It is well known that some patients with neurally mediated syncope hav
e a feeling of aura before the onset of syncope. A case is reported in
which cerebral dysfunction recorded by EEG was present before the ons
et of a vasovagal reaction. The vasovagal reaction, bradycardia and/or
asystole, was preceded by abnormal EEG findings when the patient comp
lained of feeling a headache, photophobia, and nausea. These findings
suggest that cerebral hypoperfusion, such as with cerebral vasospasms,
before the onset of bradycardia might be involved in the mechanism of
neurally mediated syncope in patients with an aura.