Novel information on anatomic factors causing grasp reflex in frontal lobe infarction: a case report.

We report a patient with a severe limitation of function in the right hand resulting from grasp reflex following a stroke affecting the left anterior cerebral artery region. We describe, using diffusion tensor tractography (DTT), a disconnection between the bilateral frontal lobes via the corpus callosum. The patient could not control his right hand at all, even though his bilateral corticospinal tracts were intact. We noted that over the infarcted lesion on DTT, the white matter was invisible from the corpus callosum to the prefrontal cortex. These findings reflected a unique pattern of white-matter disconnection between the ipsilateral medial frontal lobe and ipsilateral and contralateral frontal cortex causing hand function deterioration in the form of severe grasp reflex.