FINAL BLOG ENTRY

For me, the most intriguing topic we discussed in class this semester was phantom limb syndrome. It is understandably a painful and emotionally traumatizing experience for those who suffer from it, but it is also fascinating to learn about and study. I cannot imagine experiencing the physically agonizing pain associated with the syndrome, mainly because of the pain itself but also because of the negative consequences it would have on your brain. Your eyes usually provide the most reliable sensory information available, and for them to perceive no appendage, but for your brain to feel a somatosensory response coming from that area–it would be almost impossible to convince yourself that your brain was providing you with false information. The pain has reportedly even driven some patients to insanity. The challenge of overriding information your brain communicates to you is extremely difficult, even when it is not information about excruciating pain. Therefore, I can only imagine how strenuous and difficult the rehabilitation process for phantom limb is.

An article published in the New England Journal of Medicine (http://content.nejm.org/cgi/reprint/357/21/2206.pdf) discusses the option of mirror therapy for patients with phantom limb syndrome. It was theorized in the study that the pain is a result of crossed signals from visual feedback and proprioceptive feelings from the amputated appendage. Therefore, by creating illusions of the amputated appendage, the therapy might be able to trick the visual system into visualizing the source of the pain, and with time and training, uncrossing the mixed signals in the brain. In this study, 100% of the patients who underwent mirror therapy expressed a decrease in pain, while only 15-30% of patients undergoing alternative therapies expressed a decrease in pain. Its very clear that mirror therapy is a successful way to decrease the amount of pain, even if it is impossible to eliminate.

Dr. Ramachandran has researched, discovered, and written so much about phantom limb pain and the cortical plasticity that occurs in phantom limb patients. He has even written about the occurrence of phantom genitalia after sex change surgery! He was one of the first to discover the somatotopic reorganization that occurs in the cortex after amputation in what he calls “the remapping hypothesis” (http://archneur.ama-assn.org/cgi/content/full/57/3/317#REF-NNR8257-10). He has used mirror therapy on patients with phantom limb, hemineglect, and hemiparesis. In his research on the effects of mirror therapy on phantom limb patients, he has found that when many patients experience pain in the phantom limb, it is most likely due to non-existent propioceptive feedback. In other words, there are no signals telling the brain that he/she is clenching his/her fist too hard, but pain is still experienced. However, when a mirror is placed so that the phantom hand appears real, simultaneous opening of both fists relieves the pain (http://www.nature.com/nature/journal/v377/n6549/pdf/377489a0.pdf).

Extensive research on phantom limb has only been going on for about ten years now, and I expect that due to the increase of research dedicated to this syndrome, we will know significantly more about it in the near future.  However, as we learn more about the neural mechanisms of phantom limb syndrome, we must not forget the pioneering work of Dr. Ramachandran and others, for they laid the foundation for further research into this area.