耳小骨病変と連続周波数チンパノメトリ-

概要

論文の詳細を見る
In this new tympanometric system, air pressure in the external meatus is kept constant at either -200daPa or 0 daPa. The frequency of the probe tone is swept from 220Hz to 2000Hz in 4 seconds. During this frequency sweep, sound pressure in dB and phase angle in degrees in the external meatus are sampled and transferred to a microcomputor, which computes the differences in the sound pressure and in the phase angle between -200daPa and 0daPa pressures, and displays these results as a frequency-sound pressure curve and a frequency-phase angle curve. Four parameters in these curves are selected by discriminant analysis to provide diagnostic criteria: the minimum value and the 0-cross frequency of the frequency-sound pressure curve and the maximum value and its frequency of the frequency-phase angle curve.Normal parameters were determined in 50 normal ears. The author evaluated 40 patients with ossicular disorders. The diagnosis was correct, in 10 out of 12 cases of ossicular discontinuity and in 5 out of 6 cases of malleus and/or incus fixation. In only 12 out of 22 ears with stapes fixation, the diagnosis was correct.In summary, this system is more useful than conventional 220Hz tympanometry in the clinical diagnosis of ossicular disorders, producing a collection of curves and patterns that are distinct different for ossicular discontinuity and ossicular fixation.
耳鼻咽喉科臨床学会の論文