In medicine there is a place not only for scientific facts, but also for amazing, sometimes mystical phenomena. The latter includes the disease “alien hand syndrome”. This is a very rare pathology that the average person is unlikely to encounter in everyday life.
general information
This disease is understood as a rare disorder of a psychoneurological nature, in which the limbs make movements not controlled by the human consciousness. Just imagine: regardless of your intentions, the hand begins to perform various actions: touch objects, say hello, hit in the face.
Despite its unusual nature, this pathology is quite real. It is a variety of so-called idiokinetic apraxia. Alien hand syndrome is often accompanied by epileptic seizures.
This pathology V medical practice also known as "Dr. Strangelove's disease." In Stanley Kubrick's film, the main character, after whom the illness is named, could have his hand raised in a Nazi salute or suddenly start strangling him.
Despite the official recognition of this disease in medical circles, adherents are still actively interested in it mystical stories. Until now, many believe that this phenomenon is associated with human supernatural abilities.
Alien hand syndrome: myth or reality?
This disorder was first discovered in 1909. Since then, only 50 such cases have been recorded.
A lady once contacted a German neurologist, Goldstein, who was constantly strangling her while on vacation. own hand. The doctor was unable to detect any serious mental disorders in the patient to explain such attacks from a medical point of view. After the woman's death, Goldstein performed an autopsy and examined her brain. The doctor discovered damage that destroyed the connection between the two hemispheres.
Today, alien hand syndrome is the cause of much controversy among scientists from all over the world. There is no universal way to treat it. To reduce symptoms, doctors recommend psychotropic drugs.
Relatively recently, neurosurgeons discussed the consequences of a brain operation that resulted in the patient developing this disorder. This fact confirms that the disease develops against the background of injuries and mechanical damage brain Doctors have studied the consequences surgical intervention and came to the conclusion that this rare disease actually arose after the surgery. The woman now has to wage a daily struggle with her own limb, which once almost strangled her. The patient was prescribed a sedative, thanks to which the deviation was curbed for some time. However, it is now impossible to predict how the hand will behave in the future.
Main causes of pathology
Why does alien hand syndrome occur? The reasons for the development of this disorder still remain unknown.
Neuroscientists rely on the theory that the human brain cannot tell the difference between previously planned actions and mechanical functions. It is believed that a desire that arises in a person penetrates into that part of the brain that is subconscious, and then it becomes a mechanical function. As a result, “violent” movements of the limbs appear.
Such actions are regarded as disturbing and at times mystical. Today this theory is at the stage of speculation. Scientists still cannot explain why alien hand syndrome only affects certain
What diseases accompany this disorder?
- Stroke.
- Formations of a malignant nature.
- Injuries and mechanical damage.
- Corticobasal degeneration.
- Vascular infarctions.
- Pathologies leading to damage (agenesis, multiple sclerosis).
Clinical picture
The pathology begins its development with the patient experiencing a feeling of foreignness in his own limb. As the disease progresses, a person cannot fully control the movements of his hand; it literally does not obey him. The limbs suddenly begin to take on a life of their own, sometimes trying to attack their owner. They stop following commands given by the brain. Sometimes a person is forced to tie a limb so as not to become its accidental victim and thus curb the alien hand syndrome. The symptoms of this pathology develop very rapidly, which forces a person to seek help from a medical institution.
Ways of development of the pathological process
Doctors identify three options for the development of this disease:
- Callosal. In this case, there is a disruption of the direct connection between the right and left hemispheres of the brain.
- Frontal. As a result of damage to the anterior cingulate gyrus and motor cortex, the disease gradually spreads to the dominant limb. Research mechanisms are disinhibited, so the most pronounced is
- Thalamic. Against the background of damage to the thalamic system, control over limb movements occurs, and the body diagram is distorted. The person loses the ability to put objects on the table or touch his own nose.
The described pathways of development of the pathological process are sometimes found in mixed form. To determine the specific variant of the disease, you need to seek help from a doctor. Only a qualified specialist after full examination can confirm the diagnosis of “alien hand syndrome”.
Treatment and prognosis
Currently, doctors cannot offer effective therapy to combat this disease. Treatment and prognosis are determined by the disease that caused it. First of all, the causes of pathology are eliminated. In the presence of obvious neuropsychological disorders, prescribe medications to eliminate them. To relieve motor agitation, psychotropic medications are used.
