objective: demonstrate brain perfusion changes due to neuronal activation after functional electrical stimulation (fes). method: it was studied 14 patients with hemiplegia who were submitted to a program with fes during fourteen weeks. brain perfusion spect was performed before and after fes therapy. these patients were further separated into 2 groups according to the hemiplegia cause: cranial trauma and major vascular insults. all spect images were analyzed using spm. results: there was a significant statistical difference between the two groups related to patient's ages and extent of hypoperfusion in the spect. patients with cranial trauma had a reduction in the hypoperfused area and patients with major vascular insult had an increase in the hypoperfused area after fes therapy. conclusion: fes therapy can result in brain perfusion improvement in patients with brain lesions due to cranial trauma but probably not in patients with major vascular insults with large infarct area.