Understanding Visual Snow Syndrome
Research type
Research Study
Full title
Understanding the Pathophysiology and Neuropharmacology of Visual Snow Syndrome: A Functional Imaging and Experimental Medicine Approach
IRAS ID
174134
Contact name
Professor Goadsby
Contact email
Sponsor organisation
King's College London
Duration of Study in the UK
1 years, 6 months, 1 days
Research summary
Patients with “visual snow” suffer from continuous TV-static-like tiny flickering dots in the entire visual field. Visual snow is a unique purely visual syndrome that can be very disabling for patients. The high prevalence of migraine and typical migraine aura in this population has led to the assumption that “visual snow” is caused by persistent migraine aura. Due to the lack of objective measures, alternative diagnoses are malingering or a psychogenic disorder. However previous findings by the study author show that it seems to be clinically distinct from migraine aura. Systematic studies of its clinical features, biology and treatment responses need to be commenced to understand what has been an almost completely ignored but disabling disorder.
The study design consists of two parts:
• Part 1 is a brain imaging study using Arterial Spin Labeling (pCASL)
• Part 2 is a prospective, randomized, single-blinded, monocentric, placebo-controlled, cross-over, mechanistic study of VS pharmacology.Part 1 - We will collect a group of subjects who have visual snow according to the criteria recently published by the study authors. We will do arterial spin labeling at rest to identify areas of hyperperfusion in visual snow when compared to a control group with migraine. Further, the effect of saline-infusion on the pattern of perfusion will be assessed. These results will be compared to the PET findings in an earlier study investigating visual snow patients.
Part 2 - We will administer different well-characterized medications to observe changes in clinical symptoms. Patients will receive ketamine, flumazenil, Naloxone and diazepam in a randomized order during visits 3, 4, 5 and 6. This will allow us to assess the response to receptor-specific stimulation or inhibition to understand the pharmacology behind the syndrome.
REC name
London - Camden & Kings Cross Research Ethics Committee
REC reference
15/LO/1036
Date of REC Opinion
7 Jul 2015
REC opinion
Unfavourable Opinion