The Dix-Hallpike test is positive with upbeat-torsional nystagmus (upper pole of eye beating toward the ground when the ear is down). This is diagnostic of BPPV involving:

• A Horizontal semicircular canal — cupulolithiasis
• B Posterior semicircular canal — canalolithiasis ✓
• C Superior semicircular canal — canalolithiasis
• D Posterior semicircular canal — cupulolithiasis

Explanation

The Dix-Hallpike test produces upbeat-torsional nystagmus (geotropic, fast phase toward the ground/affected ear) in posterior canal BPPV due to canalolithiasis — free-floating otoconia in the posterior semicircular canal. The latency (5–20 seconds), brief duration (<60 seconds), and fatigability are classic for canalolithiasis. Cupulolithiasis of the posterior canal would produce persistent nystagmus without fatigue. Horizontal canal BPPV is tested by the roll (supine roll) test.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.