Leg manifestation in alien hand syndrome.

A patient with left alien hand syndrome (AHS) accompanied by leg symptoms due to right anterior cerebral artery territory infarction is reported. Magnetic resonance imaging demonstrated that the responsible lesion involved the right anterior cingulate gyrus, supplementary motor area, medical prefrontal cortex and corpus callosum extending from the genu to the isthmus. The leg symptoms included: 1) motor perseveration manifesting as compulsive straight walking with difficulty stopping on command; 2) dissociation between mind and action resulting in going to unintended places with subsequent complaints of poor memory not due to spatial disorientation; 3) discrepancy between verbal and actual leg motor responses to auditory verbal suggestions; and 4) movement dissociation between the legs resulting in transient standing still or brief sticking to the ground, a situation simulating akinesia. As the legs usually perform together to coordinate movements of standing and walking, unlike the hands performing well-learned, skilled unimanual or bimanual coordinating movements, the counterpart in the leg of the alien hand sign in AHS was not manifested. Nevertheless, in the presence of AHS, the associated leg symptoms bear similar neurobehavioral features and should be dealt with on equal terms.