Figure 1.

Schema of this study (when the right side is affected). ①: First Dix-Hallpike test, ②: Second Dix-Hallpike test, ③: Third Dix-Hallpike test. At the head positions ①, ②, and ③, positional nystagmus was recorded. At head position ①, positional nystagmus was recorded when the diagnosis of posterior canal type of benign paroxysmal positional vertigo at head position ①; thus, patients' heads were continuously turned 90° to the unaffected ear at the second position of the Epley maneuver (EM), in order to transition immediately from the Dix-Hallpike test to the EM.