Skip to main content
Pages and Files
Wiki reviewers list
Form your groups here
Put your new page here!
Alien Hand Syndrome
Alzheimer's Disease & DBS
DBS for Parkinson's
DBS & Tourette's
Exercise your way to Better Brains
Hot Chocolate cures Alzheimers?
Laughter is the best medicine
Licence to Kill
The Love Hormone is Two-faced!
Marijuana and Epilepsy
Notes & Neurons
Novel Key Factor in Generation of Febrile Seizures
Parkinson's Disease - a new approach
Psychiatric drugs & the Brain
Sleep & Learning
Stressing out about Stress
Deer in the headlights
The link between pesticide and Parkinson's disease
Psychopathy, Schizophrenia and Violence
Brain plasticity and its role in drug addiction
Locked-in Syndrome: Trapped in Silence
It'll Make You Shoot Better...
Facebook, twitter and other social media are 'brain candy'
Congenital insensitivity to pain
Monogamy and promiscuity
Girl Living With Half Of Her Brain
Neuroscience of Sexual Desire
Hypnosis Decreases Pain
Lithium in the Water
Effectiveness of Antidepressants
Autism and Thimerosal
The Neurons that Shaped Our World
Knocking Heads: Brain Damage in NFL Players
Fear: Replacing Memories
The Brain & Methamphetamine
FFI - Fatal Familial Insomnia
Guide to using wikispaces
E.T. Hand Syndrome
BBC Four "Broken Brains" Documentary - Alien Hand Syndrome (from 32:57 to 45:24)
Table of Contents
2. Neuroscientific Context
2.2.1 Frontal variant
2.2.2 Callosal variant
2.2.3 Posterior variant
2.3 Explanatory Theories
3. Critical Analysis
4.1 Search Strategy
4.2 Reviewers' Feedback
The media clip, an excerpt of an episode called
, is a part of a documentary by BBC Four, featuring a variety of neurological disorders including the one in question, Alien Hand Syndrome (AHS). BBC
Four, a British television channel run by the British Broadcasting Operation,
first aired this documentary on 12 April 2011. This an excerpt of the third episode out of three in the series
The Brain: A Secret History,
all of which detail the extraordinary ability of the brain to dictate our behaviours. Through an amalgamation of interviews, footage and narration by Dr Michael Mosley,
focuses on the life-changing experimentation of abnormal brains resulting in both rare and common neurological disorders.
As AHS is such a unique and rare disorder, it is of significant interest due to the limited scope of understanding on this matter. We decided to research AHS as our topic not only because it tied in with an earlier topic (epilepsy treatments), but mainly because we were intrigued by its eccentric symptoms. Although rare, the involuntary and often goal-orientated behaviour caused by AHS highlights the ability of neuroscience to explore human nature, including volition, intention, consciousness and identity. The potential multitude of modules coexisting in each of these, poses many fascinating questions which we sought to explore and understand through this media item that appeared scientifically informative and objective. Exploration through this media item was also prompted by its
highly prestigious reputation as a scientific channel, which The Telegraph described as one of British TV's 'unique treasures' (Midgley, 2012). Furthermore, the patient and experience orientated approach allows for great insight into such incomprehensible symptoms, as well as a personal level of understanding.
2. Neuroscientific Context
Alien Hand Syndrome (AHS) is a rare, neurological condition characterised by involuntary movements, typically of the non-dominant hand, which causes the patient to personify or experience estrangement from it. This syndrome differs from other conditions of involuntary limb movement as the affected limb is often goal-oriented. Patients have also been known to exhibit unusual behaviour, such as talking to the affected limb, and referring to it in third person (Goldberg, 2000). This presently accepted definition has been considerably broadened, having first been properly introduced in 1972 by Brion and Jedynak as a dispossession of the patient's hand and the failure of inter-hemispheric communication in patients with corpus callosum tumours. T
he first case of AHS was reported by Goldstein (1908), that a 57 year old woman had a left hand which had a will of its own and would behave in its own fashion, at one stage grabbing the woman's throat and suffocating her. A post-mortem examination revealed multiple vascular brain lesions involving the right hemisphere which included the corpus callosum.
