Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Headache. 2021 Oct;61(9):1306-1313. doi: 10.1111/head.14213. Epub 2021 Sep 27.
The aim of this narrative review is to explore the relationship between visual snow syndrome (VSS), migraine, and a group of other perceptual disorders.
VSS is characterized by visual snow and additional visual and nonvisual disturbances. The clinical picture suggests a hypersensitivity to internal and external stimuli. Imaging and electrophysiological findings indicate a hyperexcitability of the primary and secondary visual areas of the brain possibly due to an impairment of inhibitory feedback mechanisms. Migraine is the most frequent comorbidity. Epidemiological and clinical studies indicate that other perceptual disorders, such as tinnitus, fibromyalgia, and dizziness, are associated with VSS. Clinical overlaps and parallels in pathophysiology might exist in relation to migraine.
We performed a PubMed and Google Scholar search with the following terms: visual snow syndrome, entoptic phenomenon, fibromyalgia, tinnitus, migraine, dizziness, persistent postural-perceptual dizziness (PPPD), comorbidities, symptoms, pathophysiology, thalamus, thalamocortical dysrhythmia, and salience network.
VSS, fibromyalgia, tinnitus, and PPPD share evidence of a central disturbance in the processing of different stimuli (visual, somatosensory/pain, acoustic, and vestibular) that might lead to hypersensitivity. Imaging and electrophysiological findings hint toward network disorders involving the sensory networks and other large-scale networks involved in the management of attention and emotional processing. There are clinical and epidemiological overlaps between these disorders. Similarly, migraine exhibits a multisensory hypersensitivity even in the interictal state with fluctuation during the migraine cycle. All the described perceptual disorders are associated with migraine suggesting that having migraine, that is, a disorder of sensory processing, is a common link.
VSS, PPPD, fibromyalgia, and chronic tinnitus might lie on a spectrum of perceptual disorders with similar pathophysiological mechanisms and the common risk factor migraine. Understanding the underlying network disturbances might give insights into how to improve these currently very difficult to treat conditions.
本叙述性综述旨在探讨视觉雪综合征（VSS）、偏头痛以及其他一系列知觉障碍之间的关系。
VSS 的特征是存在视觉雪以及其他视觉和非视觉障碍。临床特征表明其对外界和内在刺激过度敏感。影像学和电生理学研究结果表明，大脑初级和次级视区可能存在兴奋性过高，这可能是由于抑制性反馈机制受损所致。偏头痛是最常见的合并症。流行病学和临床研究表明，其他知觉障碍，如耳鸣、纤维肌痛和头晕，与 VSS 相关。在病理生理学方面，偏头痛可能与这些知觉障碍存在临床重叠和相似之处。
我们使用 PubMed 和 Google Scholar 搜索了以下术语：视觉雪综合征、内眼现象、纤维肌痛、耳鸣、偏头痛、头晕、持续性姿势感知性头晕（PPPD）、合并症、症状、病理生理学、丘脑、丘脑皮质节律紊乱以及突显网络。
VSS、纤维肌痛、耳鸣和 PPPD 均存在对不同刺激（视觉、躯体感觉/疼痛、听觉和前庭）处理过程中中枢紊乱的证据，这可能导致过度敏感。影像学和电生理学研究结果表明，涉及感觉网络和其他涉及注意力和情绪处理的大型网络的网络障碍。这些疾病之间存在临床和流行病学重叠。同样，偏头痛在间歇期也表现出多感官过度敏感，甚至在偏头痛周期中也存在波动。所有描述的知觉障碍均与偏头痛相关，这表明偏头痛，即感觉处理障碍，是一个常见的共同因素。
VSS、PPPD、纤维肌痛和慢性耳鸣可能属于具有相似病理生理学机制和共同危险因素偏头痛的知觉障碍谱。了解潜在的网络紊乱可能有助于深入了解如何改善这些目前非常难以治疗的疾病。
