Measuring the impact of central processing on painful diabetic neuropathy

Summary

Severe and chronic pain is a common symptom of diabetes, affecting approximately 40% of patients with nerve damage. The type of pain experienced by patients is difficult to treat, and leads to extremely poor quality of life for sufferers. However, it is not clear why some people with diabetes suffer from long lasting pain and others do not. Indeed, patients with a similar medical history of diabetes and apparently identical amounts of nerve damage can have very different amounts of pain. One possible explanation for this difference is that the brain interprets the signals produced by the damaged nerves differently. In particular, regions in the brain and brainstem that normally work together to help suppress incoming nerve signals (relating to pain) may actually end up promoting painful sensations. In this project we will recruit patients with similar degree of diabetes and nerve damage, of which half will suffer painful symptoms and the other half will be pain free. We will then test the ability of the brain and brainstem to suppress incoming pain signals, by delivering a mildly painful hot stimulus to a part of the body not directly affected by the disease e.g. the arm. To do this we will use a combination of simple experiments to test pain sensitivity, and by a functional imaging brain scan, to "look" directly at the brain areas of interest. If we find differences between patients, we can then explore whether drugs, or other interventions e.g. pain coping strategies, that act on these brain centres could be employed to help reduce patients' pain.