A new study published in Cephalalgia explored whether lumbar punctures and cerebrospinal fluid (CSF) testing are useful for identifying secondary causes of Visual Snow Syndrome (VSS).
Visual Snow Syndrome is typically diagnosed based on its characteristic symptoms, including persistent visual snow/static, palinopsia, enhanced entoptic phenomena, photophobia, and nyctalopia. Neurological and ophthalmological examinations are usually normal. However, because VSS can sometimes begin or worsen alongside other medical conditions, researchers have questioned whether additional testing, such as a lumbar puncture, may help identify an underlying cause.
Researchers Tim Mader, Antonia Klein, Christoph J. Schankin, and colleagues at Inselspital, Bern University Hospital and collaborating institutions investigated whether CSF abnormalities or antibodies associated with autoimmune neurological conditions are commonly found in people with VSS.
How the Study Was Conducted
The researchers examined 36 patients who met the diagnostic criteria for Visual Snow Syndrome and had undergone a lumbar puncture. Their results were compared with 31 control participants who were matched for age, sex, and migraine status.
Researchers analyzed CSF cell counts and protein levels and, when samples were available, tested blood and CSF for a range of antibodies associated with autoimmune encephalitis and paraneoplastic neurological conditions.
Among the participants with VSS, common symptoms included photophobia, enhanced entoptic phenomena, palinopsia, nyctalopia, and tinnitus. Migraine was also common, affecting approximately 81% of the VSS group.
Key Findings
Overall, researchers found no significant differences in CSF cell counts or protein levels between people with VSS and the control group.
Importantly, none of the tested VSS patients had detectable antibodies associated with autoimmune encephalitis or the paraneoplastic neurological syndromes included in the study.
A small number of participants did have abnormal CSF findings. Four patients had elevated CSF cell counts, one had elevated protein levels, and one showed oligoclonal bands associated with possible neuroinflammation.
However, these abnormalities generally occurred in patients who also had additional symptoms or clinical findings that would be considered “red flags.” These included severe or unusual new headaches, visual snow that was noticeably stronger in one part of the visual field, neurological symptoms, or abnormalities seen on MRI.
The researchers also described patients who had both VSS and multiple sclerosis. Based on the available findings, however, the study could not establish that multiple sclerosis caused their Visual Snow Syndrome.
What This Means for People With VSS
The findings suggest that lumbar puncture should not routinely be part of the diagnostic process for someone with a typical, nonprogressive presentation of Visual Snow Syndrome, particularly when neurological and ophthalmological examinations and brain imaging are normal.
The study also found no evidence in this group to support routinely testing VSS patients for antibodies associated with autoimmune encephalitis or paraneoplastic neurological syndromes.
This is important because lumbar puncture is an invasive procedure and can result in side effects or incidental findings. Testing without a clear clinical reason may also lead to additional investigations that ultimately do not change a patient’s diagnosis or treatment.
When Could a Lumbar Puncture Be Helpful?
The researchers emphasize that the situation is different when a person with visual snow has atypical symptoms or other neurological warning signs.
A lumbar puncture may be appropriate when symptoms are accompanied by findings such as:
- A new or unusually severe type of headache
- Visual snow that is significantly stronger in one area of the visual field
- New neurological symptoms
- Progressive or atypical symptoms
- Abnormal findings on MRI or other neurological testing
In these situations, CSF testing may help doctors investigate inflammatory, autoimmune, infectious, or other neurological conditions that could be contributing to the person’s symptoms.
Moving Toward More Focused VSS Diagnosis
This study supports a more targeted approach to the diagnostic evaluation of Visual Snow Syndrome. For patients who meet the established diagnostic criteria for VSS and have otherwise normal neurological, ophthalmological, and imaging results, extensive invasive testing may not provide additional useful information.
At the same time, the findings reinforce the importance of carefully evaluating each patient individually. When symptoms do not follow the typical VSS pattern or additional neurological abnormalities are present, further investigation may still be necessary to rule out a secondary cause.
The researchers note that the study was relatively small and retrospective, meaning larger and more standardized studies will be needed to confirm these findings. Still, the results provide useful guidance for clinicians and patients seeking to better understand which diagnostic tests are and are not likely to be helpful when evaluating Visual Snow Syndrome.