Human Studies

The majority of individuals with spinal cord injury (SCI) experience chronic pain. Chronic pain can be difficult to manage because of variability in the underlying pain mechanisms. More insight regarding the relationship between pain and physical activity (PA) is necessary to understand pain responses during PA. The objective of this study is to explore possible relationships between PA levels and secondary conditions including pain and fatigue. Prospective cohort analysis of a pilot study. Community. Twenty individuals with SCI took part in the study, and sixteen completed the study. Mobile-health (mHealth) based PA intervention for two-months during the three-month study. Chronic Pain Grade Scale (CPGS) questionnaire, The Wheelchair User's Shoulder Pain Index (WUSPI), Fatigue Severity Scale (FSS), and PA levels measured by the mHealth system. A positive linear relationship was found between light-intensity PA and task-specific pain. However, the relationship between moderate-intensity PA and pain interference was best represented by a curvilinear relationship (polynomial regression of second order). Light-intensity PA showed positive, linear correlation with fatigue at baseline. Moderate-intensity PA was not associated with fatigue during any phase of the study. Our results indicated that PA was associated with chronic pain, and the relationship differed based on intensity and amount of PA performed. Further research is necessary to refine PA recommendations for individuals with SCI who experience chronic pain. ClinicalTrials.gov identifier: NCT03773692.

Background and aims Recognition of the biopsychosocial aspects of pain is important for a true understanding of the burden of pain and the necessity of pain management. Biopsychosocial aspects of pain may differ between countries and cultures. Market research methods can be well suited and effective for assessing patient perspectives of pain and biopsychosocial differences. We conducted and combined 3 cross-sectional, international surveys to document the impact of pain on physical and emotional aspects of life, as well as quality of life (QOL). Methods Online panelists from 24 countries took part in our surveys in 2014, 2016, and 2017. Fourteen countries (Australia, Brazil, Canada, China, Germany, Italy, Japan, Poland, Russia, United Kingdom, United States, Mexico, Sweden, Saudi Arabia) contributed data in all 3 surveys and comprise the analysis population. A Global Pain Index (GPI) was constructed using 8 questions in 3 categories: Physical (frequency, duration, intensity of pain), Emotional (anxiety, impact on self-esteem, happiness), and Impact on QOL and ability to enjoy life. Each item was scored as the percentage of respondents meeting a prespecified threshold indicative of a substantial pain impact. Scores for the items within each category were averaged to obtain a category score, category scores were averaged to obtain a total score for each survey, and total scores from each survey were averaged to obtain a final combined score. Scores were assessed for the overall population, by individual countries, by age and gender, and by self-identified pain-treatment status (treat immediately, wait, never treat). Results Of the 50,952 adult respondents, 28,861 (56.6%) had ever experienced musculoskeletal pain; 50% of those with pain had pain with a multifaceted impact based on the GPI (Physical: 51%; Emotional: 40%; QOL Impact: 59%). Russia (57%) and Poland (56%) had the highest scores; Mexico (46%), Germany (47%), and Japan (47%) had the lowest. GPI score was higher in women (52%) than men (48%), and initially increased with age through age 54 (18‒24 years: 45%; 25‒34 years: 52%; 35‒44 years: 53%; 45‒54 years: 54%), after which it decreased again (55‒64 years: 51%; ≥65 years: 45%). A majority (65%) of respondents wait to treat their pain, whereas 21% treat their pain immediately and 14% never treat pain. The most common reason for waiting (asked in survey 3 only) was to avoid taking medication. Conclusions In this combined analysis of 3 international surveys using a novel biopsychosocial pain assessment tool, pain had a substantial impact on ~50% of respondents' lives, spanning physical (51%), emotional (40%), and QOL effects (59%). Despite the substantial impact, a majority of patients tried to avoid treating their pain. Implications Clinicians should take a biopsychosocial approach to pain by asking patients not only about the presence and severity of pain, but the extent to which it affects various aspects of their lives and daily functioning. Patients may also need education about the efficacy and safety of available treatments for self-management of pain. The GPI may be a useful new tool for future studies of the biopsychosocial effects of pain in large populations.

Virtual reality (VR) has been shown to reduce pain, however outcome parameters of previous studies have primarily been of a subjective nature and susceptible to bias. This study investigated the effect of VR on cortical processing of evoked potentials (EPs) and subjectively reported pain. Additionally, we explored whether subjects' demographic and personal characteristics modulated the effect of VR analgesia.

Many clinical trials fail because of placebo responses. Prior therapeutic experiences and patients' expectations may affect the capacity to respond to placebos in chronic disorders.