Prognostic value of cortically induced motor evoked activity by TMS in chronic stroke: Caveats from a revealing single clinical case
1 Neurodynamic Laboratory, Departament of Psychiatry and Clinical Psychobiology Universitat de Barcelona, 08035, Barcelona, Spain
2 Cognition and Brain Plasticity Unit. Bellvitge Research Biomedical Institute (IDIBELL), Hospitalet de Llobregat, Llobregat, Spain
3 Université Pierre et Marie Curie, CNRS UMR 7225-INSERM UMRS 975, Groupe Centre de Recherche de l’Institut du Cerveau et la Möelle (ICM), Paris, France
4 Laboratory for Cerebral Dynamics Plasticity & Rehabilitation, Boston University School of Medicine, Boston, USA
5 Cognitive Neuroscience and Information Technology Research Program Open University of Catalonia (UOC), Barcelona, Spain
6 Hospital Universitary de Bellvitge (HUB), Neurology Section, Campus Bellvitge University of Barcelon, Barcelona, Spain
7 Dept. of Basic Psychology, University of Barcelona, 08035, Barcelona, Spain
8 Unit of Cognitive Neurology and Aphasia, Centro de Investigaciones Médico-Sanitarias (CIMES) University of Malaga, Campus Teatinos, Málaga, 29010, Spain
9 Department of Psychosis Studies, Institute of Psychiatry, King's Health Partners, King's College London, London, United Kingdom
10 Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany
11 Department of Neurology, University of Lübeck, Lübeck, Germany
12 CNS-LAB, International Neuroscience Institute (INI), Hannover, Germany
13 Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
BMC Neurology 2012, 12:35 doi:10.1186/1471-2377-12-35Published: 8 June 2012
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.
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.
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.