Audiometry

Audiometry
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Audiometry is the testing of hearing ability. Typically, audiometric tests determine a subject's hearing levels with the help of an audiometer, but may also measure ability to discriminate between different sound intensities, recognize pitch, or distinguished speech from background noise. Acoustic reflex and otoacoustic emissions may also be measured. Results of audiometric tests are used to diagnose hearing loss or diseases of the ear, and often make use of an Audiogram.

The most commonly used assessment of hearing is the determination of the threshold of audibility, i.e. the level of sound required to be just audible. This level can vary for an individual over a range of up to 5 dB from day to day and from determination to determination, but it provides an additional and useful tool in monitoring the potential ill effects of exposure to noise. Before carrying out a hearing test, it is important to obtain information about the person’s past medical history, not only concerning the ears but also other conditions which may have a bearing on possible hearing loss detected by an audiometric test. The hearing loss is usually bilateral, but variations in each ear have been observed. Wax in the ear can also cause hearing loss, so the ear should be examined to see if syringing is needed; also to determine if the eardrum has suffered any damage which may reduce the ability of sound to be transported to the cochlea. The audiometric test can be carried out using automatic or manual audiometers, but the essential test procedure is the same:

The subject is asked to remove anything which might upset the test results, e.g. spectacles, earrings, hearing aids.

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).


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