Only 40-60 cases have been recorded, with misdiagnosis playing a role in the low amount of cases (Kumral, 2001).
Figure 1: Patient SA was instructed to make a squeeze response with the left hand if the object presented belonged in a kitchen, and to make a squeeze response with the right hand if the object belonged in a toolbox. The experiment proved that the left and right brain cannot communicate with each other (McBride J, 2013).
AHS is typically the result of the cerebral hemispheres being surgically separated by severing the corpus callosum (mainly due to reducing epileptic seizure symptoms) or acute focal lesions from strokes. It is also sometimes associated with Alzheimer's and Creutzfeldt-Jakob disease. AHS patients have disorders of motor control, but do not have any associated disorders with their awareness of the motor system (Frith, Blakemore & Wolpert, 2000). Hence, the 'alien' hand's actions cannot be controlled by the will of the patient, but they are able to recognise the discrepancy between the hand's actions and their intentions. Although this disorder is typically viewed as a nuisance rather than a medical threat, patients have been placed in dangerous situations due to the alien limb's actions (Turkington, 2009).
AHS is a consequence of brain lesions to various different regions of the brain. For example, lesions to the supplementary motor area, anterior cingulate, corpus callosum, anterior prefrontal cortex, thalamus, and posterior parietal cortex have all been reported to result in AHS. Three distinct variants have been identified including the frontal variant, callosal variant and posterior variant, allowing for such a broad acceptable usage of the term AHS.
2.2.1 Frontal variant
This variant is associated with unilateral injury towards the frontal lobe including the supplementary motor area, anterior cingulate gyrus, medial prefrontal cortex of the dominant hemisphere, and anterior section of the corpus callosum (Epinosa, Smith & Berger 2006). It involves purposeful movement of the contralateral hand (the hand opposite the damaged brain hemisphere), such as reflexive and disinhibited grasping and groping. Often, these are exploratory where grabbing or reaching for visible objects with an arm's reach or which have been removed from contact with the hand, are done so meaningfully or functionally, however they are not intentional. Self-directed grasping may also occur during their sleep, causing the patient to wake up.
(Banks et al., 1989; Nicholas et al.,1998; Ortega-Albas et al., 2003; Giovannetti et al., 2005 cited in Mark, 2007).
Patients usually have difficulty releasing objects from their grasp (Biran and Chatterjee, 2004) and the more they attempt to release the grip, the more it tightens. This causes them to often resort to using their dominant hand to peel their other fingers off the object.
Figure 2: MRI scan displaying left mesial frontal lesion (A) and extension to corpus callosum (B) (Biran, Giovannetti, Buxbaum & Chatterjee, 2006)
2.2.2 Callosal variant
The callosal variant involves lesions to only the partially or entirely severed corpus callosum, inhibiting communication between the two hemispheres. Always left-sided, it is characterised by intermanual conflict (conflicts with intentions), with little evidence of limb paresis (partial paralysis) (Bogen, 1993). The affected hand counteracts voluntary actions by the healthy hand. For example, in this variant, the patient may pull off a sock immediately after it has been put on.
The two phenomena involved are agonistic dyspraxia and diagonistic dyspraxia:
Agonistic dyspraxia involves compulsive, involuntary execution of motor commands with the opposite hand to which they were asked to use while the other hand does not respond to the command (see Figure 3).
Diagonistic dyspraxia occurs after the unaffected act has voluntarily engaged in some action, where the affected hand seeks to oppose the purpose or outcome of this desired act.
Figure 3: MRI from a midsagittal view depicting lesioned regions along the corpus callosum of a patient with agonistic dyspraxia (arrowheads) (Aboitiz et al., 2003).
Figure 4: Cerebral MRI showing Posterior Cortical Atrophy (left parietal lobe), a cause of posterior AHS as indicated by the arrow.
