title: Incudo-stapedial joint pathology: a tympanometric approach.
abstract: 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 differences between the two types of multi-extrema curves are discussed in detail. The use of phase-angle tympanometry is recommended to enable a quick and accurate distinction between normal and abnormal types of multi-extrema tympanograms. This study also points out clearly that 220-Hz tympanograms do not allow clear differentiation between pathological and normal middle ears.
mesh_terms: D000158:Acoustic Impedance Tests / Q000379:methods; D001844:Bone Conduction; D003937:Diagnosis, Differential; D004427:Ear Diseases / Q000175:diagnosis / Q000503:physiopathology; D004429:Ear Ossicles; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D007188:Incus; D013199:Stapes