Impact of dizziness on migraine interictal burden in patients with vestibular migraine.

Introduction: Vestibular migraine (VM) remains an under-recognized condition despite its relative high prevalence and substantial impact on the interictal burden of migraine. We quantified vestibular dysfunctions and interictal migraine burden and evaluated whether dizziness contributes to the migraine interictal burden of VM. Methods: We conducted a retrospective observational study of consecutive patients fulfilling the Bárány Society and the International Classification of Headache Disorders, 3rd edition, criteria for VM who attended our outpatient clinic between December 2024 and April 2025. Multidimensional assessments included the Headache Impact Test-6 (HIT-6), Migraine Interictal Burden Scale-4 (MIBS-4), Dizziness Handicap Inventory (DHI), Self-Rating Depression Scale (SDS), Video Head Impulse Test (v-HIT), and posturography (Romberg ratio). Association between MIBS-4 and the other assessments were analyzed using Spearman's correlation and stepwise multiple linear regression. Results: Seventy-five patients were included {median age 37 years [interquartile range (IQR): 27-47]; 74.3% female; 26.7% with aura}. The median HIT-6 score was 62 (IQR: 58-65) and the median MIBS-4 was 4.0 (IQR: 1.0-7.0), with 41.3% of patients exhibiting severe interictal burden (MIBS-4 ≥5). The median DHI score was 20 (IQR: 12-36), and the Romberg ratio was 1.45 (IQR: 1.03-1.97). Vestibular-ocular reflex gains were largely normal, whereas 73.3% of patients exhibited catch-up saccade (CUS) abnormalities. In univariable analyses, MIBS-4 correlated positively with HIT-6 (ρ = 0.414, p < 0.001), DHI (ρ = 0.419, p < 0.001), and SDS (ρ = 0.433, p < 0.001). In multivariable analysis, high HIT-6 scores (β = 0.265, p = 0.016) and high DHI total scores (β = 0.250, p = 0.019) independently predicted high MIBS-4. Conclusion: In patients with VM during the interictal period, vestibular functions were largely normal except for abnormalities in the v-HIT CUS, whereas subjective dizziness assessed by DHI significantly contributed to the high degree of migraine interictal burden. The dizziness experienced in VM resembled that of persistent postural-perceptual dizziness. These results indicate that vestibular rehabilitation might be effective in alleviating migraine interictal burden in patients with VM.