Stapedial Reflex Threshold
The lowest intensity level at which contraction of the stapedius muscle is measurably elicited in response to a loud sound. It is expressed in dB HL and recorded during immittance testing.
Full Definition
The stapedial reflex threshold (SRT) refers to the minimum stimulus intensity, measured in dB HL, that reliably triggers an involuntary contraction of the stapedius muscle in the middle ear. This reflex stiffens the ossicular chain, producing a detectable change in acoustic admittance. Clinically, abnormal or absent thresholds can indicate cochlear pathology, retrocochlear lesions, or facial nerve dysfunction. Editors must be careful not to conflate the abbreviation SRT with 'speech recognition threshold,' which shares the same initialism in some reporting conventions. The stapedial reflex threshold is documented as part of a standard immittance test battery.
Usage
Usage note: The abbreviation SRT is ambiguous in audiology reports; editors should flag or clarify its meaning based on context.
In Context
- "The report noted elevated stapedial reflex thresholds bilaterally, prompting referral for retrocochlear workup." — Audiological diagnostic report
- "Editors should verify whether 'SRT' in a given document refers to the stapedial reflex threshold or the speech recognition threshold." — Editorial style guide note