The Rinne test used to evaluate the loss of hearing in one ear. The Rinne test differentiates sounds transmitted by air conduction from those transmitted through the mastoid by bone conduction. It quick screens for the conductive hearing loss. A Rinne test should be done with a Weber test to detect a sensorineural hearing loss.
Over the years, many types of tuning forks tests had been developed to assess hearing loss, but today only two have withstood the test of time: Rinne and Weber. Both these tests are now routinely taught at the medical school level and performed regularly to assess patients with hearing problems. The Rinne test is frequently recommended when one suspects conductive hearing loss. In some patients with otosclerosis, the Rinne test is performed to determine if the patient is eligible for stapes surgery.
The external ear collects sound vibrations from the air and focuses these sounds onto the tympanic membrane. Vibrations are transmitted through the middle ear by the ossicular chain (malleus, incus, and stapes). The stapes transmits these vibrations to the cochlea through the oval window (fenestra ovalis). The sound may also be transmitted through the bones of the skull to the cochlea.
The hair cells in the cochlea convert the physical vibrations into action potentials that are transmitted via the nerves in the vestibulocochlear (auditory) nerve to the brainstem for further processing.
Deafness may occur due to interruption at any point along this pathway.
The Rinne test is conducted by placing a tuning fork on the mastoid bone.
Before performing the Rinne test, it is important to know that in normal hearing, one will have air conduction that is greater than bone conduction. This means that the individual will be able to hear the tuning form when it is placed near the outer ear, even after that are no longer able to hear it when held against the mastoid.
Evaluation of hearing the loss in one ear.
Use a 512 Hz tuning fork. Please avoid use 128 Hz or 256 Hz tuning fork, as these are used to assess vibration sensation in neurological examinations.
The room should be reasonably quiet.
Test Bone Conduction
Normal finding: Air conduction should be better than bone conduction, and air conduction should persist twice as long as bone, this is a "positive test."
Abnormal: Bone conduction is better than air conduction, this suggests conductive hearing loss and is referred to as "negative test."
The Weber test is the complement for the Rinne test. They are screening tests and do not replace formal audiometry.
The tuning fork will be perceived as being louder when placed at the external auditory meatus.
Causes in the external auditory canal:
Causes due to the drum:
Causes in the middle ear:
Causes at the oval window:
A patient with profound sensorineural deafness may have a false negative Rinne. With complete loss of innervation to that ear, the patient will not hear anything from the tuning fork on the mastoid or near the canal. The patient sound transmission through their skull to the other ear on the other side and they may not be able to identify in which ear they hear the sound.
It seems that bone conduction is better than air conduction, but the ear is nonfunctional.
The way to determine the difference between a true and a false Rinne negative test is to perform Weber test.
False Negative Rinne test
Sometimes the Rinne test may be falsely negative in the following situations:
Total unilateral sensorineural hearing loss. For example, if the left ear is completely dead, on testing, the bone conduction on the left, the sound waves travel to the good right ear, and the sounds are louder when the tuning fork is held next to the external auditory meatus on the side being tested (left). The patient, in this case, will state that bone conduction is louder than air conduction, giving a falsely negative Rinne test.
Limitations of the Rinne test
It is important to remember that the Rinne test is only a screening test and does not replace a formal audiometry test. In addition, the validity of the Rinne test as a screening test is often questioned. The test is not sensitive in differentiating conductive and sensorineural loss causes of total sensorineural or severe unilateral hearing loss. False negatives are common in such situations. In any situation where there is a question about the Rinne test, the patient must be referred to an ear, nose, and throat (ENT) surgeon for formal audiometry.
The other important fact about the Rinne test is that the technique is not uniform. The orientation of the tuning fork and its exact placement vary from individual to individual. All physicians who perform the Rinne test must pay attention to the orientation of the tines of the tuning fork with respect to the long axis of the external auditory canal when testing for air conduction.
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