Corticobasal degeneration, which usually accompanies the syndrome, inevitably progresses. The main disease gradually becomes less pronounced against the background of increasing weakness in muscle tissue. According to statistics, death occurs within the first 10 years after the onset of symptoms characterizing alien hand syndrome. Photos of patients with this diagnosis can be studied in specialized medical reference books.
With absence serious damage in the brain the prognosis is favorable. As a result drug treatment patients with this syndrome recover or continue to live, gradually adapting to all changes in the body.
At the beginning of the twentieth century, the syndrome was first described by the German neurologist K. Goldstein. There are no clear data on the relevance of alien hand syndrome. But, it should be taken into account that with corticobasal degeneration it occurs in approximately half of the patients, so we can assume its prevalence is about 1 case per 200 thousand people.
Clinic
Presenters clinical symptoms for alien hand syndrome:
- The presence of subjective sensations in the patient of foreignness of the limb.
- Her uncontrolled motor activity.
- Inability to stop movements, such as:
- repetition of movements of the uninjured limb;
- levitation, rise up;
- obstruction of movements of the healthy hand;
- actions of a threatening nature: strangulation, beating, etc.;
To diagnose SFR, the patient is tested: visual control of the injured limb is excluded and its degree of sensitivity and control ability are determined. The patient cannot distinguish his hand from someone else’s, while his limb makes uncontrollable and obsessive movements, unbends, bends, grabs, etc.
Etiology and pathogenesis
Already during the first study of alien hand syndrome, Goldstein did not observe any mental abnormalities in the patient, but after a post-mortem autopsy he discovered a disruption in communication between the hemispheres of the brain. These data were indirectly confirmed in the mid-twentieth century, when attempts were made to dissect the hemispheres to treat epilepsy; this also led to the emergence of SSR.
Until now, the causes of the disease have not been fully studied, but it is assumed that due to disruption of hemispheric connections, only the subconscious begins to control the affected limb. It is not established why this happens selectively, for example, with only one hand.
Three main pathways for the development of alien hand syndrome have been identified:
- Callosal for damage corpus callosum;
- Frontal with damage to the anterior parts of the brain;
- Sensory or posterior with damage to the thalamus or brain regions in the back of the head;
Callosal
In the first option, hemispheric connections are disrupted and the non-dominant limb is alienated.
Frontal
In the frontal variant, due to damage to the anterior cingulate cortex, supplementary motor cortex, and prefrontal cortex in the medial part of the dominant hemisphere, the disease spreads to the dominant limb. Exploratory mechanisms are disinhibited, so the grasping reflex, feeling objects, and one’s own body are most pronounced. At the same time, the feeling of alienation is minimal compared to other options.
Thalamic
When the thalamic system or parts of the brain in the parieto-occipital region are damaged, control over the movement of the limb, both visual and kinesthetic, is disrupted, the body diagram is distorted, and a concomitant syndrome of ignoring the half of space opposite the affected hemisphere (most often the non-dominant one) appears. It manifests itself in the affected hand avoiding contact with objects, for example, it becomes impossible to put it on the table, touch your nose, etc. There are mixed variants of SSR.
Diseases that may accompany SCH
Alien hand syndrome can accompany the following diseases:
- Corticobasal degeneration;
- Stroke;
- Alzheimer's disease;
- Cerebral aneurysms;
- Injuries;
- Vascular infarctions;
- Tumors;
- Diseases leading to damage to the corpus callosum (multiple sclerosis, aginesia, leukodystrophy and others).
Diagnostics
When diagnosing SSR, differentiation is made with pathologies of similar genesis, such as:
- Dystonia;
- Hemiataxia;
- Hemiballism;
- Athetosis, pseudoathetosis and others;
Among the symptoms of these diseases, there is no subjective feeling of alienation of the limb.
Treatment and prognosis
No completely effective therapy for alien hand syndrome has been developed. Treatment and prognosis are determined primarily by the diseases that caused it. If possible, the causes of the syndrome are eliminated. In the presence of nervously- mental disorders held drug correction. Psychotropic drugs are used to relieve motor agitation.
Corticobasal degeneration associated with SRS progresses, but the syndrome gradually becomes less pronounced due to increasing muscle weakness. Death of patients occurs within 10 years after onset.
With absence serious pathologies in the brain, as a result effective treatment Patients with alien hand syndrome recover or continue to live, adapting to changes in the body.
