Transient neurological deficits experienced by patients with Sturge–Weber syndrome can be caused by epilepsy, or may result from temporary ischaemia of the cortex underlying the vascular malformation. To show the difficulty in distinguishing seizures from ischaemic symptoms, two male children with episodes of acute unilateral weakness are presented here as well as a review of the literature. The first child presented at 2 years of age with a sudden increase in his pre-existing right hemiparesis accompanied by screaming. Ictal epileptiform activity was recorded at the moment of the attack, and subsequent seizures were controlled by adjustment of antiepileptic drug treatment. The second child presented at 4 years of age with attacks of vomiting and a coinciding increase in the pre-existing paresis of the left leg. Electroencephalogram (EEG) recording did not show ictal epileptiform activity. The origin was presumed to be vascular. Treatment with aspirin led to control of these transient ischaemic attacks. Ictal EEG is needed to differentiate between an epileptic and an ischaemic origin of transient focal deficit. Treatment with aspirin should be considered if an ischaemic origin cannot be excluded.