Three-dimensional kinematics of ocular drift in humans with cerebellar atrophy.
Three-dimensional kinematics of ocular drift in humans with cerebellar atrophy.
复制标题
小脑萎缩患者眼漂移的三维运动学。
DOI：
10.1152/jn.2000.83.3.1125
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Solomon,D
中科院分区：
文献类型：
--
作者：
Straumann,D;Zee,DS;Solomon,D
小脑眼运动综合征的症状之一是不能保持水平和垂直固定。典型的，在小脑萎缩的情况下，眼睛表现为水平凝视诱发和垂直下拍眼球震颤。我们研究了小脑眼运动综合征是否也包括扭转漂移，特别是，它是否独立于水平-垂直平面的漂移。这种扭转漂移的存在表明，小脑在维持李斯特平面的眼睛方面起着关键作用。本文对18例经核磁共振确诊的小脑萎缩患者进行了检查，并与一组正常受试者进行了比较。在一个三场磁场框架中，通过双搜索线圈记录了在不同水平和垂直偏心率下试图注视目标时的三维眼球运动（水平、垂直和扭转）。整体眼球漂移包括在侧视时增加的向上漂移，侧视时出现的水平向心漂移，以及依赖于水平眼位的扭转漂移。垂直漂移由两个子部分组成：垂直凝视引起的漂移和恒定的垂直速度偏差。水平凝视偏心时向上漂移速度的增大是由垂直速度偏差的增大引起的；这个组成部分不符合Listing的法律。依赖于水平眼位置的扭转漂移在外拐中是内扭的，在内收中是敲诈性的，这导致了对李斯特法的额外违反。与眼睛位置相关的扭转漂移的存在表明，小脑可能通过绘制依赖于视线方向的张力扭转信号，在李斯特定律的实施中起着关键作用。该信号的大小可能反映了由眼植物力学决定的扭转静止位置与Listing定律要求的扭转位置之间的扭眼位置差异。
One of the signs of the cerebellar ocular motor syndrome is the inability to maintain horizontal and vertical fixation. Typically, in the presence of cerebellar atrophy, the eyes show horizontal gaze-evoked and vertical downbeat nystagmus. We investigated whether or not the cerebellar ocular motor syndrome also includes a torsional drift and, specifically, if it is independent from the drift in the horizontal-vertical plane. The existence of such a torsional drift would suggest that the cerebellum is critically involved in maintaining the eyes in Listing's plane. Eighteen patients with cerebellar atrophy (diagnosis confirmed by magnetic resonance imaging) were tested and compared with a group of normal subjects. Three-dimensional eye movements (horizontal, vertical, and torsional) during attempted fixations of targets at different horizontal and vertical eccentricities were recorded by dual search coils in a three-field magnetic frame. The overall ocular drift was composed of an upward drift that increased during lateral gaze, a horizontal centripetal drift that appeared during lateral gaze, and a torsional drift that depended on horizontal eye position. The vertical drift consisted of two subcomponents: a vertical gaze-evoked drift and a constant vertical velocity bias. The increase of upward drift velocity with eccentric horizontal gaze was caused by an increase of the vertical velocity bias; this component did not comply with Listing's law. The horizontal-eye-position–dependent torsional drift was intorsional in abduction and extorsional in adduction, which led to an additional violation of Listing's law. The existence of torsional drift that is eye-position–dependent suggests that the cerebellum is critically involved in the implementation of Listing's law, perhaps by mapping a tonic torsional signal that depends on the direction of the line of sight. The magnitude of this signal might reflect the difference in torsional eye position between the torsional resting position determined by the mechanics of the eye plant and the torsional position required by Listing's law.