The Untuned Visuo-temporal Cortex in Patients with Visual Snow

Visual snow (VS) is a distressing condition with persistent visual phenomena often leading to multiple unnecessary examinations and treatment attempts. VS impairs daily life by interfering with visual perception, particularly with reading. Neuronally, VS patients are thought to have differences in regional metabolism resulting in modulation of neuronal sensitivity and excitability. We hypothesize to see altered functional connectivity in patients with VS in brain regions associated with visual perception.

Tuesday, March 19th from 9:00 - 9:15 am The Untuned Visuo-temporal Cortex in Patients with Visual Snow Ghislaine Traber1, Njoud Aldusary (shared first author)2, Marco Piccirelli2, Jamaan Alghamdi2, Bujar Saliju1, Shila Pazahr2, Reza Mazloum2, Fahad Alshehri3, Klara Landau1, Spyridon Kollias2, Lars Michels2 Dept of Ophthalmology, University Hospital Zurich, University of Zurich, Switzerland, Zurich, Switzerland, Department of Neuroradiology, University Hospital Zurich, Zurich, Switzerland, Zurich, Switzerland, 3Medical Imaging Dept, Medical College, Qassim University, Buriadah, Saudi Arabia, Buriadah, Saudi Arabia 1 2 Introduction: Visual snow (VS) is a distressing condition with persistent visual phenomena often leading to multiple unnecessary examinations and treatment attempts. VS impairs daily life by interfering with visual perception, particularly with reading. Neuronally, VS patients are thought to have differences in regional metabolism resulting in modulation of neuronal sensitivity and excitability. We hypothesize to see altered functional connectivity in patients with VS in brain regions associated with visual perception. Methods: Using functional magnetic resonance imaging (fMRI), spontaneous resting-state signal fluctuations were examined in 10 patients with VS and 10 age- and gender-matched healthy controls (HC). Resting-state functional connectivity (rsFC) was assessed in- and outside visual brain regions. Further, group differences in grey matter (GM), white matter (WM), and size of the lateral geniculate nucleus (LGN) were investigated. Results: Patients with VS were found to have significant (p < 0.05, corrected) hyperconnectivity of visuo-temporal brain regions compared to HC. Symptom duration positively correlated with hyperconnected brain regions. VS patients had a lower mean LGN volume (p = 0.01). In addition, three patients had an increase in left occipital volume with left occipital bending in one of them. Conclusions: Our results support the view that VS is associated with abnormal excitability of brain regions involved in visual and motional perception. We conclude that rsFC can be used as a marker of symptom duration. LGN volume differences might reflect the LGN's involvement in higher order visual functions. References: None. Keywords: Higher visual functions, Neuroimaging Financial Disclosures: GLT reports a grant from the University of Zurich, Zurich, Switzerland (filling the gap program). Grant Support: GLT reports a grant from the University of Zurich, Zurich, Switzerland (filling the gap program). 2019 Annual Meeting Syllabus | 267