Vyznam, uskali a dalsi perspektivy tympanometrie v ORL diagnostice

Abstract

1.a. Causes of a positive pressure in the middle ear cavity in tympanometric examination We evaluate a group of 66 ears with positive middle ear pressure during tympanometric examination. A positive pressure in the middle ear may be caused by an air current during politzerization or catheterization of the auditory tube, acute tubotympanic catarrh, or by acute otitis media in the initial or regressing stage. In the majority of patients the positive middle ear pressure is not associated with conduction deafness and there is no relationship between the pressure and the hearing loss. 1.b. Effect of inhalation anaesthesia on the middle ear pressure In a group of 108 ears we confirmed, that during inhalation anaesthesia the pressure in the middle ear cavity rises. The mean pressure before operation was -80,4 daPa. Due to inhalation anaesthesia the pressure rose to +189,1 daPa. After a meantime interval after operation of 4,4 hours the pressure declined to -167,9 daPa. If before operation an exudate was present in the middle ear cavity, the inhalation mixture usually did not have an impact on the conditions in the middle ear. 2. Tympanometry in children with adenoids In a group of 384 children we confirmed a higher incidence of exudate in the middle ear in children with adenoids, as compared with controls (B curve in 40% of ears, compared with 9% in controls). Normalization of the middle ear pressure occured within two weeks after adenotomy in almost 50% children. We investigated also the relationship between the extent of adenoids and the presence of exudate in the middle ear. 3. Tympanometry in the preoperative diagnostics of congenital and acquired defects of conductive system We investigated a group of 49 ears with conductive hearing loss with the exception of otosclerosis. For tympanosclerosis is typical type B tympanometric curve, but we can find also curves A or C, especially with lower compliance. In the ears with congenital and acquired defects of conductive system we found type A curve without any stapedius reflex. The value of compliance depends on the character of ossicular chain defect. 4. Elicitability of evoked otoacoustic emissions and the middle ear pressure We evaluate elicitability of evoked otoacoustic emissions (EOAE) in the series of 100 ears with hypo- or hyperpressure in the middle ear. These results are compared to the control group of 50 healthy ears with A type curve on tympanometry. We conclude that hyper- or hypopressure in the middle ear cavity reduce TEOAE (transiently evoked OAE). Higher the pressure change is, more EOAE are reduced. 5. Tympanometric examination of the function of the auditory tube We describe the method of tympanometric examination of the ventilation function of the auditory tube. In the group of patients with traumatic rupture of the tympanic membrane a mean value of the opening pressure of 320 daPa was recorded, the active function of the auditory tube was satisfactory. In the other examined groups (otitis media secretorica, chronic otitis media, cholesteatoma, dry perforation of the tympanic membrane) obstruction of the tube predominated. In secretory catarrh there was also a higher percentage of ears with hypercompliance of the auditory tube or with a patent tube. 6. Investigation of stapedius reflex in patients with tetania We investigated latency, acoustic reflex threshold and decay test in a group of 20 ears in the patients with hypocalcemia. We compared results with a group of patients (20 ears) with normocalcemia. We confirmed elevation of acoustic reflex threshold and a longer latency of stapedius reflex in the patients with hypocalcemia. The result of decay test were normalAvailable from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi