The Impact of Preset Baseline Middle Ear Pressure on Tubomanometry and Sonotubometry in Healthy Subjects

Objectives: This study aims to investigate the impact of baseline middle ear pressure (MEP) on the detection of Eustachian tube (ET) opening using tubomanometry (TMM) and sonotubometry (STM) in subjects with healthy ET function. Tympanometry is used to evaluate the diagnostic performance of TMM. Methods: Eighty-three healthy volunteers (166 ears) underwent tympanometry to establish balanced MEP ranges. For eligible ears, balanced MEP (b-MEP), positive MEP (p-MEP), and negative MEP (n-MEP) were induced through standardized maneuvers. All subjects completed STM and TMM under 3 MEP conditions, with tympanometry performed before and after each procedure. Results: R -values were significantly higher under n-MEP conditions when compared with b-MEP at 30 mbar (median difference +0.22; P <0.001) and at 40 mbar (+0.13; P =0.002). Also, a significant increase in R-value was found under n-MEP conditions when compared with p-MEP at 30 mbar (+0.15; P =0.006). Concurrently, ET opening detection by TMM was significantly higher under n-MEP at 30 mbar (OR 3.67; P <0.05). This enhancement was also evident at 40 mbar and 50 mbar (n-MEP vs. p-MEP: OR 2.54 and 2.78, respectively; all P <0.05). TMM showed high sensitivity under n-MEP (0.93 to 0.97), but limited specificity (0.20 to 0.60). STM outcomes revealed no significant variations across MEP conditions (all P >0.05). Conclusions: The baseline MEP significantly affects TMM assessments, with elevated R -values under n-MEP indicating delayed ET opening, while improving TMM sensitivity. Conversely, STM maintains consistent ET opening rates and acoustic parameters across MEP conditions.