Brain reorganisation in cerebral palsy: a high-field functional MRI study.

Early brain damage may induce alternative organisation of cortical brain functions. This may happen even if there is no damage to the cortex. We assessed a 15-year-old girl with a perinatal left-sided subcortical lesion without cortical damage by functional MRI at 3 Tesla. The patient had congenital hemiparesis, mirrored limb movements and normal language function. Functional MRI was used to assess language using orthographic-lexical retrieval and noun-verb generation tasks, and demonstrated right-sided language dominance. Functional MRI of motor function was assessed for both hands separately, by squeezing a rubber balloon. Both hand movements induced asymmetric bilateral activation of the motor cortex, with a predominance of contralateral activation. Language-associated activity is usually left-hemispheric, but was found in the undamaged right-sided hemisphere. Motor function was associated with the unusual pattern of bilateral cortical activation. The MR findings explain the clinical features and suggest widespread alternative cortical organisation in the presence of a focal lesion confined to subcortical structures.