Constraint-induced movement therapy in congenital hemiparesis with different types of cortico-spinal reorganization: a fMRI study

Objectives: Constraint-Induced Movement Therapy (CIMT) is a functional approach focussing on hand motor improvement in hemiparetic patients. Here, we asked whether CIMT induces neuroplastic effects, and if these effects differ with regard to different patterns of cortico-spinal (re-)organization in congenital hemiparesis. Methods: 15 patients with congenital hemiparesis were included. Group 1 (n=7, mean age: 16.8 years) was characterized by an infarction in the middle cerebral artery territory and preserved crossed cortico-spinal projections to the paretic hand (as demonstrated by focal transcranial magnetic stimulation), Group 2 (n=8, mean age: 16.6 years) by unilateral periventricular white matter lesions and ipsilateral cortico-spinal projections to the paretic hand. FMRI during repetitive active movements of the paretic hand was performed in all patients. Results: After CIMT, group 1 showed an increase in activation in the (contralaterally preserved) cortical hand representation, whereas in group 2, a decrease in activation was observed in the (ipsilaterally reorganized) cortical hand representation. Conclusions: In both types of cortico-spinal (re-)organization, plastic changes were observed in the cortical motor representation of the paretic hand. Thus, functional improvement of the paretic hand after CIMT was paralleled by plastic changes in fMRI activation in functionally corresponding brain areas, but the direction of changes differed between the two different patterns of cortico-spinal (re-)organization.