Phantom limb sensation (PLS) is a very well-documented yet
poorly understood phenomenon. The most common examples occur in wounded
veterans that suffer limb loss, and it has been estimated that around 80% of
amputees have experienced some sort of PLS. It has also been reported that 64%
of amputees experience phantom limb pain (PLP). Of this group, the symptoms and
severity can vary widely. Onset of PLP can be instantaneous, can become
gradually worse over time, or patients can experience sudden onset after 25
years from the original amputation. The pain has been described as “stabbing,”
“stinging,” “itching,” and “burning,” as well as a whole host of other
uncomfortable adjectives, and can last anywhere from seconds to hours. Studies
have shown the relationship between time of original onset and degree of pain
to be negative, that is, PLP generally gets better over time, although this
still remains hotly disputed.
Interestingly,
people born without limbs have much lower instances of both PLS and PLP
(8-18%). This is evidence that PLP is a result of remapping after an amputation
and not just a secondary route that existed but was not used before amputation.
Another interesting aspect of PLS and PLP is referred
sensation, which occurs when the neural connections accidentally rewire to a different
area of the body. For example, arm amputees commonly report feeling phantom sensations
when touched around the face, especially the lips. The theory that attempts to
describe this phenomenon is called maladaptive plasticity theory, and it’s not
without its critics. One of the biggest unanswered questions is something of a
chicken and egg conundrum: does the cortical rewiring cause the sensation of
pain or does the pain provide incentive for rewiring as a coping mechanism? As
medical technology becomes more advanced using MRI and other imaging
technologies, hopefully we will get closer to understanding the way PLP comes
about, thus bringing us one step closer to finding the best treatment.
Mohlman, Jan, et.al. From
Symptom to Synapse: A Neurocognitive Perspective on Clinical Psychology. Routledge, Taylor and Francis Group. New York, New York. 2015.
http://www.painresearchforum.org/news/25670-new-challenge-maladaptive-plasticity-theory-phantom-limb-pain
I looked up treatments for phantom pain and there really isn't much consensus on what could work. According to the Mayo clinic website there are pharmacological routes to take, surgeries, and even using virtual reality headsets to allow those suffering from phantom pains to "see" there hand and recognize that their missing limb isn't being crushed or on fire. Mirror therapy runs along the same lines as using virtual reality headsets, and when reading about it I cant help but think that along with the hardware of our brains there is also some sort of psychological aspect to phantom pains.
ReplyDeletehttp://www.medicinenet.com/script/main/art.asp?articlekey=88097
http://www.mayoclinic.org/diseases-conditions/phantom-pain/basics/treatment/con-20023268