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.
There are a number of tests than can be done to check for hearing ability. This are carried out according to the type of patient and the reason the test is to be done. The type of patient can be a newborn baby, young children or even adults. Children are not able to say when they have hearing problems. The audiologist has to use special equipments to test them. The principle followed in testing children is the same but the way of doing it may vary to be able to obtain more accurate results.
An otoacoustic emission test is most preferred to test babies. This is because the test is simple to carryout, takes a very short time and the child feels no pain. It involves the placing in the childs ear a tiny earpiece attached to a microphone and a loudspeaker. A clicking sound is then produced by the speaker, which is transmitted to the cochlea. If the cochlea is functioning properly, the sound will be sent back to the ear canal and picked by the microphone.
A case where no sound is heard could mean an hearing problem though other factors have to be ruled out. These factors can be an unsettled child, a noisy room or even the presence of some fluid in the ear after birth. The test has to be done several times and if not satisfactory another more sensitive test called automated auditory brainstem response is done. Both tests have to be done when the child is asleep to avoid interruption.
Reinforcement audiometry is the technique recommended for testing young children. Using speakers, sound is relayed to the testing room and the child is expected to respond by turning towards the direction of sound. The audiologist rewards the child to motivate him as he performs the test repeatedly. The frequencies are altered at different levels to establish if the child can pick even the lowest sound. Testing older children and adult is different as a pure tone audiometry technique is employed. This includes the use of an audiometer to transmit sounds through a headphone in varied pitches and levels.
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