Phantom Limbs

An animation of a hand fading in and fading out.

Written by Nadia Siddique
Illustrated by Rebecca Michaels-Walker

We all take our limbs for granted. They allow us to perform many tasks, from hugging our friends and playing our favourite sports to flipping the pages of a book. But when you lose a limb, your brain may keenly feel its absence, and even deny it altogether. You may even experience sensations – both painful and nonpainful – as if the limb is still there. This phenomenon is known as Phantom Limb Syndrome.

Perhaps the most chilling aspect of Phantom Limb Syndrome is that the sensations experienced can be strikingly vivid. Sometimes, the phantom limb can feel “more real” than the existing limb, especially in the presence of pain. This pain is often more intense than a simple “pins and needles” sensation, and can be sharp, burning, and impossible to ignore. Amputees with phantom limbs can also experience sensations that mimic those they felt before the amputation!

So what’s the physiological mechanism behind Phantom Limb Syndrome? Many different theories have been proposed to explain it, from nerve cells generating impulses in the stump (where the absent limb used to begin) to excessive neuron firing in the spinal cord, both of which can result in “phantom” sensations. However, there isn’t a single theory that fully describes this phenomenon, as the brain and its neural representations of the body are not fully understood. Furthermore, we still cannot explain why some amputees escape Phantom Limb Syndrome, or why some people born without limbs can still experience these apparitions.

In some instances, Phantom Limb Syndrome can resolve on its own, but in other cases it causes debilitating chronic pain that must be treated with drugs, surgery, or other treatments such as shock therapy. One of the most promising treatments is mirror box therapy, where the brain is tricked into “seeing” the phantom limb, which is actually just a mirror image of the intact limb. The patient can therefore train themselves to “move” the phantom limb, and relieve its associated pain. While this solution is already quite innovative, scientists are now aiming to take it a step further by treating Phantom Limb Syndrome through virtual reality therapy!

Although it can negatively impact many lives, Phantom Limb Syndrome isn’t all bad news. Having some sensation in a missing limb can help amputees better adjust to prosthetics and can allow them to move the device much more intuitively, as if the prosthetic is actually the limb itself!

Overall, Phantom Limb Syndrome is a good example of how our experience of the world largely depends on our brains rather than reality itself.

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