title: fMRI-vs-MEG evaluation of post-stroke interhemispheric asymmetries in primary sensorimotor hand areas.
abstract: Growing evidence emphasizes a positive role of brain ipsilesional (IL) reorganization in stroke patients with partial recovery. Ten patients affected by a monohemispheric stroke in the middle cerebral artery territory underwent functional magnetic resonance (fMRI) and magnetoencephalography (MEG) evaluation of the primary sensory (S1) activation via the same paradigm (median nerve galvanic stimulation). Four patients did not present S1 fMRI activation [Rossini, P.M., Altamura, C., Ferretti, A., Vernieri, F., Zappasodi, F., Caulo, M., Pizzella, V., Del Gratta, C., Romani, G.L., Tecchio, F., 2004. Does cerebrovascular disease affect the coupling between neuronal activity and local haemodynamics? Brain 127, 99-110], although inclusion criteria required bilateral identifiable MEG responses. Mean Euclidean distance between fMRI and MEG S1 activation Talairach coordinates was 10.1+/-2.9 mm, with a 3D intra-class correlation (ICC) coefficient of 0.986. Interhemispheric asymmetries, evaluated by an MEG procedure independent of Talairach transformation, were outside or at the boundaries of reference ranges in 6 patients. In 3 of them, the IL activation presented medial or lateral shift with respect to the omega-shaped post-rolandic area while in the other 3, IL areas were outside the peri-rolandic region. In conclusion, despite dissociated intensity, the MEG and fMRI activations displayed good spatial consistency in stroke patients, thus confirming excessive interhemispheric asymmetries as a suitable indicator of unusual recruitments in the ipsilesional hemisphere, within or outside the peri-rolandic region.
authors.affiliation: Neurologia Clinica, Università Campus Biomedico, Rome, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Altamura
authors.forename: Kahtya
authors.initials: K
authors.lastname: Torquati
authors.forename: Filippo
authors.initials: F
authors.lastname: Zappasodi
authors.forename: Antonio
authors.initials: A
authors.lastname: Ferretti
authors.forename: Vittorio
authors.initials: V
authors.lastname: Pizzella
authors.forename: Francesco
authors.initials: F
authors.lastname: Tibuzzi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Vernieri
authors.forename: Patrizio
authors.initials: P
authors.lastname: Pasqualetti
authors.forename: Doriana
authors.initials: D
authors.lastname: Landi
authors.forename: Cosimo
authors.initials: C
authors.lastname: Del Gratta
authors.forename: Gian-Luca
authors.initials: GL
authors.lastname: Romani
authors.forename: Paolo
authors.initials: P
authors.lastname: Maria Rossini
authors.forename: Franca
authors.initials: F
authors.lastname: Tecchio
mesh_terms: D000368:Aged; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000294:innervation*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D013003:Somatosensory Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology*
chemical_list: D010100:Oxygen