Prospective cohort study of the impact of preventive migraine treatment on vestibular function and symptoms: The SPIRAL study.

BACKGROUND

Vestibular symptoms are common in migraine and contribute substantially to disability, even in the absence of a vestibular migraine diagnosis. Whether improvements in dizziness-related disability during preventive treatment are paralleled by measurable changes in vestibular function remains unclear.

METHODS

We conducted a prospective cohort study at a tertiary headache center including 59 patients with migraine and vestibular symptoms who initiated preventive therapy. Clinical outcomes (monthly headache days [MHDs], Headache Impact Test [HIT-6], Dizziness Handicap Inventory [DHI]) and vestibular function (video head impulse test [vHIT], bedside vestibular tests) were assessed at baseline and 3 months. The primary endpoint was the change in DHI and its correlation with vHIT parameters.

RESULTS

Participants were predominantly women (98 %, mean age 36.3 years), with 54 % chronic migraine and 66 % fulfilling criteria for vestibular migraine. Preventive therapy significantly reduced median MHDs (from 15.0 at baseline to 4.0 at 3 months, p < 0.001), HIT-6 scores (67.0-60.0, p < 0.001), and the prevalence of dizziness (75-46 %, p < 0.001) and vertigo (49-24 %, p < 0.001). Median DHI decreased modestly (38.0-32.0, median change -6.0, p < 0.001), with the largest improvement in the emotional domain. While average vHIT gains showed only minimal reductions, a decrease in vHIT asymmetry correlated with DHI improvement (r = 0.33, p = 0.010).

CONCLUSIONS

Preventive migraine therapy reduced both headache burden and vestibular symptoms. Importantly, improvement in dizziness-related disability correlated with reductions in vHIT asymmetry, suggesting that even subthreshold asymmetry values may be clinically relevant in migraine. Given the modest effect size and heterogeneous treatments, these findings should be considered exploratory.