The Effect of OnabotulinumtoxinA on Aura Frequency and Severity in Patients With Hemiplegic Migraine: Case Series of 11 Patients

Background: OnabotulinumtoxinA has been demonstrated to be effective for the preventive treatment of headache in individuals with chronic migraine and has been approved and recommended for this patient population. While the therapeutic effect of onabotulinumtoxinA on migraine headache is well documented, there is limited information on the effect of onabotulinumtoxinA on migraine aura. Objective: Given the prolonged and often debilitating nature of aura in patients with hemiplegic migraine, our group sought to examine the effect of onabotulinumtoxinA on aura frequency and severity in this specific subset of migraine patients. Methods: All clinical notes from July 1, 1994 to December 1, 2017 at our institution were retrospectively reviewed to identify patients diagnosed with hemiplegic migraine who received at least one set of onabotulinumtoxinA injections. Thirty-four patients were identified; and of those, 23 were excluded due to incomplete documentation regarding aura symptoms at follow-up visits. The clinical notes of the remaining 11 patients (4 with familial hemiplegic migraine [FHM] and 7 with sporadic hemiplegic migraine [SHM]) were reviewed, and the frequency and description of their headaches and aura before and after receiving onabotulinumtoxinA were recorded. Results: Nine of the 11 patients in our series noted a decrease in the frequency, severity, and/or duration of their aura after receiving onabotulinumtoxinA. Of the 2 non-responders, one was FHM and one was SHM. Of the 9 that noticed improved aura symptoms, 6 described a "wearing off" effect of onabotulinumtoxinA around week 9 or 10 of the 12-week cycle, with subsequent improvement after the next round. Conclusion: For 9 of 11 patients with hemiplegic migraine, onabotulinumtoxinA was helpful not only in reducing the frequency and severity of headaches but also in reducing the frequency and severity of the aura. In this manuscript, we speculate on potential pathophysiologic mechanisms that could have contributed to this effect.