Normative multifrequency tympanometric data on otosclerosis

Acoustic resistance, reactance and phase angle were assessed for the two probe tone frequencies (220 and 660 Hz) on 29 otosclerotic middle-ear systems under accurately defined experimental conditions. Only otosclerotics with normal tympanic membranes were accepted in this statistical survey. The main purpose of these measurements was to provide numerical data for middle-ear modelling. If nevertheless a diagnostic parameter is sought from these data, the immittance values can be compared with data obtained on 30 normals under identical experimental conditions. The phase angle at 660 Hz seems the best choice, but the discrimination power is still poor.