2.2.3 Posterior variant
Less commonly, the posterior form of AHS is linked towards damage to the posterolateral parietal and/or occipital lobe, usually in the non-dominant hemisphere. This occurs from corticobasal degeneration involving posterior cortical atrophy (see Figure 4) or resulting from cerebrovascular accidents. Movements of patients suffering from this variant of AHS tend
to withdraw their afflicted hand away from environmental contact, rather than making grasping motions prevalent within th
e frontal form of AHS. Non-purposeful and non-conflictual movements (for example, arm levitation), characterise this AHS variant (Bundick and Spinella, 2000). Patients experiencing damage to the posterolateral parietal and/or occipital lobe part of the brain tend to be less coordinated in their everyday activities,
differing from the hand movements seen in the frontal variant. The posterior form also involves disorders of sensation and sensory processing, involving optic and cerebellar ataxia of the left arm.
2.3 Explanatory Theories
The brain is made up of two hemispheres, each with 4 lobes (frontal, parietal, occipital and temporal) which coordinate to control speech, movement, emotion, and many other important functions. The frontal lobe, responsible for motor skills that include movement and speech, is most relevant to AHS.
Making conscious decisions for movement creates a signal within the frontal lobe, which is then directed towards the motor strip (runs from the head to toe, responsible for all movement). The corpus callosum, which is made up of 55 million nerve fibres, is the key to this sending and receiving of information, as it connects the two hemispheres together, allowing information to be shared.
AHS often arises as a result of damage to the nerves within the corpus callosum which may result from brain aneurysms (localised enlargements of an artery due to a weakening of the artery wall), stroke patients, and those with infections within the brain. However, AHS can also arise as a side effect of brain surgery, most notably from a radical procedure treating severe cases of epilepsy called "corpus callosotomy", where the corpus callosum is severed.
Figure 5: The corpus callosum is a central feature of Alien Hand Syndrome, due to its importance in connecting both hemispheres (eDoctorOnline, 2013)
Once the corpus callosum is damaged, information from one hemisphere cannot be relayed onto the other, which results in one limb being incapable of being controlled by the frontal lobe. This results in an "alien" limb acting on its own accord, occasionally in opposition to the functioning side (Turkington, 2009). A study in 2007 by Swiss doctors discovered the neuroscientific aspect of AHS, using functional magnetic resonance imaging (fMRI) tests to determine what brain activity occurred during voluntary and involuntary movement. As planned movements originate within the frontal lobe before being sent to the motor strip, unplanned 'alien' movements originate from the motor strip itself without frontal lobe involvement. The signal also remains within the motor strip used for involuntary movement without sending the usual message back to the frontal lobe, leaving patients unable to control their own movements (Assal, 2007).
Due to the exceedingly small number of cases, i
t is not known what triggers the signal within the motor strip for involuntary movements.
There is currently no known cure for AHS. However, practical treatments include controlling the symptoms by keeping the affected hand occupied with an object. Another method involves limiting this hand, with the inability to recognise a sensory feedback coming back to the hand, from the environment. This involves placing a restrictive "cloak" such as an oven mitt or glove to inhibit the hand from sensing the environment.
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 (Assal, Schwartz and Vuilleumier, 2007). Inhibiting the 'alien' hand from recognising the environment would not allow the neuroplasticity involving the voluntary will to control the actions of the hand to be fully restored.
For unilateral damage to a singe cerebral hemisphere, usually the patient has a gradual reduction in the frequency of ‘alien’ behaviours over an extended period and an eventual restoration of voluntary control over the afflicted hand. The exact method on how this occurs is not entirely understood, however one theory involves the neuroplasticity in the bihemispheric and subcortical brain systems which are involved in voluntary muscle movements. Over time, it is believed that they can re-establish a connection between the executive production process and the registration process in order to regain control of the hand. This kind of gradual recovery has been frequently reported when the lesion is confined to a single cerebral hemisphere.
Research is being undergone to develop medication to decrease the activity of the alien hand. Two types of medication have been proposed: clonazepam and botulinum. Clonazepam, a drug that is 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% (Haq et al., 2010). 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% (Karri, 2012). However, these studies are somewhat inconclusive as treatments were tailored to suit the patient, and as AHS is not a life-threatening condition, physical methods of restraint are an efficient way of keeping the alien hand from misconduct.
