Affiliations: Cleveland VA Medical Center, Neurology and Research Service, Cleveland, OH, USA | Brain Rehabilitation Research Center, MR VA Medical Center, Gainesville, FL, USA | Department of Neurology and McKnight Brain Institute, University of Florida, FL, USA | Department of Mathematics, Cleveland State University, Cleveland, OH, USA | Department of Neurology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
Note: [] Corresponding author: Svetlana Pundik, M.D., M.S., Neurology and Research Service, Cleveland VA Medical Center and, Department Neurology, Case Western Reserve University School of Medicine, 10701 East Blvd, Cleveland, OH 44106, USA. Tel.: +1 216 791 3800; Ext: 3732; Fax: +1 216 229 8509; E-mail: sxp19@cwru.edu
Abstract: Purpose: Recovery of the most basic shoulder-flexion/elbow-extension components of functional reach is critical for effective arm function following stroke. In order to understand the mechanisms of motor recovery, it is important to characterize the pattern of brain activation during the reach task. Methods: We evaluated 11 controls and 23 moderately to severely impaired chronic stroke survivors (>6 months), with impaired shoulder flexion and elbow extension. Measures were acquired for Arm Motor Ability Test (AMAT) and functional Magnetic Resonance Imaging (fMRI) during the basic shoulder/elbow reach. Results: First, in controls, lateralization of fMRI signal during the reach task was less pronounced in comparison to other tasks, and even further diminished after stroke (p < 0.05). Second, for the stroke group, centroid locations, for specific ipsilesional (contralateral to working limb) motor-sensory regions and for contralesional (ipsilateral to working arm) somatosensory and SMA regions, were significantly more distant from the centroid location of average healthy controls (p < 0.05). Third, both greater activation volume and greater degree of signal intensity were correlated with better motor function in stroke survivors. Conclusions: These findings can be useful in guiding the development of more targeted brain training methods for recovery of impaired reach coordination.
Keywords: Stroke, arm function, motor control, brain function, functional MRI, brain activation
