Jayney's Blog

A small study by scientist from Imperial College London has revealed that increased sensitivity to pain can be combatted by using virtual reality headsets. By immersing people in Arctic scenes of icebergs, cold oceans, and sprawling icescapes, participants’ ongoing pain scores reduced alongside their sensitivity to painful stimuli.

The researchers believe that the results of this study contribute to growing evidence that VR technology may be able to be used to help manage chronic pain.

They believe that the VR not only distracts the patient, but that it may trigger the body’s pain-fighting systems, therefore reducing the sensitivity to painful stimuli as well as reducing the intensity of ongoing pain.  

Dr Sam Hughes, from the MSk Lab at Imperial and first author on the paper, said: “One of the key features of chronic pain is you get increased sensitivity to painful stimuli. This means patients’ nerves are constantly ‘firing’ and telling their brain they are in a heightened state of pain. Our work suggests that VR may be interfering with processes in the brain, brainstem and spinal cord, which are known to be key parts of our inbuilt pain-fighting systems and are instrumental in regulating the spread of increased sensitivity to pain.”

VR has previously been trialled as a distracting method from pain, and has been used with some success in minor dental procedures requiring local anaesthetic. However, this latest study investigated to see whether it could work in a simulated model of chronic pain.

The trial involved 15 healthy volunteers who had a topical cream applied to their leg. The cream contained capsaicin – this is the compound found in chilis that makes your mouth burn. The capsaicin made the skin more sensitive to painful stimuli, which mimicked the heightened sensitivity of people with chronic pain.

The participants were asked to rate the pain caused by the cream on a scale of 0-100 (from ‘no sensation’ to ‘worst pain imaginable’) while they either watched a VR scene of arctic exploration through a headset, or looked at a still image of an arctic scene. A very small electric shock was also applied to the area, and participants were asked to rate the painful stimulus.

The results showed that both ongoing pain and sensitivity to painful stimuli was reduced following VR immersion, but the same effect was not seen in people who looked at the still image.

The researchers explained that although these findings are encouraging, the study is still very limited due to the small number of participants who did not have chronic pain. To confirm benefits, further randomised controlled trials with chronic pain patients will be necessary.

Despite the limitations, the researchers believe that VR could provide an alternative therapy for some chronic pain conditions by improving activity in the brain areas that are involved in the inbuilt pain relief systems.

The team plans to perform more research on the pathways involved in the VR dampening effect, and whether a dosing regimen would work – for example 30 minutes, four times a day – and whether the effects would be cumulative or temporary.

“The aim of this study was to show VR has the ability to change the pathological processing associated with chronic pain,” added Dr Hughes. “Using this approach does seem to reduce the overall intensity of the ongoing pain as well as the response we get on the skin. We think there could be changes in the body’s pain relief system’s which can affect how pain sensitivity is processed in the spinal cord.”

He added: “There are still many things to figure out, but one exciting aspect of our study is that the VR design we used is completely passive — meaning patients don’t need to use their arms. Potentially, it could mean that patients who are bed-bound or can’t move their limbs, but with chronic pain, could still benefit from this approach.”

Sam W. Hughes, Hongyan Zhao, Edouard J. Auvinet, Paul H. Strutton. Attenuation of capsaicin-induced ongoing pain and secondary hyperalgesia during exposure to an immersive virtual reality environment. PAIN Reports, 2019; 1 DOI: 10.1097/PR9.0000000000000790

https://www.sciencedaily.com/releases/2019/11/191108074900.htm