An 8 year old right-handed boy was seen in paediatric clinic for longstanding history of morning headaches localised to the top of the head since the age of two.  These were associated with nausea and photophobia, and relieved by sleep.  In addition, he has been suffering from longstanding night terrors and sleep walking, which typically occur between 10 pm and midnight.  There has been a recent increase in these events up to once to twice per week, which prompted medical evaluation, with the headaches being severe enough to frequently miss school.  His father has migraines and depression, and both younger siblings are well.  Physical examination, including neurology, was normal.  Blood tests were unremarkable.  Sleep hygiene advice was given and headache diary in relation to different foods was advised.  An outpatient sleep-deprived EEG was requested, which was performed five days later.

       The initial EEG recording, including periods of sleep, was within normal limits.  Post hyperventilation, the EEG showed widespread high amplitude slow-wave activity with posterior emphasis lasting about 4 minutes.  Clinically, this was correlated with staring, slow verbal responses, progressing to right facial droop and eventually also right arm weakness.  He was transferred to A&E.  Neurological examination revealed dysarthria, subtle right arm weakness and mild coordination difficulties on right finger-nose testing.  His symptoms and signs resolved completely after an hour.  Urgent MRI scan showed stenosis of both middle cerebral arteries with collateral vessels and silent infarcts.