Prevalence and characteristics of Alice in Wonderland Syndrome in adult migraineurs: Perspectives from a tertiary referral headache unit.

Background: Migraine affects how the brain processes sensory information at multiple levels. The aberrant integration of visual and somatosensory stimuli is thought to underlie Alice in Wonderland Syndrome, a disorder often reported as being associated with migraine. However, there is still a lack of knowledge about the epidemiology of this syndrome in migraineurs and the association between Alice in Wonderland Syndrome episodes and migraine attacks. Therefore, we conducted a prospective cohort study to systematically evaluate the prevalence and the clinical features of Alice in Wonderland Syndrome in a large sample of patients with migraine.

Methods: All the patients attending for the first time a tertiary-level headache clinic were consecutively screened for Alice in Wonderland Syndrome symptoms by means of an ad hoc questionnaire and detailed clinical interview, over a period of 1.5 years. Patients experiencing Alice in Wonderland Syndrome symptoms were contacted for a follow-up after 8-12 months.

Results: Two hundred and ten patients were recruited: 40 patients (19%) reported lifetime occurrence of Alice in Wonderland Syndrome, 90% of whom (38/40) had migraine with aura. Thirty-one patients experienced episodes of Alice in Wonderland Syndrome within 1 h from the start of migraine headache. Patients reported either visual or visual and somatosensory symptoms (i.e. somatosensory symptoms never presented alone). We collected the follow-up details of 30 patients with Alice in Wonderland Syndrome, 18 of whom had been prescribed a preventive treatment for migraine. After 8-12 months, 5 of the treated patients reported a decrease, while 13 reported no episodes of Alice in Wonderland Syndrome.

Conclusion: Alice in Wonderland Syndrome prevalence in migraineurs was found to be higher than expected. Alice in Wonderland Syndrome was mostly associated with migraine with aura and tended to occur close to the migraine attack, suggesting the existence of a common pathophysiological mechanism. Patients treated with migraine preventive treatments had a higher chance of decreasing or even resolving Alice in Wonderland Syndrome episodes.