ASYMMETRIC AND ASYNCHRONOUS INFANTILE SPASMS

Infantile spasms most commonly show symmetric behavioral and electroen cephalogram (EEG) manifestations, Asymmetric and asynchronous behavior al spasms occur occasionally, but their relationship to ictal EEG and to other localizing studies has not received much attention, We review ed 75 consecutive video-EEG recordings, done at UCLA from 1982 to 1992 , that contained infantile spasms; 8,680 spasms were scored for behavi oral and EEG asymmetry and asynchrony, Of the recorded spasms, 25% wer e asymmetric and 7% were asynchronous, Most asymmetric or asynchronous spasms were associated with an ictal EEG discharge that was contralat eral to the behaviorally more involved side, In 12 of the 60 patients (20%), more than half of the recorded spasms were asymmetric or asynch ronous. Baseline EEG, magnetic resonance imaging, positron emission to mography, and neurological examination revealed structural and functio nal brain abnormalities that involved the contralateral central region significantly more often in the children with >50% spasm asymmetry or asynchrony than in the other children. Partial seizures with laterali zed motor behavior also occurred frequently in these children. The fin dings suggest that asymmetric and asynchronous spasms are generated by a cortical epileptogenic region that involves the primary sensorimoto r area. The combination of asymmetric and asynchronous infantile spasm s, partial motor seizures involving the same side of the body, and pat hology in the contralateral central region may represent a unique subs et of symptomatic localization-related infantile epilepsy.