Structural and functional cortical abnormalities after upper limb amputation during childhood

Functional reorganization has been well documented in the human adult brain after amputation of the arm. To assess the effects of amputation on the de veloping brain, we investigated six patients with upper limb amputation in early childhood and one with right dysmelia. Transcranial magnetic stimulat ion indicated contralateral cortical disinhibition and enlargement of the e xcitable area of the stump. FMRI data corroborated these plastic changes an d also showed an ipsilateral functional reorganization. In the T1-weighted MRI, we found structural deformities of the contralateral and ipsilateral c entral sulcus in three patients and a contralateral atrophic parietal lobul e in two patients. Therefore, arm amputation in childhood affects functiona l organization as well as anatomical structure in both hemispheres. NeuroRe port 12:957-962 (C) 2001 Lippincott Williams & Wilkins.