A preliminary trial of botulinum toxin type A in patients with vestibular migraine: A longitudinal fMRI study

Abstract

Objective: This study aims to investigate the efficacy of botulinum toxin type A (BTX-A) in the prophylactic management of vestibular migraine (VM) and to determine whether this treatment modulates intrinsic functional brain network.

Methods: Vestibular migraine patients (n = 20, mean age 45.4 years) who were resistant to conventional prophylactic therapies had BTX-A injection and rs-fMRI before and 2 months after the injection. We also measured the changes in the frequency of vertigo and migraine attacks, symptomatic functional disability scores, and neuropsychiatric inventories.

Results: After BTX-A injection, the mean monthly frequencies of migraine and vertigo episodes decreased significantly compared with the baseline (p < 0.01, paired t-test). The Headache Impact Test-6 score and the Migraine Disability Assessment, and the vertigo parameters, measured by the Dizziness Handicap Inventory and the Vertigo Symptom Scale, showed an improvement, as did the anxiety and depression scores 2 months after BTX-A treatment. The low-frequency fluctuation analysis of the rs-fMRI data found significant changes in the functional connectivity of the right superior temporal gyrus. Adoption of this cluster as the seed region increased the functional connectivity with the left post-central gyrus, right supramarginal gyrus, and right middle temporal gyrus after BTX-A treatment.

Conclusion: This prospective study suggests that BTX-A treatment is effective at ameliorating migraine and vertigo symptoms in VM patients who were resistant to conventional therapies. Along with symptomatic improvements, changes in the functional connectivity within the multisensory vestibular and pain networks suggest a dysmodulation of multimodal sensory integration and abnormal cortical processing of the vestibular and pain signals in VM patients.

Keywords: botulinum toxin (BOTOX®); dizziness; headache; migraine; migraine-associated vertigo; prophylactic therapy; vertigo; vestibular migraine.

Figure 1

Comparison of symptomatic functional disability scores before (baseline) and after BTX-A treatment. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001.

Figure 2

(A) The significantly altered amplitude of the low-frequency fluctuation (ALFF) map of the right superior temporal gyrus (STG) in vestibular migraine patients after BTX-A treatment (FDR and FWE p < 0.05 corrected). The color bar denotes the t-value. (B) Functional connectivity (FC) analysis using the peak of the overlapped cluster at the right STG (5-mm green sphere; 57, −36, 3) as the seed. Positive (hot color) t-value indicates increased FC (i) between the right STG and right supramarginal gyrus (SMG); (ii) between the right STG and left postcentral gyrus (PSG); and (iii) between the right STG and right middle temporal gyrus (MTG) (FDR and FWE p < 0.05 corrected).

Figure 3

A correlation analysis showed a significant negative correlation between the functional connectivity of the right superior temporal gyrus (STG) with the supramarginal gyrus (SMG) and the MIDAS score (r = −0.56, p = 0.001).