You are currently viewing Alien Hand Syndrome :‎ Medical Notes & Mindmap

Alien hand syndrome is a neurological condition in which one of a person’s hands acts uncontrollably, as if it has its own mind. The hand may move or grip objects on its own, or it may interfere with the intentional actions of the individual. Damage to the brain, particularly the areas that control movement and feeling, is frequently the cause of alien hand syndrome. It is a rare disorder that can be treated with drugs, physical therapy, or surgery.

Alien Hand Syndrome :‎ [MEDNOTES+MINDMAP]


  • Alien hand syndrome (AHS) is a neurological disorder in which an individual’s hand seems to have a mind of its own and acts independently from their conscious control
  • It is also known as anarchic hand, Dr. Strangelove syndrome, and intermanual conflict


  • Prevalence is rare, with only a few hundred cases reported worldwide
  • Mostly affects individuals who have undergone brain surgery or have suffered from a stroke or brain injury
  • May also occur in individuals with certain neurological conditions such as Parkinson’s disease or schizophrenia

Natural history:

  • AHS typically develops gradually, with symptoms appearing over a period of days or weeks
  • Symptoms may vary in severity and may be temporary or permanent
  • In some cases, symptoms may improve with treatment


  • AHS is classified into two main types: primary and secondary
    • Primary AHS is caused by a structural brain abnormality, such as a lesion or injury
    • Secondary AHS is caused by a neurological condition or brain surgery
  • AHS is also classified into four stages based on the severity of symptoms:
    • Stage 1: mild symptoms, hand acts independently but can be easily controlled
    • Stage 2: moderate symptoms, hand acts independently and is more difficult to control
    • Stage 3: severe symptoms, hand acts independently and may cause harm or damage
    • Stage 4: extreme symptoms, hand acts independently and is impossible to control
  • Risk Factors
    • Brain surgery (particularly corpus callosum damage)
    • Stroke
    • Brain tumors
    • Brain infections
    • Degenerative neurological conditions (e.g. dementia, Parkinson’s disease)
  • Etiology/Causes
    • Damage to brain regions responsible for hand control/coordination
    • Medications (e.g. for Parkinson’s disease or psychosis)
  • Signs
    • Uncontrolled movement of one hand
    • Difficulty performing tasks with affected hand
    • Inability to control hand movements
  • Symptoms
    • Difficulty performing tasks with affected hand
    • Difficulty controlling hand movements
    • Inability to coordinate hand movements with other hand
    • Confusion or disorientation when trying to use affected hand
    • Frustration or distress related to uncontrolled hand movements
  • Pathology/Pathogenesis
    • Damage to brain regions responsible for hand control/coordination
    • Disrupts communication between brain hemispheres
    • Specific pathology/pathogenesis varies based on underlying cause
  • Diagnosis

    • Clinical evaluation by a neurologist
    • MRI or CT scan to rule out brain lesions or damage
    • Electroencephalogram (EEG) to measure brain activity
    • Neuropsychological testing to assess cognitive function
    • Genetic testing may be conducted in cases of genetic disorders as a cause
  • Tests Required

    • Physical examination
    • Neurological examination
    • Imaging tests (MRI or CT scan)
    • EEG
    • Neuropsychological testing
    • Genetic testing (if applicable)
  • Associated with

    • Brain damage or lesion in the corpus callosum (the area connecting the left and right hemispheres of the brain)
    • Traumatic brain injury
    • Stroke
    • Brain tumors
    • Neurodegenerative disorders (such as Alzheimer’s disease or Parkinson’s disease)
    • Genetic disorders (such as Down syndrome)
  • Similar diseases/syndromes

    • Apraxia (inability to perform purposeful movements)
    • Dyspraxia (difficulty planning and performing movements)
    • Neglect syndrome (inability to recognize or attend to one side of the body or environment)
  • Treatment

    • Occupational therapy to improve fine motor skills and coordination
    • Cognitive behavioral therapy to address any psychological issues related to the condition
    • Medications to improve brain function and communication between the brain hemispheres (such as anticonvulsants or antidepressants)
    • Surgical intervention (such as corpus callosotomy) may be considered in severe cases to sever the connection between the brain hemispheres and reduce involuntary movement.

Dr. Arin Nandi

Passionate About Medical Science & Helping Future Doctors Achieve Top Ranks In Medical Exams. He is professionally a dentist as well as a public health expert from JIPMER working in department