Type C Tympanogram
A tympanogram trace in which the pressure peak is shifted to a significantly negative value (typically more negative than −100 daPa), indicating negative middle ear pressure and Eustachian tube dysfunction.
Full Definition
A Type C tympanogram in the Jerger classification system displays a well-defined peak, but one that occurs at a pressure more negative than −100 daPa, reflecting poor Eustachian tube function and negative middle ear pressure. This pattern is commonly seen in early or resolving otitis media with effusion, or in patients with chronic Eustachian tube dysfunction. The peak admittance value may be normal or reduced. Editors should ensure the numeric pressure value is reported alongside the tympanogram type to convey clinical severity. The label 'Type C' is sometimes further subdivided (e.g., C1, C2), though this subdivision is not universally adopted.
Usage
Usage note: Capitalise 'Type C'; always accompany with the peak pressure reading in daPa.
In Context
- "The left ear showed a Type C tympanogram with a peak at −175 daPa, suggestive of Eustachian tube dysfunction." — ENT referral letter
- "Editors should confirm that the daPa pressure value is included whenever a Type C tympanogram is reported." — Audiological report editorial guide