Abstract W MP45: Longitudinal MEG Measures for Cortical Reorganization Underlying Paretic Hand Recovery After Subacute Stroke
Background: Post-stroke cortical reorganization in relation to sensorimotor recovery has been largely recognized by functional magnetic resonance imaging. However, altered hemodynamics in cerebrovascular diseases may hamper the results based on blood oxygen level-dependent signals. Magnetoencephalography (MEG) directly measures neural activities with high temporal resolution, but very few studies in stroke patients are available. In this study, we sought to characterize MEG sensorimotor oscillations and sensorimotor network during post-stroke recovery.
Subjects and Methods: We longitudinally assessed patients with first-time, unilateral, ischemic subcortical stroke in the middle cerebral artery territory with mild to moderate hand weakness for upper extremity motor function scales, unilateral finger lifting-related MEG and functional connectivity analysis at 2, 4 and 8 weeks after stroke in comparison with healthy controls. All stroke patients received standardized intensive rehabilitation during post-stroke 2-4 weeks. Minimum-norm estimate was used for MEG source reconstruction.
Preliminary Results: Compared with the controls (n=13), the stroke patients (n=15) had markedly reduced task-related desynchronization and synchronization in mu (8-13Hz) and beta (16-30Hz) rhythms. At sensor level, the induced activities shifted spatiotemporally from the ipsilesional primary sensorimotor cortex towards the supplementary motor and even contralesional areas. After rehabilitation, the patients had significant functional improvements in correlation with increased beta rhythm functional connectivity at the ipsilesional somatosensory cortex and the contralesional premotor cortex. More delicate anatomic information provided by MEG souce projection was established and under final analysis.
Conclusions: The results provide neurophysiological measures of cortical plasticity and insights into target regions for neuromodulation strategies after stroke.
Author Disclosures: C. Tang: None. I. Lee: None.
- © 2014 by American Heart Association, Inc.