Analgesia through the looking-glass? A randomized controlled trial investigating the effect of viewing a 'virtual' limb upon phantom limb pain, sensation and movement

The extent to which viewing a 'virtual' limb, the mirror image of an intact limb, modifies the experience of a phantom limb, was investigated in 80 lower limb amputees before, during and after repeated attempts to simultaneously move both intact and phantom legs. Subjects were randomly assigned to one of two conditions, a control condition in which they only viewed the movements of their intact limb and a mirror condition in which they additionally viewed the movements of a 'virtual' limb. Although the mirror condition elicited a significantly greater number of phantom limb movements than the control condition, it did not attenuate phantom limb pain and sensations any more than the control condition. The potential of a 'virtual' limb as a treatment for phantom limb pain was discussed in terms of its ability to halt and/or reverse the cortical re-organisation of motor and somatosensory cortex following acquired limb loss.