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Μερικές γραπτές πληροφορίες για το Rinne's test:Rinne's test is named after Adolf Rinne of Gottingen, who described this test in 1855 (1)
it compares the patients ability to hear a tone conducted via air and bone - the mastoid process.
the base of a vibrating 512Hz tuning fork is first placed on the mastoid process and then after the sound is no longer appreciated the vibrating top is held one inch from the external auditory meatus (1)
the patient is asked whether the sound is louder behind or in front - referring to bone and air conduction respectively
normally the note is audible at the external meatus
when nerve deafness is present then the note is audible at the external meatus, as air and bone conduction are reduced equally, so that the air conduction is better (as is normal) than bone conduction - this is termed Rinne-positive
Rinne-negative occurs with a conductive hearing loss - no note is audible at the external meatus (i.e. bone conduction is better than air conduction)
Note: the following should be observed:
strike the tuning fork against the knee or the elbow, not the table, otherwise the vibrations will be excessive and cause the patient discomfort
hold the fork for 2-3 seconds to allow sufficient time to make a mental note of the stimulus intensity
Reference:
(1) Hearing testing. American Hearing Research Foundation.2002
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ΕίσοδοςΚαι για το Weber's test:Weber's testwas developed to detect unilateral hearing loss (1)
it compares bone conduction in both ears. It is most valuable in distinguishing between a true and false Rinne's negative test. It is frequently done post-operatively, to check that the ear is active.
A vibrating 512Hz tuning fork is placed on the centre of the patients forehead. The patient is asked whether the sound is heard in the middle or to one side.
If the sound lateralizes (is louder on one side than the other), it suggests the following:
an ipsilateral conductive hearing loss
a contralateral sensorineural hearing loss.(2)
Reference:
(1) Correspondence to article: D. F. Boatman, et al. How accurate are bedside hearing tests? Neurology 2007; 68: 1311-1314
(2) Hearing testing. American Hearing Research Foundation.2002
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