Alien Hand Syndrome
Published: 01 June 2022
Published: 01 June 2022
How would you feel if one of your hands began to move and perform actions on its own, and you were completely unable to control it?
It would surely be a highly distressing and frustrating experience.
As bizarre as it sounds, this condition, known as alien hand syndrome, is a very real and disabling, albeit rare, complication of certain neurological pathologies.
So, what exactly is this phenomenon and why does it occur?
Alien hand syndrome (AHS) is a rare neurological disorder wherein a person experiences involuntary, purposeful limb movements without having any conscious intention of performing them (Bru et al. 2021; Hassan & Josephs 2016).
Rather than spasms or convulsions, these involuntary movements are purposeful, coordinated and goal-directed actions that appear as if the limb is being controlled by another person (Moawad 2016; Pacella & Moro 2022).
AHS has only been observed to affect one limb at a time, and while it typically affects the hand, there have been cases of similar symptoms occurring in the legs (Anderson & Juber 2022).
Individuals with AHS often feel a loss of ownership and control over their affected limb, with many describing it as having ‘a mind of its own’ (Hassan & Josephs 2016; Panikkath et al. 2014). Some patients even speak about their limb in the third person (Horton 2015).
The condition is sometimes referred to as ‘Dr Strangelove syndrome’, based on the 1964 movie Dr Strangelove, wherein the titular character experiences AHS (Helmstaedter et al. 2021).
AHS is associated with damage to parts of the brain caused by:
(Cronkleton & Morrison 2018)
Although more research is needed in order to fully understand why AHS occurs, MRI scans of those with the condition have provided one possible explanation (Anderson & Juber 2022; Panikkath et al. 2014).
In a typical person, motor activities involve the activation of a vast array of neural networks. However, in those with AHS, only the contralateral primary motor area - which is responsible for initiating motor movements - appears to activate. This excludes the nonprimary motor cortex, which is involved in the planning and selection of movements. Therefore, the spontaneous and unintentional movements caused by AHS may occur because the contralateral primary motor area is being triggered without the activation of intentional planning systems (Panikkath et al. 2014; Guy-Evans & Mcleod 2021).
AHS appears to be associated with injury to one of three specific regions of the brain. These are:
(Anderson & Juber 2022; Panikkath et al. 2014)
Depending on the location of the injury, AHS can be categorised as either anterior (frontal or callosal injury) or posterior (parietal injury) in nature (Hassan & Josephs 2016).
People with AHS may experience a variety of involuntary movements from the affected limb, such as:
(Cronkleton & Morrison 2018; Panikkath et al. 2014; Anderson & Juber 2022)
The patient might display autocriticism in response to these involuntary movements, for example, slapping the ‘alien’ hand with their unaffected hand (Panikkath et al. 2014).
AHS seems to present differently depending on the area of the brain that has been injured. For example, damage to one side of the frontal lobe often causes the hand on the opposite side of the body to perform purposeful movements such as reaching and grasping, and the person might have difficulty releasing an object being held. Posterior injury seems to cause the affected limb to withdraw rather than reach, and it may ‘levitate’ upward and away from surfaces. Corpus callosum injury appears to affect the person’s non-dominant hand and causes intermanual conflict (where the hands perform opposing actions) (Bionity n.d.).
AHS is difficult to diagnose for several reasons:
(Anderson & Juber 2022; Moawad 2016)
Consequently, diagnosis requires thorough observation and evaluation of symptoms, as well as patient history, clinical examination and an MRI scan to look for lesions in the brain (Moawad 2016; Fitzgerald 2021).
There is no specific cure for AHS, but symptoms may resolve on their own. This has been found to take anywhere between 30 minutes to several years (Panikkath et al. 2014).
There are a variety of treatments that have been attempted with varying degrees of success, but many of these are based on anecdotal evidence only. They include:
(Cronkleton & Morrison 2018; Anderson & Juber 2022)
When caring for a patient who is experiencing AHS, you may wish to consider the following strategies:
(Horton 2015)
In the event of a situation wherein a patient grips or gropes a staff member, patience is required in managing the incident. If required, release the patient's grip gently by prising off the little and ring fingers followed by the remaining fingers. Pulling away or forcing the release will in many instances only increase the force of the grip. Panic will increase anxiety for both the staff member and the patient, which could exacerbate the situation further (Horton 2015).
Remember that AHS is an often frustrating and disabling condition that can be highly distressing for patients. It’s therefore essential to provide empathetic and patient care to these individuals.
Question 1 of 3
True or false: Alien hand syndrome can resolve on its own.