Multifrequency tympanometry in normal ears.

Susceptance and conductance tympanograms were recorded from 10 normal subjects with probe frequencies ranging from 220 to 910 Hz. Tympanometric shapes progressed through an orderly sequence of patterns, becoming more complex with increasing probe frequency. When the direction of ear-canal air pressure change was from negative to positive values, more complicated tympanometric shapes occurred for all subjects, compared to the positive to negative direction. The results are discussed in relation to the Vanhuyse et al. [Scand. Audiol. 4:45-50, 1975] model of tympanometric shapes. In general, the model is a good first approximation to the distribution of tympanometric patterns from normal ears.