Pain asymbolia: characteristics, symptoms and causes.

A summary of the characteristics of Pain asymbolia, a rare neuropsychological phenomenon.

We have all experienced physical pain to a greater or lesser degree. However, some people have lost this ability, or have it altered.

Let's take a closer look at the subject of pain asymbolia to see the implications of this pathology and what are the causes that may be causing this dysfunction in the perception of pain as we know it.

What is pain asymbolia

Pain asymbolia, also known by the medical term analgognosia, refers to an inadequate reaction to a painful stimulus, due to difficulties in identifying it.due to difficulties in identifying it. Some of these reactions can be not removing the part of the body that is suffering the damage of the aversive stimulus (not removing the hand from the fire, for example), not expressing pain gesture on the face, or not showing psychological reaction to the damaging element.

The expression of pain asymbolia was coined by Paul Schilder and Erwin Stengelneurologists, psychiatrists and also psychoanalysts, based on a study carried out in 1927. In fact, in some manuals it is possible to find the Schilder-Stengel syndrome to refer to pain asymbolia, since as a result of that publication their own names were also used as nomenclature for this newly discovered pathology.

The case that these researchers studied was that of a woman affected by a sensory aphasia who repeatedly self-injured herself, without showing any reaction to the pain she should be feeling in the face of tremendous aggressions to her body. Tests were made with electrical stimulation, each time of increasing intensity, and only in the higher ranges did they obtain a facial response to the aversive stimulus, but at no time did she try to respond to the pain she should be feeling in the face of the tremendous aggression to her body.but at no time did he try to get away from the devices.

Asymbolia of danger

Pain asymbolia refers not only to experiencing pain sensation, but also to pain-seeking.. Somehow, it would seem that the person suffering from this anomaly would try by all means to try to feel the harm, as incredible as it may seem. For this reason, it would carry out more and more intense self-aggressions, in an escalation to recover that disappeared sensation, no matter how unpleasant it might be.

And the fact is that, although the subject perceives the stimulus that is hurting him, his body is disconnected from the painful response that should be given, so that the stimulus loses the aversive component.Therefore, the stimulus loses the aversive component (only at the level of response, since it is still harmful) and consequently the individual tends to experience more and more, attracted by the performance of harmful behaviors, which do not involve any pain.

The big problem with this issue is that, although the patient has lost the ability to feel pain, the injuries that he is self-inflicting are real, and therefore may experience serious sequelae at the organic leveldepending on how intense these behaviors have been. This is why we sometimes also speak of the concept of asymbolia for danger, since they are not aware of the harm they are doing to themselves in their search for the sensation of pain.

Causes

But what is the origin of pain asymbolia? This pathology seems to come from organic lesions in the brain, specifically in the lobe of the brain.Specifically in the left parietal lobe or in both hemispheres at the same time, and more specifically in the supramarginal gyrus, affecting the insula or insular cortex, in the Sylvian fissure. The lesion could be caused by a cranioencephalic trauma or by some internal pathology affecting this area.

It is considered that the specific area that would be directly involved with pain asymbolia would be number 43 in Brodmann's list of areas. When suffering a lesion in this region of the cerebral cortex, the connections between the sensory system and the limbic system would be eliminated.This would explain why patients affected by this pathology do not have the physical capacity to relate the aversive stimulus with the painful reaction to it, as they are not able to process it.

Depending on the severity of the lesion, it is possible to suffer from partial or total pain asymbolia, depending on whether the aforementioned connections have been completely destroyed or whether there are still some active neuronal circuits capable of transmitting, even partially, the information related to the uptake of pain in the body's receptors and thus translate it into a consequent reaction, which will normally be much less than it should be, as only part of the intensity of the stimulus is perceived.

Comorbidity

Pain asymbolia also has the peculiarity that it can be associated with other pathologies of different it can be linked to other pathologies of different nature, such as Wernicke's aphasiasuch as Wernicke's aphasia (difficulties in understanding language), conduction aphasia (problems in repeating words), constructive apraxia (loss of the ability to make patterns of movements to build elements or to draw).

These are not the only disorders that can occur as associated morbidity of pain asymbolia.. Others would be ideomotor apraxia (problems in carrying out movements devised in the mind), autotpoagnosia (difficulty in perceiving the determined position of a part of one's own body) or aprosody (impaired ability to perform or interpret correctly the sound characteristics of language, i.e. prosody).

It is not strange that there is a whole variety of neurological disorders that can appear in the patient at the same time as pain asymbolia, since it should not be forgotten that such pathologies are caused by a brain injury, so it is not strange that the same lesion affects different areas of the brain that, although contiguous, have very different functions and therefore can trigger such a varied symptomatology as we have seen.

Other pain disorders

But asymbolia is not the only pain-related disorder. There are others with very peculiar characteristics. For example, we find analgothymia, a pathology in which the patient feels the pain caused by an aversive stimulus, is able to identify it and localize it.The patient is able to identify and localize it without any problem, and yet is absolutely indifferent at the affective level. Both disorders would share a lack of response to pain, but in the second case the sensation is experienced.

Another disorder that is quite popular because of its symptomatology is PLP, or phantom limb pain.. This ailment manifests itself in some people who have suffered an amputation of one of their limbs, either an arm or a leg, and yet suffer a recurrent pain in that part of the body, which is no longer present. It may seem that this pathology escapes logic, but the patient experiences a real sensation and therefore needs a treatment that relieves it.

In fact, one of the techniques used to alleviate the pain of PLP is that of mirrors, in which, visualizing the healthy limb in front of a mirror, the patient tries to focus the pain sensations of the phantom limb. Some studies show that this technique helps to calm these sensations, causing an improvement in the PLP patient.

The opposite case

And, at the other extreme of pain asymbolism, we would find a disorder as frequent in our society as fibromyalgia, a disease that causes a hypersensitivity to pain.fibromyalgia, a disease that causes a hypersensitivity to pain, with no apparent specific cause and that can also extend to different areas of the body, and can cover a large part of it. The big problem with fibromyalgia is that it is a very broad disorder, which affects each person differently and therefore it is difficult to generalize an effective treatment.

Also in disorders opposite to pain asymbolia we can find the pathology known as hyperalgesia. This disease would be caused by damage to the nervous system and would cause the subject to experience an abnormally high pain sensation in relation to the aggression of the damaging stimulus that is triggering it.

Finally, another pathology associated with pain, but which is also at the opposite pole to pain asymbolia, would be allodynia.. It would also imply an inordinate perception of the painful sensation, but in this case it would not be provoked by an aversive stimulus, but by a stimulus that in principle should be neutral, such as tactile pressure and even a simple caress in some cases.

In addition, allodynia is not only associated with stimuli generated by skin pressure, but can also be caused by thermal sensations, so that contact with a substance at pleasant temperatures could also trigger in the subject a perception of immense pain, as if the stimulus were at a very low or very high temperature, when in fact it would be at room temperature, so it should not cause any pain.

Bibliographical references:

• Gil, R. (2003). Neuropsychology. Barcelona. Elsevier.
• Kim, S.Y., Kim, Y.Y.. (2012). Mirror therapy for phantom limb pain. The Korean journal of pain.
• Piulachs, P., Vara, R. (1974). The Sense of Pain. Institute of Spain. Royal National Academy of Medicine.
• Schilder, P., Stengel, E. (1931). Asymbolia for pain. Archives of Neurology & Psychiatry.