Tympanometry
Tympanometry is an objective diagnostic procedure used to measure the compliance (mobility) of the tympanic membrane and the condition of the middle ear system by varying air pressure in the external ear canal.
Jerger’s Classification (Tympanograms)
| Type | Description | Clinical Association |
|---|---|---|
| Type A | Normal peak at 0 daPa. | Normal middle ear function. |
| Type As | Shallow peak (reduced compliance). | Otosclerosis, ossicular fixation. |
| Type Ad | Deep peak (high compliance). | Ossicular discontinuity, TM scarring. |
| Type B | Flat (no peak). | Otitis media with effusion, cerumen impaction. |
| Type C | Negative pressure peak (< -100 daPa). | Eustachian tube dysfunction. |
High-Yield Exam Pearl:
- Type B Interpretation: If the ear canal volume is normal, it suggests middle ear fluid. If the volume is large, it suggests a perforated TM or an open grommet tube.
- Purpose: Tympanometry is not a hearing test; it is a test of middle ear mechanics. It is vital for diagnosing middle ear pathologies objectively in children and non-compliant patients.