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Showing entries tagged amputation.  Show all entries

December 4, 2011

Phantom Limb Pain and Cortex Reorganization


Feeling pain in the arm that you lost in an accident? Does your arm you lost in the war itch terribly? This sensation of feeling like a lost limb is still attached to the body is known as a phantom limb pain (PLP). The purpose of this study was to identify plastic changes in the somatosensory and motor cortex in patients with and without phantom limb pain. Most sensations regarding these phantom limbs are painful as if the limb was contorted into an awkward position. Although in many cases the complaint is pain, some patients experiencing a phantom limb experience sensations such as itching, burning, or feeling as though the limb is too short. Although PLP is more common in the early stages following an amputation, some have reported pain for years after. It was previously discovered that PLP had a strong correlation with representational plasticity in the somatosensory cortex; however, its correlation with the plasticity in the motor cortex was unknown. This experiment used methods such as Transcranial Magnetic Stimulation (TMS) of the motor cortex, and neuroelectric source imaging of the somatosensory cortex to study the correlation of plasticity in these cortices.

In this study, participants included five upper-limp amputees experiencing PLP and five upper-limb amputees experiencing no PLP. A German version of the West Haven- Yale Multidimensional Pain Inventory was used to evaluate each patient's stump and limb pain. To test for motor reorganization, focal TMS was delivered from a magnetic stimulator through an 8-shaped magnetic coil. The leads were positioned to cause currents to flow approximately perpendicular to the central sulcus, optimally causing the largest peak-to-peak motor evoked potential in each muscle. In patients experiencing PLP, a map of outputs determined by neuroelectric source imaging of EEGs done showed significantly larger motor-evoked outputs on the side lacking the arm than the side with the remaining arm, whereas excitability in the motor neurons of amputees remained unchanged. Since it was previously known that motor reorganization in amputees takes place at a cortical level, the leap was made that. "It is likely that cortical mechanisms are also responsible for the differences in reorganization observed in both patient groups (Karl, Anke et. al., 2011)."

While these findings support the notion that increased plasticity is present in the motor cortex of PLP patients, the evidence used to support this main point is presented in a very odd fashion. Immediately following this claim about cortical mechanisms and presenting supporting evidence, they state that their results "do not rule out the possibility of additional subcortical reorganization." This statement is saying that other factors could be causing or contributing to the claims being made by their research, thus making the research inconclusive as a whole. Another problem with the research methods is that the patient's amputations all occurred at different times. Some more recent than others, which could have a profound effect on the plasticity levels reached at the time of testing.
All in all the research conducted further supports already claimed notions, while having no real additions of any validity or originality. These limitations could be reduced by choosing patients who's amputations occurred within the same month. The potential that could be reached through studies similar to this are immense, but further research needs to be conducted in order to draw on more valuable conclusions.




The Journal of Neuroscience, 15 May 2001, 21(10): 3609-3618;
Posted by      Madelyn K. at 8:29 PM MST

August 1, 2011

Beauty is only... flesh-deep?


Everyone cares about their appearance to a certain extent. Animals groom themselves while people wear makeup, get piercings, and tattoo themselves to enhance their appearance. Shows like The Swan, Nip/Tuck and Extreme Makeover convey how the use of cosmetic surgery has escalated in this country. Despite the agreement that everyone wants to look good, there is a growing concern that this drive for a certain physical appearance can stem from mental illness rather than social persuasion.
Body dysmorphic disorder is a mental illness in which one is obsessed with what they think is a flaw in their appearance, a flaw that is either insignificant or imagined. With BDD people seek out cosmetic surgery to change their appearance, however, some are never satisfied. About one third of those who desire rhinoplasty (a "nose job") have been found to have BDD symptoms and scarcely 2 percent need rhinoplasty for exclusively medical reasons.
One of the more disturbing forms of BDD is Body Integrity Identity Disorder (BIID). BIID is a condition where someone desires to have a missing limb. One man with BIID interviewed by FOXNews.com claimed that he fantasized about loosing a limb from the age of about 4 years old. Now as an older man, he has admitted to his wife and the public his curious need to "get a leg lopped off." People with BIID have indeed gotten rid of limbs and claimed they feel better and "more complete" afterwards. They say their condition is a lot like what used to be called Gender Identity Disorder (when someone is born male and they feel as if they are female, and vice versa). Surprisingly, the medical community leaves people with BIID very few options. People with BIID have been known to use prosthesis to pretend they have an amputation or will even mutilate their unwanted limbs. A popular example of this is a man who put his legs in 100 pounds of dry ice for six hours until they turned black, then went to the hospital where a surgeon had no choice but to remove the mans legs. Surgeons refuse to surgically remove limbs from people with BIID, and up until May 2011, there has been no medical treatment alternative to surgery.
The first successful long-term psychotherapy to treat BIID was done at the clinical center of the Goethe University in Frankfurt. Up until this introduction to using psychotherapy on BIID patients, there was no medication that seemed to help with the disorder and the only successful treatment for BIID known to work was removal of the limbs. During psychotherapy a 37 year-old man who wanted to amputate both his legs the origin and meaning of the desire to amputate were uncovered. The psychologists concluded that by using psychodynamic oriented therapy in conjunction with cognitive-behavioral elements, further treatment could then be developed to help with the disorder.
There is no consensus by neuroscientists as to why people have BIID, however, one possibility discussed is that something went wrong in the body-mapping regions of the cerebral cortex. One part of the cerebral cortex is the primary somatosensory cortex where sensory information of touch is relayed from the body. In front of this region is the primary motor cortex, the region involved in movement. BIID might have come from lesions or a disruption in these parts of the brain.
The drive people feel to look a certain way can develop with errors and can cause a person to reach such lengths as mutilating their own body to ease their psychological illness. Despite the fact that we should all respect other peoples desire to do what they want with their own body, the medical community should seek out and encourage alternatives that are less physically invasive.

Main article: http://www.thedailybeast.com/newsweek/2008/05/28/cutting-desire.html
Posted by      Alma S. at 10:06 PM MDT
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