when negative or positive pressure is applied.

They used to do it with a small rubber tip placed in the ear to seal the ear canal but these days they tend to use pressure controlled headsets where air is pumped in (or out). At the same time sound is emitted and the return signal is measured. As the eardrum stiffens (pushed in or out) the eardrum acts like a reflector sending the echo back to the tympanometer. The degree of compliance (transmission of sound through the eardrum) against the pressure applied is measured and the result is what is shown as your tympanogram (flexibility) score.

Lack of movement of the eardrum can indicate a build up fluid behind the middle ear. This can be caused by an infection or it may indicate blockage of the Eustachian tube. If these conditions existed, you would see a flat tympanogram score on your report.

Bone Conduction testing
Now this is easy and you can try this yourself. Get a tuning fork, give it a good whack to get it started, then place the dead end of the fork on the bone just behind your ear. Have a quick listen then bring the tuning fork about an inch away but just in front of your ear (not touching your head). Determine if the sound becomes louder or softer.

If you have hearing loss, doing this will establish if it is in the nerves or in the bones of the middle ear. The fact that the skull is resonant allows sound to travel directly to the inner ear by-passing the bones on the middle ear. So, if the sound is louder when you hold the tuning fork to the bone behind your ear, it's fair to assume the middle ear is stuffed. The reverse is also true. If the sound is louder when the tuning fork is held just away but in front of your ear than it is when you hold it on the bone behind your ear, the hearing problem (called sensorineural), is more likely to be with the inner ear hair cells or nerves.

Sensorineural hearing losses can be caused by the natural process of aging or exposure to excessive noise. There is virtually no treatment and you may as well settle back and get ready to enjoy a life of perceived stupidity until old age allows you to grow into societies acceptance of being deaf. Conductive hearing loss, on the other hand, can occur due to otosclerosis (fixation of the stapes) or an inner infection. Medical or surgical treatment can often correct conductive losses. But don't hold your breath on this one. Nobody we have ever spoken to in the audio industry has learned to enjoy anything other than hearing loss through noise abuse.

What to do if you think you may have a problem
The most important thing you can do is to go see your doctor. Your doctor can try to determine what is causing your hearing problem. He or she can check to see if it is related to blood pressure, kidney function, diet, or allergies. Your doctor can also determine whether your hearing problem is related to any medicine you are taking.

To learn more about what is causing your hearing disorder, your doctor may refer you to an otolaryngologist, an ear, nose, and throat doctor. He or she will examine your ears and your hearing to try to find out why you have a problem. Another hearing professional, an audiologist, can measure your hearing.

Just as a bit of a tip. Even though good hearing is suggested as being from 20Hz to 20kHz, it is extremely unlikely anybody has this enormous range. As far as most audiologists are concerned, they tend to only check your hearing between approximately 125/250Hz up to about 8kHz (if you're lucky). If you want a full frequency check, you will have to be very specific about it when making the request.