Benign Paroxysmal Positional Vertigo (BPPV) most commonly affects the posterior semicircular canal and is treated with the Epley canalith repositioning maneuver. In horizontal canal BPPV (HC-BPPV), the Dix-Hallpike test is NEGATIVE and the diagnosis is made by the supine roll (Pagnini-McClure) test. Which direction of geotropic nystagmus on the roll test indicates which ear is affected?

• A Geotropic nystagmus: the AFFECTED ear is the UP ear (ear away from the ground), opposite to the nystagmus direction
• B Apogeotropic nystagmus (away from the ground): the affected ear is the DOWN ear in all cases
• C Geotropic (toward the ground) nystagmus: the AFFECTED ear is the side where nystagmus is MORE INTENSE (the DOWN ear is the affected ear in geotropic HC-BPPV) ✓
• D The roll test cannot differentiate the affected side; MRI is required for lateralization

Explanation

In geotropic HC-BPPV (canalolithiasis subtype, most common), rolling the head to either side causes horizontal nystagmus beating TOWARD the ground (geotropic). The AFFECTED ear is identified as the side with MORE INTENSE/prolonged nystagmus — this is the DOWN ear position where the nystagmus is stronger (cupulolithiasis and canalolithiasis differ in this). Treatment is the Barbecue (Lempert) 360-degree roll maneuver or the Gufoni maneuver. In apogeotropic HC-BPPV (cupulolithiasis), nystagmus beats away from the ground and the AFFECTED ear is the DOWN ear where nystagmus is less intense.

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.