Admittance
Pronunciation: ad-MIT-ance
A measure of the ease with which energy flows through the middle ear system, expressed in millimhos (mmho) or millilitres (ml) of equivalent volume. It is the reciprocal of impedance.
Full Definition
In audiological diagnostics, admittance describes how readily the middle ear transmits acoustic energy, and is the inverse of impedance. It is the preferred term in modern immittance audiometry, replacing the older term 'compliance' in many clinical and research contexts. Admittance is quantified in millimhos (mmho) and plotted against pressure to produce a tympanogram. High admittance may indicate a flaccid or perforated tympanic membrane, while low admittance suggests effusion or ossicular fixation. Editors working with audiological reports should note that 'admittance' and 'compliance' are sometimes used interchangeably but carry distinct technical meanings.
Usage
Usage note: Prefer 'admittance' over 'compliance' in contemporary clinical documentation; flag if an author uses both terms interchangeably.
In Context
- "Peak admittance values exceeding 1.4 mmho were recorded, suggesting hypermobile tympanic membranes." — Immittance audiometry report
- "The term 'admittance' should not be substituted freely with 'compliance' without verifying the instrument and era of testing referenced." — Editorial review note