Abstract 153: Motor Imagery During Movement Activates the Brain More Than Movement Alone After Stroke

Abstract

Introduction: Task-oriented training is a key component of many stroke rehabilitation programs. Motor imagery activates movement execution circuits as well as brain areas related to cognitive aspects of movement training, such as planning or functional relevance. Movement execution and imagery might work synergistically in activating the motor system after stroke, but to date have only been studied separately. The current study examined the neural correlates of imagery in conjunction with execution, hypothesizing that the combined approach would increase brain activation in areas important to movement training. METHODS: Seven patients with chronic right hemiparetic stroke were studied, with age 55.1±.3 years (mean±SD), 13.1±12.8 mo post-stroke, and arm motor Fugl-Meyer score 50.9±11.9. Each performed a paretic arm pronation/supination task under 2 conditions during functional MRI: [1] Movement execution task: subjects were instructed to pronate/supinate the arm in response to a visual cue. [2] Movement execution+imagery task: subjects were instructed to pronate/supinate the arm in response to the visual cue, but in addition were told to imagine that these movements were being performed to open and close a doorknob. fMRI analyses used SPM8 with threshold p<0.001 (uncorrected for multiple comparisons). RESULTS: For each condition, significant activation was present within the expected motor network, including left sensorimotor cortex and right cerebellum. Activation was significantly greater during performance of the movement execution+imagery task, compared to the movement execution task, within the left inferior parietal lobule and the right dorsolateral prefrontal cortex. No brain region showed greater activation during the movement execution task compared with the movement execution+imagery task. CONCLUSIONS: The movement execution+imagery task preferentially activated inferior parietal lobule and dorsolateral prefrontal cortex, regions that support goal-directed, complex movements. The addition of motor imagery to movement may provide a practical, accessible way to modulate activity in both the planning and the execution components of the motor network, and thereby further promote motor recovery after stroke.