Early cognition, communication and language in children with focal brain injury.

The authors report a longitudinal study of the first stages of cognitive, communicative and linguistic development of six Italian-speaking infants with unilateral brain lesions acquired before the point at which language acquisition normally would begin. Substantial variability was observed in the language-cognition profiles displayed by these children. To unify these diverse profiles, the authors propose a 'cognitive infrastructure' or 'threshold' model of early language development, in which the appearance of speech depends on the presence of certain cognitive prerequisites; once those are in place, some degree of dissociation between linguistic and cognitive development can be observed. The contribution of neurological factors to these profiles appears to be complex, suggesting an interaction between lesion site, lesion size and the presence of seizure disorders and/or anticonvulsant drugs.