Abstract
Sonotubometry is used in diagnosis of the patulous Eustachian tube (PET).
When using the apparatus, either one of the following parameters is used as a positive sign for the PET, i.e., the extension of the duration of ET opening upon swallowing and the decrease in the test tone sound pressure level applied to the nostril. However, these parameters are known to include considerable rates of false-positive and cut-off values for these parameters in diagnosing the PET are not yet standardized. In this report, we performed sonotubometry in 102 ears of 51 cases with unilateral sensorineural hearing loss (SNHL) without PET, in order to evaluate the specificity of sonotubometry in the diagnosis of the PET.
Either ‘the extension of the duration of ET opening upon swallowing’ or ‘the decrease in the test tone sound pressure level applied to the nostril’ was found in 66.7% of the SNHL cases without PET, showing the low specificity of these parameters in the diagnosis of the PET. On the other hand, one distinct pattern of sonotubometry recording (plateau type), representing continuous opening of the ET after swallowing, was never found in SNHL cases without PET, and therefore thought to be specific for PET.
