Uses Of An Audiometer As A Diagnostic Tool In Audiometry

By Marissa Velazquez


Hear loss and other disorders related to the sense of hearing are usually monitored using an instrument called an audiometer. It is calibrated with standardized units of measure to obtain the accurate results concerning the disorder. The test requires to be done in a room that is quite and is fitted with soundproof material. The patient is usually given a set of headphones to put on the ears. He is then expected to remain seated and be calm.

The headphones are then attached to a device that produces tones at varied frequencies and different intensity. The audiologist then waits to see the patient raise a hand in acknowledgement of sound heard. To specify the ear that picks the sound, you are expected to raise the corresponding hand to the ear, which is either left or right hand respectively. There is also the provision of buttons to confirm hearing by the patient. The results are then studied and recorded on an audiogram.

There are many conditions that can cause a person to lose his ability to hear. Acoustic neuroma is one of such conditions. This is a slow growing tumor on the cranial nerve which is responsible for hearing and balance. Apart from hear loss it also causes facial paralysis.

Sporting activities or accidents can damage the eardrum which in turn causes hear loss. Vestibulocochlear nerve is also very sensitive and when damaged can affect the ability to hear. Conditions like tinnitus and vertigo can also result to hear loss if care is not taken.

Audiometry is comprised of many tests which are done according to the age and the type of test. The principle which is used to check for hear loss on a newborn baby is the same as that used on an adult the only difference is the way of doing it. Babies cannot report when there is a problem with their ears and they require special equipment to test them. It is important to test a baby when asleep to avoid interruptions.

To test babies, the audiologist uses an otoacoustic emission test. This test is fast, simple and the child does not feel any pain. A tiny earpiece which contains a microphone and a small loudspeaker is securely placed in the ear. The loudspeaker produces clicking sound inside the ear which is passed to the cochlea. A well functioning cochlea responds by resending the sound to the ear canal which is heard by the microphone.

If the sound is not heard, there could be a problem with the ear though the audiologist has to rule out other factors. If the child was not steady, he could have interrupted the process of testing and also a noisy room can also affect the results. If the test is repeated and no change is seen then an automated auditory brainstem response test is done to give accurate results.

A technique called reinforcement audiometry is used to test young children. This test uses speakers as the sound outlet. The child is required to respond by confirming the location of the speaker when he hears the sound. This is done repeatedly at different frequencies. Adults and much grown children are tested using a technique called pure tone audiometry where an audiometer is used to produce sound which is relayed to the headphones at varied intensities and frequencies.




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