The language proficiency of 6 right-handed children (ages 7-14 years) with Rasmussen’s syndrome, who underwent left hemidecorticectomy after 5 or more years of normal language development before seizures, were investigated at the Johns Hopkins Hospital, Baltimore, MD. The ability to discriminate consonants and vowels was improved within 4 to 16 days after surgery, when compared to that before surgery, whereas other language functions remained severely impaired until 6 months. Word repetition and phrasal comprehension recovered fully within 1 year, while expressive functions and naming were delayed, and spontaneous speech was telegraphic and restricted to single words. All patients could walk unaided, but had little use of the right arm or hand. Seizures were controlled and antiepileptic drugs were withdrawn in 3.
Rapid recovery of receptive language after surgery suggests that the intact right hemisphere has an innate ability to analyse phonemes and discriminate consonants and vowels. Delayed and partial recovery of expressive language functions may be attributed to plasticity of the right hemisphere, persisting after 5 years of age, the proposed critical age for completion of language acquisition and lateralization. 
COMMENT. Explanations offered for the immediate improvement in phoneme discrimination after left hemispherectomy in these patients included: 1) the innate receptive language capability of the right hemisphere; and 2) a bilateral representation of phoneme processing, at least until adolescence. The right hemisphere is capable of functioning when receptive, and to some extent expressive, language abilities have been undermined by seizures and damage to the left hemisphere in young children.