Method & Technique

Obtaining a reliable tympanogram: seal, sweep, artefact, and common pitfalls.

A reliable tympanogram begins with a good hermetic seal. The probe tip must be the right size for the canal and seated so that no air leaks during the pressure sweep. Otoscopy first — to clear the canal of obstructing cerumen and to confirm the drum is visible — is part of good technique. [British Society of Audiology 2013]

The recording sweep

• Seat the probe and confirm a stable seal.
• The pump sweeps ear-canal pressure, conventionally from positive (around +200 daPa) toward negative.
• The instrument records admittance continuously and identifies the peak.
• ECV, static admittance, TPP and tympanometric width are reported.

Common artefacts and pitfalls

• Leak — a poor seal mimics a flat or noisy trace; re-seat the probe.
• Probe against the canal wall — blocks the opening and produces a flat trace with a very small ECV.
• Cerumen occlusion — also yields a flat trace; otoscopy distinguishes it.
• Patient movement, swallowing or vocalisation during the sweep introduces irregularities. [British Society of Audiology 2013]

Reading the ECV is the key to disambiguating flat traces: a flat trace with a very small ECV suggests an occluded probe or impacted wax, a normal ECV suggests middle-ear effusion, and a large ECV suggests a perforation or a patent ventilation tube. [Fowler CG 2002][Onusko E 2004]

Probe placement — interactive

Acoustic reflex testing builds on the tympanometry setup. Explore where the immittance probe and the contralateral earphone sit, and how ipsilateral and contralateral recording differ.