Syncope (whether vasovagal, orthostatic, cardiogenic, etc.) may present as convulsive syncope: a brief loss of consciousness associated with a short period of jerking or posturing. While a true seizure involves an abnormal discharge of neurons in the brain, convulsive syncope involves seizure-like activity due to cerebral hypoperfusion. Convulsions, loss of consciousness & loss of muscle tone last a few seconds followed by complete recovery, without the postictal period of an epileptic seizure.