Probe Tone
A low-intensity continuous tone of a specified frequency introduced into the sealed ear canal to measure acoustic immittance in tympanometry and acoustic reflex testing.
Full Definition
A probe tone is the stimulus delivered by the probe assembly of an immittance audiometer into a hermetically sealed ear canal to measure the acoustic properties of the middle ear system. The standard probe tone frequency for tympanometry is 226 Hz in adults and older children; a 1000 Hz probe tone is recommended for infants under six months of age owing to differences in ear canal compliance. Editors must recognise that the probe tone frequency is a clinically significant variable that must be stated in reports and should not be omitted or assumed to be standard. Documents describing paediatric tympanometry should specify the 1000 Hz probe tone explicitly, as its use changes the interpretation of tympanogram type classification.
Usage
Usage note: Always state the probe tone frequency (e.g., 226 Hz or 1000 Hz) in reports. The 1000 Hz probe is standard for infants; failure to specify can lead to misinterpretation of results.
In Context
- "Tympanometry was performed using a 226 Hz probe tone; a flat (Type B) tympanogram was obtained in the right ear." — Paediatric audiology report
- "Authors must specify the probe tone frequency used; do not assume 226 Hz when reporting infant tympanometry." — Paediatric audiology journal style note