View clinical trials related to Chronic Pain, Psychogenic.
Filter by:Pain is a nociceptive somatosensory process that can arise as a debilitating and chronic symptom in various diseases or following an injury. How pain is experienced can vary widely within and across individuals, and can be shaped by cognitive processes such as learning. Nocebo effects, negative changes in symptom severity attributed to learned outcome-expectations, demonstrate how learning processes can be detrimental for the experience of pain. Research to date has produced inconclusive findings regarding the electrophysiological correlates on nocebo effects. The few studies that have applied electroencephalography (EEG) in this field have pointed towards a potential involvement of alpha-band activity, but the direction of this involvement remains unclear. For example, an EEG study of conditioned nocebo hyperalgesia found a pre to post increase in resting state alpha band power that was correlated with pain catastrophizing scores and not with the magnitude of the nocebo effect. Later, other studies also found pre to post changes in alpha band power, however, these changes were correlated with the magnitude of nocebo effects and not pain catastrophizing. Given the discrepancy in findings, in this study the investigators plan to primarily investigate whether EEG components predict the magnitude of nocebo responses to thermal-pain stimuli. The investigators will also explore electrophysiological correlates during pain anticipation and whether nocebo responses would be significantly related to spectral and temporal EEG biomarkers. This study will utilize a validated model of instructional and associative learning methods (i.e., negative suggestions and classical conditioning, respectively) to experimentally induce nocebo effects on heat-evoked pain. Developing objective, brain-derived markers for nocebo responses, or the detection of individuals most susceptible to nocebo hyperalgesia, will aid in the comprehensive management of pain. This study is conducted at Leiden University.
Nocebo hyperalgesia is characterized by adverse pain outcomes, induced by patients' expectations. In the lab, nocebo effects are commonly studied via classical conditioning, a method that employs pairings of neutral cues/treatments with different pain intensities to install differential pain-related expectations. In such conditioning experiments, participants are typically taught that a (sham) treatment exaggerates their pain, by surreptitiously administering high intensity (e.g. pain) stimuli in combination with this treatment. Verbal suggestions are also often used to inform participants of the supposed adverse effects of such treatments. In nocebo studies, higher pain levels and suggestions that are of more threatening nature may induce fear, thereby adding a crucial element to the experimental manipulation. Since nocebo effects are hypothesized to arise in clinical settings due to a combination of several psychological and cognitive mechanisms, it is important to study the role that factors such as higher pain levels, conditioned pain-related fear, or more threatening verbal suggestions may play in the formation of nocebo hyperalgesia. To date, no studies have focused on the fear-inducing effect that different pain intensities or verbal threat suggestions may have and how this fear, in turn, may strengthen the acquisition of nocebo effects. This study aims to investigate whether higher pain intensity or higher pain-related fear induced via threatening suggestions facilitate the acquisition and hinder subsequent extinction of nocebo hyperalgesia. This study will be conducted at Leiden University.