A patient undergoes cervical VEMP testing using a 500 Hz tone burst stimulus. In superior semicircular canal dehiscence, the cVEMP threshold compared to normal is typically:

• A Elevated (higher dB nHL required to elicit response)
• B Lowered (response present at much lower intensities) ✓
• C Unchanged from normal thresholds
• D Absent at all stimulus intensities

Explanation

In superior semicircular canal dehiscence, the 'third window' lowers impedance of the inner ear, causing enhanced sensitivity of the saccule to sound. cVEMP thresholds are characteristically lowered, often below 70 dB nHL. Elevated thresholds occur in labyrinthine or neural disease. Absent response would indicate saccular or inferior vestibular nerve loss.

Reference: Vertigo and Disequilibrium, 1st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.