Diseases and Disorders

A Peculiar Disorder: Phantom Limb Syndrome

Divya Venkataraman


Abstract

It was the month of July 1886 when “The Case of George Dedlow” had been published. Due to unfortunate events in the Civil War, Dedlow had lost both his arms and legs. The ultimate phenomenon was when Dedlow complained of experiencing clenching and burning in the area where his limbs would have been. Dedlow recounts, “I had begun to suffer the most acute pain in my left hand, especially the little finger; and so perfect was the idea which was thus kept up of the real presence of these missing parts, that I found it hard at times to believe them absent.” Unfortunately, this syndrome was discovered by Ambroise Paré in 1552, through the study of the treatment of wounded soldiers (like Dedlow), and it did not gain recognition until Silas Weir Mitchell named the syndrome years later in 1871 [9]. He decided to name it ‘Phantom Limb Syndrome,’ due to the presence of the ‘ghost’ of a body part [6]. The peculiar Phantom Limb Syndrome, which affects 7 out of 10 people who undergo amputation, is when a patient feels like an amputated limb is still attached to the body. Severe cases of the Phantom Limb Syndrome cause chronic pain, which unfortunately drives some patients to commit suicide [7].
 

Causes and Risk Factors

Muscle movement is triggered by signals from the brain, especially the motor cortex and the cerebellum. However, whenever this relay network (brain, spinal cord, nerves: peripheral nerve, or joints) is damaged, the signals are unable to pass, and this prohibits muscle movement. While environmental conditions are more common causes of paralysis (such as accidents during war), genetic factors do influence this as well. In fact, birth defects, such as Spina Bifida, often cause paralysis in newborns. Additionally, gender or race does not affect paralysis nor Phantom Limb Syndrome in any way [2].

Although the exact causes of a paralyzed limb becoming a phantom limb are unclear, Dr. V.S. Ramachandran, a neurologist and professor at the University of California, San Diego, studying neurological mechanisms, explained this theory: After the limb has been amputated, since the signals have nowhere else to go, the brain remaps the pathways, with the help of many proteins. The remapping is due to confusion in the brain and the spinal cord. These new pathways are then redirected towards another body part with another sensory circuit to transmit the signal. So, when this new body part is touched, it is almost as if the amputated limb was touched, due to the tangled wires. Since the brain doesn’t know how to act when this happens, the resulting response is pain [3]. Dr. Ramachandran proved this using a simple experiment. Blindfolded patients with Phantom Limb Syndrome were touched at various parts of their bodies, and they were asked to report whenever they felt pain in their phantom limb. Just like the hypothesis stated, when the face on the same side of the amputated limb was touched, patients reported pain in the phantom limb [7]. This articulates that the brain had remapped its nerves to react to a stimulus touching the face rather than the amputated limb.

Dr. Ramachandran also explained another possible cause of this syndrome: learned paralysis. This refers to patients who had to get their limb amputated due to prior paralysis. When the limb, before the amputation, was intact, but paralyzed, the brain tried to send commands to the limb, saying ‘move’. However, the only visual feedback the brain received said ‘no’. After multiple repetitions of the same thing, this new pattern gets wired into the brain, causing the learned paralysis. The brain learns this new Hebbian (associative) link, so much so that the command to move the limb causes the later amputated limb to create the sensation of the paralyzed limb [8].

There are two primary risk factors for Phantom Limb Syndrome. First, when a patient shows signs of pain before amputation, they are most likely to experience pain afterward as well. This can also be explained by learned paralysis. The second risk factor is residual limb pain. Usually, if the patient experiences pain in the remaining part of the amputated limb, they are at a higher risk of Phantom Limb Syndrome, since residual limb pain usually represents damaged nerve endings or abnormal growth [3].

 

Symptoms

The first type of symptom a patient may experience are non-painful sensations. This will typically cause the patient to experience movement, contact, temperature change, or itchiness in the once amputated, now phantom, limb [5]. The brain, brain lobes, and nervous system play huge roles in these symptoms since the brain becomes very puzzled when sending a nerve signal to the amputated limb to do a specific function. Why? Since the limb is no longer attached to the body, the lobe in charge of the function doesn't respond. So, the only reaction the brain knows to give is pain [3].

