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Phantom Pain
Rebecca Brightwell, Farm Again Co-Director
The word phantom means something that you can feel but cannot see. After a part
of the body, like an arm or leg is amputated by an accident or from surgery, the
person sometimes feels that the arm or leg is still there. This is called phantom
sensation. If the person has pain as though the arm or leg is still there, it is called
phantom pain. Phantom limb pain may occur because the brain
sends signals to a missing limb as if it were still there
but doesn't get feedback and keeps resending and
amplifying the signals.
Many individuals with amputations have a sensation that they are able to ‘move’ their missing limbs voluntarily
but others experience the missing limb as ‘paralyzed’ in a painfully awkward position. The illustration to the left shows some of the positions that have been reported.
Is it possible to get relief from phantom pain without using medications? Some doctors and researchers believe so. New approaches, based on a better understanding of the brain’s role in pain, are opening the way to innovative treatments.
Dr. V.S. Ramachandran, a researcher at the University of California, San Diego, devised a seemingly simple experiment to explore phantom pain. One of Ramachandran's patients complained that he was suffering from an excruciating cramping in his phantom arm. He felt that his phantom hand was clenched so tightly, he could feel his fingernails digging into his phantom palm. Ramachandran came up with an unusual treatment. He placed a mirror in a cardboard box and instructed the patient to place his existing hand inside the box, next to the mirror. When the patient looked down at the mirror, the reflection of his existing hand stood in as a visual replacement of his phantom limb. The patient was told to imagine that the reflection was in fact the lost limb, and to practice clenching and unclenching his hand while looking in the mirror.
To the patient's surprise — and Ramachandran's — the illusion worked. After two weeks, the patient's pain vanished, along with his perception of a phantom arm. Dr. Ramachandran was recently interviewed by NPR to explain mirror therapy.
Click here to listen to the interview (Courtesy of NPR).
Mirror Therapy is now being adopted by many doctors to combat phantom pain. It can also be used to aide people who have had a stroke and other types of pain conditions.
University of Manchester professors are taking this idea and are working on a virtual reality system for Phantom Limb Pain. The system uses specially developed software; off-the-shelf components including a standard PC and an Nvidia graphics card; and standard VR gear including a head-mounted display, a data glove, and electromagnetic trackers, said lecturer Steve Pettifer. So far, he noted, they haven’t built the system to work with a data sock for lower-limb amputees. Amputees put on the display and move the one arm they have, triggering a virtual 3D display of a torso that still has the missing limb. The image of the limb moves exactly the way the user is moving the real arm, Pettifer said. Technicians enhance the effect by configuring the system so that the body and clothing look like that of the user, he explained. This use of VR may work by dampening the brain signals to the missing limb that cause the Phantom Limb Pain, according to Murray. Five patients participated in limited tests for several months, and four reported less Phantom Limb Pain, saying they got longer relief after a greater number of sessions, said Murray. The researchers want to conduct further research with additional patients as time and money allow. For example, they want to determine whether treatment is more effective immediately following an amputation, what type of amputations the system is best for, whether treatments must be ongoing, or whether they eventually become unnecessary.
Expanding on this research, Dr. Laurel Buxbaum, with the Moss Rehabilitation Research Institute in Pennsylvania conducted research trials with patients who had lower limb amputations. Using similar Virtual Reality set ups, and a sock custom built to go over the amputated limb, she had participants play a number of games. Throughout the study, the participants all reported lower levels of Phantom Limb Pains and contracted feelings from the beginning of each session to the end and also the participants reported lower levels of Phantom Limb Pain at the onset of each new session. Over 23 months, 14 participants completed games using VR headsets and by the end most reported much lower levels of Phantom Limb Pain, while some reported no pain at all by completion of the sessions. As well, the project tracked the participants after the study to measure the long term effectiveness of VR therapy treatments for Phantom Limb Pains. Six months after treatments the overall the pain levels the participants were still much lower, some participants started to report that pain was beginning to increase but it was not near to the levels they were before the treatments.
Additionally, Dr. Thomas Rutledge of the University of California San Diego conducted a similar study around the same time. His study participants included 14 veterans who had amputations of either lower or upper limbs. In the study, participants wore commercially available VR headsets, connected to personnel computer similar to what a person may own, motion detectors that are wired to the system and a pedal stand that the participant used by operating with their non-amputated limb while their prosthesis was strapped to the other pedal. Then they would then participate in one of three environment settings depending on their limb that had been amputated. Before the therapy sessions, 9/14 participants reported instances of throbbing Phantom Limb Pains, after the sessions, 0/14 participants reported having throbbing Phantom Limb Pains. Additionally, other instance of phantom sensations decreased for the participants after the sessions. Overall only 1 participant reported any phantom sensations, that participant reported tingling sensations still existing, which before sessions was the second highest overall instance of phantom limb sensations with 4/14. The study did not include a prolonged post treatment contact with the participants though, so it is unknown if the positive effects remained for the participants after the session for any period of time.
At this time, more research still needs to be conducted with larger groups, one of the difficulties research are facing are lack of qualifying candidates located in a near enough geographical area to expand the sample size. As research further develops though, Dr. Buxbaum believes that people who experience Phantom Limb Pain could see much lower rates of pain and other sensations with a 5-6 week therapy session using Immersive Virtual Reality and then need to come in for booster sessions periodically as the pain begins to come back.
Web Sites of Interest
Recommended YouTube Videos
Phantoms of the Brain (Part One)
Visit YouTube for other sections of this BBC Special (search terms: Phantoms In The Brain)
Part Two
Disclaimer: The information listed does not represent an endorsement by AgrAbility in Georgia and is provided only as an introduction to the topic of Phantom Pain. Contact a physician prior to starting any type of health treatments.