Wednesday, October 9, 2013

Perception Apparatus - Kitching Tool for Tuning Fork Hearing Tests

Tuning fork tests: Weber's test and Rinne's test are basic hearing tests that are usually performed in audiology clinics.  A patient with normal hearing should hear equally as well in both ears.

Weber 's test - this is performed in conjunction with Rinne's test. The vibrating fork is placed in the middle of the forehead and the patient is asked whether any sound is heard and, if so, whether it is equally heard in both ears or not. In a patient with normal hearing, the tone is heard centrally. If the patient has unilateral hearing loss and the sound is louder in the weaker ear, this suggests a conductive hearing loss. If the sound is louder in the better ear, it is more likely to be a sensorineural hearing loss.

Rinne's test - strike a tuning fork and hold it vertically with its nearest prong about 1 cm away from the patient's external auditory meatus, making sure that it is not touching any hair. Then immediately transfer it to the mastoid process and hold it firmly there (applying counter pressure to the opposite side of the head) for 2 seconds. The patient is asked to report on which of the two positions was the louder. Normally, the patient should hear the air conduction better than the bone conduction (ie. first position better than the second). This is a positive Rinne's test. If the Rinne's test is positive and there is hearing impairment, it is a sensorineural and not a conductive problem. If there is a negative Rinne's test with hearing loss, then the problem is a conductive one.

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