However, patients more frequently experience the second type of symptom, painful sensations, named Phantom Limb Pain. This may cause patients to feel sharp and tingling pain in the area where the once amputated limb was. The pain tends to be excruciating, and patients have described the pain like tons of needles being pushed through the amputated area, shooting, stabbing, cramping, crushing, throbbing, or burning sensations [5]. This pain is primarily caused by the brain and spinal cord’s confusion after being forced to remap nerves that should have travelled to the amputated limb, to a new body part. While the pain for a few patients may come and go, many patients experience continuous pain, usually in the part of the limb that is the farthest from the body. For example, one would experience pain from the foot of their amputated leg, as shown in Figure 2 [3]. This excruciating pain that is experienced has horrible effects on a patient’s lifestyle, disabling them from doing many things that need limbs. As mentioned before, patients can even be driven to self-harm and suicide due to their inability to live with this unsourced pain.

 

Diagnosis

Although there is no official medical test to diagnose this peculiar syndrome, doctors can identify whether the patient has the syndrome based on their symptoms and prior circumstances. However, to do so, patients must precisely describe the pain they experience, to heighten the level of accuracy of the diagnosis, which could deeply affect the treatment they receive [7].

A few characteristics doctors use to help diagnose this syndrome are the symptoms experienced and the prior circumstances of the patient. The symptoms patients experience is the most straightforward way to characterize Phantom Limb Syndrome since doctors primarily look out for the symptoms described above. However, the patient's condition before the amputation is a more complex contributor to diagnose this syndrome. Since, as described above, there are two potential causes of this syndrome, doctors can narrow their symptom search if they know the circumstance of the patient before the amputation [7]. Since not much is known about this syndrome, these are the main methods of diagnosing Phantom Limb Syndrome. Another possible complication to the diagnosis would be the varying levels of pain experienced with this syndrome, since some patients experience intermittent pain, whereas others experience continuous pain.

 

Treatment and Ethical Views

There are many therapeutic treatments for Phantom Limb Syndrome. Some are pharma-therapeutic, including drugs such as gabapentin, tricyclic antidepressants, ketamine, amitriptyline, etc.. Others are non-pharmacological, like repetitive transcranial magnetic stimulation (not an approved treatment yet, but it sends pulses to specific nerve clusters) [3], spinal cord stimulation, acupuncture (eases pain) [3], hypnosis, and more. However, although these treatments work, they may not necessarily be the most economically efficient or financially viable.[1].

Dr. Ramachandran has recently experimented with a new treatment, called Mirror Therapy. Although it is more recent than most of the treatments mentioned above, it has potential in the neuroscience and medical fields. Dr. Ramachandran first started brainstorming this idea after he realized that Phantom Limb Syndrome has more connections to the brain than previously thought. Based on the causes mentioned above, he realized that to effectively treat this syndrome, he must trick the brain into unlearning the association between pain and phantom limbs. Unlike the expensive treatments mentioned in the first paragraph, Dr. Ramachandran used a $5 mirror box. This box was set on a table that was parallel to the patient’s face. The patient struggling from chronic Phantom Limb Syndrome was instructed to place his amputated arm on the non-reflective side of the mirror, and his normal arm on the reflecting side of the mirror (as shown in Figure 3). Although, when looking at the reflective side of the mirror, one would only see the reflection of the normal arm, the patient believed that reflection to be the phantom arm and thought that their phantom arm had returned! Once this occurred, Dr. Ramachandran instructed the patient to move their normal arm. The patient then saw the mirror reflection of their normal hand, thought to be the phantom hand, moving. This command had been sent to the phantom arm, which then caused the visual illusion that the phantom limb is moving, obeying the brain’s command. This then tricks the brain into thinking that the phantom limb is not paralyzed anymore, which stops the brain’s confusion, causing no more pain signals to be sent. This may be hard to believe at first, but since patients typically don’t suffer from delusions, they do know that their phantom limb has actually not returned. Then why does it still work? Well, the visual illusion is still enough to allow them to trick their own brains into subconsciously thinking that the phantom limb has returned, stopping the brain’s confusion, hence stopping the excruciating and suicide-driving pain [7].

