目的:通过回顾现有的关于视觉雪(VS)作为视觉雪综合征(VSS)的症状或一部分的临床研究,我们的目标是提高我们对VSS是一种网络障碍的理解。背景:VSS患者患有连续的视觉障碍,类似于调谐不良的模拟电视的视野(即,VS)和其他视觉,以及非视觉症状。这些症状可以持续多年,通常会严重影响生活质量。确切的患病率仍然未知,但高达2.2%的人口可能受到影响。目前,没有既定的治疗方法,潜在的病理生理学是未知的。近年来,已经有几种方法来识别所涉及的大脑区域及其相互作用来解释复杂的表现。方法:我们通过搜索PubMed和GoogleScholar术语“视觉雪”,从目前发表的有关VS及其综合征的原始研究中收集了临床和临床证据。我们纳入了英语或德语的原始研究,并排除了所有评论,没有为本审查主题添加新信息的病例报告,以及在PubMed或GoogleScholar中无法检索的文章。我们根据所使用的方法对研究进行分组。结果:本综述共发现53项研究。在VSS中,临床频谱包括额外的视觉障碍,如过度的漂浮物,Palinopsia,夜蛾,畏光,和内视现象。与其他知觉和情感障碍以及认知症状也有关联。这篇综述中包含的研究证明了结构,功能,以及大脑主要和/或次要视觉区域的代谢改变。除此之外,结果表明,皮层前视觉通路和包括默认模式网络和显著性网络在内的大规模网络中断.讨论:临床表现以及视觉和视觉外区域广泛的功能和结构改变的结合表明VSS是一种网络障碍。皮层前视觉结构和注意网络的参与可能会导致“过滤”受损,并将刺激作为自上而下的过程优先考虑,随后在暴露于无关的外部和内部刺激时过度激活视觉皮层。现有文献的局限性在于并非所有作者都使用了VSS的ICHD-3定义。有些人是指症状VS,在很多情况下,对照组的偏头痛或偏头痛先兆不匹配.
Aim: By reviewing the existing clinical studies about visual snow (VS) as a symptom or as part of visual snow syndrome (VSS), we aim at improving our understanding of VSS being a network disorder. Background: Patients with VSS suffer from a continuous visual disturbance resembling the view of a badly tuned analog television (i.e., VS) and other visual, as well as non-visual symptoms. These symptoms can persist over years and often strongly impact the quality of life. The exact prevalence is still unknown, but up to 2.2% of the population could be affected. Presently, there is no established treatment, and the underlying pathophysiology is unknown. In recent years, there have been several approaches to identify the brain areas involved and their interplay to explain the complex presentation. Methods: We collected the clinical and paraclinical evidence from the currently published original studies on VS and its syndrome by searching PubMed and Google Scholar for the term visual snow. We included original studies in English or German and excluded all reviews, case reports that did not add new information to the topic of this
review, and articles that were not retrievable in PubMed or Google Scholar. We grouped the studies according to the methods that were used. Results: Fifty-three studies were found for this
review. In VSS, the clinical spectrum includes additional visual disturbances such as excessive floaters, palinopsia, nyctalopia, photophobia, and entoptic phenomena. There is also an association with other perceptual and affective disorders as well as cognitive symptoms. The studies that have been included in this
review demonstrate structural, functional, and metabolic alterations in the primary and/or secondary visual areas of the brain. Beyond that, results indicate a disruption in the pre-cortical visual pathways and large-scale networks including the default mode network and the salience network. Discussion: The combination of the clinical picture and widespread functional and structural alterations in visual and extra-visual areas indicates that the VSS is a network disorder. The involvement of pre-cortical visual structures and attentional networks might result in an impairment of \"filtering\" and prioritizing stimuli as top-down process with subsequent excessive activation of the visual cortices when exposed to irrelevant external and internal stimuli. Limitations of the existing literature are that not all authors used the ICHD-3 definition of the VSS. Some were referring to the symptom VS, and in many cases, the control groups were not matched for migraine or migraine aura.