3. Critical Analysis
is a television documentary episode aired by BBC Four in 2011, the third of three hour long episodes, under its Science and Nature programme. Dr Mosley conducts this documentary, whom having received a degree in psychiatry in London, largely contributes to the overall credibility of this documentary. BBC operates BBC Four and is a public service corporation funded by a television license fee set by the British Government which does not induce commercial motivations but genuinely seeks to inform. It can be concluded that it seeks to present information in an impartial manner, as enshrined through their six policies enacted by the Royal Charter and Agreement for the general public.
embodies the characteristics of "popular science" as it
educates its audience of various neuroscientific disorders including AHS, by forming a platform between general knowledge and professional scientific research. As BBC Four is multi-genre, and even under this Science and Nature programme, explores a range of sciences, it can be concluded that it targets all open-minded, curious adult audiences in support of the scientific method. It is unlikely to be suitable for children due to the surgery footage. Scientific information is presented in layman terms, allowing high-level scientific concepts to be easily comprehended through the use of analogies and metaphors. For example, the corpus callosum and its neurological function is described as the "highway connecting the two brains", and AHS is described as a "power struggle" between the two sides. These examples illustrate the tendency for layperson's terminology to substitute any technical or scientific jargon.
Video footage, (Karen's alien hand attacking her) and an interview between Dr Mosley and Karen are two types of evidence presented to support the claims made in the documentary. Footage of Karen's initial suffering portrays her stress and vulnerability, both factors highly effective in contributing towards connecting with the audience on an emotional level. Nonetheless, these are relatively minor cinematic effects and it remains relatively unsensationalised.
As the documentary targets the general population, there is a lack of scientific depth throughout the video.
This documentary analyses to a minimal extent, the underlying neurological mechanisms behind this rare disorder but rather, explores the experience of one sufferer.
Rather than asking open-ended questions about how Karen coped with her disobedient hand during her interview, Dr Mosley instead asked her futile questions, such as "do you find it disturbing?" which negligibly informs us of the struggles of an AHS patient. Additionally, even though concepts are simplified, minimal depth in scientific facts is explored. It would have been advisable to include further quotes or research by other scientists or doctors to add to the scientific depth and analysis of this syndrome. However as AHS is very rare, more research must be conducted to contribute to a deeper understanding of AHS.
Furthermore, various unsupported claims throughout the documentary contradict its accuracy. Towards the end of the interview Karen mentions that she has managed, with medication, "bringing her alien hand back to her conscious control." Clarification is needed as it is unclear if she refers to medication that has cured this condition, which is what she appears to suggest. This contradicts the consensus that there is no known cure but manipulations of the affected hand to control it to an extent. Additionally, w
e are left with the explanation that Karen was only "extremely unlucky" to be left with AHS after the operation, and "for whatever reason", the right hemisphere of her brain refused to be dominated by the left which is highly uninformative.
Despite limitations of the generalised presentation of scientific facts in displaying factual information to a meaningful extent,
nonetheless fulfils its purpose to allow the general adult population without requiring thorough neuroscientific background, to glean some insight and potentially interest into the rare AHS. Although it provides a reasonable foundation for understanding AHS, more research is required to fully understand the neurological mechanisms of this rare disorder.
4.1 Search Strategy
Shortly after forming our group, we brainstormed a multitude of topics including sleep paralysis, hereditary sensory and autonomic neuropathy, phantom limbs and alien hand syndrome. An agreement was made by the group to research the topic, AHS as the video we found on YouTube captivated our interest, as justified in the introduction. Initially, we watched videos, read articles and websites including Wikipedia to gain a general, preliminary understanding of the issue. Emma created a discussion page through Facebook, where ideas and roles were exchanged between the members of our group.
Upon feedback from Dr. Vickery, we realised that we needed to locate the original source of the video. As it was only available in Switzerland, we decided to use this documentary by BBC Four, which also explores AHS and overlaps with our initial video in many aspects.
