Human Studies

Poor sleep is commonly reported in pediatric chronic pain. There are signals that intensive interdisciplinary pain treatments (IIPT) may inadvertently improve objective sleep, but this claim cannot be substantiated without baseline sleep data prior to IIPT. This study followed the objective sleep/wake patterns (e.g., duration, quality, timing, consistency) of pediatric patients with severely functionally disabling chronic pain before, during, and after inpatient IIPT (the Functional Independence Restoration Program-"FIRST Program"), alongside a similarly-disabled chronic pain Comparison Group. The final sample included = 10 FIRST Patients and = 9 Comparison Group patients. At baseline, the whole sample showed healthy sleep duration (~9 h), average sleep efficiency <90%, late sleep onset and offset (mean = 11:56 p.m.-8:50 a.m.), and highly inconsistent sleep schedules night to night. During IIPT, FIRST Patients maintained healthy sleep durations, moved sleep schedules 2 h earlier, and decreased timing and duration variability by >60 min while the Comparison Group maintained similar sleep to baseline. At follow up (1-2 months later), FIRST Patients' sleep schedules shifted later but were still less variable than at baseline. Results point to the malleability of sleep/wake patterns within treatment contexts with strict environmental control but suggest that these gains may be difficult for youth with chronic pain to maintain in the home environment.

Existing studies on cognitive impairments in chronic pain do not investigate peripheral neuropathic pain (PNP) or compare pain conditions in a satisfactory manner. Here we aimed to compare executive dysfunctions in PNP patients with fibromyalgia (FM) and healthy controls (HC). Patients who self-reported cognitive impairments were assessed according to criteria for PNP or FM. Seventy-three patients met criteria and completed testing on executive functioning and IQ measures. We also included twenty matched healthy controls. Regression models controlling for age, sex and IQ, tested associations between group category (PNP, FM or HC) and outcomes. If a substantial association was detected, we followed up with head-to-head comparisons between PNP and FM. Multivariate regression models then tested associations between executive functioning and pain type, controlling for significant confounders. Results from head-to-head comparison between pain conditions showed significant differences on years lived with pain (FM > PNP), the use of anticonvulsants (PNP > FM) and use of analgesics (PNP > FM). When controlled for all significant differences, PNP patients had significantly lower scores on an attention-demanding cued-recall task compared to FM. Poor performance on attention-demanding cued-recall task was associated with PNP, which translate into problems with retaining fast-pace or advanced information.

Medical outcomes are strongly affected by placebo and nocebo effects. Prediction of who responds to such expectation effects has proven to be challenging. Most recent approaches to prediction have focused on placebo effects in the context of previous treatment experiences and expectancies, or personality traits. However, a recent model has suggested that basic somatosensory characteristics play an important role in expectation responses. Consequently, this study investigated not only the role of psychological variables, but also of basic somatosensory characteristics. In this study, 624 participants underwent a placebo and nocebo heat pain paradigm. Additionally, individual psychological and somatosensory characteristics were assessed. While no associations were identified for placebo responses, nocebo responses were associated with personality traits (e.g. neuroticism) and somatosensory characteristics (e.g. thermal pain threshold). Importantly, the associations between somatosensory characteristics and nocebo responses were among the strongest. This study shows that apart from personality traits, basic somatosensory characteristics play an important role in individual nocebo responses, in agreement with the novel idea that nocebo responses result from the integration of top-down expectation and bottom-up sensory information.

While knee and hip replacements are intended to relieve pain and improve function, up to 44% of knee replacement patients and 27% of hip replacement patients report persistent postoperative joint pain. Improving surgical pain management is essential. We conducted a single-site, three-arm, parallel-group randomized clinical trial conducted at an orthopedic clinic, among patients undergoing total joint arthroplasty (TJA) of the hip or knee. Mindfulness meditation (MM), hypnotic suggestion (HS), and cognitive-behavioral pain psychoeducation (CBE) were each delivered in a single, 15-minute group session as part of a 2-hour, preoperative education program. Preoperative outcomes – pain intensity, pain unpleasantness, pain medication desire, and anxiety – were measured with numeric rating scales. Postoperative physical functioning at 6-week follow-up was assessed with the Patient-Reported Outcomes Measurement Information System Physical Function computer adaptive test. TJA patients were randomized to preoperative MM, HS, or CBE (n=285). MM and HS led to significantly less preoperative pain intensity, pain unpleasantness, and anxiety. MM also decreased preoperative pain medication desire relative to CBE and increased postoperative physical functioning at 6-week follow-up relative to HS and CBE. Moderation analysis revealed surgery type did not differentially impact the three interventions. Thus, a single session of a simple, scripted MM intervention may be able to immediately decrease TJA patients' preoperative clinical symptomology and improve postoperative physical function. As such, embedding brief MM interventions in surgical care pathways has the potential to improve surgical outcomes for the millions of patients receiving TJA each year.