Idiom comprehension in children and adults with unilateral brain damage

The comprehension of literal and familiar idiomatic (nonliteral) expressions was assessed in (a) a group of adults with left hemisphere (LH) or right hemisphere (RH) brain damage, (b) a group of children who suffered perinatal brain damage to either the left or right hemisphere, and (c) a control group of healthy children and adults. The normal developmental data showed an expected dissociation between literal and idiomatic phrase comprehension, with idiomatic expressions being learned significantly later. The data from adults with brain damage replicated previous findings of a double dissociation along hemispheric lines, with idiomatic expressions being more impaired by RH than LH damage. In contrast with the adults, the children with focal brain damage showed no association between side of brain damage and comprehension of either familiar idiomatic or literal language. The data support a theory of developmental plasticity of language functions in both the LH and RH.