What is the Dix-Hallpike maneuver used for and what constitutes a positive result?

• A. Used to diagnose posterior canal BPPV; a positive result shows upbeating torsional nystagmus with vertigo in provocative position.
• B. Used to diagnose horizontal canal BPPV; a positive result shows geotropic horizontal nystagmus.
• C. Used to diagnose utricular maculopathy; a positive result shows no nystagmus.
• D. Used to test VOR; a positive result is improved gaze stability.

Answer: (A)

The Dix-Hallpike maneuver is used to diagnose posterior canal BPPV, by moving the head so that the posterior semicircular canal is stimulated and any displaced otoconia cause endolymph flow. A positive result is the appearance of vertigo accompanied by a brief (latency can be a moment) nystagmus that is upbeating with a torsional component toward the tested ear. The nystagmus is typically fatigable with repeated tests and lasts less than a minute.

This test is specific for posterior canal involvement. Horizontal canal BPPV would produce horizontal nystagmus and is identified with a different maneuver (head-roll). Utricular maculopathy wouldn’t produce a reliable nystagmus, and testing VOR (gaze stability) isn’t what Dix-Hallpike assesses.