Clinical Interpretation of Positional Nystagmus Provoked by both Dix-Hallpike and Supine Head-Roll Tests

BACKGROUND: Both the Dix-Hallpike test and the supine head-roll test can provoke positional nystagmus in a group of benign paroxysmal positional vertigo patients, including but not limited to those with multiple canal involvement. This study aimed to determine the incidence and interpret the clinical significance of positional nystagmus provoked by both the Dix-Hallpike and the supine head-roll tests. METHODS: The results of video-nystagmography sessions recorded in the computer database that included both the Dix-Hallpike and the supine head-roll tests were examined. RESULTS: The records belonging to 2880 video-nystagmography sessions of 2387 patients were examined. Nystagmus was detected in both the Dix-Hallpike and the supine head-roll tests of 131 (5.5%) patients. The video images belonging to 142 session records of 122 patients were accessed and further analyzed. The diagnosis was posterior canal BPPV in 9.0%, and lateral canal BPPV in 62.3%. More than one canal was involved in 3.3%, one rehabilitation maneuver was performed in 75.0%, and recurrence was observed in 7.4% of those patients. CONCLUSION: In both geotropic and apogeotropic variants of lateral canal BPPV, nystagmus can be observed during the Dix-Hallpike test in addition to the supine head-roll test. In patients with posterior canal benign paroxysmal positional vertigo, nystagmus can also be observed in the head-roll test. To reach a correct and comprehensive diagnosis and apply appropriate treatment in benign paroxysmal positional vertigo, the Dix-Hallpike test and the head-roll test should be completely performed on both sides, and the results of those tests must be interpreted concomitantly.