Visual Auras in Epilepsy and Migraine – An Analysis of Clinical Characteristics

OBJECTIVE: To evaluate the characteristics of visual auras (VA) in epilepsy and migraine. BACKGROUND: Both disorders are usually diagnosed on clinical grounds, but differentiation might be challenging in isolated auras or because of the similar presentation in migraine and epilepsy. METHODS: A retrospective study of two cohorts was performed to compare the VA characteristics of 27 epilepsy patients and 27 age-matched migraine patients. RESULTS: The duration of VA was significantly shorter in epilepsy (median: 56s; 1st quartile Q1: 26s; 3rd quartile Q3: 130s) than in migraine (20 min; Q1: 10 min; Q3: 30 min) (P < .0001). A cutoff duration of ≥5 minutes identified all migraine patients (100% sensitivity, 92% specificity). VAs of epileptic etiology were characterized by restriction to a visual hemifield (74.1% vs 29.6% in migraine, P = .0024) with stereotypic affection of one hemifield (55.5% vs 7.4% in migraine, P = 0.0003). Centrifugal or centripetal spread of visual phenomena only occurred in migraine (37.0%), but not in epilepsy (P = 0.0007). If present, accompanying symptoms such as nausea/vomiting (19/27) or photo-/phonophobia (17/27) identify migrainous auras (vs 0/27 in the epilepsy patients; P < .0001). Headache presented in all migraine patients, but was also observed in six of the epilepsy patients during cephalic auras or the postictal phase (P < .0001). None of the visual migrainous auras evolved into an epileptic seizure, a concept called migralepsy. CONCLUSIONS: Several clinical characteristics differentiate VA of epileptic and migrainous origin - if presenting in classical manner. Additional EEG evaluations should be performed in patients with VA of unclear etiology and epileptic VA features added to current classifications to increase their discriminatory power.