Abstract
A 46-year-old right-handed Japanese woman demonstrated right grasp reflex and right compulsive manipulation of tools associated with cerebral hemorrhage. Magnetic resonance imaging revealed a lesion involving the medial aspect of the frontal lobe, part of the anterior cingulate gyrus, and the body of the corpus callosum on the left.
It was notable that the patient's grasp reflex and compulsive manipulation of tools occurred without damage of the supplementary motor area. Her compulsive manipulation of tools was triggered by obsessive intent to use the objects against her will.
The mechanisms behind these signs and symptoms were speculated as follows. Her grasp reflex and compulsive manipulation of tools may be the result of damage to the pre-supplementary motor area in the left frontal lobe. We speculate that neural disconnections between the thalamic and motor areas in the left frontal lobe are crucial for producing grasp reflex and compulsive manipulation of tools.
