Hemiparesis and hemiplegia are the most common disorders after stroke. Motor functional recovery from the neurological deficit can occur, but the extent of recovery varies widely. Previous studies using functional magnetic resonance imaging, positron emission tomography, and electroencephalography demonstrated that abnormal activation patterns in motor-related areas, such as the primary sensorimotor cortex, premotor cortex, supplementary motor areas, and the cerebellum, could be seen during unilateral finger or hand movement in stroke patients. During affected-hand movement, motor-related activations in the hemisphere ipsilateral to the moving hand are often observed. The activations in the ipsilateral motor network cause a change in lateralization balance from normal contralateral to abnormal bilateralor ipsilateral-predominant laterality. In addition, a reallocation back from the abnormal control to normal contralateral control may play an important role in good functional recovery. Intra- and inter hemispheric interactions during voluntary hand movement were assessed with fMRI and dynamic causal modeling. The functional connectivity studies suggested that a dysfunction of the connectivity between both sides of primary motor cortex underlies hemiparesis after stroke, and a reinstatement of functional connectivity between PM and ipsilesional primary motor cortex is an important feature of motor recovery.
Near-Infrared Spectroscopy and Motor Lateralization after Stroke: A Case Series Study: Kotaro Takeda, Yukihiro Gomi and Hiroyuki Kato
Last date updated on July, 2014