A test for unilateral deafness. A vibrating tuning fork held against the midline of the top of the head is perceived as being so located by those with equal hearing ability in the ears; to persons with unilateral conductive-type deafness, the sound will be perceived as being more pronounced on the diseased side; in persons with unilateral nerve-type deafness, the sound will be perceived as being louder in the good ear.
A hearing examination where a tuning fork’s vibrations, when placed on the forehead of a person with normal hearing, are perceived equally in both ears. In cases of middle ear deafness on one side, the sound is more pronounced in the affected ear. Conversely, in cases of deafness caused by auditory nerve disease on one side, the sound is heard more clearly in the unaffected ear.