Abstract Details

Title Functional and metabolic changes in visual snow syndrome: a combined BOLD fMRI and MR-spectroscopy study

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) S32 - Neuro-ophthalmology/Neuro-otology (4:42 PM-4:54 PM)

Poster/Presentation
Number 007

Objective

In order to understand more about the pathophysiology of visual snow (VS), we performed a combined magnetic resonance spectroscopy (MRS) and functional MRI study in patients with visual snow compared to healthy volunteers.

Background Patients with VS suffer a pan-field, dynamic visual disturbance described as continuous tiny flickering dots, frequently with additional visual symptoms. A previous [¹⁸F] FDG PET neuroimaging study in patients showed increased glucose metabolism in the right lingual gyrus (LG).

Design/Methods Subjects with VS (n = 24) and matched healthy volunteers (n = 24) took part in the study. Scanning was performed on a 3T GE MR750 MRI scanner. For MRS, proton spectra were acquired using a point resolved spectroscopy protocol from right LG. BOLD responses were obtained with a single fMRI experiment consisting of a 40 seconds on/off block-design, characterized by a simulation of visual snow alternated with darkness.

Results

There was a significant increase in lactate concentrations in the VS group compared to controls (0.66±0.9 mM vs. 0.07±0.2 mM p<0.001). We found BOLD signal deactivation in VS patients but not controls in the left anterior insula in a whole brain analysis (k=291; p=0.025; x=-34, y=12, z=-6) and, following small volume correction, in the contralateral insula as well (k=100; p=0.003; x =44, y=14, z=-2). Furthermore, there was a significant negative correlation between lactate concentrations and BOLD response in the LG (p = 0.004; r = -0.42), dependent on belonging to the patient group.

Conclusions

These results confirm that patients with VS have an increased anaerobic metabolism in the extrastriate visual cortex, which may cause a decreased metabolic reserve for the regular processing of external visual stimuli. As shown by the BOLD task analysis, visual snow is also characterized by a difference in bilateral insular response to a visual stimulus mimicking VS itself.

Authors/Disclosures
Francesca Puledda (King's College London) PRESENTER	Ms. Puledda has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Teva. Ms. Puledda has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for TEVA.
	No disclosure on file
	No disclosure on file
	No disclosure on file
Christoph J. Schankin, MD (Department of Neurology, Inselspital, Bern University Hospital)	The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Lilly. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Teva. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Lilly. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Lundbeck. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Teva. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Grünenthal. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Lilly. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Novartis. The institution of Dr. Schankin has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Teva. The institution of Dr. Schankin has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Lundbeck. Dr. Schankin has stock in Zynnon.
	No disclosure on file
Peter Goadsby, MD, PhD, FRS (University of California, Los Angeles)	Dr. Goadsby has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Abbvie. Dr. Goadsby has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Eli-Lilly. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Aurene. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Teva Pharmaceuticals. Dr. Goadsby has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Lundbeck. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Satsuma. Dr. Goadsby has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Pfizer. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Shiratronics. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for CoolTech LLC. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Linpharma. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for PureTech Health LLC. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Vial. Dr. Goadsby has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Aeon Biopharma. Dr. Goadsby has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Massachusetts Medical Society. The institution of Dr. Goadsby has received research support from NIHR. The institution of Dr. Goadsby has received research support from Kallyope. Dr. Goadsby has received publishing royalties from a publication relating to health care. Dr. Goadsby has received publishing royalties from a publication relating to health care. Dr. Goadsby has a non-compensated relationship as a Trustee with Migraine Trust that is relevant to AAN interests or activities. Dr. Goadsby has a non-compensated relationship as a Trustee with Organisation for Understanding Cluster Headache (UK) that is relevant to AAN interests or activities. Dr. Goadsby has a non-compensated relationship as a Executive roles with American Headache Society that is relevant to AAN interests or activities.

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