Unlearning the ABCs of Tympanometry.

Interpretation of tympanometry commonly relies on the historical convention of classifying findings according to large and arbitrary threshold shifts of tympanometric peak pressure (TPP). This convention had value for prior generations of otolaryngologists in diagnosing severe, chronic middle ear disease requiring surgical intervention but may not be well suited for the present-day evaluation of less severe disease. The existing definition of a type C curve (less than -100 daPa) is likely insensitive to detect subtle abnormalities, including some presentations of obstructive eustachian tube dysfunction. The accuracy of clinical diagnosis may be improved by reporting the absolute values of TPP and moving beyond classification according to arbitrary thresholds.