On videonystagmography (VNG), a head shake test is performed. The appearance of horizontal nystagmus with the fast phase beating toward the RIGHT after vigorous head shaking for 20 seconds indicates which of the following?

• A Right peripheral vestibular lesion
• B Left peripheral vestibular lesion ✓
• C Central vestibular lesion
• D Bilateral vestibular loss

Explanation

Head shake nystagmus results from a velocity storage asymmetry. A unilateral peripheral lesion creates a latent imbalance that is unmasked after head shaking, with the fast phase beating toward the intact (contralesional) side. A right-beating nystagmus after head shake therefore indicates a LEFT peripheral lesion. Central lesions do not typically produce this directional pattern, and bilateral loss produces no asymmetric nystagmus.

Reference: Cummings Otolaryngology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.