Alien Hand Syndrome: Symptoms, Causes And Treatment
Our brain is made up of two hemispheres joined by a bundle of nerve fibers that make up the corpus callosum. Thanks to this structure, both hemispheres can exchange information and, together with the action of other brain areas, we can be aware of our own body.
However, when this structure fails or is injured a strange disorder known as alien hand syndrome may appear by which the person is unable to control the movements of their own arm and hand, which can be experienced as foreign or even possessed.
Also known as “strange hand syndrome”, “alien hand syndrome” or “dr. Strangelove”, this strange disorder of neurological origin is distinguished by causing the person who suffers from it all types of involuntary and uncontrolled movements in one of the upper extremities
Furthermore, another of the peculiarities of foreign hand syndrome is the feeling of strangeness that the person feels with respect to said limb. That is, the patient experiences a personification of the arm and the hand, which seem to him to have a life of their own
The first time this syndrome was described was in 1908. The famous German doctor Kurt Goldstein discovered these strange symptoms in patients who had undergone a commissurotomy. This intervention consists of making a cut in the corpus callosum and was typical of treatments for very severe epilepsies, with the aim of preventing said attacks from spreading from one cerebral hemisphere to another.
There are two different types of alien hand syndrome, which differ in relation to the causes and anatomical correlates of this syndrome.
1. Acute variant of the syndrome
One of the ways in which the syndrome manifests is the acute variant, which is due to damage to the corpus callosum that cause temporary changes in the supplementary motor area It is hypothesized that this damage is due to hemispheric retraction during commissurotomy.
This acute variant is characterized by more intense and exaggerated movements, but of short duration.
2. Chronic variant
The second form that alien hand syndrome takes is the chronic variant. The cause of this is due to an injury to the corpus callosum, as well as injuries to the supplementary motor area, which is located in the medial frontal lobe.
What symptoms appear?
The clinical picture of alien hand syndrome has two fundamental symptoms. These symptoms are:
Dissociation
Sensation of dissociation of the affected limb. The person firmly believes that said arm is not part of their body and that, therefore, it cannot exercise any control over its movements. However, tactile sensitivity is preserved so, although the person cannot control it, they can feel everything that happens to the limb.
Lack of control of movements
The patient is not aware of the actions performed by the affected arm and hand That is, the person does not realize when the limb is performing any type of movement, no matter how complicated or exaggerated it may be.
In many cases, the movements made by the limb considered foreign cause interference with the movements or actions carried out by the healthy limb. Furthermore, this neurological alteration dissociate intention from action so the impulses of the foreign hand are totally opposite to those of the healthy hand.
After observing cases, it has been detected that these “foreign limbs” tend to react in response to nearby stimuli such as eye-catching objects that are within your reach. Hence, it is hypothesized that the behavior of these extremities is guided by contextual stimuli.
The intensity of the symptoms can vary fluctuatingly. In highly stressful or anxious situations the clinical picture of alien hand syndrome tends to increase both in quantity and intensity.
Finally, these symptoms can cause a large number of psychological and emotional side effects. This associated symptomatology can range from a feeling of confusion and anxiety, to experiencing fear and fear or panic attacks However, the psychological consequences can vary greatly between patients since many of them learn to live with this type of disorder.
What causes does it have?
As mentioned above, the origin of alien hand syndrome is found in a lesion of the corpus callosum This structure is responsible for uniting and transmitting information between both cerebral hemispheres, as well as ensuring that both work in a coordinated manner.
However, there is numerous research that points to the idea that this syndrome cannot be explained only by this type of injury, but that it is surely also due to some type of cortical damage or injury to the frontal lobe.
These brain damages can be due to numerous incidents such as tumor masses, cerebral aneurysms, craniocerebral trauma or brain surgeries such as the aforementioned commissurotomy.
Which is the diagnosis?
Because alien hand syndrome has exclusively organic causes, its diagnosis is based almost exclusively on taking a medical history and performing a thorough physical examination
The tests that the doctor must carry out for an effective diagnosis of this disorder include neuroimaging tests, such as computerized axial tomography (CAT) or nuclear magnetic resonance. These techniques allow us to assess the state of the nervous system and the severity of brain injuries.
Is there a treatment?
At the moment, no type of effective treatment protocol for alien hand syndrome has been developed. When this condition is caused by brain lesions associated with tumors or aneurysms, Treatment of these should reduce the symptoms of this syndrome
However, symptomatic treatment can be performed for psychological symptoms. In addition, the patient can undergo training through which he can keep the affected limb busy and thus reduce the amount of unwanted movements
