a desire for amputation linked to abnormalities in the structure of the brain

Body Identity Dysphoria (BID), formerly known as Body Integrity Identity Disorder (TIIC), is a rare mental disorder. People who suffer from it feel terribly uncomfortable in their bodies, as if one of their healthy members is not supposed to be part of it. The discomfort is such that they sometimes ask to have their limb amputated to feel complete. According to an article in the journal Current Biology on May 7, this desire for amputation could be linked to specific abnormalities in the structure of the brain.

To explore the brain mechanisms associated with ICD, Gianluca Saetta, doctoral student at the University of Zurich, and Peter Brugger, from the University Psychiatric Clinic (PUK) in Zurich (Switzerland), recruited 16 men who want to have their legs removed healthy left and 16 healthy witnesses.

The researchers thus discovered alterations in two key regions associated with the BID. Thus, the right paracentral lobule (rPCL), which houses the primary somatosensory representation of the affected left leg, has shown a reduction in intrinsic functional connectivity to other parts of the brain. They also observed a reduction in intrinsic functional connectivity and a reduced concentration of gray matter in the right upper parietal lobule (rSPL).

The importance of functional connectivity and gray matter density

Thus, the interaction between the characteristics of gray matter and the functional connectivity of certain regions could be at the origin of the fact that a person feels at home in his body or not.

“The feeling that a member belongs to us depends on the extent to which the sensorimotor zone of the member is functionally connected to all other regions of the brain ”says Gianluca Saetta. Here, the researchers therefore found that the sensorimotor area of ​​the leg to be removed for IDB was less connected to other parts of the brain. “Functional connectivity and the density of gray matter in the most crucial area for the representation of the appearance of our body – the right parietal region of the brain – are also crucial factors in this sensation. ”

“It is interesting to note that the less gray matter in the right parietal region of the brain, the stronger the desire for amputation, and the more people who suffer from BID act as if they were amputated., he continues. This simulation behavior helps them cope with the distressing mismatch between the appearance they want to give to their body and the way they see it.. ”

Brain stimulation techniques to treat the sick?

“We show clear associations between a mental state and changes in the structure and functionality of the brain, details Peter Brugger. We do not know if the neural signature of the IDB comes first and hinders the development of normal property of the limbs or if decades of concern about the lack of such property modulate the brain circuits mediating body awareness ”, he continues. Thus, it is difficult to say whether it was the IDB that caused a lack of functional connectivity in the brains of these patients or the opposite.

These results suggest that brain stimulation techniques, such as transcranial magnetic stimulation, could help people with BID, say researchers, who recommend further studies on the subject. Currently, many variants of the IDB are still unknown, especially concerning patients who believe they should be paraplegic or blind, say the researchers.

Accept dysphoria of bodily integrity as an official mental disorder

Another unknown: the number of people suffering from BID. Indeed, it is a safe bet that many patients have never told their doctor about their symptoms. This is why researchers are campaigning for the “dysphoria of bodily integrity” be included in the 11^e revision of the International Classification of Diseases (ICD-11) as “distress or bodily experience disorder”. Once the disease officially “accepted as a disorder, more people will come out and identify themselves as suffering ”hope the researchers, interviewed by the News-Medical site in the margins of their study.

The origins of the IDB are also uncertain. “Most sufferers can trace their dysphoria back to early childhood. Some claim that there was a certain trigger event, for example being fascinated by the observation of an amputee, the scientists explained to News-Medical. It is even possible that there is an innate component, which allows the normal physical development of a limb, but which hinders the development of a normal cortical representation ”, they detail.

Anyway, for researchers, this disorder is definitely an evil of the century. “The identification with sociale the social image of the body ’is important and is reflected in the fact that CID is mainly a disease of our western society, similar to anorexia, which is an entirely different dysphoria concerning bodily experience”. That’s why, Gianluca Saetta plans to compare subjects with BID with people who are dissatisfied with their sex or with anorexia.

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