A search for the most suitable imminent components and probe tone frequency in tympanometry.

The relative occurrence of bell-shaped and various types of W-shaped susceptance-conductance and admittance-phase tympanograms at a probe-tone frequency of 660 Hz was determined from registrations on normal ears. The diagnostic value of the susceptance-conductance versus the admittance-phase representation of tympanograms was studied on pathological middle-ear systems. Using probe-tone frequencies from 510 Hz up to 910 Hz, tympanograms for all four imminent components were recorded on 10 pathological ears and the diagnostic value compared.

Optimizing tympanometric variables for detecting middle ear traumas.

The combination of the results of different studies lead to the conclusion that the susceptance-conductance immittance audiometer at 660 Hz is not the only useful instrument for the detection of middle-ear traumas. Measurements at probe-tone frequencies from 510 up to 910 Hz prove that the admittance tympanogram combined with the electrical phase angle tympanogram recorded in the 500-700 Hz frequency range have definite advantages.

Incudo-stapedial joint pathology: a tympanometric approach.

Two-component tympanometry with a high probe-tone frequency enables a better distinction to be made between mobile but normal middle-ear systems and middle-ear systems suffering from necrosis, luxation, or disruption. Susceptance and conductance tympanograms obtained from 14 patients with confirmed pathological middle-ear lesions and 8 postmortem temporal bones, experimentally manipulated either surgically or with a 1 N HCl solution, were compared to tympanograms obtained from 80 normal subjects of an earlier study. With a 660-Hz probe tone, normal middle ears generate bell-shaped or normal sharp W-shaped patterns, whereas the pathologies of the middle ear give rise to irregular multi-extrema tympanograms.

The diagnostic value of phase-angle tympanograms.

The diagnostic value of susceptance, conductance, resistance, reactance, admittance and phase-angle tympanograms is compared. Phase-angle tympanograms seem to be best suited for the discrimination between normal W patterns and broad irregular curves obtained from ossicular disruptions, luxations and necroses. Several possibilities are proposed: phase-angle tympanograms at the drum, phase-angle tympanograms at the tip of the measuring probe and corresponding phasor curves.

Tympanometry-detection of middle ear pathologies.

Two component susceptance-conductance tympanometry at a probe tone frequency of 660 Hz is superior to admittance tympanometry at 220 Hz for the detection of an ossicular discontinuity, a luxation or a necrosis. It is, however, essential to understand well the difference between non-pathological W-patterns and pathological broad multi-extrema tympanograms. The systematics of normal W-patterns is reviewed and the influence of the sign and magnitude of the pumpspeed on the shape of both types of tympanograms is discussed.