Alien hand syndrome is a complex psychological and neurological disorder in which the purposeful movements of one or both upper extremities are impaired. In some patients it is accompanied by epilepsy. The syndrome has another name - “Dr. Strangelove's disease.” It appeared after the release of a film directed by Stanley Kubrick, about a character whose hand made involuntary movements. This pathology is very rare and little studied.
With alien hand syndrome, the deviation does not develop in the dominant hand (for example, if a person is right-handed, he is more likely to disobey left hand, and vice versa)
The disease was first discovered in 1909. The first to encounter the syndrome was a neurologist from Germany, Kurt Goldstein. One day, a patient came to him with complaints that while she was sleeping, she was being strangled by her own left hand. The doctor spent a lot of time searching for the causes of such a strange disorder, but was forced to stop observing the patient after he could not establish any mental disorders. In addition, attacks of the mysterious syndrome ceased to appear.
Later for a long time, after the woman's death, Dr. Goldstein performed an autopsy and determined that there was damage to her brain that made the transmission of signals between the hemispheres impossible. This led to the development of a strange disease.
Since then, medicine has known about 100 cases of alien hand syndrome, and therefore the disorder cannot be considered average.
Types of syndrome
Doctors distinguish 3 types of alien hand syndrome. Their classification depends on the location.
- Frontal. This type of syndrome affects the accessory motor cortex and the anterior cingulate cortex. This confirms the possibility of the development of the syndrome due to disorders in these areas of the brain. The damage also spreads to the most developed parts of the brain - the prefrontal cortex, in particular to its medial section. It is noted that the leading limb suffers the most, and its grasping reflex increases significantly: the hand begins to feel everything; after the patient grabs an object, it is difficult for him to let go of it without outside help. This reaction occurs due to the fact that exploratory reflexes are provoked in the parietal part of the cerebral cortex.
- Posterior or sensory type. Manifests itself as a result of damage to the parietal and occipital regions of the thalamus. With this type, it is violated Feedback and visual control of hand manipulations. Compared to the previous view, the hand here will act in the “opposite direction” - trying to avoid contact with objects. For example, when the patient sits down, the arm involuntarily rises to avoid contact with the chair or table.
- Callosal. Characterized by lesions in the anterior and middle lobes of the corpus callosum. This is where the neural connections of the right and left premotor parts pass. With this type of disease, the disorder spreads to the hand, which performs auxiliary functions. Despite the absence frontal signs, an intermanual conflict occurs, that is, the affected limb prevents the healthy limb from somehow acting.
Interesting fact! In the 50s of the last century, doctors performed operations to cut the connections of the hemispheres. This method made it possible to successfully treat epilepsy. But this practice had to be stopped, because... As a result of the operation, alien hand syndrome developed.
This disorder should be distinguished from athetosis and pseudoathetosis - these diseases are associated with loss of sensation in the limbs.
Reasons for violation
Alien hand syndrome can be caused by traumatic brain injury
Despite the fact that this disorder is quite rare, it receives considerable attention in psychiatry. Alien hand syndrome also arouses considerable interest in occult circles, where it is attributed to a supernatural origin. But scientific medicine has not yet found a clear answer to the question of what causes the syndrome.
In neurology, it is believed that the brain in this disease does not understand the difference between planned actions and those classified as mechanical functions. Some experts believe that this is a transformation of the subconscious into a mechanical one. Therefore, pathology is perceived by the patient as something alarming and mystical. It was not possible to establish why the syndrome spreads to only one limb.
It is known that the course of certain diseases can provoke alien limb syndrome. Among them:
- various head injuries;
- oncological processes in the brain;
- ischemic stroke and myocardial infarction;
- dementia;
- congenital absence of a body part, organ or part of an organ (agenesis);
- defects of the corpus callosum;
- tuberous sclerosis.
Previously, this disease was diagnosed only against the background of epilepsy, but over time, other cases appeared. Clinical picture depends on the disease that gave rise to the development of the syndrome. For example, with oncology it can develop very quickly, but with corticobasal degeneration it is necessary to wait 2-3 years before an accurate diagnosis can be established.
Symptoms
With strong negative emotions, the hand can perform uncontrollable actions
Symptoms are expressed in the following features:
- The patient begins to feel that this is not his hand, as if someone else’s limb was sewn on or a prosthesis was installed.
- The hand performs uncontrolled motor and grasping manipulations. Without any human participation, the limb can grab objects, clothing, and perform suffocating actions towards the patient or people around him.
