Audiometry 2

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Audiometry 2

Post  meodingu on Wed Sep 29, 2010 1:53 pm

Instructions are given about the test procedure and the subject is required to indicate whether he/she can just hear or cannot hear a certain sound (the sound level may be increased from a very low level or reduced from a high level).

Earphones are fitted carefully over the ears and the test is then carried out on each ear.

Firstly, a threshold test is undertaken in which each ear is subjected to sound at a frequency of 1 kHz at varying levels of intensity ranging from low to high and high to low. The procedure is repeated several times so that an average threshold can be derived for the test. Thresholds can vary due to slight changes in the procedures adopted in setting up the test, e.g. variation of the position of the earphone on the ear. � Following this pre-check, both of the subject’s ears are tested through a range of frequencies (usually 0.5, 1, 2, 3, 4 6 and 8 kHz) and hearing loss recorded for each frequency, again via a series of sound exposures. From them an average result can be computed.

When the test is completed, a second threshold check should be carried out to see that no errors have crept in during the test. Both threshold checks should agree within a maximum of 10 dB. If they do not, a re-test must be performed. The accuracy of audiometry can be affected by four main factors:

Technical limitations - how accurately can either the frequency or the hearing level be determined?




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meodingu

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