Abstract
BackgroundThe accurate diagnosis of Eustachian tube (ET) dysfunction can be very difficult. Our aim is to determine whether a 678 Hz probe tone is a more accurate indicator of Patulous ET (PET) than the 226 Hz probe tone when used in compliance over time (COT) testing.MethodsTwenty subjects (11 normal ET ears and 7 PET ears) were individually seated in an examination room and connected to a GSI TympStar Middle Ear Analyzer. The order of probe tone frequency (678 or 226 Hz) was randomized. Baseline “testing” COT recordings for each ear undergoing testing were completed. Subjects were instructed to occlude their contralateral nostril and to breathe forcefully in and out through their ipsilateral nostril until the test had run to completion. This process was repeated with the probe tone that had not been previously run. For the control group, each subject had one random ear tested. For the experimental group, only the affected ear(s) was tested. Wilcoxon rank rum tests were performed to determine statistical significance.ResultsThe baseline COT measurements for the control group and PET group were similar, 0.86 mL (SD = 0.34) and 0.74 (SD = 0.33) respectively. Comparing the 226 Hz tone between groups revealed that PET patients had a median COT difference 0.19 mL higher than healthy ET patients, and for the 678 Hz tone, PET patients had a median COT difference of 0.57 mL higher than healthy ET patients. Both were deemed to be statistically significant (p = 0.002, p = 0.004 respectively). The was a statistically significant median COT difference between the 678 Hz and 226 Hz of 0.61 mL (p = 0.034) for the PET group, while the same comparison for the control group of 0.05 mL was not significant (p = 0.262), suggesting that the 678 Hz tone yields a larger response for PET than the 226 Hz tone, and no difference for the control group, thus making it less prone to artifact noise interference.ConclusionThe 678 Hz probe tone is a more reliable indicator of ET patency, and should be preferably used over the 226 Hz tone for future COT testing.
Highlights
The accurate diagnosis of Eustachian tube (ET) dysfunction can be very difficult
The aim of this study was to evaluate results of compliance over time (COT) testing in presumed closed and patulous Eustachian tubes, and to compare the 226 Hz and 678 Hz probe tones to determine if the latter provides a clearer distinction between patulous ET and closed ET, which has not been previously described
All Patulous ET (PET) subjects were examined with otoscopy and microscopy to confirm that there was no obstruction in the ear canal, no current visible ear disease, and that the tympanic membrane (TM) was moving with respiration prior to testing
Summary
The accurate diagnosis of Eustachian tube (ET) dysfunction can be very difficult. Our aim is to determine whether a 678 Hz probe tone is a more accurate indicator of Patulous ET (PET) than the 226 Hz probe tone when used in compliance over time (COT) testing. The Eustachian tube (ET) is a narrow, epithelial-lined osseocartilaginous tube that connects the middle ear cavity to the nasopharynx [1, 2]. It functions to maintain middle ear health and to facilitate sound transmission from the tympanic membrane (TM) to the inner ear [3]. Patients with obstructive ETD can develop cholesteatoma, perforation, middle ear effusions and conductive hearing loss [4, 9]. A patulous Eustachian tube (PET) is a far less common type of ETD where the ET remains abnormally open intermittently or permanently, allowing for excessive communication between the middle ear and nasopharynx [10]. Reported potential risk factors for PET include sudden and severe weight loss, pregnancy, radiation therapy and congenital ET defects; many patients do not have any predisposing factors [10,11,12,13,14,15,16]
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