Clinical significance of periodic lateralized epileptiform discharges in children with relation to level of consciousness.

Six children with acute cerebral insult, ranging in age from 3 days to 8 years, revealed periodic lateralized epileptiform discharges in their electroencephalographic recordings. Their etiologic factors were cerebral infarction, intracranial bleeding, purulent meningitis, acute infantile hemiplegia, and encephalitis. Each patient exhibited a different type of convulsive seizure. Computer tomography or magnetic resonance imaging revealed diffuse lesions covering the cerebral cortex and subcortical white matter in 2 patients, a lesion of the subcortical white matter in 1 patient, a linear lesion in the cortex and along the borderline between the cortex and the subcortical white matter in 1 patient, and localized lesions in the cortex and basal ganglia in 1 patient. There were findings indicating the disconnection of the cerebral cortex with deeper structures in 3 patients. The appearance rate of periodic lateralized epileptiform discharges increased at levels of consciousness from 5 to 7 on a pediatric modification of the Glasgow Coma Scale. At levels of consciousness from 8 to 14 and below 4, the rate was very low.