Possible new assessment of patulous Eustachian tube function: Audiometry for tones presented in the nasal cavity

Objective - To assess the acoustic transfer function of the Eustachian tube by means of audiometric measurements in order to evaluate the severity of the patulous condition. Material and Methods - Detection thresholds for tones presented in the nasal cavity (at the nostril) were measured in subjects with a patulous Eustachian tube (PET) and in normal subjects. Results - In typical cases, these thresholds were lower in the subjects with PET and were markedly elevated to the same level as those of normal subjects by the insufflation of Lugol's solution (iodine solution). The pre- versus post-insufflation threshold differences seemed to reflect the effects of a patulous tube on the acoustic characteristics via the Eustachian tube. Based on the obtained results, sound patency via a patulous tube appeared to be dominant in lower frequency tones. Conclusion - The present method seems to be another easy way to assess PET.