[Utilization and imitation behavior following right parietotemporal lesions].

A 65 year-old man showed bilateral, but more marked on the right, instinctive grasp reaction, utilization and imitation behavior after a right parietotemporal lobe infarction. Attention disturbance, left unilateral spatial neglect, and constructional disturbance were also observed. Fluid attenuated inversion recovery (FLAIR) MRI revealed high intensity lesions over the right parietotemporal cortex and white matter. Magnetic resonance angiography showed occlusion of the right internal carotid artery, and ultrasonography revealed left moderate internal carotid artery stenosis. Utilization and imitation behavior is usually attributed to a frontal lesion, rarely to a basal ganglionic or thalamic lesion, but not to a parietotemporal lesion. In this patient, the utilization and imitation behavior was thought to be attributed to right frontal lobe dysfunction without apparent MRI abnormalities, supposedly because of the right internal carotid artery occlusion in addition to the right parietal lobe infarction, both of which are thought to suppress the executive center in the left parietal lobe.