Fortunately, there aren’t many ethical issues surrounding Phantom Limb Syndrome, however this can be attributed to the fact that very few people know that this syndrome even exists! However, there are a few issues surrounding this peculiar syndrome. Way back when, when Ambroise Paré first discovered this syndrome in 1552, doctors would not believe that this was true, and usually sent the patients to a psychiatry ward. Although many doctors and researchers now know better, much of the population who has heard of this syndrome and who aren’t educated about the science behind it, still believe this syndrome to be ‘crazy’ and ‘impossible’ [6]. This is why scientists such as Dr. Ramachandran are trying to educate the public on the Phantom Limb Syndrome, and how it is actually a serious and debilitating  chronic.

 

Discussion

The most recent research surrounding Phantom Limb Syndrome has been Dr. Ramachandran’s breakthrough work with the mirror box, providing a feasible, efficient, and economically stable solution to patients who may suffer from this syndrome. Mirror therapy is an effective treatment for this unfortunate syndrome and is helping several patients even as you are reading this. The primary issue with mirror therapy (in 2016) was that, unlike other treatments mentioned, it had not undergone as much testing as needed to assess its accuracy, prohibiting it from becoming a first intention treatment for the syndrome [1]. However, as of this writing, more testing has been done. Since this new treatment is not only beneficial for patient health but also is helpful in financial aspects and monetary cost, there aren’t many societal or ethical issues about the treatment. Besides this new treatment, Dr. Ramachandran has also written various books, including The Tell-Tale Brain, which has gained exposure for this peculiar syndrome called Phantom Limb Syndrome, a disorder that was not very well known nor perceived in the past, but is slowly gaining proper recognition [7]. So, if we were to travel back in time to the civil war, when George Dedlow lost his limbs, we can hopefully help with this newly discovered mirror therapy, saving his, and many others’, lives.


References


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  2. Clinic, C. (2017, April 21). Paralysis: Causes, Symptoms, Diagnosis & Treatment. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/15345-paralysis. Retrieved: 7/12/20.

  3. Clinic, M. (2018, October 30). Phantom pain. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/phantom-pain/symptoms-causes/syc-20376272. Retrieved: 7/03/20.

  4. Flor, H., Nikolajsen, L., & Jensen, T. S. (2006, November 1). Phantom limb pain: a case of maladaptive CNS plasticity?https://www.nature.com/articles/nrn1991. Retrieved: 7/8/20.

  5. Neuropathy, M. P. (2017, January 10). Phantom Limb Syndrome: Marlton Peripheral Neuropathy: Elite Neuropathy and Chronic Conditions of South Jersey. Marlton Peripheral Neuropathy | Elite Neuropathy and Chronic Conditions of South Jersey. https://www.ihatemypain.com/conditions/phantom-limb-syndrome/. Retrieved: 7/11/20.

  6. Puglionesi, A. (2017, November 8). The Civil War Doctor Who Proved Phantom Limb Pain Was Real. https://www.history.com/news/the-civil-war-doctor-who-proved-phantom-limb-pain-was-real. Retrieved: 7/12/20.

  7. Ramachandran, V. S. (2007, March). 3 clues to understanding your brain. TED. https://www.ted.com/talks/vs_ramachandran_3_clues_to_understanding_your_brain. Retrieved: 7/07/20.

  8. Ramachandran, V. S. (2011, February 14). V.S. Ramachandran's Tales Of The 'Tell-Tale Brain'. NPR. https://www.npr.org/2011/02/14/133026897/v-s-ramachandrans-tales-of-the-tell-tale-brain. Retrieved: 7/12/20.

  9. Rugnetta, M. (2020, July 3). Phantom limb syndrome. Encyclopædia Britannica. http://www.britannica.com/science/phantom-limb-syndrome. Retrieved: 7/07/20

  10. Staff, S. X. (2018, September 6). A new theory for phantom limb pain points the way to more effective treatment. https://medicalxpress.com/news/2018-09-theory-phantom-limb-pain-effective].html. Retrieved: 7/12/20.

Divya Venkataraman

Divya Venkataraman


Divya is a high school sophomore in Monta Vista High School. She has always been incredibly fascinated with biology, neuroscience, and psychology. Her passion lies in research and medicine, and she is especially interested in neurological/neurodegenerative diseases. She enjoys making a positive impact in the world around her, whether it be through research, public speaking, tutoring, leading organizations, or advocating for mental health. In her free time, Divya loves to play the piano, dance, and read!