Abnormal Central Pain Processing in Painful Diabetic Neuropathy: A Functional Magnetic Resonance Imaging Study
Abstract Number: 114-OR
Authors: DINESH SELVARAJAH, ADITHYA SANKAR, JENNIFER DAVIES, ELAINE CACHIA, MIKE HUNTER, IRENE TRACEY, IAIN D. WILKINSON, SOLOMON TESFAYE
Institutions: Sheffield, United Kingdom, Oxford, United Kingdom
Results: Painful diabetic neuropathy (DN) is a distressing diabetic complication associated with a high degree of suffering. Using functional magnetic resonance imaging (fMRI) we sought to investigate regional brain activation during pain processing.
Methods 15 painful-DN and 12 healthy volunteers (HV) underwent neurophysiological assessment. DN subjects had neuropathic pain below the knees. Mood disorders were assessed using the Hospital Anxiety and Depression Scale (HADS). All subjects underwent box car fMRI whilst heat pain was applied to the anterior thigh (non-neuropathic region) at a pain level of at least 7 on an 11-point Likert scale. Images were analysed using SPM5.
Results In painful-DN, there was significantly (p<0.001, uncorrected) greater activation in the ventromedial prefrontal cortex (Brodmann's area (BA) 9, stereotactic coordinates: x=28, y=34, z=24; peak t=3.15; Figure 1B) and cingulate gyrus (-8,2,30;3.09; Figure 1A) compared with HV. Subjects with painful DN were then divided into two groups based on HADS-D. Painful-DN subjects with depression (HADS-D>8,n=9) had significantly greater activation (p<0.001, uncorrected) in the prefrontal cortex (BA 9, 8,46,52;3.72) compared with those without (HADS-D<8,n=6).
Discussion BA9 and the cingulate gyrus are involved in emotional pain processing. Increased activation in these regions suggests a greater perception of suffering in painful-DN. Increased activation in BA9 in subjects with depressive symptoms suggests a neurocortical link between mood disorders and abnormal acute pain processing. Using this novel technique, we are gaining new insights into brain regions involved in abnormal pain processing which maybe amenable to targeted treatments.[figure1]