Phantom Pain: A Therapeutic Trial Using Transcranial Magnetic Stimulation

Phantom pain refers to the sensation of pain felt by patients who have had a limb amputated. The treatment of phantom pain is often disappointing and is unable to provide adequate relief to the patients. The area of the brain involved (posterior parietal cortex [PPC]) is found on the opposite side of the amputated limb. For example, if a patient has the right arm amputated, the left posterior parietal cortex is involved in the phantom pain.

Researchers believe that if they can decrease activity in the posterior parietal cortex they may be able to reduce phantom pain.

Researchers plan to use low frequency (1 Hz) transcranial magnetic stimulation (TMS) to decrease the excitability of the PPC opposite the side of the amputated limb. TMS involves the placement of a cooled electromagnet with a figure-eight coil on the patient's scalp and turning on the magnetic flux. This permits non-invasive, relatively localized stimulation of the surface of the brain (cerebral cortex). When an area of the brain is stimulated a period follows when that area cannot be stimulated again. In this case, researchers plan to use TMS to stimulate the PPC in order to decrease the level of excitability there.