MOTOR SYSTEMSTranscranial direct current stimulation of the unaffected hemisphere in stroke patientsFregni, Felipea *; Boggio, Paulo S.b c d *; Mansur, Carlos G.c; Wagner, Tima; Ferreira, Merari J. L.d; Lima, Moises C.c; Rigonatti, Sergio P.c; Marcolin, Marco A.c; Freedman, Steven D.a; Nitsche, Michael A.e; Pascual-Leone, AlvaroaAuthor Information aHarvard Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA bDepartments of Experimental Psychology cPsychiatry, University of Sao Paulo dMackenzie University, Sao Paulo, Brazil eDepartment of Clinical Neurophysiology, Georg-August-University, Goettingen, Germany Correspondence and requests for reprints to Felipe Fregni, MD, PhD, Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, KS 452, Boston, MA 02215, USA Tel: +1 617 667 5272; e-mail: firstname.lastname@example.org *Equally contributing authors. Received 4 July 2005; accepted 8 July 2005 NeuroReport: September 28th, 2005 - Volume 16 - Issue 14 - p 1551-1555 doi: 10.1097/01.wnr.0000177010.44602.5e Buy Metrics Abstract Recovery of function after a stroke is determined by a balance of activity in the neural network involving both the affected and the unaffected brain hemispheres. Increased activity in the affected hemisphere can promote recovery, while excessive activity in the unaffected hemisphere may represent a maladaptive strategy. We therefore investigated whether reduction of the excitability in the unaffected hemisphere by cathodal transcranial direct current stimulation could result in motor performance improvement in stroke patients. We compared these results with excitability-enhancing anodal transcranial direct current stimulation of the affected hemisphere and sham transcranial direct current stimulation. Both cathodal stimulation of the unaffected hemisphere and anodal stimulation of the affected hemisphere (but not sham transcranial direct current stimulation) improved motor performance significantly. These results suggest that the appropriate modulation of bihemispheric brain structures can promote motor function recovery. © 2005 Lippincott Williams & Wilkins, Inc.