Background: Studies have shown that migraineurs have an enhanced photic-drive response when exposed to a visual chirp compared to healthy controls. Visual Snow Syndrome (VSS) is associated with migraines, but patients have continuous visual symptoms indicating dysfunction in visual processing. For this reason, we want to determine whether VSS patients show a similar reaction as migraineurs when exposed to visual chirp stimulation. Additionally, we want to see whether t-ACS stimulation lowers their reaction significantly.
Method: One VSS patient (female, 37) with comorbid migraines was exposed to visual chirp stimulation (5.55 – 60 Hz) in a dimly lit room in front of a PC monitor (50 cm). There were 66 flashes per trial, totaling 792 flashes. A 64-electrode EEG grid was used for the measurement, with the occipital electrodes used for analysis. Power spectral density was calculated for stimulus responses and corrected for baseline. A wavelet transformation was applied before averaging the data. The patient received a total of 9 t-ACS stimulations over a period of 5 days between measurements.
Results: The VSS patient showed a high occipital response to visual chirp stimulation pre-t-ACS stimulation and a lower occipital response to visual chirp stimulation post-t-ACS stimulation across all frequencies.
Conclusion: This study shows that visual chirps could serve as a potential biomarker for VSS and that t-ACS stimulation over an extended period of time might be able to lower the photic-drive response, which could represent a novel treatment approach for VSS
