This study aims to investigate neurophysiological differences that might exist between cases of chronic fatigue syndrome (CFS) that demonstrate central sensitization as compared to healthy volunteer controls that do not demonstrate central sensitization. To this end, up to 20 participants will be recruited to each group, who will undergo quantitative sensory testing to assess for the presence of central sensitisation (non-sensitised CFS cases and sensitized healthy controls will be excluded). All participants will be screened for major psychiatric disorder by structured clinical interview and for psychophysical variables by questionnaire. They will be further genetically screened for the COMT met/val haplotype that is known to be involved in pain perception and the metabolism of the brain chemicals of interest. Participants will subsequently undergo functional neuroimaging that combines functional MRI scans (fMRI) with amisulpride (a drug affecting dopamine in the brain), naltrexone (a drug affecting the opioids in the brain) or an inactive tablet (that has no chemical effect on the brain). During each scan, participants will be subjected to ‘moderate pain’ (a level of pain determined on an individual basis) by way of a device attached to their thumbnail.
This approach will allow us to compare the responses of dopamine and the opioids to acute pain between cases of CFS demonstrating central sensitisation and healthy, non-centrally sensitized, controls.
Dr Julius Bourke
Tel: +44 20 346 57232