Which bedside test is used to diagnose posterior canal BPPV?

• A. Romberg test
• B. Dix-Hallpike maneuver
• C. Head thrust test
• D. Caloric testing

Answer: (B)

The test you use at the bedside to diagnose posterior canal BPPV is the Dix-Hallpike maneuver. This maneuver moves the head and body in a way that drags dislodged otoconia into the posterior canal, provoking endolymph flow that produces the characteristic symptoms. When performed correctly, a patient with posterior canal BPPV experiences brief vertigo and a distinct nystagmus that is upbeating with a torsional component toward the tested ear. The nystagmus and vertigo typically appear within seconds, last less than a minute, and fatigue with repetition, which helps confirm the diagnosis.

Other bedside tests don’t target the posterior canal specifically. The Romberg test assesses static balance and proprioception, not canalithiasis. The head thrust test checks horizontal semicircular canal function and is used for unilateral vestibular loss, not BPPV. Caloric testing is a laboratory test that evaluates horizontal canal function at low frequencies and isn’t used to diagnose posterior canal BPPV at the bedside.