On impedance audiometry of a patient with a large eardrum perforation, which tympanogram pattern is expected?
- A Type B with a very large volume (high Vea) ✓
- B Type A (normal compliance and pressure)
- C Type C (negative peak pressure)
- D Type AD (abnormally deep)
Correct answer: A. Type B with a very large volume (high Vea)
Explanation
A large tympanic membrane perforation results in a flat (Type B) tympanogram but with an abnormally large equivalent ear canal volume (Vea) because the probe is effectively measuring the volume of both the ear canal and the middle ear cavity combined. This high Vea distinguishes perforation from secretory otitis media (Type B with normal Vea). Acoustic reflexes are absent in both but the Vea differentiates them.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.