Eustachian tube function measured as pressure equilibration and sound transmission capacity. A comparison in healthy ears.

In a series of 68 healthy ears the muscular opening function of the Eustachian tube was assessed in two different ways. A pressure equilibration capacity of +/- 100 mm H2O was tested by a quantitative impedance technique using a pressure chamber and compared to sound transmission capacity recorded by sonotubometry at frequencies of 6, 7 and 8 kHz. In contrast to the pressure equilibration test, sonotubometry does not allow a quantitative assessment of Eustachian tube function and furthermore, sonotubometry yields false-positive as well as false-negative results due to the great variations in sound pressure generated by the deglutition maneuvers themselves.