Distinct Peripheral and Central Vestibular Phenotypes in Vestibular Migraine

Background/Objective: To characterize vestibular phenotypes associated with vestibular migraine (VM) and explore the potential underlying pathophysiological mechanisms. Methods: This consecutive observational comparative study included 98 participants (63 with VM and 35 healthy controls). All participants underwent caloric testing and the video head impulse test (vHIT). Vestibular recruitment, unilateral weakness, caloric hyperreflexia, caloric dysrhythmia, and high gain on vHIT were assessed. Associations between VM and vestibular variables were evaluated using logistic regression. Caloric responses were compared between groups using multivariate analysis of covariance (MANOVA), adjusted for age and sex. The association between vestibular recruitment and markers of vestibular hyperexcitability was assessed using contingency tables, Pearson’s chi-square test and Fisher’s exact test. Results: Patients with VM exhibited higher frequencies of vestibular recruitment (p = 0.0009), unilateral weakness (p = 0.0017), and caloric dysrhythmia (p = 0.0076). Multivariate analysis demonstrated significantly greater caloric responses in patients with VM across all irrigations (p = 0.0129). High gain on vHIT was not associated with VM (p = 0.6878). No association was observed between vestibular recruitment and caloric dysrhythmia (p = 0.3320) or between vestibular recruitment and caloric hyperreflexia (p = 0.3725). Conclusions: These findings suggest that VM is associated with both peripheral vestibular abnormalities and vestibular hyperexcitability. The absence of associations between vestibular recruitment and markers of hyperexcitability suggests that these abnormalities may represent distinct vestibular phenotypes, supporting an integrative model in which peripheral and central mechanisms coexist in a partially independent manner in the vestibular pathophysiology of VM.