Objective
Determine if Eustachian Tube (ET) function (ETF) tests can identify ears with physician-diagnosed ET dysfunction (ETD) in a mixed population at high sensitivity and specificity and define the inter-relatedness of ETF test parameters.
Methods
ETF was evaluated using the Forced-Response, Inflation-Deflation, Valsalva and Sniffing tests in 15 control ears of adult subjects after unilateral myringotomy (Group I) and in 23 ears of 19 adult subjects with ventilation tubes inserted for ETD (Group II). Data were analyzed using logistic regression including each parameter independently and then a step-down Discriminant Analysis including all ETF test parameters to predict group assignment. Factor Analysis operating over all parameters was used to explore relatedness.
Results
The Discriminant Analysis identified 4 ETF test parameters (Valsalva, ET opening pressure, dilatory efficiency and % positive pressure equilibrated) that together correctly assigned ears to Group II at a sensitivity of 95% and a specificity of 83%. Individual parameters representing the efficiency of ET opening during swallowing showed moderately accurate assignments of ears to their respective groups. Three factors captured approximately 98% of the variance among parameters, the first had negative loadings of the ETF structural parameters, the second had positive loadings of the muscle-assisted ET opening parameters and the third had negative loadings of the muscle-assisted ET opening parameters and positive loadings of the structural parameters.
Discussion
These results show that ETF tests can correctly assign individual ears to physician-diagnosed ETD with high sensitivity and specificity and that ETF test parameters can be grouped into structural-functional categories.
The mTVP activity had a shorter duration but greater amplitude than the mLVP activity and was associated with peak ET opening by sonotubometry. The mLVP activity occurred before that of the mTVP, the submental muscle group, and peak ET opening. The mLVP contractions were associated with movements of the soft palate, anterior ET orifice, and rotation of the ET cartilage.
Background-Gas exchange between the middle ear and adjacent compartments determines the trajectory of middle ear pressure change. Little information is available regarding the permeability of the tympanic membrane (TM) to physiological gases.
Background
Past in vivo studies in humans showed that the tympanic membrane (TM) is permeable to physiological gases. Animal studies show that transTM CO2 conductance is increased by TM pathology.
Objective
Determine if transTM CO2 exchange in humans is affected by atrophic and sclerotic pathologies.
Methods
An ear canal (EC) probe (ECP) constructed from a custom-fitted acrylic body, a glass capillary tube enclosing an oil meniscus to maintain ambient ECP+EC pressure and a silica glass microtube linked to a mass spectrometer (MS) for measuring gas composition was hermetically sealed within the ear canal of the test ear. ECP+EC volume was measured and gas samples taken at 10 minute intervals for 1 hour. The fractional CO2 pressure measured in the ECP+EC for each sample was regressed on time and the slope of the function multiplied by the ECP+EC volume and divided by the estimated transTM CO2 gradient at the start of the experiment to yield transTM CO2 conductance (uL/min/Pa). Data were complete for 15 normal, 13 sclerotic and 9 atrophic TMs.
Results
The average (±std) transTM CO2 conductances were 1.76×10−4 ± 7.27×10−5, 2.26×10−4 ± 1.5×10−4 and 2.36×10−4 ± 1.14×10−4 uL/min/Pa/TM for the normal, sclerotic and atrophic TMs, respectively. A pairwise comparison of data for the normal and atrophic TMs under the directional hypothesis of a greater CO2 exchange rate for thinner TMs approached statistical significance (P=.07). A similar pairwise comparison for the sclerotic and normal TMs did not approach statistical significance (P=.28)
Conclusion
The effect of TM pathologies on CO2 conductance is limited.
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