Choi Kwang-Dong, Kim Ji Soo
Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea.
Ann N Y Acad Sci. 2009 May;1164:338-43. doi: 10.1111/j.1749-6632.2008.03737.x.
Mechanisms of head-shaking nystagmus (HSN) require further exploration in central vestibular disorders. To determine whether impaired uvulonodular inhibition over the velocity storage of the vestibulo-ocular reflex (VOR) is the mechanism of ipsilesional HSN in lateral medullary infarction (LMI), 17 patients with ipsilesional HSN and LMI underwent measurements of the VOR gains during low-frequency sinusoidal harmonic accelerations, and the time constants (TC) of the VOR and tilt suppression of the post-otatory nystagmus during step-velocity rotation. Compared with normal controls, the patients showed increased VOR gains without difference between ipsi- and contralesional rotations, while the VOR TCs were decreased without directional asymmetry during step-velocity rotation. In contrast, the patients showed impaired tilt suppression of the postrotatory nystagmus, and the impairment of tilt suppression was more severe after contralesional than ipsilesional rotation. The asymmetric tilt suppression may generate ipsilesional HSN by increasing contralesional velocity storage during head shaking, and may be ascribed to disruption of ipsilesional nodulo-uvular inhibition of the velocity storage mechanism.
摇头性眼震（HSN）的机制在中枢性前庭疾病中仍需进一步探索。为了确定延髓旁正中核（uvulonodular）对前庭眼反射（VOR）速度存储的抑制受损是否是延髓外侧梗死（LMI）同侧HSN的机制，17例患有同侧HSN和LMI的患者在低频正弦谐波加速度期间接受了VOR增益测量，以及在阶跃速度旋转期间VOR的时间常数（TC）和眼震后性眼震的倾斜抑制。与正常对照组相比，患者的VOR增益增加，同侧和对侧旋转之间无差异，而在阶跃速度旋转期间VOR的TC降低，且无方向不对称。相反，患者的眼震后性眼震倾斜抑制受损，对侧旋转后的倾斜抑制损害比对侧旋转后更严重。不对称的倾斜抑制可能通过在摇头期间增加对侧速度存储而产生同侧HSN，并且可能归因于同侧延髓旁正中核-小脑扁桃体对速度存储机制的抑制破坏。
