Liu Yao, Zhang Xueqing, Deng Qiaomei, Liu Qiang, Wen Chao, Wang Wei, Chen Taisheng
Department of Otorhinolaryngology Head and Neck Surgery, Tianjin First Central Hospital, Tianjin, China.
Institute of Otolaryngology of Tianjin, Tianjin, China.
Front Neurosci. 2022 Dec 13;16:988733. doi: 10.3389/fnins.2022.988733. eCollection 2022.
The aim of this study was to observe the 3-dimensional (3D; horizontal, vertical, and torsional) characteristics of nystagmus in patients with posterior semicircular canal canalithiasis (PSC-can)-related benign paroxysmal positional vertigo (BPPV) and investigate its correlation with Ewald's.
In all, 84 patients with PSC-can were enrolled. The latency, duration, direction, and slow-phase velocity induced by the Dix-Hallpike test in the head-hanging and sitting positions were recorded using 3D video nystagmography (3D-VNG). The characteristics of the horizontal, vertical, and torsional components of nystagmus were quantitatively analyzed.
3D-VNG showed that the fast phase of the vertical components and torsional components of left and right ear PSC-can as induced by the head-hanging position of the Dix-Hallpike test were upward, clockwise and counterclockwise, and horizontal components were mainly contralateral. The median slow-phase velocity of each of the three components for consecutive 5 s was 26.3°/s (12.3-45.8), 25.0°/s (15.7-38.9), and 9.2°/s (4.9-13.7). When patients were returned to the sitting position, the fast phase of the vertical and torsional components of nystagmus was reversed. Only 54 patients had horizontal components of nystagmus, and 32 of them remained in the same direction. The median slow-phase velocity of the three components for consecutive 5 s was 9.4°/s (6.0-11.7), 6.8°/s (4.5-11.8), and 4.9°/s (2.8-8.0). The ratios of the slow-phase velocity of the horizontal, vertical, and torsional components of the head-hanging position to the sitting position were close to 1.85 (1.0-6.6), 3.7 (1.9-6.6), and 5.1 (2.6-11.3). The ratios of the slow-phase velocity of the vertical to horizontal component, the torsional to horizontal component, and the vertical to torsional component of the head-hanging position were close to 3.3 (1.7-7.6), 3.9 (1.8-7.6), and 1.0 (0.5-1.8). The ratios of the slow-phase velocity of the vertical to horizontal component, the torsional to horizontal component, and the vertical to torsional component of the sitting position were close to 2.1 (1.1-6.8), 1.5 (1.0-3.8), and 1.2 (0.8-2.8).
There were three components of nystagmus induced by the Dix-Hallpike test in patients with PSC-can. The vertical component was the strongest and the horizontal component was the weakest. The 3D characteristics of nystagmus were consistent with those of physiological nystagmus associated with the same PSC with a single-factor stimulus, in accordance with Ewald's law.
本研究旨在观察后半规管耳石症（PSC-can）相关的良性阵发性位置性眩晕（BPPV）患者眼震的三维（3D；水平、垂直和扭转）特征，并探讨其与埃瓦尔德定律的相关性。
共纳入84例PSC-can患者。使用三维视频眼震图（3D-VNG）记录Dix-Hallpike试验在头悬垂位和坐位时诱发的潜伏期、持续时间、方向和慢相速度。对眼震的水平、垂直和扭转成分的特征进行定量分析。
3D-VNG显示，Dix-Hallpike试验头悬垂位诱发的左耳和右耳PSC-can的垂直成分和扭转成分的快相向上，分别为顺时针和逆时针，水平成分主要为对侧。连续5秒各三个成分的慢相速度中位数分别为26.3°/秒（12.3-45.8）、25.0°/秒（15.7-38.9）和9.2°/秒（4.9-13.7）。当患者恢复到坐位时，眼震的垂直和扭转成分的快相反转。仅54例患者有眼震的水平成分，其中32例保持相同方向。连续5秒三个成分的慢相速度中位数分别为9.4°/秒（6.0-11.7）、6.8°/秒（4.5-11.8）和4.9°/秒（2.8-8.0）。头悬垂位与坐位的水平、垂直和扭转成分的慢相速度之比分别接近1.85（1.0-6.6）、3.7（1.9-6.6）和5.1（2.6-11.3）。头悬垂位的垂直与水平成分、扭转与水平成分以及垂直与扭转成分的慢相速度之比分别接近3.3（1.7-7.6）、3.9（1.8-7.6）和1.0（0.5-1.8）。坐位的垂直与水平成分、扭转与水平成分以及垂直与扭转成分的慢相速度之比分别接近2.1（1.1-6.8）、1.5（1.0-
