Equivalent Ear Canal Volume
An estimate of the volume of air between the probe tip and the tympanic membrane, measured during tympanometry and used to interpret tympanogram findings.
Full Definition
Equivalent ear canal volume (Vea or Vec) is obtained at the beginning or end of a tympanometric sweep and reflects the volume of the enclosed air space between the probe assembly and the tympanic membrane. In adults, normal values typically range from 0.6 to 1.5 ml. An abnormally large equivalent ear canal volume combined with a flat (Type B) tympanogram strongly suggests a tympanic membrane perforation or patent pressure equalisation tube, because the probe is effectively measuring the volume of both the canal and the middle ear space. Editors must ensure this value is reported in millilitres (ml) and included whenever a Type B tympanogram is documented.
Usage
Usage note: Report in millilitres (ml). Always include alongside Type B tympanogram findings.
In Context
- "The equivalent ear canal volume of 3.2 ml in the left ear confirmed a tympanic membrane perforation." — Immittance audiometry report
- "Editors should flag any Type B tympanogram result that omits the equivalent ear canal volume." — Editorial review checklist