Weber test

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In the Weber test of hearing, a tuning fork is struck and placed on the patient's forehead. The patient is asked to report in which ear the sound is heard louder.

This test cannot confirm normal hearing, because hearing defects affecting both ears equally will produce an apparently normal test result. To avoid this a Rinne test should always be performed first to establish in which ear bone conduction is loudest; if both ears have a positive Rinne (i.e. they are normal) the Weber test will give little information (does give information if there is a nerve deafness). If the Rinne test shows that air conduction is greater than bone conduction in both ears and the weber test lateralizes to a particular ear then there is near deafness in the opposite ear. In the case that one or both ears has a negative Rinne (indicating that conduction through bone is more effective that the normal route through the outer and middle ear) then Weber should be used to confirm the type of hearing defecit.

A patient with normal hearing, positive Rinne both sides, would hear the sound equally in both ears or may not even hear it at all if the room is noisy enough to mask the subtle sound of the tuning fork. A patient with very similar hearing lost bilaterally (e.g. Presbycusis) would give the same result.

A patient with a unilateral (one-sided) conductive hearing loss would hear the tuning fork loudest in the affected ear. This is because the conduction problem masks the ambient noise of the room, whilst the well-functioning middle ear picks the sound up via the bones of the skull causing it to be perceived as a louder sound than in the unaffected ear.

A patient with a unilateral sensorineural hearing loss would hear the sound loudest in the unaffected ear, because the affected ear is less effective at picking up sound even if is transmitted directly by conduction into the middle ear.

Conductive hearing loss can be mimicked by plugging one ear with a finger and performing the Rinne and Weber tests, which will help clarify the above.

This test, and its complement, the Rinne test, are quick screening tests and are no replacement for formal audiometry.