Two-component versus admittance tympanometry.

The probe tone frequency of electro-acoustic bridges has a direct effect on the shape of the tympanograms obtained. At higher frequencies (800 Hz) typical patterns are generated for eardrum abnormalities and ossicular discontinuities. The 625- and 660-Hz frequencies sometimes prove to be not quite high enough to obtain the expected 'W' or undulating admittance tympanograms. Our investigation proves that much more certainty is given even at 660-Hz probe tone when components B and G are both recorded. The same information for ossicular disruption is found in an admittance (Y) together with a new kind of tympanogram, namely the phase tympanogram.