Tympanometria

Tympanometry, or tympanometria in some languages, is a diagnostic test that assesses middle-ear function by measuring the movement of the tympanic membrane in response to controlled changes in ear canal pressure. A tympanometer seals a probe in the external auditory canal and varies air pressure while recording the amount of sound energy reflected from the tympanic membrane.

From these measurements a tympanogram is produced, typically reporting peak middle-ear pressure, static compliance (mobility of the tympanic membrane), ear canal volume, and tympanometric width. A normal result suggests adequate tympanic membrane mobility and intact middle-ear transmission, while abnormal curves point to middle-ear pathology.

The classification most often used is Jerger’s types: Type A indicates normal pressure and mobility; Type As denotes a stiff or shallow curve (reduced mobility); Type Ad shows a highly compliant or hypermobile curve; Type B is flat and may reflect fluid in the middle ear or a perforation depending on ear canal volume; Type C indicates negative middle-ear pressure, consistent with eustachian-tube dysfunction.

Indications for tympanometry include assessment of otitis media with effusion, eustachian-tube dysfunction, barotrauma, tympanic membrane perforation, baseline evaluation before tympanostomy tube placement, and monitoring after treatment. It is usually performed alongside audiometry.

Limitations include susceptibility to cerumen blockage, poor probe seal, or patient movement, and the test should be interpreted within the broader clinical context, as it does not diagnose all middle-ear conditions.