Alien Hand Syndrome


What is an Alien Hand Syndrome?

Alien hand syndrome is a neurological disorder resulted from a specific kind of brain damage. It is defined as uncontrollable and unwilled but appears to be purposeful movements of an upper limb. This type of disorder greatly troubles the patients and can be mistakenly give an impression of psychiatric illness. The patient will be unable to describe the source of such movement. It is a feeling that one’s hand is possessed by a force which is out of their control.


Symptoms & Signs

Some typical symptoms and signs related to alien hand syndrome are as follows:

  • Lack of awareness of arm movement
  • Inability to feel the hand movements
  • Lack of control over hand movements
  • Feels as if one of their limbs is not really a part of their body
  • Autonomous and purposeful behaviours that are perceived as being controlled by an external body
  • Stuffing food into mouth involuntarily
  • Tearing the clothes involuntarily

Symptoms can vary depending upon a particular condition involved.

Causes & risk factors

There are some possible causes for alien hand syndrome based on studies of different cases. The

right and left cerebral hemispheres are connected by Corpus callosum . Lesions in the corpus collosum can cause Alien hand syndrome.

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MRI from a midsagittal view depicting lesioned regions along the corpus callosum of a patient with agonistic dyspraxia (arrowheads) (1).

The nervous tissue which allows communication connecting the two hemispheres of the brain gets damaged at the medial frontal cortex due to one of the most common brain malformations. This may lead to certain neurodegenerative diseases. It rapidly deteriorates the patient’s mental capacity and manifests involuntary movements. When the blood flow stops to the brain, the brain cannot get oxygen and blood cells die. As such the brain suffers a stroke.


This stroke is of two types. They are hemorrhagic stroke and Ischemic stroke. When a blood vessel leading to the brain is blocked by a clot an ischemic stroke occurs. The number one risk factor for the stroke is high blood pressure. The risk factor is higher for those with high cholesterol, diabetes and above the age of 55. Moyamoya disease as discovered by Japanese is also one of the causes for alien hand syndrome. It is caused by the blocks of tiny vessels that compensate arteries formed around the basal ganglia near the brain are blocked.

AHS Motor Strip + Corpus Callosum Alien Hand Syndrome

Diagnosis

The diagnostic features of alien hand syndrome are broad. A wide variety of disorders may be associated for alien hand syndrome. The criteria for alien hand syndrome seem to be arbitrary. The diagnosis of alien hand invites the physiologic basis for willed movements. The grasp reflex is seen in the alien hand syndrome. But it is the common feature that normally occurs in infancy. The disturbance is less to disrupt patient activities. It differs from alien hand syndrome by not involving in voluntary movements. Cases in which spontaneous arm levitation is associated with denial of limb ownership have been termed alien hand (2) but appear to represent variants of somatoparaphrenia instead. Progressive supranuclear palsy is not associated with alien hand (5).

In cortical basal ganglionic degeneration an unilateral spontaneous arm levitation is often seen. Unilateral spontaneous arm levitation appears in progressive supranuclear palsy. But we can distinguish between these two illnesses as in spontaneous arm levitation no apparent goal directed behaviour is evident. The diagnosis may facilitate the site of injury and its etymology. The behaviour of the patient should be accurately described about the involuntary limb activity. The examiner of the patient should more carefully examine whether the limb movements are appropriate or inappropriate of the circumstances. Keen neurologic examination can indicate the alien hand syndrome.

Treatment

Currently there is no absolute cure for alien hand syndrome. Recent studies have found conditions to help people at risk and control symptoms even.

  • The symptoms can be controlled by practical treatment by keeping the affected hand occupied with an object.
  • Limiting the alien hand placing a restrictive glove or oven mitt to inhibit the hand from sensing the environment
  • To regain the control over the hand a connection between the executive production process and the registration process can be re-established.
  • The activity of the alien hand can be decreased by two types of medication, Clonazepam and botulinum
  • Clonazepam, a drug, currently used to control certain types of seizures and to relieve panic attacks, functions by reducing abnormal electrical activity in the brain. When administered, the drug is able to reduce alien hand activity by 73% (4).
  • Botulinum, a purified toxin, functions by inhibiting nerve signals from the brain to the muscle, and when administered through an injection, is able to reduce alien hand activity by 84% (4).

Theoretically, carrying out these methods can restrict the patient from recovering because neural activity in the primary motor cortex controls the type of unconscious motor movement patients with AHS (2).

Prevention

  • Blind fold the alien hand covered by gloves. Make the hand away from the environment
  • Drugs like botulinium and clonazepam can prevent from alien hand syndrome
  • The alien hand can be kept busy by holding an umbrella, a cane, briefcase, etc. While walking. So that alien hand may not pop into automatic action
  • Healthy life styles like avoiding excessive alcohol, salt, smoking and obesity can decrease the stroke

If only one hemisphere of the brain has been injured the recovery of alien hand syndrome can occur.


References:

  1. Aboitiz, F. Carrasco, X. Schroter, C. Zaidel, D. Zaidel, E. Lavados, M, (2003). The Alien Hand Syndrome: Classification of Forms Reported and Discussion of a New Condition. Journal of Neurological Science. 24, pp.252-257
  2. Assal, F. Schwartz, S. Vuilleumier. P, (2007). Moving with or without Will: Functional Neural Correlates of Alien Hand Syndrome. Annals of Neurology. 62 (3), pp.301-306
  3. Carrilho PE, Caramelli P, Cardoso F, Barbosa ER, Buchpiguel CA, Nitrini R. Involuntary hand levitation associated with parietal damage: another alien hand syndrome. Arq Neuropsiquiatr 2001;59: 521-5.
  4. Karrie, D. (2012). Possessed—the Alien Hand Syndrome. From http://catalyst.rice.edu/discoveries/2012/11/19/
  5. Litvan I, Campbell G, Mangone CA, et al. Which clinical features differentiate progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome) from related disorders? A clinicopathological study. Brain 1997;120:65-74.

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