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    • What is Visual Snow Syndrome >
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      • Eye Floaters
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Accelerating Research to Cure Visual Snow Syndrome and give patients their lives back

Colorado rTMS study enrollment has concluded in CO, and data analysis will being in January 2023

9/18/2022

 
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Colorado rTMS study enrollment has concluded in CO, and data analysis will being in January 2023.

Study details:

The study will gather information about the treatment of up to 10 people with VS using rTMS. Treated participants will undergo 10 sessions of rTMS administered 5 times a week over 2 weeks. All visits will take place in the University of Colorado School of Medicine NeuroMag/Transcranial Magnetic Stimulation laboratory on University of Colorado Anschutz Medical Campus.

The specific aims for this feasibility study include:

Determine whether any participant experiences untoward effects of rTMS in the setting of visual snow syndrome and determine the potential drop-out rate of larger study.
Determine the performance of a novel scale (Colorado Visual Snow Scale) and two three psychophysical visual processing tasks

Determine the standard deviation and test-retest reliability for the novel scale and two visual processing tasks
Determine whether the visual processing tasks perform similar to performance found by the developer
Describe changes in outcome measures between pre- and post-treatment with rTMS

​Study overseen by Dr. Pelak.



Treatment Study for VSS - Dr. Schankin and Dr. Klein

7/20/2022

 
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With this project, we aim at reducing VSS symptoms (i.e. visual snow, palinopsia, entoptic
phenomena, photophobia, nyctalopia) using transcranial electric stimulation (tACS).

Targeted treatment approach doing neuromodulation planned at Inselspital Bern

Start will be in autumn 2022

We have promising preliminary data from a previous study performed with support by EOV foundation

Treatment will be over one week a in Bern

Lead researchers are Prof. Dr. med. Christoph Schankin and Antonia Klein, MD

Study has partial funding but would need 90000 USD for completion of the study

Donations are accepted at EyeOnVision.org

Jo Fielding - Research at Monash University on Visual Snow Syndrome

2/21/2022

 

Visual snow syndrome, the spectrum of perceptual disorders, and migraine as a common risk factor: A narrative review

1/22/2022

 
Antonia Klein MD, Christoph J. Schankin MD
First published: 27 September 2021
 https://doi.org/10.1111/head.14213
Abstract

Objective

The aim of this narrative review is to explore the relationship between visual snow syndrome (VSS), migraine, and a group of other perceptual disorders.

Background

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.

Methods

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.

Results

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.

Conclusion

​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.
To view full article click here 

We have partnered with Dr. Schankin for over a decade

1/19/2022

 
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We are grateful for our collaboration with Dr. Puledda

1/19/2022

 
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Occipital cortex and cerebellum gray matter changes in visual snow syndrome

1/4/2022

 
Francesca Puledda, Muriel Bruchhage, Owen O'Daly, Dominic Ffytche, Steven C.R. Williams,  Peter J. Goadsby
First published August 5, 2020, 
DOI: https://doi.org/10.1212/WNL.0000000000010530


Abstract

Objective 

To determine whether regional gray and white matter differences characterize the brain of patients with visual snow syndrome, a newly defined neurologic condition, we used a voxel-based morphometry approach.

Methods
 

In order to investigate whole brain morphology directly, we performed an MRI study on patients with visual snow syndrome (n = 24) and on age- and sex-matched healthy volunteers (n = 24). Voxel-based morphometry was used to determine volumetric differences in patients with visual snow. We further analyzed cerebellar anatomy directly using the high-resolution spatially unbiased atlas template of the cerebellum.

Results
 

Compared to healthy controls, patients with visual snow syndrome had increased gray matter volume in the left primary and secondary visual cortices, the left visual motion area V5, and the left cerebellar crus I/lobule VI area. These anatomical alterations could not be explained by clinical features of the condition.

Conclusion
 

Patients with visual snow syndrome have subtle, significant neuroanatomical differences in key visual and lateral cerebellar areas, which may in part explain the pathophysiologic basis of the disorder.

To access the full article please download the PDF below or download here
e1792.full.pdf
File Size: 379 kb
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Disrupted connectivity within visual, attentional and salience networks in the visual snow syndrome

1/4/2022

 

Francesca Puledda
, 
Owen O'Daly, Christoph Schankin, Dominic Ffytche, Steven CR Williams, Peter J Goadsby
First published: 15 January 2021
 https://doi.org/10.1002/hbm.25343


Abstract

Here we investigate brain functional connectivity in patients with visual snow syndrome (VSS). Our main objective was to understand more about the underlying pathophysiology of this neurological syndrome. Twenty-four patients with VSS and an equal number of gender and age-matched healthy volunteers attended MRI sessions in which whole-brain maps of functional connectivity were acquired under two conditions: at rest while watching a blank screen and during a visual paradigm consisting of a visual-snow like stimulus. Eight unilateral seed regions were selected a priori based on previous observations and hypotheses; four seeds were placed in key anatomical areas of the visual pathways and the remaining were derived from a pre-existing functional analysis. The between-group analysis showed that patients with VSS had hyper and hypoconnectivity between key visual areas and the rest of the brain, both in the resting state and during a visual stimulation, compared with controls. We found altered connectivity internally within the visual network; between the thalamus/basal ganglia and the lingual gyrus; between the visual motion network and both the default mode and attentional networks. Further, patients with VSS presented decreased connectivity during external sensory input within the salience network, and between V5 and precuneus. Our results suggest that VSS is characterised by a widespread disturbance in the functional connectivity of several brain systems. This dysfunction involves the pre-cortical and cortical visual pathways, the visual motion network, the attentional networks and finally the salience network; further, it represents evidence of ongoing alterations both at rest and during visual stimulus processing.

