Incorporation of another person's limb into body image relieves phantom limb pain: a case study.

Phantom limb phenomena are well characterized, but the underlying mechanisms remain unclear. Here we report a patient who relieves his phantom sensations and pain, experienced as itching and cramping, through scratching or massaging his prosthesis or the leg of another person. This pain relief occurs only when phantom limb sensations are present. We hypothesize that symptom relief results from incorporation of the foreign limb into the patient's body image, mediated by the sensory mirror neuron system, relieving pain by restoring concordance between sensory systems.