Testing for Hearing Loss - the Weber and Rinne Test

Hearing loss occurs when there is loss of sound sensitivity produced by an abnormality anywhere in the auditory system. A wide variety of conditions can cause hearing loss, including otosclerosis, cholesteatoma, and others. While physicians can sometimes identify the causes of hearing loss, in some cases the causes are unknown, or idiopathic.

Conductive hearing loss occurs when sound waves are prevented from passing from the air to the fluid-filled inner ear. This may be caused by a variety of problems including buildup of cerumen, infection, fluid in the middle ear, a punctured eardrum, or fixation of the ossicles. Other causes include scarring, narrowing of the ear canal, tumors in the middle ear, and perforation of the tympanic membrane. Once the cause is found and removed or treated, hearing usually is restored.

Sensorineural hearing loss develops when the auditory nerve or hair cells in the inner ear are damaged. The source may be located in the inner ear, the nerve from the inner ear to the brain, or in the brain. Sensorineural hearing loss frequently occurs as a result of the aging process in the form of presbycusis, which is a gradual loss occurring in both ears. Tumors such as acoustic neuromas can lead to sensorineural hearing losses, as can viral infections, Meniere's disease, meningitis, and cochlear otosclerosis.

Sensorineural hearing loss can also be the result of repeated, continuous loud noise exposure, certain toxic medications, or an inherited condition. Generally, it is non-reversible however there has been great progress in uncovering the genes responsible for a number of forms of congenital hearing impairments/ deafness, and this genetic research may in time lead to therapies for some congenital causes of hearing loss. The Weber and Rinne tuning fork tests can distinguish between conductive and sensorineural hearing losses.