Episodic Visual Snow Associated With Migraine Attacks

Hodak, Julius; Fischer, Urs; Schankin, Christoph

doi:10.1001/jamaneurol.2019.4050

Cited by 19 publications

(18 citation statements)

References 6 publications

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“…Thirty-eight patients in our series experienced episodic VS with their migraine attacks, similar to cases recently reported in the literature (6). While this implies that “TV-static” visual phenomena may be seen in the context of migraine aura, persistent VS is thought to represent a different underlying pathophysiology (7,8).…”

Section: Discussionsupporting

confidence: 87%

Two hundred and forty-eight cases of visual snow: A review of potential inciting events and contributing comorbidities

2021

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Objective To review characteristics and outcomes of all cases of visual snow seen at our institution, with attention to possible triggering events or comorbidities. Methods This is a retrospective case series of patients seen at our tertiary care center from January 1994 to January 2020. Charts were reviewed if they contained the term “visual snow”. Results Of the 449 charts reviewed, 248 patients described seeing visual snow in part or all of their vision. Thirty-eight reported transient visual snow as their typical migraine aura. Of the remaining 210 patients, 89 were reported to have either an inciting event or contributing comorbidity for their visual snow symptoms, including: Post-concussion (n = 15), dramatic change in migraine or aura (n = 14), post-infection (n = 13), hallucinogen persisting perception disorder (n = 10), ocular abnormalities (n = 7), idiopathic intracranial hypertension (n = 4), neoplastic (n = 1), and posterior cortical atrophy (n = 1). Some patients had partial improvement with benzodiazepines (n = 6), lamotrigine (n = 5), topiramate (n = 3) and acetazolamide (n = 3). Presenting characteristics were similar, but patients with visual snow attributed to an inciting event or contributing comorbidity were more likely to have some improvement in their symptoms by last follow-up compared to spontaneous visual snow ( p < .001). Conclusions Though most cases of visual snow are spontaneous, potential secondary causes should be recognized by clinicians. Patients who develop visual snow after an inciting event or related to an underlying comorbidity may have a better prognosis than those in whom it develops spontaneously. In select cases, treatment of the suspected underlying cause may significantly alleviate the otherwise typical intractable visual disturbances associated with visual snow.

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Section: Discussionsupporting

confidence: 87%

Two hundred and forty-eight cases of visual snow: A review of potential inciting events and contributing comorbidities

2021

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“…The data so far suggest that the VSS does often become a chronic disease. There are also published cases of episodic VS as part of a migraine attacks, but different from aura ( 33 ).…”

Section: Resultsmentioning

confidence: 99%

Visual Snow Syndrome as a Network Disorder: A Systematic Review

Schankin

2021

Front. Neurol.

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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.

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“…1 The distinction of VSS from migraine with aura mainly depends on clinical features. VSS affects the whole visual field, shows no evidence of cortical spreading depression-like mechanism, 19 lacks classic migraine features like fortification spectra and scotomas, 20 and cannot be treated effectively with antimigraine drugs. 8 However, there is no denying that migraine is still a prevalent comorbidity of VSS.…”

Section: Migraine With Visual Auramentioning

confidence: 99%