Twelve children with Rasmussen's encephalitis underwent hemispherectom
y and have been followed for an average of 9.15 years. Our decision-ma
king process leads to early, rather than late operation. Because hemip
legia is inevitable with or without operation, earlier operation may a
llow such children to resume a more normal life. We postulate that ear
lier operation may prevent some of the intellectual decline that accom
panies the continued seizures and their treatment. In view of the vari
able pathologic findings and lack of evidence of a viral etiology, we
suggest either use of the term ''progressive unilateral encephalopathy
of childhood'' or ''Rasmussen's syndrome'' in recognition of its heri
tage.