Objective Determination of the Middle-Ear Pressure

Abstract

Direct measurement of the middle-ear pressure is hardly possible. It can be determined by means of various pressure balance methods, in which the pressure in the external meatus is changed until it must be supposed to be identical with the middle-ear pressure. The best known of these methods is the pneumophone method of v. Dishoeck. In the pneumophone method maximal hearing is used as an indicator of pressure identity.

At the XIIIth Scandinavian otologic congress in Copenhagen 1957 the author presented a method in which impedance measurement was used to indicate pressure identity. The equipment then used did not allow isolated pressure changes in the auditory canal, and the measurements therefore had to be performed in a pressure chamber. After the construction of a new electro-acoustic impedance measuring bridge, allowing isolated pressure changes in the ear canal, the principle is made usable as a practical clinical method. The result of the measuring is registered on a two channel recorder.