The Dix-Hallpike (Barany) Maneuver
This test is used to elicit positional vertigo. It consists of moving a patient rapidly from a sitting position to a supine position with the head turned to one side and positioned 30 degrees below the horizontal plane (see above image). The patient is asked to keep her eyes open to view any nystagmus that may occur. The patient is left is this position for 30 seconds, if no symptoms or nystagmus occur, the patient is sat up and the maneuver is repeated with the head turned the opposite direction. The test is considered positive if nystagmus is observed or the symptoms of vertigo are reproduced.
The Dix-Hallpike maneuver can also be helpful in distinguishing between central and peripheral causes of positional vertigo. Features consistent with a central source for the vertigo include, immediate onset of symptoms after the position change, duration of symptoms greater than 1 minute, no fatigability (repetition of the maneuver continues to reproduce the symptoms), relatively mild symptoms of vertigo, and vertical nystagmus. Features consistent with a peripheral source include delayed onset of symptoms after the position change, duration of symptoms less than 1 minute, fatigability with repeated maneuvers, often marked subjective symptoms of vertigo, and rotational nystagmus. In patioents with a peripheral source for their positional vertigo, the pathology will be located in the ear that is dependent when the Dix-Hallpike maneuver is positive (affected ear will be down).