Depending on the type of syndrome, the “independent” hand may interfere normal life second hand. Also, many patients note the emergence of a threat to their life: a “foreign” limb strangles them in their sleep, or can grab onto hot objects or wires. Some scientists hypothesize that in this way a person’s subconscious fears or desires are manifested. For example, if the patient is hungry, and there is no way to satisfy this feeling right now, then the hand can snatch food from others or from the counters. When a person has to control his anger or negative emotions, then the hand may begin to perform aggressive actions.
Only a few cases have been described in medicine successful treatment alien hand syndrome. As a rule, deviations develop gradually, but they are noticeable to a person. The limb stops listening and makes illogical and contradictory actions. If the patient collects something, the other hand scatters things and the like.
Interestingly, deviations develop more often not in the dominant hand. For example, if a person is right-handed, his left hand is more likely to disobey him, and vice versa.
Complications and consequences
Alien hand syndrome in itself is a complication, but there are also cases when it does not develop against the background of epilepsy, but vice versa (this example is only valid for epilepsy). The consequences of this syndrome depend on the success of treatment of the disease that provoked its appearance. There are cases where the symptoms disappeared after simple treatment and never bothered the person again. With diseases such as dementia or brain cancer last stage, it is practically impossible to overcome the syndrome.
Diagnostics
Differential diagnosis and examination of the patient are aimed at distinguishing the syndrome from other diseases. At the initial stage of development of the disorder, symptoms similar to:
- some mental illnesses;
- neurological abnormalities;
- ailments of the musculoskeletal system;
- dysarthria in ischemic stroke.
First of all, an anamnesis is collected. During the interview, the doctor is obliged to determine whether the patient has epilepsy, oncological diseases etc. The patient is also sent to see a neurologist and psychiatrist. This is followed by a series of clinical tests:
- echo-encephalography;
- MRI and CT scan of the brain.
This will allow us to establish the presence of pathological processes in the organ, their extent and effect on healthy tissue.
Treatment and prognosis for recovery
If the syndrome is accompanied by neuropsychic pathologies, it is prescribed drug therapy, which includes antipsychotics, nootropics, sedatives and tranquilizers, treatment is selected individually
Unfortunately, currently unavailable effective treatment SCHR. Therapy will be aimed at eliminating symptoms and ridding the patient of the root cause of the syndrome.
Treatment with medications is carried out individually. As a rule, it includes the following groups of drugs:
- antipsychotropic;
- nootropics;
- tranquilizers;
- sedatives.
With a diagnosis of “corticobasal degeneration,” the syndrome becomes less pronounced after some time and without specific treatment. This occurs due to gradual weakness in the muscles. Once such a diagnosis is made, death occurs within approximately 10 years.
When were they discovered in the brain? benign formations, then the manifestations of SSR can be partially stopped through medications. But the main thing for the patient here is to get used to his illness and some of its symptoms, which cannot be eliminated. The life prognosis is generally favorable.
There is no direct connection between the patient’s age and his gender, although people of working age (30-60 years) suffer more from the pathology.
If on initial stages When patients with diseases try to control the limb, over time many simply tie it down or fix it. Moreover, the hand can resist. What is most interesting is that the sensitivity of the limb is not turned off. That is, when a person gets injured, gets burned and harms himself, he feels it, but, unfortunately, cannot prevent it.
There are many amazing, inexplicable anomalies in medicine that are beyond understanding modern science. These phenomena include alien hand syndrome, a rare disease that occurs in disorders of brain function. There is still no consensus on what causes this deviation. There are only assumptions about the neurological nature of the disease. It was first discovered in 1909. A woman developed uncontrollable hand movements after undergoing surgery that affected the brain. In most cases, the syndrome appeared in epileptic patients, as well as after removal of the corpus callosum of the brain - the largest bundle of nerves in the brain connecting the hemispheres.
Pathology affects only upper limbs. The disease is not congenital and is not caused by genetic predisposition; it arises as a result of human life activity.
Features of the syndrome
Alien hand syndrome is a pathology of a neuropsychic nature in which the hand independently performs actions that are contrary to the person’s intentions. Since movements are not controlled and are performed arbitrarily, mystical meaning is often attributed to this pathology. The hand can do various movements and cause harm not only to its owner, but also to others. In medical practice, there are cases when a person began to strangle himself, tear off his clothes, and injure himself.
