Phantom-Limb Pain Traced to Brain Circuitry

Pain that appears to come from an amputated limb may be caused by how the brain reorganizes itself after the limb is lost, a study suggests.

Researchers found that the degree of phantom-limb pain in 13 people was closely related to how much their brain circuitry had reorganized in response to the amputation. The more reorganization, the more the pain.

That was the opposite of what was expected, said researcher Edward Taub of the University of Alabama at Birmingham.

The study does not prove that the reorganization causes the pain, he said. But if that is the case, drugs that reduce the amount of reorganization might prove effective for treating phantom-limb pain, he said.

Phantom-limb pain is common among people who have had an amputation. It can be severe. It is usually intermittent and resists treatment.

Normally, messages about touch, pain and movement from each body part go to a specific target area in the brain. If a limb is amputated, its target no longer gets inputs. The brain reorganizes so that this target area starts getting inputs from other body parts instead.

It’s not clear why more reorganization would lead to more phantom-limb pain, Taub said.

Taub and German researchers reported the work in the June issue of the journal Nature.