Eeg normal. had facial and limb twitching during eeg. history of convulsion after head injury. no history of epilepsy so far. any ideas of cause?

Myoclonus or tremor: Most likely either a tremor on myoclonus. If it's rare in frequency, then you have nothing to worry about.

Can not say: Go see a neurologist. He/she can find the cause and prescribe medication. You need to make sure you are not having seizures again.

Not epilepsy: If the EEG was normal during the movements you described, they do not represent seizure activity. Pseudoseizures are triggered by anxiety. You should see a psychiatrist or psychologist to get help.

One convulsion at time of head injury does not imply future epilepsy. A normal EEG in presence of "twitching" suggests an emotional response at time of study. If no true episodes of altered consciousness, you do not have post-traumatic epilepsy.