Cervical VEMP (cVEMP) tests the integrity of the saccule and inferior vestibular nerve. In a patient with superior semicircular canal dehiscence (SCCD), the expected cVEMP finding is:
- A Absent cVEMP bilaterally
- B Elevated cVEMP thresholds bilaterally
- C Abnormally low (enhanced) cVEMP threshold on the affected side ✓
- D Normal cVEMP with prolonged latency
Correct answer: C. Abnormally low (enhanced) cVEMP threshold on the affected side
Explanation
Superior semicircular canal dehiscence creates a third mobile window in the labyrinth, lowering the threshold required to stimulate vestibular receptors. This results in abnormally low (enhanced/elevated amplitude at lower dB levels) cVEMP thresholds on the affected side. Patients also classically experience Tullio phenomenon (sound-induced vertigo) and Hennebert sign (pressure-induced vertigo). Absent or elevated thresholds would indicate hypofunction.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.