Brain structural and neurometabolic correlates of visual snow disorder (P1.291)

OBJECTIVE: To describe the structural and metabolic pattern of the brain of patients with visual snow (VS). BACKGROUND: Patients with VS complain of a visual disturbance resembling that of a badly-tuned analogue television-channel along with other visual symptoms. The pathophysiology is not known. Recently, hypermetabolism of the lingual gyrus has been shown (Schankin et al. Headache. 2014;54:957-66). DESIGN/METHODS: Twenty patients and 20 matched control subjects underwent [18F]FDG-PET and structural T1-weighted MRI. Data preprocessing and statistics were conducted using SPM8 and the voxel-based morphometry toolbox VBM8. RESULTS: VS patients were metabolically more active than controls in the right lingual gyrus (BA 19). Guided by the metabolic data (region of interest analysis of right BA 19), VBM identified increased gray matter volume in the right fusiform gyrus in VS patients. There were additional areas of hypometabolism in patients as determined with PET in the right superior temporal gyrus (BA 22) and the left inferior parietal lobule (BA 40) without corresponding changes in gray matter volume in the VBM analysis. CONCLUSIONS: The correspondence of structural gray matter changes in the fusiform gyrus and functional hypermetabolism of the nearby lingual gyrus implicates a role for the supplementary visual cortex in the generation or perception of VS. Similar patterns of hypometabolic activity in the superior temporal gyrus and inferior parietal lobule have been described in migraineurs, thereby supporting a pathophysiological overlap between migraine and VS. Study Supported by: Deutsche Forschungsgemeinschaft DFG (grant SCHA 1676/1-1). Disclosure: Dr. Schankin has received personal compensation for activities with Allergan Inc. Dr. Maniyar has nothing to disclose. Dr. Sprenger9s institution has received research support from Novartis, ElectroCore, Genzyme, Actelion, Mitsubishi Pharma Europe, and Biogen Idec. Dr. Chou has nothing to disclose. Dr. Eller has received personal compensation for activities with the Fromm Institute. Dr. Eller has received personal compensation in an editorial capacity for Journal Watch Neurology. Dr. Goadsby has received personal compensation for activities with Allergan, Inc., eNeura, Autonomic Technologies, Amgen, AlderBio, Pfizer, Zogenix, Nevrocorp, Impax, DrReddy, Zosano, Colucid, Eli Lilly, Avanir, Heptares, and Teva Neuroscience. Dr. Goadsb