Chen Chih-Chung, Bery Anand K, Chang Tzu-Pu
Dizziness and Balance Disorder Center, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan.
Taipei Neuroscience Institute, Taipei Medical University, New Taipei City, Taiwan.
Front Neurol. 2023 Dec 15;14:1327735. doi: 10.3389/fneur.2023.1327735. eCollection 2023.
Weak nystagmus with fixation removed can be seen both in normal individuals and in recovery from a unilateral vestibular insult, thus its clinical significance is unclear in patients with dizziness. We thus sought to compare features of nystagmus at various stages following unilateral vestibular loss (UVL).
We enrolled thirty consecutive patients after acute UVL with impaired vestibulo-ocular reflex (VOR) gain. The patients were allocated into three groups according to time from onset of symptoms: acute (1-7 days), subacute (8-30 days), and chronic (>30 days). Patients underwent video-oculography (with and without fixation) and video head impulse testing (vHIT) to determine VOR gain. We examined the relationships amongst SPV, VOR gain, and time from symptom onset across groups.
There were 11, 10, and 9 patients in the acute, subacute, and chronic stages of UVL, respectively. With visual fixation, only 8 patients (26.7%) demonstrated nystagmus, all from the acute group. With fixation removed, 26 patients (86.7%) exhibited spontaneous nystagmus, including 90.9%, 90%, and 77.8% of the patients from the acute, subacute, and chronic groups, respectively. Horizontal nystagmus was paralytic (i.e., fast phase contralesional) in 25 (96.7%) cases. Horizontal SPV was negatively correlated with logarithm of time from onset to examination ( = -0.48, = 0.007) and weakly negatively correlated with ipsilesional VOR gain ( = -0.325, = 0.08).
In the subacute or chronic stages of UVL, paralytic nystagmus with fixation removed persisted at a low intensity. Therefore, weak nystagmus in the dark may have diagnostic value in chronic dizziness.
去除注视后出现的微弱眼球震颤在正常个体以及单侧前庭损伤恢复过程中均可出现，因此其在头晕患者中的临床意义尚不清楚。我们因此试图比较单侧前庭丧失（UVL）后不同阶段的眼球震颤特征。
我们纳入了30例急性UVL后伴有前庭眼反射（VOR）增益受损的连续患者。根据症状出现时间将患者分为三组：急性组（1 - 7天）、亚急性组（8 - 30天）和慢性组（>30天）。患者接受了视频眼震图检查（有无注视）和视频头脉冲试验（vHIT）以确定VOR增益。我们研究了各组间慢相速度（SPV）、VOR增益与症状出现时间之间的关系。
UVL急性、亚急性和慢性阶段分别有11例、10例和9例患者。在有视觉注视时，仅8例患者（26.7%）出现眼球震颤，均来自急性组。去除注视后，26例患者（86.7%）出现自发性眼球震颤，分别占急性组、亚急性组和慢性组患者的90.9%、90%和77.8%。25例（96.7%）患者的水平眼球震颤为麻痹性（即快相指向对侧）。水平SPV与检查时症状出现时间的对数呈负相关（r = -0.48，P = 0.007），与同侧VOR增益呈弱负相关（r = -0.325，P = 0.08）。
在UVL的亚急性或慢性阶段，去除注视后的麻痹性眼球震颤以低强度持续存在。因此，暗处的微弱眼球震颤对慢性头晕可能具有诊断价值。
