The influence of visual feedback in phantom limb pain and perception – Application of a novel augmented reality platform in basic research and treatment

This work concerns a series of three studies investigating how cortical plastic changes and pain processes are affected by changing the body perception through the manipulation of visual feedback in both healthy individuals and amputees with phantom limb pain.
A novel augmented reality platform was created and tested in the initial study. The second study investigated the impact of creating a sensation of a phantom hand in healthy participants by making their hand seem invisible. Participants experienced a shortening of their arm and hand, reminiscent of a phenomenon known as telescoping observed in about 50% of amputees with phantom limbs. Electroencephalography recordings revealed that electrical stimuli applied to the invisible hand was processed differently from both normal vision of the hand and occluded vision of the hand. The third study employed the augmented reality platform in an intervention for amputees with phantom limb pain. The system allowed the amputees to see a virtual visualization of their phantom, overlaid onto the location of the phantom, thereby restoring visual feedback of their missing limb. Following two weeks of intervention, functional magnetic resonance imaging indicated cortical reorganizations and phantom limb pain had decreased by up to 52%.