Please click here to read full article 
human_brain_mapping_-_2021_-_puledda_-_disrupted_connectivity_within_visual__attentional_and_salience_networks_in_the.pdf
File Size: 4234 kb
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‘Visual snow’ – a disorder distinct from persistent migraine aura

1/4/2022

 
Christoph J. Schankin, Farooq H. Maniyar, Kathleen B. Digre, Peter J. Goadsby
Brain, Volume 137, Issue 5, May 2014, Pages 1419–1428, https://doi.org/10.1093/brain/awu050
Published:18 March 2014

Abstract

Patients with ‘visual snow’ report continuous tiny dots in the entire visual field similar to the noise of an analogue television. As they frequently have migraine as a comorbidity with ophthalmological, neurological and radiological studies being normal, they are offered various diagnoses, including persistent migraine aura, post-hallucinogen flashback, or psychogenic disorder. Our aim was to study patients with ‘visual snow’ to characterize the phenotype. A three-step approach was followed: (i) a chart review of patients referred to us identified 22 patients with ‘visual snow’. Fifteen had additional visual symptoms, and 20 patients had comorbid migraine, five with aura; (ii) to identify systematically additional visual symptoms, an internet survey (n = 275) of self-assessed ‘visual snow’ subjects done by Eye On Vision Foundation was analysed. In two random samples from 235 complete data sets, the same eight additional visual symptoms were present in >33% of patients: palinopsia (trailing and afterimages), entoptic phenomena (floaters, blue field entoptic phenomenon, spontaneous photopsia, self-light of the eye), photophobia, and nyctalopia (impaired night vision); and (iii) a prospective semi-structured telephone interview in a further 142 patients identified 78 (41 female) with confirmed ‘visual snow’ and normal ophthalmological exams. Of these, 72 had at least three of the additional visual symptoms from step (ii). One-quarter of patients had ‘visual snow’ as long as they could remember, whereas for the others the mean age of onset was 21 ± 9 years. Thirty-two patients had constant visual symptoms, whereas the remainder experienced either progressive or stepwise worsening. Headache was the most frequent symptom associated with the beginning or a worsening of the visual disturbance (36%), whereas migraine aura (seven patients) and consumption of illicit drugs (five, no hallucinogens) were rare. Migraine (59%), migraine with aura (27%), anxiety and depression were common comorbidities over time. Eight patients had first degree relatives with visual snow. Clinical investigations were not contributory. Only a few treatment trials have been successful in individual patients. Our data suggest that ‘visual snow’ is a unique visual disturbance clinically distinct from migraine aura that can be disabling for patients. Migraine is a common concomitant although standard migraine treatments are often unhelpful. ‘Visual snow’ should be considered a distinct disorder and systematic studies of its clinical features, biology and treatment responses need to be commenced to begin to understand what has been an almost completely ignored problem.

To read the full article please click here or download the PDF below 
​
visualsnow.pdf
File Size: 555 kb
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Visual snow syndrome: a comparison between an Italian and British population

1/4/2022

 

M. Viana
, 
F. Puledda, P. J. Goadsby
First published: 01 June 2020
 https://doi.org/10.1111/ene.14369


Abstract

Background and purpose

Visual snow manifests as a pan-field, dynamic visual disturbance described as continuous television static-like tiny flickering dots. Current diagnostic criteria further require at least two additional symptoms for visual snow syndrome (VSS) from: palinopsia (afterimages and trailing); entoptic phenomena (floaters, blue field entoptic phenomenon, photopsia, self-light of the eye); photophobia and nyctalopia. Our objective was to compare the phenotype of VSS in an Italian and British population.

Methods

Patients with VSS were characterized clinically using the current criteria. An online survey was prepared in collaboration with the patient group Eye-on-Vision. Patients were directed to the site if they contacted us by email asking to be involved in research. After data collection, we compared the phenotypic characteristics of a subgroup of British versus Italian patients taking part in the survey. As we expected more responses from the UK, we matched 100 UK patients for gender and age with our Italian cohort.

Results

Patients were enrolled from the UK (n = 100) and Italy (n = 100). The populations had similar demography. After multiple correction testing there were no differences in VSS features between the two groups. The same was true for the prevalence of migraine and previous use of recreational drugs.

Conclusion

This is the first study comparing the phenotype of VSS between two distinct populations. Our findings suggest that the visual snow phenotype, as well as migraine comorbidity, is similar across the two groups.

To read full article please click here or download the PDF below 

euro_j_of_neurology_-_2020_-_viana_-_visual_snow_syndrome__a_comparison_between_an_italian_and_british_population.pdf
File Size: 157 kb
File Type: pdf
Download File

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  • Home
  • WHAT IS VISUAL SNOW SYNDROME
    • What is Visual Snow Syndrome >
      • Visual Snow Syndrome Overview
    • Visual Snow Resources
    • Symptoms >
      • Blue Field Entoptic Phenomenon
      • Brain Fog
      • Eye Floaters
      • Glare
      • Nyctalopia
      • Oscillopsia
      • Palinopsia
      • Paresthesia
      • Phosphenes
      • Photophobia
      • Silent Migraine
      • Tinnitus
      • Vertigo
  • HOW TO HELP
    • Donate Once
    • Make a Recurring Donation
    • Corporate Giving & Partners
    • Subscribe
    • Connect with us on Social Media
    • Share your VSS story
    • You Can Fundraise >
      • Volunteer Agreement
    • Events
  • WHAT WE DO
    • About
    • Research & News
    • Research Collaborations
    • Meet our VSS Community
  • Donate