[Middle ear dynamic characteristics of patients obtained by a newly developed measuring apparatus]

A tympanometer is well known to be a valuable apparatus for the diagnosis of secretory otitis media (SOM). However, it is insufficient for the diagnosis of ossicular chain disorders. Therefore, an attempt was made to develop a new measuring apparatus, which had a function of sweeping both frequency and pressure and was measurable the absolute sound pressure variations at the external auditory canal, owing to the carefully designed probe. In the previous papers, the middle ear dynamical characteristics of normal subjects were measured by this apparatus, and the measurement results were compared with the theoretical analysis. In this paper, the middle ear dynamical characteristics of patients were measured, and the effects of various kinds of middle ear diseases upon its dynamical characteristics were examined. The measurement results of the patients with ossicular chain separation, ossicular chain fixation, SOM and tympanic membrane perforation had their own distinctive patterns, and were also clearly different from those of normal subjects. Therefore, this apparatus seems to have a high degree of the clinical applicability to the diagnosis of these diseases.