Aim and Objectives This test is done to compare the auditory acuity of each ear to bone and air conduction. It helps to detect the type and degree of hearing loss. It is interpreted in association with Weber test.
- The procedure is first explained to the patient. The tuning fork is stuck gently so as not to produce overtones and disharmonics. It can be stuck against a rubber pad or any bony prominence of the examiner.
- The vibrating tuning fork is held about 1 inch away from the ear, such that the prongs are parallel to the external auditory canal.
- The patient is asked to indicate when he stops hearing the sound. When he indicates so, the tuning fork is immediately placed on the mastoid cortex. If the patient does not hear sound on the mastoid cortex it indicates, air conduction is better than bone conduction.
Inference: The procedure is done by all three tuning forks (256 Hz, 512 Hz, 1024 Hz).
|In an ear with normal hearing and an ear with sensorineural hearing loss, air conduction (AC) is more than bone conduction (BC)||AC > BC||Positive|
|In an ear with conductive hearing loss, bone conduction (BC) is better than air conduction (AC)||BC > AC||Negative|
|Tuning fork frequency negative (Hz)||Tuning fork frequency positive (Hz)||Hearing loss (dB)||Degree of conductive loss|
|256 and 512||1024||30-45||Moderate|
|256, 512 and 1024||–||45-60||Severe|
False Negative Rinne When a patient has unilateral severe sensorineural hearing deafness in the test ear, Patient does not perceive any sound of tuning fork by air conduction but responds to bone conduction. This response to bone conduction is from the opposite ear because of transcranial transmission of sound. Hence, it can be interpreted as Rinne negative. In such cases Weber test will be lateralized to the normal ear thus confirming false Rinne negative result. The above can also be avoided by giving masking sound to the non- test ear.