Visual snow” (VS) is a disabling disorder with patients complaining about TV-snow-like tiny flickering dots in the entire visual field. The symptoms can be continuous and might persist over years. In a recent study, almost all patients
with VS had additional visual symptoms, such as palinopsia, entoptic phenomena (floaters, blue field entoptic phenomenon, and others), nyctalopia (impaired night vision), photophobia, and tinnitus suggesting that VS is likely a clinical syndrome. In our study population, the majority of patients with VS had comorbid migraine Selleck LY294002 (58%), and 31% had typical migraine aura. This high comorbidity, when compared with the general population, has led to the assumption that VS might represent persistent migraine aura as often discussed in the initial case series,1-3 although the clinical presentation is clearly different from typical migraine aura. Here, we sought to understand whether the VS syndrome manifests differently in patients with migraine or typical aura. For that, a cohort of VS patients was
carefully phenotyped in respect to the clinical presentation and comorbidities. We found that VS patients, who also have migraine according to International Classification of Headache Disorders – 2nd edition had a significantly higher likelihood of having palinopsia, photophobia, nyctalopia, and tinnitus. Of the entoptic phenomena, ie, visual perceptions arising from the optic apparatus itself, only spontaneous photopsia was more prevalent SCH772984 solubility dmso in VS patients
with migraine history, while floaters, blue field entoptic phenomenon, and self-light of the eye were equally distributed. Three major conclusions might be drawn from this: First, the presence of migraine might aggravate the manifestation of the VS syndrome by worsening some, but not all additional click here visual symptoms. Second, our study population was recruited via a self-help group, and it is possible that patients with a more severe clinical manifestation are more eager to participate in a research study. Therefore, a more severe manifestation of the VS syndrome in migraineurs indicates that the high prevalence of migraine in our VS study population might be subject to a selection bias suggesting that the relevance of migraine for VS pathophysiology might be overrated as well. In contrast, the presence of typical migraine aura, ie, the putative correlate of cortical spreading depression that presents with a homonymous, centrifugally moving scintillating scotoma shaped in zigzag lines,[16, 17] does not substantially alter the distribution of the additional visual symptoms in the VS syndrome. Typical migraine aura may thus not influence the VS phenotype suggesting that the high prevalence of aura is less subject to selection bias than migraine. Although VS is clearly not persistent migraine aura, typical migraine aura might share some pathophysiological background with the VS syndrome.