The relationship between phantom limbs and virtual reality
Technology is moving forward so quickly that it is impossible to predict what new applications will be developed. And some of the most interesting developments are in the field of health and wellness, including some unexpected uses of virtual reality or ‘VR’.
Many of us have had the sensation of a limb ‘going to sleep’ and feeling as if it isn’t really ours until the numbness fades. Thanks to the way we’ve evolved our brains can be tricked by certain sensations, and become fundamentally confused about what is happening with our body.
Phantom limb syndrome
A particularly strange example is ‘phantom limb syndrome’. This occurs when someone loses a body part (for example a foot that must be amputated due to the ravages of diabetes), but the brain ‘thinks’ that the body part is still there.
For all intents and purposes the affected person will still feel as if the missing body part remains attached. And this is remarkably common. Over 40% of amputees report that they experience feelings from their removed body part.
This might be a peculiar sensation for them, but it can actually be very useful. Research has concluded that having a ‘phantom limb’ is crucial if one wishes to learn how to use a prosthetic replacement. After all: the brain still thinks the limb is there, so it interprets any new feelings (whatever they might be) as being part of the missing limb. Learning to use the artificial body part becomes all the easier with the brain’s eager cooperation.
These ‘phantom’ removed parts can even feel itchy, or cold.
And they can experience pain, even unbearable pain.
This is the downside of phantom limb syndrome: ‘phantom limb pain’ or PLP.
Imagine that you are in a car accident where your hand becomes trapped in the wreckage, and badly damaged. Making the decision to have the hand removed will be difficult. But one can at least console oneself that the pain will soon be over.
But what would you do if the pain persisted, even once the hand was gone? A man in England recently attempted to end decades of pain by amputating his own hand using a homemade guillotine. Afterwards he found to his dismay that his hand was still hurting.
It is very difficult to heal a wounded limb when the limb is entirely imaginary.
Previous approaches to treating PLP involved tricking the brain using mirrors, and they have had some success. But a more advanced approach is currently being developed.
Using virtual reality to treat phantom limb pain
In this approach the patient puts on a VR headset and is exposed to a lifelike representation of the world, including the existence of their missing limb.
To appreciate why this might work to alleviate pain one needs to understand why the brain still thinks the missing limb is in distress in the first place. The briefest explanation is that before the limb was removed the brain felt that it was in pain. Once the limb was gone the brain, obviously, could not receive any additional information from it.
So the brain ‘thinks’ the limb is still in pain and will remain so, forever. In essence the brain is confused about what’s happening with the limb.
And the VR resolves the confusion.
It shows the brain that the limb is still there and is doing fine. With the confusion resolved the pain receptors quiet down.
This might seem like a wholly bizarre form of treatment but it actually does work. A recent study in China on three patients with PLP found that the VR treatment reduced the pain for one of the participants and completely removed it for two others.
Virtual reality may be enjoying a recent resurgence as a form of entertainment. But it is also providing relief to sufferers of PLP.
And there is no telling what other amazing advances in healthcare will come out of the explosive growth of new technology.