Application of tympanometry and acoustic reflex measurements.

The probe tone of an impedance bridge has a direct effect on the results of tympanometry. The frequency of the probe tone should be close to the resonant frequency of the middle ear. Of three electroacoustic bridges using three different probe tones 800, 625 and 220 Hz, the one using 800 Hz provided the most identifiable tympanographic pattern in cases with ossicular discontinuity. Five different types of tympanograms could be identified when an 800 Hz tone is used. Important clinical information can be obtained by combining the type of tympanogram with the results of stapedius reflex measurements.