The alien hand syndrome. Clinical and postmortem findings

Area of Science:

• Neuroscience
• Neurology
• Clinical Neuroanatomy

Background:

• Alien hand syndrome is a rare neurological disorder.
• It is characterized by involuntary, seemingly purposeful movements of a limb.

Observation:

• Two patients presented with alien hand syndrome affecting their left upper extremities.
• Autopsy in one case revealed bilateral medial frontal white matter damage, corpus callosum lesions, and damage to the right basal ganglia, internal capsule, and thalamus.
• The second patient had a history of a ruptured anterior communicating artery aneurysm with subsequent right frontal gyrus rectus resection.

Findings:

• The observed alien hand syndrome in both patients is postulated to stem from a combination of partial callosectomy and mesial frontal lobe damage.
• These specific brain lesions disrupt motor control and proprioceptive feedback, leading to the characteristic involuntary movements.

Implications:

• Understanding the neuroanatomical basis of alien hand syndrome is crucial for diagnosis and patient care.
• This research contributes to the understanding of brain-behavior relationships, particularly concerning motor control and self-awareness.
• Further investigation into callosal and mesial frontal lobe functions may reveal insights into other complex neurological disorders.