Cortical Neuromodulation by Constraint-Induced Movement Therapy in Congenital Hemiparesis: An fMRI Study

OBJECTIVE: The aim of this study was to assess neuromodulative effects of CIMT in congenital hemiparesis. PATIENTS AND METHODS: Ten patients (age range: 10-30 years) with congenital hemiparesis due to unilateral cortico-subcortical infarctions in the middle cerebral artery territory, and with preserved cortico-spinal projections from the affected hemisphere to the paretic hand, were included. After a twelve-day period of constraint-induced movement therapy (CIMT), all showed a significant improvement of paretic hand function. Immediately before and after therapy, functional MRI during active and passive hand movements was performed to monitor cortical activation. RESULTS: Four patients showed consistent increases in cortical activation during movements of the paretic hand in the primary sensorimotor cortex of the affected hemisphere. Of the remaining six patients, three showed similar changes, but these results were potentially contaminated by an improved task performance after therapy. No significant alteration in activation was observed in two patients, and one showed movement artifacts. CONCLUSIONS: Even a short period of CIMT can induce changes of cortical activation in congenital hemiparesis. In our sample, increases in fMRI activation were consistently observed in the primary sensorimotor cortex of the affected hemisphere. Thus, the potential for neuromodulation is preserved in the affected hemisphere after early brain lesions.