Visual vertical (VV), visually perceived direction of gravity, is widely measured to assess the vestibular function and visuospatial cognition. VV has been assessed by comparing orientation and variability of measured values separately between subject groups. However, changes in orientation and variability often differ in patients with unilateral spatial neglect (USN). Here, we developed a novel classification of VV that combines orientation and variability and characterized the effects of USN on VV. Forty-three subacute stroke patients with or without USN (USN+, n = 17; USN-, n = 26) and 33 age-matched controls were included in the study. In darkness, a luminous line, initially tilted at 30° either to the left or right, gradually rotated towards the vertical. The VV was defined as the deviation of the subjectively-perceived vertical from the true vertical. The new classification demonstrated that, while the majority of USN + patients (14/17) exhibited large variability, nine showed normal orientation and five showed greater contra-lesional deviation of orientation, suggesting different underlying mechanisms for orientation and variability. Further analyses revealed VV deviation to the initial tilt in all groups. However, the deviation in USN + was larger and more variable, indicating attentional disorders. Such characterization would contribute to individually specified clinical rehabilitation.

中文翻译：

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单侧空间忽视患者主观视觉垂直度的新表征

视觉垂直 (VV)，视觉感知的重力方向，被广泛测量以评估前庭功能和视觉空间认知。VV 已通过分别比较对象组之间测量值的方向和可变性来评估。然而，单侧空间忽视（USN）患者的方向和可变性的变化往往不同。在这里，我们开发了一种新的 VV 分类，它结合了方向和可变性，并表征了 USN 对 VV 的影响。该研究包括 43 名有或没有 USN 的亚急性卒中患者（USN+，n = 17；USN-，n = 26）和 33 名年龄匹配的对照。在黑暗中，一条发光线，最初向左或向右倾斜 30°，逐渐向垂直方向旋转。VV 被定义为主观感知垂直与真实垂直的偏差。新分类表明，虽然大多数 USN + 患者 (14/17) 表现出很大的变异性，但 9 名表现出正常方向，5 名表现出更大的病灶对侧方向偏差，表明方向和变异性的潜在机制不同。进一步的分析揭示了所有组中初始倾斜的 VV 偏差。然而，USN + 的偏差更大且变化更大，表明注意力障碍。这种表征将有助于单独指定的临床康复。九个显示正常方向，五个显示方向的对侧偏差更大，表明方向和变异性的不同潜在机制。进一步的分析揭示了所有组中初始倾斜的 VV 偏差。然而，USN + 的偏差更大且变化更大，表明注意力障碍。这种表征将有助于单独指定的临床康复。九个显示正常方向，五个显示方向的对侧偏差更大，表明方向和变异性的不同潜在机制。进一步的分析揭示了所有组中初始倾斜的 VV 偏差。然而，USN + 的偏差更大且变化更大，表明注意力障碍。这种表征将有助于单独指定的临床康复。