Alien hand syndrome: what it is how to recognize and care for it

Anyone who has seen Stanley Kubrick’s film will remember the bizarre Doctor Strangelove, a mad and eccentric scientist whose right hand – covered in a creepy black leather glove – occasionally tries to strangle him or makes the Nazi salute, as if animated by a will. own. This character brings a cinematic example of the so-called alien hand syndromea rare ailment neurological characterized by the loss of control of one of the two hands, which becomes “rebellious”. “Unlike what happens in Kubrick’s film, usually it is the left hand to be affected by the problem », Professor specifies Fabio Cirignotta, neurologist at the Villalba Private Clinic in Bologna. “The movements escape the will of the patient, but are apparently aimed at a purpose that is sometimes banal, such as manipulating an object, but sometimes it is bizarre, as in the case of Doctor Strangelove”.

How to recognize alien hand syndrome and its causes

The name, alien hand syndrome, refers to the fact that the patient does not recognize the anarchist hand as his own, but considers it foreign, alien in fact, as if he were wearing a mechanical prosthesis that it moves without offering the possibility of control. “There may be the underlying problem different causes: lesions of the frontal lobe, for example a stroke in the territory of the anterior cerebral artery; lesions or tumors of the corpus callosum, the area in the middle of the brain that connects the two cerebral hemispheres; vascular lesions of the posterior arterial circulation, which can affect the thalamus or the parieto-occipital region “, says the expert. Sometimes, the problem can be temporary and be limited to the acute phase of the injury, and thereafter gradually regress spontaneously.

Alien hand syndrome has also been observed in neurodegenerative diseases such as Alzheimer’s disease or Creutzfeld-Jacob encephalitis, better known as mad cow, but in any case these are extremely rare phenomena. “The neurophysiological mechanisms of the alien hand have not been fully elucidated. Typically, the expression of a disturbance of interhemispheric connectionsbut there are also those who hypothesize an alteration of a specific control system on bilateral hand movements that regulates priorities, activating one hand and simultaneously inhibiting the other, so that they do not go into antagonism “, explains the expert .

How it manifests itself, the symptoms

Depending on where the lesion is present, alien hand syndrome can present different symptoms. For example, the anterior variant is associated with the so-called “groping”, ie the patient’s hand seems to continuously search for objects on the table or in space or grabs them, manipulates them, palpates them compulsively.

“In the callous variant, on the other hand, an intermanual conflict occurs, in which the anarchist hand acts against the other healthy hand, perhaps grabbing it to prevent it from moving or by removing an object that has just been placed on a work surface or by unbuttoning the shirt button just buttoned », Professor Cirignotta explains. «Finally, the later variant is characterized by the phenomenon of levitationthat is to say the sudden lifting of the arm in a casual way, at rest or in association with certain gestures or situations: walking, coughing, on the occasion of sudden noises ».

Be careful not to confuse it with other hand ailments

This syndrome should not be confused with other much more frequent movement disorders, such as i tremors or the coree, that is, abnormal, rapid, arrhythmic and non-suppressible involuntary movements, similar to jerks. “While these movements do not have a precise purpose, those of the alien hand are apparently finalistic, because they carry out a precise action”, explains Professor Cirignotta. «The alien hand is also distinguished from the ballismanother disorder linked to vascular lesions of the brain stem, in which the patient makes sudden, violent and involuntary movements of the arm or leg, as if throwing them into the void ».

How to cure

Currently there is no standardized treatment protocol for this syndrome, because any intervention always goes customized according to the individual situation. For example, if the discomfort is heavy and persistent, the symptoms can be reduced and contained by “blocking” the alien hand with gloves or braces that prevent it from moving.

“It is also possible to resort to injections of botulinum toxin to” paralyze “the limb or to benzodiazepines with a muscle relaxant effect, but especially the cognitive-behavioral techniques which can be learned during a specific rehabilitation program that teaches how to manage the most common everyday situations, “training” the anarchist limb or keeping it busy with objects to make it less problematic », concludes Professor Cirignotta. “At the same time, the patient is educated to accept his condition and this helps to deal with those states of anxiety, depression and discomfort that can manifest themselves in common social contexts, where confrontation with others can create embarrassment “.

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