The middle ear as a baroreceptor.

Under pressure in the middle ear is thought to be important in the pathogenesis of chronic otitis media with effusion and its sequelae, but the cause of the under pressure and the mechanisms responsible for regulation of the normal middle ear pressure are a matter of debate. Numerous studies have examined the effect of large pressure changes on the ear; however, the ear's sensitivity to smaller pressure changes has received little attention. This study examines the sensitivity of the ear to atmospheric air pressure changes induced in the external ear canal. It is concluded that the normal ear is a very sensitive pressure receptor, and that the sensation is probably registered by stretch receptors in the tympanic membrane. Pathological changes in the tympanic membrane are associated with impaired baroreceptor function. The implications of these findings in the physiology of the ear and the regulation of middle ear pressure are discussed.