title: Brain plasticity in recovery from stroke: an MEG assessment.
abstract: The aim of this paper was to deepen understanding about the role played by brain plasticity in obtaining clinical recovery. Eighteen patients, who had recovered partially or totally from dysfunctions due to a monohemispheric infarction within the middle cerebral artery territory, underwent magnetoencephalographic (MEG) recordings of rolandic areas cerebral activity both in rest state (spectral power properties) and in response to the electrical stimulation of the contralateral median nerve (M20 and M30 cortical sources). MEG evaluation was performed in acute (T0: mean 5 days from ischemic attach) and post-acute phase (T1: median 6 months). At T1, all the inter-hemispheric asymmetries were reduced for both spontaneous and evoked activity parameters with respect to T0. In post-acute phase, lower cortical excitability, higher delta and theta power and lower spectral entropy were associated to a worse clinical state. An unusual recruitment-as revealed by an excessive inter-hemispheric asymmetry of M20 cortical source position-correlated with higher level of clinical amelioration in the patients who showed a partial recovery. In addition to confirmative evidence that "normalization" of neural activity in both the affected and unaffected hemispheres subtends best clinical recovery, present data provide support to the positive role of cerebral plasticity phenomena--i.e. unusual neural recruitments--to regain lost functions in those patients unable to achieve total recovery.
authors.affiliation: Department of Neuroscience, MEG Unit, Istituto di Scienze e Tecnologie della Cognizione (ISTC)-CNR, Ospedale Fatebenefratelli, Isola Tiberina, Rome, Italy. franca.tecchio@istc.cnr.it
authors.forename: Franca
authors.initials: F
authors.lastname: Tecchio
authors.forename: Filippo
authors.initials: F
authors.lastname: Zappasodi
authors.forename: Mario
authors.initials: M
authors.lastname: Tombini
authors.forename: Antonio
authors.initials: A
authors.lastname: Oliviero
authors.forename: Patrizio
authors.initials: P
authors.lastname: Pasqualetti
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Vernieri
authors.forename: Matilde
authors.initials: M
authors.lastname: Ercolani
authors.forename: Vittorio
authors.initials: V
authors.lastname: Pizzella
authors.forename: Paolo Maria
authors.initials: PM
authors.lastname: Rossini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D015331:Cohort Studies; D004558:Electric Stimulation; D004569:Electroencephalography; D019277:Entropy; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008475:Median Nerve / Q000502:physiology; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology*; D013003:Somatosensory Cortex / Q000473:pathology / Q000503:physiopathology; D020521:Stroke / Q000473:pathology / Q000503:physiopathology*