Resources

Here are a list of research articles if you are interested in learning more:

Evidence of dysfunction in the visual association cortex in visual snow syndrome

• By Eren, et al., 2018

• This study compared the visual processing of 18 patients with VS, 18 age-matched patients with migraine, and 18 controls using a method called electroencephalography, which measures electrical signals produced by the brain. They found that people with VS had slower and smaller responses to visual stimuli compared to the migraine and control groups.

Prevalence of visual snow syndrome in the UK

• By Kondziella et al., 2020

• The purpose of this study was to estimate the prevalence of visual snow and visual snow syndrome in the UK adult population. Researchers did so by asking participants "rare medical condition" questions (the participants did not know the study was about VSS). Their findings suggest that 3.7% met the criteria for visual snow and 2.2% met the criteria for Visual Snow Syndrome.

The Relation Between Migraine, Typical Migraine Aura and “Visual Snow” - Schankin - 2014 - Headache: The Journal of Head and Face Pain

• By Schankin et al., 2014

• The purpose of this study was to clinically investigate the relationship between visual snow syndrome, comorbid migraine, and migraine withoug VSS using functional brain imaging. Researchers assessed their participants’ visual symptoms and migraines via phone interview and then used PET scans and parametric mapping to identify the brain activity and compare them to healthy controls (aka people without visual snow syndrome). Researchers found that comorbid migraines worsen the clinical phenotype of visual snow syndrome.

Visual Snow Syndrome ~ A clinical and phenotypical description of 1,100 cases

• By Francesca Pudledda, Christoph Schankin and Peter J. Goadsby, 2020

• This study aimed to define what visual snow syndrome is and validate the current diagnostic criteria which can be found here. They found some interesting information about the sample such as VSS starts early in life, with aprox. 40% of individuals stating they've had it all of their life. The average age for study participants was 29 and there is no prevalence based on sex, meaning there is no significant findings showing that VSS is found more in those born male or female at birth. To learn more, click on the link above to access the full study.

Structural and functional footprint of visual snow syndrome

• by Christoph J Schankin, Farooq H Maniyar, Denise E Chou, Michael Eller, Till Sprenger, Peter J Goadsby, 2020

• The purpose of this paper was to study the pathophysiology of Visual Snow Syndrome. Pathophysiology is the study of the functional changes that occur to the individual with a particular syndrome or disease. They wanted to improve understanding of VSS through the exploration of different brain areas that differ in structure and/or function compared to the controls. Participants underwent a multitude of different scans such as MRIs, EEGs, FDG PET scans, and VBM. FDG PET scans and VMBs are two different brain imaging scans. The results include information on comorbidities, brain metabolism, and changes in gray matter in the brain in patients with VSS.

Overall, this paper covers numerous subtopics, but their results do not substantially overlap with the pathophysiology profile of migraines, and it is unlikely that their findings are due to comorbid migraines. They also state that these results may suggest that a multimodal and multidisciplinary course of treatment may be the most effective as treating VSS symptoms and the symptoms occurring due to comorbidities. This is not to say that is a guarantee as the study did not test the effects of treatment plans. It may be useful in future studies as evidence to support that should someone find a significant treatment plan.

Short-Wave Sensitive ("Blue") Cone Activation Is an Aggravating Factor For Visual Snow Symptoms

• By Hepschke et al., 2021

• This study from the University of Sydney, Australia investigated how color can improve or worsen visual snow symptoms. They asked 20 participants to read crowded text with different colored backgrounds and rate their visual comfort on a 5-point scale. People with VSS preferred orange-yellow and turquoise-blue colors, while blue-violet exacerbated VSS symptoms.

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

• By Mehta et al., 2020

• This was a retrospective case series that reviewed 449 charts from January 1994 to January 2020. The study sought out mentions of “Visual Snow” within patients’ charts. There were many exclusion factors such as no mentions of visual snow, no clear diagnosis, not enough details included within their charts to confirm visual snow, as well as refusal of research participation. In the end, they reviewed a total of 248 charts. There was not only a search to determine whether their described symptoms constituted as VSS, but also possible comorbidities (definition: the presence of 2 or more diseases at one time). After examining the list, they found 13 different comorbidities spanning throughout the 248 charts they reviewed after taking into account refusals and exclusion factors. Beyond that, they also reviewed medications taken, and any imaging done such as MRIs. In the end, not all patients who presented symptoms of Visual Snow had VSS; some VSS symptoms could have been due to other conditions. Some had spontaneous onset of VSS while others experienced VS their entire lives. This study aimed to garner more information, but cannot prove that any one event caused each of these individuals’ experiences. It is a very insightful paper that shows the experiences of many individuals symptoms throughout the 16 year review period. To learn more, click the link above to access figures and the full article.