These tests are use for assessment of hearing in an individual, hearing loss. We can also differentiate between conductive hearing loss and sensory hearing loss using these tests.
Hearing Pathway: The sound first reaches the tympanic membrane via external auditory canal then via auditory ossicles (Malleus, Incus, Stapes) reaches the cochlea from where VIIIth nerve takes the impulse and take to brain in the temporal lobe. The pathway till cochlea is the conductive pathway.
So now for the test we need tuning fork, 512hz frequency is ideal as lesser frequencies produce more vibration on the bone and the tone of higher frequencies decay faster.
Air Conduction: It the conduction via normal pathway as described above. It is usually better than bone conduction.
Bone Conduction: When we put the base of tuning fork on the mastoid, or middle of forehead the sound waves travel directly via cranial bones to the cochlea bypassing the normal pathway. This is called bone conduction.
Below is a video showing how to do a Rinne Test.
Now there are usually three tests that we use in Tuning Fork Test
Hearing Pathway: The sound first reaches the tympanic membrane via external auditory canal then via auditory ossicles (Malleus, Incus, Stapes) reaches the cochlea from where VIIIth nerve takes the impulse and take to brain in the temporal lobe. The pathway till cochlea is the conductive pathway.
So now for the test we need tuning fork, 512hz frequency is ideal as lesser frequencies produce more vibration on the bone and the tone of higher frequencies decay faster.
Air Conduction: It the conduction via normal pathway as described above. It is usually better than bone conduction.
Bone Conduction: When we put the base of tuning fork on the mastoid, or middle of forehead the sound waves travel directly via cranial bones to the cochlea bypassing the normal pathway. This is called bone conduction.
Below is a video showing how to do a Rinne Test.
Now there are usually three tests that we use in Tuning Fork Test
- Rinne Test: It is done using a 512hz tuning fork. 1st we check the bone conduction by ringing the tuning fork and then placing the base of the tuning for on mastoid process. Ask the patient whether he can hear a sound or not and if he can hear the sound then ask him to raise his hand or simply tell you when the ringing stops. Note that time. Then again hit the tuning fork and place it near his ears and repeat the same procedure.
- Rinnes test is positive in normal people as Air Conduction > Bone conduction.
- Rinnes Test is negetive In conductive hearing loss the BC>AC as there is problem in conductive pathway leading to decreased conduction but when we bypass the pathway via bone conduction the soun is percieved normally as cochlea is healthy.
- Rinnes is positive in sensory neural hearing loss i.e. AC>BC but the duration of the ringing is reduced for both AC and BC, as cochleae is damaged so there is no bypass pathway left to carry sound energy to brain.
2. Webers Test: It is done by placing the tuning fork in the middle of the forehead of the patient. Then ask the patient on which side he can hear the sond better. In conductive hearing loss the sound lateralises to bad ear while in sensory neaural hearing loss sound goes to better ear
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