Sean Froudist-Walsh, Carles Grau, Nurja Rojo, Pablo Ripollés, Jordi Montero, Julià L. Amengual, Antoni Valero-Cabré, Misericordia Veciana de las Heras, Nils Bodammer, Antoni Rodríguez-Fornells, Thomas F. Münte, Bahram Mohammadi, Universitat de Barcelona, Université Pierre et Marie Curie, Boston University School of Medicine, Universidad de Málaga, Universitat Oberta de Catalunya (UOC), Neurodynamic Laboratory, Universitat de Barcelona (UB), Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière (CRICM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Neurology Section, Hospital Universitary de Bellvitge (HUB), Cognition and Brain Plasticity Unit, Institut d'Investigació Biomèdica de Bellvitge [Barcelone] (IDIBELL), Dept. of Basic Psychology, University of Barcelona, Unit of Cognitive Neurology and Aphasia, Universidad de Málaga [Málaga] = University of Málaga [Málaga]-Centro de Investigaciones Médico-Sanitarias (CIMES), Center for Lifespan Psychology (LIP), Max Planck Institute for Human Development, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Department of Neurology, Universität zu Lübeck [Lübeck], CNS-LAB, International Neuroscience Institute (INI), Institució Catalana de Recerca i Estudis Avançats (ICREA), This project has been partially supported by la Fundació La Marató TV3 (Spain), by the DZNE (German Center for Neurodegenerative Diseases) and by Spanish MICINN R + D plan SEJ2006-1399 project., BMC, Ed., and Universität zu Lübeck = University of Lübeck [Lübeck]
Background We report the case of a chronic stroke patient (62 months after injury) showing total absence of motor activity evoked by transcranial magnetic stimulation (TMS) of spared regions of the left motor cortex, but near-to-complete recovery of motor abilities in the affected hand. Case presentation Multimodal investigations included detailed TMS based motor mapping, motor evoked potentials (MEP), and Cortical Silent period (CSP) as well as functional magnetic resonance imaging (fMRI) of motor activity, MRI based lesion analysis and Diffusion Tensor Imaging (DTI) Tractography of corticospinal tract (CST). Anatomical analysis revealed a left hemisphere subinsular lesion interrupting the descending left CST at the level of the internal capsule. The absence of MEPs after intense TMS pulses to the ipsilesional M1, and the reversible suppression of ongoing electromyographic (EMG) activity (indexed by CSP) demonstrate a weak modulation of subcortical systems by the ipsilesional left frontal cortex, but an inability to induce efficient descending volleys from those cortical locations to right hand and forearm muscles. Functional MRI recordings under grasping and finger tapping patterns involving the affected hand showed slight signs of subcortical recruitment, as compared to the unaffected hand and hemisphere, as well as the expected cortical activations. Conclusions The potential sources of motor voluntary activity for the affected hand in absence of MEPs are discussed. We conclude that multimodal analysis may contribute to a more accurate prognosis of stroke patients.