In a recent observational study, the loss of habituation and lower threshold for occipital cortex excitability were demonstrated electrophysiologically in patients with visual snow syndrome (VS). While statistically significant loss of habituation was seen in both VS patients with or without migraine in the right eye, statistically significant loss of habituation in the left eye and decreased threshold of left occipital cortex excitability was seen in patients who had VS with migraine. Researchers investigated the role of neurophysiological assessments of the occipital cortex in VS patients with (VS m) or without migraine (VS wom) and in healthy control (HC). They found:
- Twenty-nine volunteers were recruited for the study; the VS m (n=10), the VS wom (n=7), and the HC group (n=12) did not differ demographically.
- Flickering and floaters were reported in all VS patients and flickering in the dark was the most distressing symptomology in both VS groups.
- Higher visual analogue scale (VAS) scores for palinopsia, photophobia, and concentration difficulty were more frequent in VS m patients.
- In the post hoc analysis, the VS patients did not differ according to the presence of migraine from right or left eye stimulations.
Yildiz FG, Turkyilmaz U, Unal-Cevik I. The clinical characteristics and neurophysiological assessments of the occipital cortex in visual snow syndrome with or without migraine. [Published online ahead of print March 8, 2019]. Headache. doi:10.1111/head.13494.