A new review, “Visual Snow vs. Migraine Aura: Debate Summary and Novel Insights into the Syndrome,” published in Cephalalgia, examines the relationship between Visual Snow Syndrome (VSS) and migraine with aura. The review evaluates decades of clinical, neuroimaging, and neurophysiological research to determine whether the two conditions share the same underlying neurological mechanisms or represent distinct disorders.
The article was authored by Dr. Simone Braca, Dr. Viviana Santoro, Dr. Gabriele Sebastianelli, Dr. Christoph Schankin, Dr. Peter Goadsby, Dr. Francesca Puledda. Because migraine, particularly migraine with aura, is common among people with VSS, researchers have long questioned whether the two conditions share the same underlying neurological process. This review brings together the latest evidence to answer that question.
Dr. Francesca Puledda, Dr. Christoph Schankin, and Dr. Peter Goadsby also presented these findings at the International Headache Congress (IHC) 2025 in São Paulo, Brazil, where researchers from around the world gathered to share the latest advances in headache medicine and related neurological disorders. The presentation highlighted the growing body of evidence supporting Visual Snow Syndrome as a distinct neurological disorder with its own underlying mechanisms.
Visual Snow Syndrome vs. Migraine Aura
Visual Snow Syndrome is characterized by persistent visual snow, which appears as countless flickering dots or static across the entire visual field. To meet the diagnostic criteria for VSS, visual snow is typically accompanied by at least two additional symptoms, including palinopsia, enhanced entoptic phenomena, photophobia, and nyctalopia.
Migraine aura, by comparison, is temporary. Visual aura may include zigzag patterns, flashing lights, blind spots, or other visual changes that occur before or during a migraine attack.
One of the clearest distinctions identified by the researchers is the difference between persistent and episodic symptoms.
VSS symptoms are continuous and do not fluctuate with the migraine cycle. Migraine aura occurs in episodes and usually resolves within an hour. Standard migraine treatments have also not been shown to effectively treat VSS, further supporting the idea that VSS is a separate neurological condition.
Shared Features, Different Disorders
There are important areas of overlap between VSS and migraine with aura.
Both conditions have been associated with increased cortical excitability, changes involving visual processing areas of the brain, and alterations in serotonin-related brain networks.
However, the review found that these similarities do not mean that VSS and migraine aura are manifestations of the same condition.
Instead, researchers suggest that both conditions may share a broader predisposition toward heightened cortical excitability while developing through different neurological mechanisms.
What Brain Imaging Shows
Neuroimaging research has increasingly suggested that VSS involves more than one isolated part of the visual system.
Studies have identified differences involving the visual, attentional, and salience networks of the brain. Researchers have also reported changes involving areas such as the lingual gyrus, visual cortex, anterior insula, anterior cingulate cortex, and other regions involved in determining which sensory information reaches conscious awareness.
These findings support the growing understanding of VSS as a network disorder.
According to the review, the VSS brain may have difficulty filtering or suppressing sensory information that would normally remain in the background. Signals that the brain would normally filter as insignificant visual noise may instead remain noticeable and enter conscious awareness.
This mechanism may help explain not only persistent visual snow, but also symptoms such as excessive floaters and entoptic phenomena, afterimages, and light sensitivity.
Migraine aura appears to follow a different neurological pattern. It is strongly associated with cortical spreading depression, a temporary wave of altered electrical activity that travels across areas of the brain and is believed to produce many aura symptoms.
Differences in Brain Activity
Electrophysiological studies, including EEG and MEG research, also point to differences between the two conditions.
In VSS, researchers have observed changes involving alpha and gamma brain wave activity. These findings may indicate both excessive visual signaling and a reduced ability of the brain to suppress unnecessary sensory information.
The researchers describe this as a combination of increased feed-forward activity and impaired top-down suppression.
Migraine with aura shows a different pattern, with more prominent changes involving slower brain rhythms and asymmetry between different areas of the brain.
Together, these findings further support the conclusion that VSS and migraine aura share certain neurological characteristics but have different underlying mechanisms.
Why This Research Matters
The distinction between Visual Snow Syndrome and migraine aura has important implications for diagnosis, research, and future treatment.
For many years, people experiencing visual snow symptoms have sometimes had those symptoms attributed to migraine or persistent migraine aura. The growing body of scientific evidence summarized in this review supports recognizing VSS as its own neurological disorder, rather than viewing it as a form of migraine aura.
The review also highlights a potentially important finding involving glutamate, one of the brain’s major neurotransmitters. Research has identified glutamatergic connectivity differences specifically in VSS, while serotonin-related alterations have been observed in both VSS and migraine with aura.
Understanding these VSS-specific neurological differences may eventually help researchers identify biomarkers and develop treatments specifically designed for Visual Snow Syndrome.
Continued research into sensory filtering, brain network connectivity, neurotransmitters, and cortical activity may help researchers move closer to developing targeted treatments for Visual Snow Syndrome and improving quality of life for those affected.
