Epley 法施行中の眼振について

抄録

　A single Epley maneuver was performed for 145 patients with unilateral posterior canal-benign paroxysmal positional vertigo (BPPV) caused by canalolithiasis, and the efficacy of repositioning was evaluated using the Dix-Hallpike test on the following day. The nystagmus pattern observed during the Epley maneuver and the results of repositioning were analyzed. Of the 145 patients, 114 (79%) exhibited a resolution of BPPV, whereas 19 (13%) exhibited typical posterior canal-BPPV caused by canalolithiasis, 7 (5%) exhibited a variant of posterior canal-BPPV inducing a positional downbeat nystagmus, and the remaining 5 (3%) exhibited conversion to other forms of BPPV such as lateral canal-BPPV. During the Epley maneuver, upbeat-rotatory toward the affected ear nystagmus, downbeat-rotatory toward the healthy ear nystagmus, downbeat-rotatory toward the affected ear nystagmus, and no nystagmus were observed. However, the nystagmus pattern during the Epley maneuver was not correlated with the results of repositioning. An upbeat-rotatory toward the affected ear nystagmus indicates the movement of free debris toward the non-ampullated end of the posterior canal. A downbeat-rotatory toward the healthy ear nystagmus might imply a secondary phase of nystagmus elicited in the previous head position or the co-existence of a posterior canal-BPPV caused by canalolithiasis of the short-arm. A downbeat-rotatory toward the affected ear nystagmus indicates free debris moving toward the non-ampullated end of the anterior canal to the common crus. No nystagmus indicates that the debris did not move during the head positioning, possibly suggesting that free debris moving through the common crus did not result in the development of nystagmus.