Alien hand syndrome: report of two cases

Abstract

Alien hand syndrome (AHS) refers to the occurrence of apparently purposeful movements in the hand which are independent of volitional control. Two subtypes of AHS have been proposed: frontal AHS, with grasp reflex and compulsive manipulation of tools by the dominant hand, and callosal AHS, which occurs in the nondominant hand and is characterized mainly by intermanual conflict. Here, we report two cases of frontal-type alien hand syndrome with symptoms of reflexive grasping, impulsive groping, and apraxia (in case 1), and compulsive manipulation of tools (in case 2). Brain computed tomography revealed a left anterior cerebral artery (ACA) territory infarct and multiple small infarcts of both hemispheres in patient 1 and a left ACA infarct in patient 2. The involuntary movements were bothersome to these patients in their daily activities. Both patients attended conventional physical and occupational therapies, and patient 2 received additional biofeedback training. Follow-up studies showed the spontaneous grasping behavior was still present in patient 1 and AHS had subsided in patient 2. We also describe a potentially effective technique involving biofeedback for patients with alien hand syndrome.