Background: Stroke often leads to permanent neurological deficit despite extensive therapeutic and rehabilitative efforts; and in chronic stages, it is difficult to restore neurological function. Recently, bipolar and intermittent cortical stimulation combined with rehabilitation has been reported to be effective in chronic hemiparetic stroke. However, optimal parameters of cortical stimulation for chronic stroke have not been determined to restore neurological function in chronic stages of stroke.
Case descriptions: We report 2 cases of chronic stroke whose neurological functions were improved by continuous, unipolar cortical stimulation combined with rehabilitation. Patient 1 presented motor and language deficit associated with cortical infarct in the left middle cerebral artery territory, which occurred 18 months before admission. Patient 2 presented motor deficit associated with subcortical infarct in the internal capsule 8 months before admission. Unipolar electrodes were implanted epidurally to cover the contralateral premotor and motor cortex in both cases, and an additional electrode was implanted over the Broca area in patient 1. Follow-up evaluation after 4 months of stimulation and concurrent rehabilitation showed improvement of Fugl-Meyer and FIM scores in both patients, and of speech and articulation in patient 1, whose electrode covered the Broca area. No adverse effects were observed during the period of treatment.
Conclusion: Unipolar and continuous cortical stimulation with rehabilitation is beneficial for improving neurological deficit in selected cases of chronic stroke.