Some of you reading this blog may have seen Stanley Kubrick’s 1964 film Dr. Strangelove in which he titular character played by Peter Sellers suffers from alien hand syndrome (AHS), and where his hand clutches his own throat and (at other times) carries out a Nazi salute. Far from being fictional, AHS is one of the strangest neurological disorders and is where an individual’s hand appears to have a mind of its own and acts autonomously (and where the person feels as though their hand doesn’t belong to them and may be seen as ‘disobedient’ – even though they can feel a normal sensation in the ‘alien’ hand). In a 2004 literature review of AHS by Dr. I. Biran and Dr. A. Chatterjee in the Archives of Neurology, the authors note that:
“This syndrome is characterized by a limb that seems to perform meaningful acts without being guided by the intention of the patient. Patients find themselves unable to stop the alien limb from reaching and grabbing objects, and they may be unable to release these grasped objects without using their other hand to pry open their fingers. These patients frequently express astonishment and frustration at the errant limb. They experience it as being controlled by an external agent and often refer to it in the third person”.
AHS was first identified in 1908 by German Dr. K. Goldstein, but was not clearly defined until 1972 by French neurologists Dr. S. Brion and Dr. C.P. Jedynak. However, according to a 2000 editorial in the Journal of Neurology, Neurosurgery and Psychiatry by Dr. Gary Goldberg, the term ‘alien hand syndrome’ was coined by Joseph Bogen to describe a curious wayward behaviour occasionally seen during recovery from certain types of brain surgery. Dr. Goldberg writes that “such patients would react with surprise, concern, and perplexity at the capacity of their non-dominant hand to perform purposeful acts over which they felt no control”.
Cases of AHS have been reported among patients who have had the left and right brain hemispheres separated through surgery (as has been the case in very severe cases of epilepsy where the corpus callosum that connects the two hemispheres is cut). AHS may also occur due to other types of brain surgery as well as some types of infections and strokes. According to an online article on AHS by Charles Bryant, there have only been around “four dozen reported cases” of alien hand syndrome (confirmed by a more scientific paper in the journal Behavioral and Cognitive Neuroscience Reviews, by Dr. Lisa Scepkowski and Dr. Alice Cronin-Golomb who said there are “no more than 50 published cases”).
AHS sufferers typically display sensory deficits as a consequence of dissociating themselves from the actions of their hand. The Wikipedia entry on AHS notes that:
“Alien behaviour [in the hand] can be distinguished from reflexive behaviour in that the former is flexibly purposive while the latter is obligatory. Sometimes the sufferer will not be aware of what the alien hand is doing until it is brought to his or her attention, or until the hand does something that draws their attention to its behaviour”
A 1992 paper by Dr. R.S. Doody and Dr. J. Jankovic on “the alien hand and related signs” in the Journal of Neurology, Neurosurgery and Psychiatry said there were four classic hallmarks of AHS. These were: (i) a feeling of foreignness of the limb, (ii) failure to recognize ownership of it when visual clues are removed, (iii) autonomous motor activities that are perceived as involuntary and are different from other identifiable movement disorders, and (iv) personification of the affected body part.
Research does indeed indicate that AHS sufferers often personify the alien hand and may believe the hand is ‘possessed’ by some other spirit or alien life form. Their hands may even appear to act in opposition to each other (such as when AHS sufferers who are also cigarette smokers put a cigarette in their mouth to set it alight, only for the alien hand to pull it out and throw the cigarette away). Such behaviour is an example of ‘intermanual conflict’ and has been given the name ‘diagnostic ideomotor apraxia’. This type of AHS behaviour is typically caused by damage to the corpus callosum where an injury to a right-handed person would typically give rise to purposeful movements of the left hand.
However, other variants of AHS exist including those who have suffered frontal lobe brain damage (that tend to trigger purposive reaching and grasping movements), and those who have suffered parietal and occipital lobe damage (that tend to trigger hand withdrawal and/or levitation movements away from tactile stimuli). It has also been reported that more complex hand movements (e.g., unbuttoning clothes) are more associated with strokes, brain tumours, and aneurysms. The Wikipedia entry on AHS claims that the common emerging factor in AHS is that “the primary motor cortex controlling hand movement is isolated from premotor cortex influences but remains generally intact in its ability to execute movements of the hand”. Having said that, Dr. Scepkowski and Dr. Cronin-Golomb in their Behavioral and Cognitive Neuroscience Reviews paper assert that:
“The lack of uniformity in reported assessment methods (behavioural tests, neuroimaging) in published cases contributes to the difficulty in establishing clear subtypes of alien-hand phenomena”
Unfortunately, there is no known treatment for AHS although the symptoms can be minimized and managed to some extent by keeping the affected hand occupied and involved in a task (e.g., by giving it an object to hold in its grasp). Some research on case studies note that particular learned tasks can in some cases restore voluntary control to the alien hand. Charles Bryant’s online article on AHS concludes that “regardless of how few cases of alien hand syndrome exist, or how little we know about its cause, the mystery and intrigue of the condition will no doubt continue to inspire writers and filmmakers to explore its horrific and comedic potential”. For the same reasons, I hope it inspires further empirical research.
Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK
Biran, I. & Chatterjee, A. (2004).Alien Hand Syndrome. Archives of Neurology, 61, 292-294.
Brion, S. & Jedynak, C.P. (1972). Troubles du transfert interhemisphérique (callosal disconnection). A propos de trois observations de tumeurs du corps calleux. Le signe de la main étrangère. Revue Neurol, 126, 257- 266.
Bundick, T. & Spinella, M. (2000). Subjective experience, involuntary movement, and posterior alien hand syndrome. Journal of Neurology, Neurosurgery and Psychiatry, 68, 83-85.
Carrilho, P.E.M., Caramelli, P. Cardoso, F. Barbosa, E.R., Buchpiguel, C. & Nitrini, R. (2001). Involuntary hand levitation associated with parietal damage. Another alien hand syndrome. Arquivos Neuro-Psiquiatria, 59 (3-A), 521-525.
Doody, R.S. & Jankovic, J. (1992). The alien hand and related signs. Journal of Neurology, Neurosurgery and Psychiatry, 55, 806-810.
Goldberg, G. (2000). When aliens invade: multiple mechanisms for dissociation between will and action. Journal of Neurology, Neurosurgery and Psychiatry, 68, 7.
Goldberg, G. & Bloom, K.K. (1990). The alien hand sign. Localization, lateralization and recovery. American Journal of Physical and Medical Rehabilitation, 69, 228-238.
Goldstein, K. (1908). Zur lebre der motorischen apraxia. Z Physiol Neurol, 11, 169-187.
Heilman KM, Valenstein E Bogen JE (1993) The callosal syndromes. in Clinical neuropsychology. eds Heilman KM, Valenstein E (Oxford University Press, New York), 3rd ed. pp 337–407.
Scepkowski, L.A. & Cronin-Golomb, A. (2003). The alien hand: Cases, categorizations, and anatomical correlates. Behavioral and Cognitive Neuroscience Reviews, 2, 261-277.
Wikipedia (2012). Alien hand syndrome. Located at: http://en.wikipedia.org/wiki/Alien_hand_syndrome