Abstract：
Direction-changing nystagmus on positional testing is classically ascribed to a central pathology. We herein report a case of a patient with Benign Paroxysmal Positional Vertigo (BPPV) who demonstrated the unusual phenomenon of spontaneously reversing nystagmus, and discuss the theorised mechanisms with a novel illustration. In left lateral position, our patient\'s Videonystagmography (VNG) demonstrated an initially fast-phase geotropic nystagmus (leftward-beating, SPV 29°/s) which then paused for 8 s, then spontaneously reversed direction into a slow-phase ageotropic nystagmus (rightward-beating, SPV 7°/s). The rest of the neurootological examination and audiometry were normal. An MRI Brain scan also revealed no intracranial pathology. In subsequent reviews the vertigo resolved after repositioning manoeuvres for Left Horizontal Canal BPPV. With review of existing literature, this case may have exhibited coexistent left canalolithiasis and cupulolithiasis, resulting in simultaneous ampullopetal then ampullofugal forces in a single head position. Other posited theories include that of Endolymphatic Reflux and short-term central adaptation of the Vestibulo-Ocular Reflex. This case highlights a diagnostic challenge the otolaryngologists and neurologists may face with an atypical spontaneously reversing nystagmus in BPPV. However it remains a priority to rule out central pathologies first, and calls for specialists to take care in diagnosing horizontal canal BPPV by observing for a period of latency and spontaneous reversal of nystagmus first, so as to perform the appropriate repositioning manoeuvres. Laryngoscope, 2024.
摘要：
位置测试中的方向变化性眼球震颤通常归因于中枢病理学。我们在此报告了一例良性阵发性位置性眩晕（BPPV）患者，该患者表现出自发逆转眼球震颤的异常现象，并用新颖的插图讨论理论机制。在左侧横向位置,我们的患者的视频眼震描记术（VNG）显示了最初的快速相位的地性眼震（向左跳动，SPV29°/s),然后暂停8s,然后自发地反转方向为慢相增龄眼球震颤（向右跳动，SPV7°/s)。其余的神经耳科检查和听力检查均正常。MRI脑部扫描也未显示颅内病理。在随后的评论中，在重新定位左水平运河BPPV的动作后，眩晕得以解决。通过对现有文献的回顾，该病例可能表现为左泪管结石和杯管结石并存，导致在单个头部位置同时发生壶瓣瓣瓣，然后同时发生壶瓣膜力。其他假定的理论包括内淋巴反流和前庭眼反射的短期中枢适应。此病例突显了耳鼻喉科医师和神经科医师可能面临的BPPV中非典型自发逆转眼球震颤的诊断挑战。然而，首先排除中心病变仍然是一个优先事项，并呼吁专家首先通过观察眼球震颤的潜伏期和自发逆转来诊断水平管BPPV，以便执行适当的重新定位操作。喉镜,2024.
