The cognitive outcome of hemispherectomy in 71 children

Long-term neuropsychological outcome was studied in 71 patients who underwent hemispherectomy for severe and intractable seizures at The Johns Hopkins Hospital between 1968 and 1997 and who agreed to participate. Seizures were due to cortical dysplasias (n = 27), Rasmussen syndrome (n = 37), or vascular malformations or strokes (n = 7). Both presurgical and follow-up results are available and reported for 53 patients.

Patients and caretakers were interviewed, and patients were administered standard measures of intelligence, receptive and expressive language, visual-motor skills, adaptive/developmental functioning, and behavior.

Mean age at surgery was 7.2 years. At follow-up, on average 5.4 years after surgery, 65% are seizure free, 49% are medication free, and, of those responding, none rated quality of life as worse than before surgery. Mean IQ was in the 70s for Rasmussen and vascular patients and in the 30s for cortical dysplasia patients. Language and visual-motor skills were consistent with IQ. For Rasmussen patients only, language was significantly more impaired for left than for right hemispherectomy, both before surgery and at follow-up. Adaptive skills were mildly impaired, with greatest impairment in the physical domain. Cognitive measures typically changed little between surgery and follow-up, with IQ change <15 points for 34 of 53 patients; of the remainder, 11 declined and eight improved. Behavior was free of major problems, but social interactions and activities were limited.

The most significant predictor of cognitive skills at follow-up was etiology, with dysplasia patients scoring lowest in intelligence and language but not in visual-motor skills. Regardless of etiology, most patients showed only moderate change in cognitive performance at follow-up.