Eeg&mri tests4 seizures.result neg.so what's split-second loss of consc.,falling 4ward&muscles very tense,brain feels 'shaken'.just had this1st time.

You may have one: Despite the fact that the EEG and MRI were negative you still may have a seizure. A Neurologist would be the M.D. to better help you with that situation.

Probably not seizure: A single momentary lapse of consciousness is unlikely to be a seizure. Other causes include heart arrhythmias, or vasovagal syncope, also called "fainting,". Seizure that causes loss of consciousness almost always leaves the patient very lethargic, tired and confused for at least 5-30 minutes and often longer. But a single normal EEG between episodes does not totally rule out seizures.