Figure 4 Supine roll test (Pagnini–McClure maneuver) to detect horizontal canal benign paroxysmal positional vertigo (BPPV)

The patient may be taken from sitting to straight supine position (1). The head is turned to the right side (2) with observation of nystagmus and then turned back to face up (1). Then the head is turned to the left side (3). The side with the most prominent nystagmus is taken to be the affected horizontal semicircular canal. The direction of nystagmus in each position determines whether the horizontal canal BPPV is of the geotropic or apogeotropic type.