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Localised increase in regional cerebral perfusion in patients with visual snow syndrome: A pseudo-continuous arterial spin labelling study

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Pages (from-to)918-926
Number of pages9
JournalJournal of Neurology, Neurosurgery and Psychiatry
Volume92
Issue number9
DOIs
Accepted/In press2021
Published1 Sep 2021

Bibliographical note

Funding Information: Funding This study represents independent research part funded by the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care. The study was part supported by the Visual Snow Initiative and by crowdfunding from the self-help group for visual snow Eye On Vision Foundation. Publisher Copyright: © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

King's Authors

Abstract

We aimed to investigate changes in regional cerebral blood flow (rCBF) using arterial spin labelling (ASL) in patients with visual snow syndrome (VSS), in order to understand more about the underlying neurobiology of the condition, which remains mostly unknown. We performed an MRI study in which whole-brain maps of rCBF were obtained using pseudo-continuous ASL. Twenty-four patients with VSS and an equal number of gender and age-matched healthy volunteers took part in the study. All subjects were examined with both a visual paradigm consisting of a visual-snow like stimulus, simulating key features of the snow, and a blank screen at rest, randomly presented. Patients with VSS had higher rCBF than controls over an extensive brain network, including the bilateral cuneus, precuneus, supplementary motor cortex, premotor cortex and posterior cingulate cortex, as well as the left primary auditory cortex, fusiform gyrus and cerebellum. These areas were largely analogous comparing patients either at rest, or when looking at a ‘snow-like’ visual stimulus. This widespread, similar pattern of perfusion differences in either condition suggests a neurophysiological signature of visual snow. Furthermore, right insula rCBF was increased in VSS subjects compared with controls during visual stimulation, reflecting a greater task-related change and suggesting a difference in interoceptive processing with constant perception of altered visual input. The data suggest VSS patients have marked differences in brain processing of visual stimuli, validating its neurobiological basis.

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