A phantom limb is a complex phenomenon involving asensation that an amputated or a missing limb is still attached to the body.
Approximately60 to 80 % of individuals who have undergone amputations have reported thissensation. Phantom sensation is also observed in those who are born withoutlimbs and in those who are paralyzed.
The phantom limb feels shorter, distorted and, is often, painful. The pain occursintermittently, can be quite agonizing and is aggravated by stress, anxiety andby weather changes. The frequency of these painful attacks is usuallyameliorated with time.
Painis not reported by all the amputees, however, various types of phantom sensations,have been reported such as itches, twitching, tightness, burning, gesturing oreven as if they are picking up something. Phantom sensations also occur whenother body parts have been removed, such as breasts, tooth and eye.
Until recently, it was assumed that the irritation caused at thenerve endings, or the neuromas, of the amputated limbs was the reason behindphantom sensation.
During amputation, several nerve endings become terminated at theresidual part of the limb. It was once believed that these nerve endings sendthe wrong signal to the brain, which is interpreted as pain. Treatment based onthis assumption was never successful.
In some cases, when the pain was too severe, the surgeon wouldperform a second amputation to further remove the end of the amputated limb, inorder to provide temporary relief to the patient. However, in many, the painincreased after the second surgery and the phantom sensation doubled.
In the late1980s, Ronald Melzack proposed the theory of the ‘‘neuromatrix.’ Accordingto this theory, our body’s experience is created by a large network ofinterconnecting neural structures. In 1991, Tim Pons and colleagues at the NIHdemonstrated that sensory areas of the brain get substantially reorganized followingloss of sensory inputs.
All this information caught the attention of V.S. Ramachandran, whotheorized that phantom limb sensations could be the result of reorganization ofthe sensory areas of the brain, which receive inputs from all over the body,including the limbs. Ramachandran and colleagues proved this point throughan amazing illustration - while stroking various parts of the face, thepatient perceived that various parts of the missing limb was being touched.According to Ramachandran, this perception was because the brain cortex becamereorganized after the amputation.
In 2009, researchers Lorimer Moseley and Peter Bruggerexperimented with seven arm amputees who were encouraged to use visual imageryto contort their phantom limbs into various impossible configurations. Four ofthe seven patients succeeded in using their phantom limbs to achieve impossiblemovements. The study revealed that motor commands were modified to executethese movements. These experiments have put forth the fact that the brain is aplastic entity, and that the way we perceive our body parts can be changed bychanging the internal mechanisms of the brain.
In 2012, Karen Reilly and colleagues proposed that the movement ofphantom limbs is "real" and that they obeyed a motor command.
During thepast two decades, doctors have attempted to treat phantom limb pain with avariety of methods including antidepressants, spinal cord stimulation,hypnosis, acupuncture and biofeedback. Unfortunately, most methods have failedto bring about any constant relief.
One methodwhich was far more effective than the rest is the ‘mirror box’ developed by V.SRamachandran and colleagues. They carried out an experiment on a 57-year oldwoman who lost a hand in an accident when she was 18 yrs old. This womanexperienced phantom sensation in the amputated arm. Using a mirror box,Ramachandran super imposed the image of the normal hand onto the amputated armfor 30 minutes each day. After two weeks, the woman was able to move herphantom fingers, which she now perceived to be of normal length, and wastotally relieved of pain.
Of late, graded motorimagery, which employs mirror therapy and sensory discrimination training tothe affected individuals, has emerged as another promising tool for treatment.Further research is warranted to study the underlying mechanisms of the phantomdisease in order to generate better treatment options for this strangelydelusive but very “real” disorder.
Latest Publications and Research on Phantom Limb SyndromePhantom Sensations Following Brachial Plexus Nerve Block: A Case Report. - Published by PubMed
Reaffirming the link between chronic phantom limb pain and maintained missing hand representation. - Published by PubMed
MEG-BMI to Control Phantom Limb Pain. - Published by PubMed
Development of a Multimodal Analgesia Protocol for Perioperative Acute Pain Management for Lower Limb Amputation. - Published by PubMed
Exploring the Role of Cortical Reorganization in Postamputation Phantom Phenomena, Including Phantom Limb Pain in Lower Limb Amputees: A Cross-Sectional Study of the Patterns of Referral of Sensations into the Phantom. - Published by PubMed