If the leader is right hand, then the pathology will affect left limb, and vice versa. Patients have to tie their affected arm to minimize the risk of injury and other negative consequences.
It is difficult to predict how the affected limb will behave. It is also unknown how effective drug therapy will be.
Reasons for the anomaly
IN medical science the exact reasons for the formation have not yet been determined of this disease. A relationship has been identified between alien hand syndrome and brain dysfunction. In this case, dysfunction of neuronal conductivity is observed, leading to a breakdown in the interaction of the brain hemispheres. Uncontrolled limb movements are caused by the state of the brain, when it loses the ability to distinguish between planned actions and those movements that are defined as mechanical.
There is a high probability of developing pathology in a person who has had a stroke. The disease is often diagnosed in patients with epilepsy when all the nerve cells in a certain part of the brain are simultaneously excited.
Among the factors that can cause irreversible phenomena in the brain and lead to the development of alien limb syndrome, the following are considered the main ones:
- traumatic brain injury;
- neoplasms in the brain (benign and malignant);
- disruption of cerebral vascular activity;
- surgery in the head area;
- pathological processes associated with the functioning of the corpus callosum of the brain; Alzheimer's disease, which causes loss of cognitive function;
- corticobasal degeneration - pathological processes observed in various parts of the brain, mainly in the frontoparietal zone.
Clinical picture
Alien hand syndrome begins with manifestations of emotional instability. The patient either experiences ecstatic joy, or, on the contrary, is devastated. Feelings of fear and anger are replaced by a depressed and depressed state.
Next, motor, associative and sensory functions body. It seems to a person that someone is controlling his emotions, feelings and movements from the outside. He withdraws into himself, trying to hide his feelings.
The third stage of disease development involves complete loss control over the actions of the injured hand.
Depending on where the pathological focus is located in the brain, several types of syndrome are distinguished.
| Frontal (frontal) | The front parts of the brain are damaged. Loss of control over the leading hand. The grasping reflex is clearly expressed. A person unconsciously takes an object, but cannot let it go on his own. One of the main symptoms of this type of syndrome is the desire to feel everything, especially own body. |
| Callosal | There are disturbances in the functioning or structure of the corpus callosum of the brain, and the connection between the hemispheres suffers. Pathological process affects the non-dominant hand. There is a phenomenon called intermanual conflict, which manifests itself in the fact that the damaged hand prevents the healthy hand from performing any actions. There is a high probability of harming your own body. |
| Sensory (thalamic) | The thalamic region of the brain is damaged. The patient incorrectly perceives the body diagram and loses control over space. Unlike the frontal type of syndrome, a person cannot grasp an object, but tries to avoid any contact with it. The affected hand performs all actions above or below the object. In this case, the patient cannot touch his own body. There are disruptions in the visual and kinesthetic functions of hand control. A person perceives sounds, light, taste incorrectly. It seems to him that he stops hearing and seeing. Pseudohallucinations may appear. Sometimes the patient shouts out words and makes sounds that are accompanied by sudden movements of the arms, legs, and body. |
Accompanying illnesses
Alien limb syndrome does not occur on its own. It may develop due to pathological changes in the brain or be a complication of the following diseases:
- diseases associated with traumatic injuries heads;
- ischemic stroke;
- heart attack;
- oncological diseases;
- agenesis various parts brain;
- cerebrovascular disease, when normal blood flow is disrupted;
- sclerosis in acute form;
- corticobasal degeneration, including Alzheimer's disease.
Therapy and prognosis
Treatment of any disease involves eliminating the causes that caused it. There is still no consensus in science about why alien hand syndrome develops. Research continues, but the disease is very rarely diagnosed. There is no exact treatment regimen, just as there is no effective method for eliminating the syndrome.
In most cases, the pathology is accompanied by deviations in mental state human, which is caused by damage nervous system, in particular the brain.
In this case, drug therapy is used aimed at stopping motor activity limbs. Psychotropic drugs are prescribed medicines(“Haloperidol”, “Triftazine”), supplemented herbal preparations(antidepressants and antipsychotics).
After the therapeutic course has been completed and positive dynamics have appeared, psychological rehabilitation and, if necessary, adjustments.
IN rehabilitation period the patient needs:
- Take part in psychotherapeutic sessions. Usually these are group classes, but in some cases individual visits are scheduled.
- Follow a special diet, excluding foods containing large amounts of copper (legumes, nuts, chocolate).
