Clinical Characteristics of Patulous Eustachian Tube and the Diagnostic Efficiency of Compliance-Over-Time Testing.

IMPORTANCE: Evidence regarding the diagnosis of patulous Eustachian tube (PET) remains a challenge. This study employed compliance-over-time (COT) testing with different breathing patterns to reflect tympanic membrane (TM) "respiration" and its oscillatory movement, which is beneficial for the development of diagnostics of PET. OBJECTIVE: To summarize the clinical characteristics of patients with PET and to assess the diagnostic efficiency of COT testing under single breathing patterns and the COT protocol. DESIGN: Retrospective observational study. SETTING: Clinical audiology center in a tertiary-care hospital, December 2018 to October 2024. PARTICIPANTS: One hundred thirty-eight PET patients (189 ears) and 102 healthy controls (204 ears). EXPOSURES: Data were collected on clinical symptoms, pure-tone audiometry, tympanometry, otoscopy, and COT testing. MAIN OUTCOME MEASURES: Positivity rates of otoscopic, COT under the protocol, and COTs under single breathing patterns were compared. Agreements between COT under the protocol and COTs under single breathing patterns were examined. RESULTS: Clinical characteristics of PET included autophony (86.8%), fullness (82.0%), aerophony (91.0%), and symptomatic alleviation after posture changing (76.2%) or sniffing (66.1%). Respiratory fluctuation of the TM was observed in 55.0% of PET ears. 96.3% of PET ears had a positive response in the COT protocol. Among COTs under different breathing tasks, COT under ipsilateral nostril deep breathing exhibited the highest diagnostic accuracy, closely mirroring the sensitivity and specificity of the COT protocol. CONCLUSION: The COT protocol is a practical and reliable test with high sensitivity and specificity for diagnosing PET in routine clinical settings. Additionally, COT under ipsilateral nostril deep breathing is expected to be a rapid screening method for diagnosing PET. RELEVANCE: The investigated approach holds potential to improve diagnostic efficiency. It may expand diagnostic options for patients with PET.