Acoustic Reflex Decay
The reduction in stapedius muscle contraction amplitude during sustained loud-tone stimulation, used as a marker of retrocochlear pathology.
Full Definition
Acoustic reflex decay (also called reflex adaptation) is assessed by presenting a continuous tone at 10 dB above the acoustic reflex threshold for 10 seconds and observing whether the immittance change decreases by 50% or more of its initial amplitude. Significant decay is considered a positive (abnormal) finding and is associated with retrocochlear lesions such as vestibular schwannoma. The test is typically performed at 500 Hz and 1000 Hz because higher frequencies yield false-positive decay in normal ears. Editors should distinguish this dynamic measurement from the static acoustic reflex threshold, and should not abbreviate it as 'ARD' without prior definition.
Usage
Usage note: A 'positive' reflex decay finding means the reflex is abnormal (decays significantly); editors should be alert to authors using 'positive' in the lay sense of 'good.'
In Context
- "Positive acoustic reflex decay at 1000 Hz prompted referral for MRI to rule out vestibular schwannoma." — Audiological diagnostic report
- "The manuscript incorrectly used 'reflex decay' and 'reflex threshold' interchangeably; these terms require editorial correction." — Peer-review editorial note