The clinical characteristics of 105 patients with sporadic hemiplegic migraine (SHM) were compared with those of patients with migraine with typical aura (MA) and patients with familial hemiplegic migraine (FHM) in a study at the Danish Headache Center, Glostrup Hospital, Gentofte Hospital, University of Copenhagen, and the John F Kennedy Institute, Denmark. In patients with SHM, 72% had 4 typical aura symptoms: visual, sensory, aphasic, and motor. Compared with MA, the duration of each aura symptom was prolonged and bilateral symptoms were more frequent. Symptoms typical of basilar migraine occurred during attacks of SHM in 72% of cases. SHM has symptoms identical to FHM and different from MA. The aura is usually followed by the headache in SHM, similar to FHM but not MA. Sporadic hemiplegic migraine should be classified with FHM and is separate from migraine with aura. The age of onset is under 15 years in 40% of cases, and one third have an onset between 10 and 14 years. Females outnumber males, 4 to 1. Only 3% have attacks after age 52. 
COMMENT. In an editorial, Goadsby PJ of Queen Square, London, comments that the extent of investigation in a case of sporadic hemiplegic migraine should be exponentially increased as the length of the aura exceeds 60 minutes, but it is reassuring to know that the aura may be prolonged and can be benign . About two thirds have symptoms lasting no longer than an hour, but in one third the aura is prolonged, 8% longer than a day. Clinical characteristics include sensory symptoms in 98%, and brainstem symptoms in 75%. Diagnostic criteria require motor symptoms and at least one visual, sensory, or speech symptom, resembling basilar migraine. Differential diagnoses of SHM include epilepsy (Todd paresis), stroke, systemic lupus, metabolic disorders, and inherited disorders such as mitochondrial myopathy. The workup should include the elimination of these and other disorders with similar symptoms.