Using virtual reality to misrepresent how far the neck is turned can change pain experiences in individuals who suffer from chronic neck pain, according to new research.
Findings from the study were published Feb. 17 on the website of Psychological Science, a journal of the Association for Psychological Science.
It might seem like a person’s experiences of pain stem from some objective, physiological source, but research has shown many factors — including sensory, cognitive and emotional cues — can have a significant influence on if, when and how someone feels pain. These new results suggest altering the visual cues that inform the brain about the body can affect pain.
“Our findings show that the brain does not need danger messages coming from the tissues of the body in order to generate pain in that body part — sensable and reliable cues that predict impending pain are enough to produce the experience of pain,” physiotherapist and researcher G. Lorimer Moseley, PhD, of the University of South Australia said in a news release. “These results suggest a new approach to developing treatments for pain that are based on separating the nondanger messages from the danger messages associated with a movement.”
For the study, Moseley, co-author Daniel S. Harvie and colleagues recruited 24 chronic neck pain sufferers from physiotherapy clinics. The participants had experienced the pain for an average of 11 years, and their pain was stemming from issues including posture, tension, repeated strain, trauma and scoliosis.
The researchers had participants sit in a chair while wearing a virtual reality head-mounted display called Oculus Rift. The display showed a virtual indoor or outdoor scene while simultaneously recording participants’ head movements using gyroscopes. The participants wore seat belts that prevented them from moving their torsos, and they also wore headphones that blocked out incidental noise.
For each scene that was presented on the VR display, the participants were asked to rotate their heads, either to the left or to the right, until they experienced pain. The participants were unaware that for some trials, the researchers were manipulating the visual feedback so it didn’t accurately represent the degree to which the head was turned. In some cases, it looked to the participants as if they weren’t turning their heads as far as they actually were — it understated the degree of rotation. In other cases, the visual feedback indicated to participants they were turning their heads farther than they were, overstating the degree of rotation.
Results showed the visual feedback played an important role in determining when the participants reported feeling pain.
When the display understated actual head rotation, participants had a broader range of pain-free motion; they were able to turn their heads about 6% farther than they normally would. But when the display overstated head rotation, their pain-free range of motion shrank by an average of 7%.
The participants didn’t report any differences in the intensity of pain across the various conditions.
“We were surprised at how robust and predictable this pattern of results was,” Moseley said in the release. While previous research has indicated external cues can influence the intensity of pain experiences, results from the new study show external cues also can shift the physical point at which pain is experienced.
According to the study authors, these findings, though experimental, could have implications for the clinical treatment of pain. If the external cues do trigger or affect pain, then the cues could be a target for therapy.