J Korean Bal Soc.  2008 Dec;7(2):188-192.

A Mathematical Consideration on the Dix-Hallpike maneuver

• Byun SW

Abstract

BACKGROUND AND OBJECTIVES: At the beginning of the Dix-Hallpike maneuver, one of the two functional pair planes of the vertical canals is presumed to lie in the sagittal plane. However, this presumption is not correct. This paper aims to describe this problem more clearly and speculate on clinical implications. Mathematical and theoretical reasoning will be discussed.
MATERIALS AND METHODS
Two sets, each composed of three perpendicular planes, were modeled for simplified semicircular canals in the anatomical position with a 3D modeler. After a yaw rotation of 45 degrees, the surface normal of the vertical canal plane is compared with that of the true sagittal plane.
RESULTS
The angle between the two normals was approximately 21.1 degrees. The theoretical vertical canal plane did not lie in the sagittal plane at the beginning position of Dix-Hallpike maneuver.
CONCLUSIONS
More exact Dix-Hallpike maneuvers may require a roll tilting about 20 degrees toward the affected side.

Keyword

Benign paroxysmal positional vertigo; Dix-Hallpike maneuver; Semicircular canals

MeSH Terms

Semicircular Canals
Vertigo
Vertigo