Age and etiology as predictors of language outcome following hemispherectomy.

We report on the effects of etiology and age on the linguistic outcomes in a large pediatric hemispherectomy population. Four populations were considered separately: cortical dysplasia (multilobar involvement), Rasmussen's encephalitis, infarction as a primary etiology and, fourth, children who failed to develop language, regardless of etiology. We argue against the 'the-earlier-the-better' hypothesis and propose our own hypothesis that weds maturational factors to etiological factors to predict language outcomes following pervasive brain insult. The implications of our 'critical impact point' hypothesis are discussed.