We searched for peer-reviewed articles on the UNSW databases such as PsycINFO, along with Google Scholar, to form our neuroscientific context, aiming for those published recently. For diagrams in the neuroscientific context, we looked at images on Google to find pictures of parts of the brain affected and journal articles that contained illustrations of specific processes related to AHS.
4.2 Reviewers' Feedback
The comments given by our reviewers were very helpful and provided us with direction, particularly when there was a general consensus between them regarding the strengths and weaknesses. Upon receiving feedback from our reviewers, we first highlighted all the specific areas of the wikipage that needed to be changed, edited accordingly to the specific suggestions of improvement (grammatical mistakes) and inserted comments on parts of the wikipage we were unsure about. We also researched and included suggestions that we agreed could enhance our page such as statistics and diagrams, and added them too.
Our wikipage was lacking in in-text referencing and a proper bibliography so we sought to include this immediately. We also included a section on explanation to address the lack of depth provided in the variants sections.
An overlapping comment among certain reviewers was wordiness of certain sentences and worked on concision by reading through the page while making sentences clearer where possible and to delete words that were unnecessary.
E.T. Hand Syndrome Work Plan
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
American Society for Dermatologic Surgery. (2013). What is botulinum toxin?. From
American Society of Health System Pharmacists, Inc. (2010). Clonazepam. RFrom
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
Biran, I. Chatterjee, A., (2004). Alien Hand Syndrome. Archives of Neurology. 61 (2), pp.292-294
Biran, I., Giovannetti, T., Buxbahm, L., Chatterjee, A., (2006). The alien hand syndrome: What makes the alien hand alien? Psychology Press Taylor & French Group. 23 (4) 563-582
British Broadcasting Corporation. (2013). Inside the BBC - Mission and Values. From
Bundick Jr, T., Spinella, M (1999). Subjective experience, involuntary movement, and posterior alien hand syndrome. Journal of Neurology, Neurosurgery, & Psychiatry. 68 (1) pp.83-85
Croisile, B. (2004). Benson's Syndrome or Posterior Cortical Atrophy. From
eDoctorOnline. (2013). Cerebrum Anatomy. From
Fitzgerald, D. B. Drago, V. Jeong, Y. Chang, Y. White, K. D. Hellman, K. D., (2007). Asymmetrical Alien Hands in Corticobasal Degeneration. Movement Disorders. 22 (4), pp.581-584
Goldberg, G, (2000). When Aliens Invade: Multiple Mechanisms for Dissociation Between Will and Action. Journal of Neurology, Neurosurgery, & Psychiatry. 68 (1), pp.7
Goldstein, K., (1908). Zur Lehre von der motorischen Apraxie. Journal Fur Psychologie and Neurologie. 11, pp.169-187, 270-283.
Huang, Y. Jia, Jianping., (2013). Corpus callosum hematoma secondary to cerebral venous malformation presenting as alien hand syndrome. Neurocase: The Neural Basis of Cognition. 19 (4), pp.377-381
Karrie, D. (2012). Possessed—the Alien Hand Syndrome. From
Kumral, E, (2001). Compulsive Grasping Hand Syndrome: A Variant of Anarchic Hand. Neurology. 57 (11), pp.2143-2144
Mark, V. (2013). Alien Hand Syndrome. From
Mcbride, J. Sumner, P. Jackson, S. R. Bajaj, N. Husain, M, (2013). Exaggerated Object Affordance and Absent Automatic Inhibition in Alien Hand Syndrome. Cortex. 49 (8), pp.2040-2054
Midgely, N. (2012). As BBC Four turns 10, are its best years already over?. From
Noggle, C. Dean, R. Horton J. A, (2011). The Encyclopedia of Neuropsychological Disorders. 1st ed. New York: Springer Publishing Company
Schaefer, M. Heinze, H. Galazky, I., (2013). Waking up the alien hand: rubber hand illusion interacts with alien hand syndrome. Neurocase: The Neural Basis of Cognition. 19 (4), pp.371-376
Turkington, C. Harris, J, (2009). The Encyclopedia of the Brain and Brain Disorders. 2nd ed. New York: Infobase Publishing.
help on how to format text
Turn off "Getting Started"