PubMed · 6776207
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A Belal, B D Forquer. 1980. Experimental tympanometry.. https://doi.org/10.1017/s0022215100089301
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OBJECTIVE: To estimate the rate of exchange of selected gases across the middle ear (ME) mucosa and define the exchange limitations. DESIGN: At separate sessions, the ME was inflated via the eustachian tube with a bolus of pure nitrogen, carbon dioxide, oxygen, or nitrous oxide, and ME pressures were recorded by tympanometry at selected intervals for up to 4 hours. The slope of the function relating pressure change to pressure was calculated by least squares regression and used as an estimate of the rate constant for exchange of that gas (experiment 1). Because of the slow rate of nitrogen exchange, a second experiment was performed in which the tensor veli palatini muscle was unilaterally paralyzed. The ME was inflated with nitrogen, and the slope of the rate-pressure function for measurements at 24-hour intervals was used to estimate the rate constant. SUBJECTS: Ten juvenile cynomolgus monkeys, six for experiment 1 and four for experiment 2. RESULTS: The relative, average rate constants for carbon dioxide, nitrous oxide, oxygen, and nitrogen were 1, 10.7, 18.6, and greater than 700, respectively. Comparisons of these rates with those predicted by theory show that oxygen and carbon dioxide exchange is diffusion limited, and nitrous oxide and nitrogen is perfusion limited. CONCLUSIONS: The perfusion limitation for nitrogen suggests that its exchange rate is notably increased by inflammation from increased mucosal blood flow. Targeting inflammation for therapy of persistent ME effusions may decrease the rate of nitrogen exchange and reestablish normal ME pressure regulation.
In this report, we describe the findings of a noninvasive assessment of the intralabyrinthine pressure in two patients from a family with X-linked progressive, mixed deafness syndrome in whom a perilymphatic gusher occurs during stapes surgery. The so-called tympanic membrane displacement measurement technique could be successfully applied in these two patients (from a total of five patients who were studied) because they still showed a stapedial reflex at 1 kHz, which is mandatory for application of the tympanic membrane displacement measurement technique. The findings were compared with those of age-related control subjects and indicated a significantly elevated intralabyrinthine pressure in the two patients who were observed. The results suggest that the tympanic membrane displacement measurement technique may serve as a screening test in audiological diagnostic studies of perilymphatic hypertension.
A representative sample of Grade 1 (first year school entry) schoolchildren in Swaziland were surveyed during a single week to determine the prevalence of ear and hearing disorders: 79.8% had both normal ears and normal hearing, 16.8% had an ear disorder, but 80% of them had normal hearing. The most common disorder was impacted wax, with a prevalence rate of 74/1000. Middle ear disorders were common and the prevalence rate for children with active middle ear disease was 30/1000 (17/1000 having a hearing loss), and for children with inactive ear disease, the prevalence was 21/1000 (5/1000 having a hearing loss); 8/1000 children were found to have a sensorineural hearing loss, 5.3/1000 unilateral and 2.1/1000 bilateral. Improved treatment of acute otitis media, which is also common in the pre-school age group, could reduce the sequelae of the disorder, which has a deleterious effect on hearing and impairs educational achievement once the children enrol at school.