Vestibular Migraine and Visual Snow Syndrome: Diagnostic Challenges and Visual Function Assessment

Abstract

Background: Vestibular migraine (VM) and visual snow syndrome (VSS) are distinct yet often overlapping neuro-ophthalmologic conditions characterized by disordered sensory perception.  Objective: To compare the clinical, visual, vestibular, and electrophysiological characteristics of patients with vestibular migraine and visual snow syndrome, identifying key diagnostic features that aid in differentiation.

Methods: This cross-sectional analytical study was conducted at department of Ophthalmology Institute of Ophthalmology and Allied Vision Sciences, Multan from May 2024 to May 2025. It included 135 patients, 78 diagnosed with vestibular migraine and 57 with visual snow syndrome, recruited through non-probability consecutive sampling. All participants underwent detailed clinical evaluation, visual acuity and contrast sensitivity testing, automated perimetry, visual evoked potentials (VEPs), motion perception analysis, and vestibular assessments, including caloric testing, head impulse test, and video-nystagmography.

Results: The mean age of participants was 34.6 ± 8.7 years, with a female predominance (60.7%). Vestibular migraine patients primarily presented with episodic vertigo (82%) and motion intolerance (68%), while VSS patients exhibited continuous visual static (100%), palinopsia (49.1%), and photophobia (70.2%). Contrast sensitivity was significantly lower in VSS (1.35 ± 0.09) than in VM (1.46 ± 0.07; p < 0.001), and visual field defects were detected in 19.2% of VSS patients. VEP testing revealed prolonged P100 latency in VSS (119.4 ± 6.2 ms) compared to VM (106.3 ± 5.8 ms; p < 0.001). Vestibular testing showed abnormalities in 67.9% of VM patients, whereas 94.7% of VSS patients had normal vestibular function (p < 0.001).

Conclusion: It is concluded that vestibular migraine and visual snow syndrome, though clinically overlapping, represent distinct neurophysiological entities. VM is characterized by episodic vestibular dysfunction and transient cortical dysmodulation, while VSS reflects persistent visual cortical hyperexcitability and impaired sensory inhibition.