Multifrequency tympanometry.

The tympanogram shape has been investigated in 290 patients as a function of probe tone frequency (from 200 to 2000 Hz). As the frequency of the probe tone rises, the tympanogram undergoes characteristic modifications which have been grouped, according to their morphologic similarities, in three classes: V, W and inverted-V shape. These three tympanometric configurations are consistently observed both in normals and in some patients with middle ear disorders. Exceptions to this regular behaviour are the pathological pictures of the middle ear in which the structure or the dynamics of the tympano-ossicular system are significantly altered (massive tympanosclerosis, glue ear and cholesteatoma). The frequency interval at which the characteristic tympanometric configurations appear is the most important factor for differentiating pathophysiologic conditions of the middle ear.