Phantom Limb - Recent Research

Recent Research

In 2009 Lorimer Moseley and Peter Brugger carried out an experiment in which they encouraged seven arm-amputees to use visual imagery to contort their phantom limbs into impossible configurations. Four of the seven subjects succeeded in performing impossible movements of the phantom limb. This experiment suggests that the subjects had modified the neural representation of their phantom limbs and generated the motor commands needed to execute impossible movements in the absence of feedback from the body. The authors stated that: "In fact, this finding extends our understanding of the brain's plasticity because it is evidence that profound changes in the mental representation of the body can be induced purely by internal brain mechanisms--the brain truly does change itself."

In 2012 V.S. Ramachandran and Paul McGeoch reported the case of a 57-year-old woman (known as R.N.) who was born with a deformed right hand consisting of only three fingers and a rudimentary thumb. After a car crash at the age of 18, the woman's deformed hand was amputated, which gave rise to feelings of a phantom hand. The phantom hand was experienced, however, as having all five fingers (although some of the digits were foreshortened). 35 years after her accident, the woman was referred for treatment after her phantom hand had become unbearably painful. McGeoch and Ramachandran trained R.N. using mirror box visual feedback, for 30 minutes a day, in which the reflection of her healthy left-hand was seen as superimposed onto where she felt her phantom right hand to be. After two weeks she was able to move her phantom fingers and was relieved of pain. Crucially, she also experienced that all five of her phantom fingers were now normal length. Ramachandran and McGeoch stated that this case provides evidence that the brain has an innate (hard-wired) template of a fully formed hand.

In 2012 Karen Reilly, at the Neuroscience Research Center, University of Lyon in France, and her colleagues, Pascal Giraux and Estelle Raffin, conducted an experiment in which they demonstrated that the movement of phantom limbs are "real" movements that involve the execution of a motor command. Amputees can also carry out imaginary movements of their phantom limbs, however these movements do not lead to a feeling that the phantom limb has changed position. Lorimer Moseley points out that this research indicates that clinicians using motor training for pain relief need to distinguish between imagined movements and real movements of phantom limbs.