Yang Xiaokai, Gao Lidan
Neurology Department, Third Affiliated Hospital of Shanghai University, Wenzhou Third Clinical Institute Affiliated to Wenzhou Medical University, Wenzhou People's Hospital, Wenzhou, China.
Front Neurol. 2022 May 6;13:874699. doi: 10.3389/fneur.2022.874699. eCollection 2022.
To analyze the mechanism and clinical significance of Benign paroxysmal positional vertigo (BPPV) fatigability and discuss how to eliminate BPPV fatigability. A physical simulation model of BPPV was developed to observe the effect of the Dix-Hallpike test on otolith location and explore strategies to eliminate fatigability. Dix-Hallpike test can keep the otoliths in the lower arm of the posterior semicircular canal away from the ampulla. When the head is tilted 30° forward, the otolith slides to the lower arm near the ampulla, which is sufficient to ensure that the starting position of the otolith is consistent when the Dix-Hallpike test is repeated. When the head is tilted 60° forward, the otolith can enter the ampulla and reach the bottom of the crista ampullaris, which leads to long latency because the otolith sliding in the ampulla does not cause an obvious hydrodynamic effect during the Dix-Hallpike test. The otoliths located on the short arm side of the posterior semicircular canal will break away from the short arm side and enter the utricle when the head is tilted 120° forward. The stable and consistent nystagmus induced by the improved diagnostic test may be a more important feature of BPPV.
分析良性阵发性位置性眩晕（BPPV）易疲劳性的机制及临床意义，并探讨如何消除BPPV易疲劳性。建立了BPPV的物理模拟模型，以观察Dix-Hallpike试验对耳石位置的影响，并探索消除易疲劳性的策略。Dix-Hallpike试验可使后半规管下臂的耳石远离壶腹。当头向前倾斜30°时，耳石滑向下臂靠近壶腹处，这足以确保重复Dix-Hallpike试验时耳石的起始位置一致。当头向前倾斜60°时，耳石可进入壶腹并到达壶腹嵴底部，这会导致潜伏期延长，因为在Dix-Hallpike试验期间耳石在壶腹内滑动不会引起明显的流体动力学效应。当头向前倾斜120°时，位于后半规管短臂侧的耳石将从短臂侧脱离并进入椭圆囊。改良诊断试验诱发的稳定且一致的眼震可能是BPPV更重要的特征。
