Simple impedance test for Eustachian tube function.

A simple impedance method to evaluate Eustachian tube function has been reported. The principle of the test consists of recording the impedance of the eardrum during Valsalva's maneuver and during swallowing. By this procedure, the inflow and outflow of air through the tube is recorded as a simple pattern of impedance change that is classified into the following three groups: normal, obstructive, and patent. The conformity of these test results to those of an aerodynamic test has indicated the reliability of the test for clinical use.