Thread by @JanetBultitude

Very pleased to share my first research paper in collaboration with Dr Karin Petrini, my @BathPsychology colleague. Free to download to the first 50 people if yo use this link (which doesn't work on chrome for some reason) authors.elsevier.com/a/1bqj0brwf8Y4d

One theory is that some conditions of unexplained pain happen because of conflict between sensory signals received in the brain and signals for movement or intended movement that are generated in the brain.

This 'sensorimotor incongruence' theory is supported by evidence that when you use illusions to induce this kind of conflict, pain increases. In fact, even people without chronic pain report unusual sensations when they are exposed to this kind of illusion.

What hasn't been extensively tested is whether there is any evidence that people with certain chronic pain conditions combine sensory and motor information differently to people without chronic pain. This is what we tested.

We flashed points of light on the surface of a table and tested how accurately people with or without #CRPS could keep track of the locations of these flashes. They did this using vision alone, using movement alone, and using both vision and movement together.

We expect that everyone would be worse at doing this task when they used vision or movement alone. But pain-free people normally will be better at this when they can use both vision and movement, indicating that they benefit from using both cues at the same time.

We found that people with #CRPS performed normally when they located the flashes that appeared in the unaffected side of space using the hand of the unaffected side of the body.

However, when the task involved the affected side of space and/or the body, they performed differently to controls.

The differences between the people with #crps and the control group were a bit complex: in one condition they even performed better than controls, which suggests that maybe the people with pain make use of additional information to compensate for their difficulties.

Overall, what is striking is that the people with #CRPS COULD use both vision and movement together, even when using their painful limbs. However, they appear to do this in different ways to the people without chronic pain.

This is interesting, because both movement and perception of limb location is often impaired in people with CRPS. So despite this degraded information, they were still able to use it together with visual information.

The differences between people with and without CRPS suggest that people with CRPS use different strategies.

We think that our results mean that it might be possible to take advantage of this intact cue combination to come up with new therapies.

/end

PS. Our results also call into question the sensorimotor incongruence theory, at least as an explanation for #CRPS, because we show that people are able to use to sources of information to improve their performance, even when one type (movement) is degraded.