- Get busy physical therapy. Specially selected exercises are aimed at strengthening muscle tone, recovery motor functions. As a result general state the patient is improving.
Each case of pathology development requires an individual approach. The severity of mental disorders, the initial cause of the disease, as well as the characteristics of the patient’s body are taken into account.
There is a rare neuropsychiatric disease called alien hand syndrome. Its peculiarity is that the hand independently performs various movements and functions. Based on the symptoms, the disease is also called “anarchist hand”.
In a person suffering from this disease, the hand acquires autonomy, and often contradicts the actions that the person intends to perform. For example, if a healthy hand combs and smoothes the hair, then the sick hand ruffles it at the same time.
The action of an unhealthy limb is purposeful. There are known cases when such a hand pinched the owner, tore his clothes, beat him, and tried to strangle him. In addition, the hand can cause harm to itself by grabbing exposed wires or touching hot objects.
In this regard, patients simply tie their hand to prevent unwanted actions. The first cases of this disease were noted in 1909, and today approximately fifty such cases are known. It has been found that the disease develops more often after the corpus callosum is removed, which is usually practiced in therapy.
As you know, the corpus callosum is a connection of nerve fibers that connect the cerebral hemispheres. In addition, the disease can appear if a person suffers from a stroke or aneurysms. In any case, the disease is caused by the presence of disturbances between the hemispheres.
Moreover, if a person is right-handed, then the left hand becomes a stranger, and if the patient is left-handed, the right hand becomes a stranger. According to scientists, a diseased limb can carry out commands that are given on an unconscious level, but so far this assumption has not been confirmed.
Features of the disease
Alien hand syndrome is currently a source of controversy in scientific world, and even famous scientists cannot answer the question about it. There is no specific way to get rid of this disease. Doctors prescribe psychotropic drugs, and other treatment methods have not yet been developed.
This disease continues to be studied, taking into account known cases. In the world of neurosurgery, the consequences of a brain operation were recently discussed, after which the patient began to suffer from this rare disease, alien hand syndrome. This factor is another confirmation that the disease develops if the patient has suffered a brain injury.
Experts studied the consequences of the operation, and it was confirmed that the patient actually began to suffer from this rare disease after the operation. The patient has to fight every day with her own hand; the limb has completely unexpectedly lost control and acts on its own.
The patient claims that at one point her own hand almost strangled her. Doctors were confident that the operation was successful until the patient began to move independently. The hand began striking the owner’s face, and then it became obvious that something had unexpectedly gone wrong during the operation. The patient was prescribed a sedative, and gradually the deviation was curbed. It is impossible to predict how the hand may behave in this case in the future.
Causes
Despite the rarity of the disease, alien hand syndrome has received significant attention in scientific circles, and in occult circles this condition has been given the status of a supernatural abnormality. What exactly causes this unusual illness?
Neuroscientists theorize that the brain is unable to tell the difference between planned actions and those that end up happening. human body defines how mechanical functions. It is assumed that any desire coming from the subconscious can penetrate the part of the brain that is subconscious, and then it becomes a mechanical function, which causes violent movements of the limb.
As a result, such actions are regarded by humans as alarming and even mystical. Currently, such theories are at the stage of speculation, and it is not precisely established how this syndrome can affect only part of the body.
Now experts have identified three variants of the syndrome, which are considered the main ones. In the “frontal” variant, there is a connection with the affected additional motor cortex, the anterior cingulate gyrus, and the medial part of the prefrontal cortex in the dominant hemisphere is also affected.
If this is a “frontal” variant, then the dominant limb is mainly involved, while the grasping reflex is pronounced, and there is a desire to feel all surrounding objects, as well as one’s own body. This happens because exploratory automatisms mediated by the parietal cortex are disinhibited. The patient grabs a certain object impulsively, and he is often unable to let go of it. In addition, the “frontal” variant is distinguished by the severity of the subjective alienness of the limb.
Other variants of the syndrome
A “callosal” variant may occur, which is caused by disturbances in the area of the middle and anterior part of the corpus callosum. In this zone there are pathways connecting the right and left premotor areas. Typically, the non-dominant hand is involved. This variant is characterized by pronounced intermanual conflict, although there are no frontal signs. With alien hand syndrome, there is a third option, sensory, or posterior. It may appear if there is a focal lesion of the parietal and occipital parts, thalamus.
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