良性発作性頭位めまい症診断のためのDix-Hallpike testとsupine head roll test

抄録

The Dix-Hallpike test and supine head roll test are head positioning nystagmus tests that are mainly used for the diagnosis of benign paroxysmal positional vertigo (BPPV) and identification of the affected side. There are several issues to consider while performing these tests, and those performing the tests should have a common understanding. The Dix-Hallpike test must be performed on both sides, but if the head torsion angle is large, it may lead to misdiagnosis of bilateral posterior canal-BPPV. In addition, the speed of head positioning must be fast. In Japan, the supine head roll test is often performed in the supine position without the head raised by 30 degrees. By changing the head position between the left and right ear-down positions at approximately the same angle and at the same speed, and with the assumption that the otoliths move the same distance in the same area, the affected side can be estimated by Ewald's law. Elevating the head by 30 degrees while the patient lies supine is not always necessary. In lateral canal BPPV-canalolithiasis, nystagmus induced by rapid head positioning is strong, while in lateral canal BPPV-cupulolithiasis, there is no difference in the intensity of the induced nystagmus depending on the speed of head positioning. Therefore, head positioning should be performed quickly. However, to evaluate the affected side in lateral-canal BPPV, findings of lying-down nystagmus and positional nystagmus in the sagittal plane (face-up supine, sitting and prone positions) are required, in addition to performance of the supine head roll test.