In an attempt to distinguish normal from abnormal eustachian tube function, two groups of adults with nonintact tympanic membranes were tested. Six subjects had traumatic perforations of the tympanic membrane and a negative otologic histroy while five subjects had perforations as a sequela of otitis media. The subjects were tested with two methods: the middle ear inflation-deflation technique and a newly introduced forced-response technique. The comparison of the two groups revealed marked differences between normal subjects and patients with middle ear disease in active tubal dilation mechanisms and biomechanics of the eustachian tube. The forced-response test appeared to be a better method to determine the degree of actual tubal function.

New measurements of acoustical transmission through the eustachian tube (ET) have been obtained in a series of experiments directed toward the development of a clinical instrument to assess ET function behind an intact tympanic membrane (TM). Using a sound conduction method, a sound source was placed in one nostril, and the acoustical energy that was transmitted through the ET was measured by a microphone placed in the ear canal. The present study used a broadband noise as the acoustical stimulus, in contrast to the tonal stimuli employed in previous investigations. This stimulus was chosen because it is believed to reduce the variability in the data due to intersubject differences in the acoustics of the nasopharynx and ET, and to avoid any a priori assumptions concerning the specific frequencies that would be of greatest diagnostic significance. Averaged spectra of the sound transmitted to the ear canal were obtained for three experimental conditions: acoustical source present during subject swallowing, source present with no swallowing, and subject swallowing with source absent. A Bayesian classification scheme based on the statistics of these spectra was used in classifying subjects into one of two possible categories, normal and abnormal ET function. A comparison was made between sonometric classification and classification based on a tympanometric ET function test. Correlation between the two methods was 87.1%.

The present study is a preliminary report on the development of a nonhuman primate model of cleft palate and middle ear (ME) disease. The causal relationship between a surgical cleft of the soft palate only or a cleft of the hard and soft palate and otitis media with effusion (OME) was investigated in rhesus monkeys. Prior to clefting, ME status was documented by pneumatic otoscopy or otomicroscopic examination and tympanometry over a period of at least five months. A minimum of four preoperative eustachian tube (ET) function evaluations were performed employing the inflation-deflation and the forced-response tests. These procedures were repeated following surgery and during a long-term follow-up. Seventeen of the 18 ears developed a recurrent OME. Postoperative ME pressures were initially high negative values. After the first two postoperative months, high positive ME pressures were recorded. The forced-response test showed little to no long-term changes in passive and active tubal resistances or in the efficiency of tubal dilation as a result of surgery. The inflation-deflation test showed higher opening and closing pressures and a limited and more variable ability to equilibrate applied positive and negative ME pressures following surgery. Both ME status and ET function appeared to improve with time. These findings indicated that the pathogenesis of recurrent OME in this animal model may have been due to changes in ET function associated with an abnormal nasopharynx rather than aberrant tensor veli palatini (TVP) muscle function.

Fifty children aged 1 to 13 years with chronic or recurrent otitis media with effusion received a single dose of cefaclor (15 mg/kg body weight) by the oral route 30 minutes to seven hours before the removal of middle ear effusion and insertion of tympanostomy tubes. Serum and middle ear aspirate concentrations of the antibiotic were determined employing a microbiological assay technique by a disk diffusion method. Middle ear specimens were also cultured for aerobic bacteria. The mean peak serum concentration level (8.49± 7.89 μg/ml) was observed after 30 minutes, whereas the middle ear peak level (0.47± 0.78 μg/ml) occurred after one hour. Of the 87 middle ear specimens, 37 had cefaclor concentrations which were detectable within the resolution of the bioassay method (>0.16 μg/ml). There was no correlation between the type of middle ear effusion (mucoid or serous) and the concentration of cefaclor in the middle ear. Only 18% of the middle ear cultures were positive for aerobic bacteria; Hemophilus influenzae was the most common organism.

A pilot study was conducted to evaluate the efficacy of a membrane ventilating tube as a Eustachian tube prosthesis in 20 patients with otitis media. The design was based partly on assumptions since many of the physiological parameters required to calculate the gas transport processes have not been previously reported. An elementary gas transport model with assumed partial pressures of gases was developed. A semipermeable membrane covering a tympanostomy tube was fashioned and used to ventilate the middle ear cavity. From this preliminary investigation, the device successfully maintained atmospheric pressures in the tympanum, compensated for Eustachian tube malfunction, prevented otorrhea and recurrence of middle ear effusions.