Cervical vestibular evoked myogenic potential asymmetry, but not amplitude, differentiates vestibular migraine during prolonged unidirectional visual motion

Introduction Vestibular migraine (VM) is the leading cause of episodic vestibular complaints. It arises from altered brain states that disrupt sensory processing. A reliance on clinical history for diagnosis highlights the need for bedside biomarkers, particularly in emergency settings where misdiagnosis is common. Methods In this cross-sectional study, 30 VM patients (median-age = 40.5; 27 females) from University College London vestibular clinics and 30 age-gender matched healthy controls (median-age = 32.5; 27 females) were recruited, between May 2024 and October 2025. Cervical Vestibular Evoked Myogenic Potential (cVEMP) responses were measured before and after a Unidirectional Visual Motion Stimuli delivered via virtual reality goggles. Results Mixed linear modeling (MLM) showed no significant effects of group, condition or ear on cVEMP amplitude (all p > 0.05). MLM on asymmetry revealed a significant effect of group, F (1, 57.21) = 11.89, p = 0.001 and condition, F (1, 56.53) = 14.47, p = <0.001; but no significant group × condition interaction, F (1, 56.53) = 1.57, p = 0.215. Spearman correlations showed no association between cVEMP delta amplitude and DHI. VM patients scored higher on all symptom’s measures compared with controls (All p < 0.001). Conclusion Prolonged unidirectional visual stimulation does not significantly affect cVEMP amplitude responses in VM, limiting its value as a differential diagnostic tool. The need to further explore asymmetry and interaural/interhemispheric sensory integration in VM is underscored.