ABSTRACT

To evaluate and describe the postictal EEG features after generalized tonic-clonic seizures with reference to interictal EEG.

The study included 22 patients who had generalized onset (n=6; 5 males; mean age 27 years; range 11 to 37 years) or partial onset (n=16; 8 females; mean age 22 years; range 12 to 40 years) tonic-clonic seizures. Postictal serial EEG monitoring was performed for 15 consecutive days and an interictal EEG was obtained on the 45th day following the index seizure. The background activity together with asymmetries and epileptiform abnormalities were evaluated.

Fourteen patients with partial onset seizures showed a background slowing or attenuation for a mean of 11.6 days (range 2 to 15 days) and five patients with generalized seizures exhibited a background slowing for 4.5 days (range 2 to 7 days). Hemisphere asymmetry was a striking feature in the partial onset group. Focal and diffuse epileptiform activities were more frequent during the postictal period than those of the interictal EEG.

The postictal period represents both a dynamic course in terms of background activities and a sensitive period for the detection of epileptiform abnormalities. Postictal EEG may be instrumental in patients with new onset epilepsy and in patients with unclaşified epilepsy.

Keywords: Electroencephalography; epilepsy/physiopathology;epilepsy, temporal lobe/physiopathology;epilepsies, partial/physiopathology;epilepsy, tonicclonic;time factors.