A patient with Rasmussen's encephalitis underwent a right central resection at the age of 6 as a treatment for status epilepticus. She became seizure free, but suffered a left hemiplegia which improved so that she could walk. Because of the recurrence of seizures an enlargement of the resection to a hemispherectomy was carried out 17 years after the first operation. Various examinations, including H(2)(15)O PET and amytal testing, performed before this second operation indicated that a compensatory reinforcement of the ipsilateral uncrossed corticospinal and spinocortical pathways had taken place. This was confirmed postoperatively. The patient had no new sensorimotor deficits.