CHSU Discovery

Abstract

Alien Hand Syndrome (AHS) is a rare neurological disorder caused by lesions in the
frontal lobe, corpus callosum, or parietal lobe, leading to a disconnect between motor
control, sensory input, and body awareness (1).
• The pathophysiology of AHS is unclear. One theory describes a disruption in the
coordinated actions of both hemispheres that are needed for bilateral hand
movement; another describes the malfunction of the premotor area negative
inhibition, preventing patients from reaching for nearby objects; a third one is that
damage to the corpus callosum disrupts cross-inhibition network between
contralateral hemispheres (2).
• AHS manifests as involuntary limb movements, in which a patient performs task-driven
movements without intentionally initiating them.
• Based on the lesion’s location, the disorder can co-occur with asomatognosia, in which
patients do not recognize their limbs as their own, despite no physical detachment.
• Most documented cases of AHS and asomatognosia are caused by ischemic and
hemorrhagic strokes, traumatic brain injury, or neurodegenerative diseases (3,4).