E. Dixon

Contributions of Physical Function and Satisfaction with Social Roles to Emotional Distress in Chronic Pain: A Collaborative Health Outcomes Information Registry (CHOIR) Study

Abstract Individuals with chronic pain show greater vulnerability to depression or anger than those without chronic pain, and also show greater interpersonal difficulties and physical disability. The present study examined data from 675 individuals with chronic pain during their initial visits to a tertiary care pain clinic using assessments from Stanford Universitys Collaborative Health Outcomes Information Registry (CHOIR). Using a path modeling analysis, the mediating roles of Patient-Reported Outcomes Measurement Information Systems (PROMIS) Physical Function and PROMIS Satisfaction with Social Roles and Activities were tested between pain intensity and PROMIS Depression and Anger. Pain intensity significantly predicted both depression and anger, and both physical function and satisfaction with social roles mediated these relationships when modeled in separate 1-mediator models. Notably, however, when modeled together, ratings of satisfaction with social roles mediated the relationship between physical function and both anger and depression. Our results suggest that the process by which chronic pain disrupts emotional well-being involves both physical function and disrupted social functioning. However, the more salient factor in determining pain-related emotional distress seems to be disruption of social relationships, than global physical impairment. These results highlight the particular importance of social factors to pain-related distress, and highlight social functioning as an important target for clinical intervention in chronic pain.

Development of the Sensory Hypersensitivity Scale (SHS): a self-report tool for assessing sensitivity to sensory stimuli

Sensory hypersensitivity is one manifestation of the central sensitization that may underlie conditions such as fibromyalgia and chronic fatigue syndrome. We conducted five studies designed to develop and validate the Sensory Hypersensitive Scale (SHS); a 25-item self-report measure of sensory hypersensitivity. The SHS assesses both general sensitivity and modality-specific sensitivity (e.g. touch, taste, and hearing). 1202 participants (157 individuals with chronic pain) completed the SHS, which demonstrated an adequate overall internal reliability (Cronbach’s alpha) of 0.81, suggesting the tool can be used as a cross-modality assessment of sensitivity. SHS scores demonstrated only modest correlations (Pearson’s r) with depressive symptoms (0.19) and anxiety (0.28), suggesting a low level of overlap with psychiatric complaints. Overall SHS scores showed significant but relatively modest correlations (Pearson’s r) with three measures of sensory testing: cold pain tolerance (−0.34); heat pain tolerance (−0.285); heat pain threshold (−0.271). Women reported significantly higher scores on the SHS than did men, although gender-based differences were small. In a chronic pain sample, individuals with fibromyalgia syndrome demonstrated significantly higher SHS scores than did individuals with osteoarthritis or back pain. The SHS appears suitable as a screening measure for sensory hypersensitivity, though additional research is warranted to determine its suitability as a proxy for central sensitization.

Dynamic Quantitative Sensory Testing to Characterize Central Pain Processing

Central facilitation and modulation of incoming nociceptive signals play an important role in the perception of pain. Disruption in central pain processing is present in many chronic pain conditions and can influence responses to specific therapies. Thus, the ability to precisely describe the state of central pain processing has profound clinical significance in both prognosis and prediction. Because it is not practical to record neuronal firings directly in the human spinal cord, surrogate behavior tests become an important tool to assess the state of central pain processing. Dynamic QST is one such test, and can probe both the ascending facilitation and descending modulation of incoming nociceptive signals via TS and CPM, respectively. Due to the large between-individual variability in the sensitivity to noxious signals, standardized TS and CPM tests may not yield any meaningful data in up to 50% of the population due to floor or ceiling effects. We present methodologies to individualize TS and CPM so we can capture these measures in a broader range of individuals than previously possible. We have used these methods successfully in several studies at the lab, and data from one ongoing study will be presented to demonstrate feasibility and potential applications of the methods.