Transient global amnesia and epilepsy. Electroencephalographic distinction.

Electroencephalographic recordings were obtained during 13 episodes of transient global amnesia in 13 patients. Eight were entirely normal; none showed seizure discharges or other epileptiform activity. Electroencephalographic recordings were also obtained after 103 episodes of amnesia in 96 patients with transient global amnesia (TGA) alone, five patients who had both TGA and epilepsy independently, and three patients with amnesia related to epilepsy. The majority (60.8%) of waking records were normal during or after episodes of TGA. Mild or moderate and nonfocal abnormalities were found in a minority. Genuine epileptiform activity was observed only among patients who had seizure disorders. Amnestic episodes attributable to seizures were more brief and more apt to be repeated than TGA and usually responded to anticonvulsant drugs. Differentiation of TGA from epilepsy is essential for appropriate management.