Establishment of the Normative Value of Classical Bluestone's Nine-Step Inflation/Deflation Tympanometric Eustachian...

The nine-step inflation/deflation tympanometric Eustachian tube function test (commonly referred to as the nine-step test) is a widely utilized method for evaluating Eustachian tube function (ETF). This study aimed to establish normative values for the nine-step test to facilitate the diagnosis of Eustachian tube dysfunction (ETD).

A total of 160 adults, including 70 healthy volunteers and 90 patients with chronic rhinosinusitis (CRS), were recruited for this study. Participants were further categorized into "fair ETF" and "poor ETF" groups based on their scores on the Eustachian Tube Dysfunction Questionnaire (ETDQ-7). Eustachian tube function was assessed using both the nine-step test and the ETDQ-7. The diagnostic accuracy of the maximal peak pressure difference (MPD) from the nine-step test was evaluated, using an ETDQ-7 score of ≥14 as the reference standard. Discriminative ability was analyzed using receiver operating characteristic (ROC) curves.

An MPD value of ≤4 yielded an area under the ROC curve (AUC) of 0.619, indicating moderate discriminative ability in the Taiwanese population. The median MPD value on the nine-step test was 9.5 (interquartile range [IQR]: 4.5-14.0) in participants with an ETDQ-7 score of <14, compared to a median MPD value of 7.5 (IQR: 2.5-12.0) in those with an ETDQ-7 score of ≥14 (p = 0.033). This finding suggests a potential association between MPD values and ETDQ-7 scores.

This study identified an MPD value of 4 as a normative cutoff for screening ETD in a Taiwanese population. However, the diagnostic discriminative power of this parameter was moderate.