A patient with a cochlear hearing loss (sensory SNHL) due to noise exposure has an acoustic stapedial reflex threshold of 85 dB HL. A patient with a vestibular schwannoma of similar hearing threshold has an acoustic reflex threshold of 110 dB HL or absent reflex. What is the term for this phenomenon where the reflex threshold is elevated relative to hearing threshold in retrocochlear pathology?
- A Recruitment
- B Tone decay
- C Elevated reflex threshold (reflex threshold elevation) ✓
- D Hyper-recruitment
Correct answer: C. Elevated reflex threshold (reflex threshold elevation)
Explanation
In cochlear hearing loss, the acoustic reflex threshold is typically within 60-80 dB of the hearing threshold (recruitment phenomenon). In retrocochlear pathology (vestibular schwannoma), the reflex threshold is disproportionately elevated or the reflex is absent despite only mild-to-moderate hearing loss. This 'reflex threshold elevation' or 'reflex decay' is a key retrocochlear sign. Recruitment is the abnormal growth of loudness in cochlear loss.
Reference: Katz Handbook of Clinical Audiology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.