Seizure symptomatology in infants with localization-related epilepsy

The clinical characteristics of seizures in adults and children with localization-related epilepsy have been clearly described and classified, but few data are available based on video EEG studies of postneonatal infants under 2 years of age. We analyzed 125 videotaped seizures from 23 infants aged 2 to 24 months with localization-related epilepsy defined by localized ictal EEG or localized lesion on neuroimaging with seizure-free surgical outcome. Seizure symptomatology was classified based on observable behavioral and motor manifestations and then correlated with location of the epileptogenic zone. Seizures characterized by decrease in behavioral motor activity with indeterminate level of consciousness and minimal or no automatisms ("hypomotor" seizures) arose from temporal, temporoparietal, or parieto-occipital regions (7 patients). Seizures with localized or bilateral clonic, tonic, or atonic motor phenomena arose predominantly from frontal, frontocentral, central, or frontoparietal areas (12 patients). One patient had versive seizures arising from the contralateral occipital lobe, 2 patients had infantile spasms (one with a frontal tumor, one with temporo-parieto-occipital dysplasia), and one patient had unclassifiable seizures. Disruption of temporal or temporoparietal function resulted primarily in diminution of behavioral activity, whereas ictal activation of motor areas during frontal or central onset seizures resulted mainly in localized or generalized motor phenomena. Infantile spasms occurred because of lesions in either location. Using an approach based on easily observable behavioral and motor phenomena, it was possible to classify the seizures in all but one infant.