Pain acceptance and psychological inflexibility predict pain interference outcomes for persons with chronic pain receiving pain psychology.

OBJECTIVES: Awareness (being present), acceptance, and engagement (committed action) are three dimensions of psychological flexibility. Understanding these in the context of chronic pain may identify treatment targets to help refine individual treatment. Our objective was to test the predictive capacity of three dimensions within the psychological flexibility model on the longitudinal trajectory of pain interference. METHODS: Patients receiving pain psychology treatment at a pain management center participated in this pragmatic clinical longitudinal study (n=86 with at least three assessments; Mean age=51 years; Gender=60 females, 26 males). Measures included the Five Facet Mindfulness Questionnaire (FFMQ-SF); Chronic Pain Acceptance Questionnaire (CPAQ-8); Psychological Inflexibility in Pain Scale (PIPS-12); and Committed Action Questionnaire (CAQ-8). The dependent variable was the Patient Reported Outcomes Information System (PROMIS) Pain Interference (PI). We used latent growth modelling to analyze scores assessed within 180 days of patient care. RESULTS: Psychological inflexibility (PIPS-12) and pain acceptance (CPAQ-8) measured at baseline predicted PI outcomes (n=86). PIPS-12 showed a direct relationship with pain interference (PI), where higher PIPS-12 scores predicted significantly higher PI mean scores on average across the study period (ρ=0.422, r2=0.382) but also predicted significantly greater decreases in PI across time (ρ=-0.489, r2=0.123). Higher CPAQ-8 scores predicted significantly lower PI mean scores on average across the study period (ρ=-0.478, r2=0.453) but also significantly smaller decreases in PI across time (ρ=0.495, r2=0.076). Awareness (FFMQ-SF) and engagement (CAQ-8) were not predictive of PI outcomes. CONCLUSIONS: Patients who entered pain psychology treatment with lower pain acceptance and higher psychological inflexibility showed the largest reductions in pain interference across time. These results contribute towards a novel prognostic understanding of the predictive roles of an enhancing dimension and limiting dimension of psychological flexibility.

Mindfulness-Based Stress Reduction, Cognitive Behavioral Therapy, and Acupuncture in Chronic Low Back Pain: Protocol for Two Linked Randomized Controlled Trials.

BACKGROUND: Nonpharmacologic mind-body therapies have demonstrated efficacy in low back pain. However, the mechanisms underlying these therapies remain to be fully elucidated. OBJECTIVE: In response to these knowledge gaps, the Stanford Center for Low Back Pain-a collaborative, National Institutes of Health P01-funded, multidisciplinary research center-was established to investigate the common and distinct biobehavioral mechanisms of three mind-body therapies for chronic low back pain: cognitive behavioral therapy (CBT) that is used to treat pain, mindfulness-based stress reduction (MBSR), and electroacupuncture. Here, we describe the design and implementation of the center structure and the associated randomized controlled trials for characterizing the mechanisms of chronic low back pain treatments. METHODS: The multidisciplinary center is running two randomized controlled trials that share common resources for recruitment, enrollment, study execution, and data acquisition. We expect to recruit over 300 chronic low back pain participants across two projects and across different treatment arms within each project. The first project will examine pain-CBT compared with MBSR and a wait-list control group. The second project will examine real versus sham electroacupuncture. We will use behavioral, psychophysical, physical measure, and neuroimaging techniques to characterize the central pain modulatory and emotion regulatory systems in chronic low back pain at baseline and longitudinally. We will characterize how these interventions impact these systems, characterize the longitudinal treatment effects, and identify predictors of treatment efficacy. RESULTS: Participant recruitment began on March 17, 2015, and will end in March 2023. Recruitment was halted in March 2020 due to COVID-19 and resumed in December 2021. CONCLUSIONS: This center uses a comprehensive approach to study chronic low back pain. Findings are expected to significantly advance our understanding in (1) the baseline and longitudinal mechanisms of chronic low back pain, (2) the common and distinctive mechanisms of three mind-body therapies, and (3) predictors of treatment response, thereby informing future delivery of nonpharmacologic chronic low back pain treatments. TRIAL REGISTRATION: ClinicalTrials.gov NCT02503475; https://clinicaltrials.gov/ct2/show/NCT02503475. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/37823.

Relationship Between Blood Cytokine Levels, Psychological Comorbidity, and Widespreadness of Pain in Chronic Pelvic Pain.

Background: Low-grade inflammation has been implicated in the etiology of depression, long-term fatigue and chronic pain. TNFα and IL-6 are perhaps the most studied pro-inflammatory cytokines in the field of psychoneuroimmunology. The purpose of our study was to further investigate these relationships in patients with chronic pelvic pain specifically. Using plasma samples from a large, well-described cohort of patients with pelvic pain and healthy controls via the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network, we examined the relationship between TNFα and IL-6 and comorbid psychological symptoms. We also investigated the relationship between IL-8 and GM-CSF, and widespreadness of pain. Methods: We included baseline blood samples in the analyses, 261 patients (148 women) and 110 healthy controls (74 women). Fourteen pro- and anti-inflammatory or regulatory cytokines were analyzed in a Luminex® xMAP® high-sensitivity assay. We used regression models that accounted for known factors associated with the outcome variables to determine the relationship between cytokine levels and clinical measures. Results: There were no statistical differences in cytokine levels between patients and healthy controls when controlling for age. In patients, TNFα was significantly associated with levels of fatigue (p = 0.026), but not with pain intensity or depression. IL-6 was not significantly related to any of the outcome variables. Women with pelvic pain showed a negative relationship between IL-8 and widespreadness of pain, while men did not (p = 0.003). For both sexes, GM-CSF was positively related to widespreadness of pain (p = 0.039). Conclusion: Our results do not suggest low-grade systemic inflammation in chronic pelvic pain. Higher TNFα blood levels were related to higher fatigue ratings, while higher systemic GM-CSF levels predicted more widespread pain. Our study further suggests a potentially protective role of IL-8 with regard to with regard to the widepreadness of pain in the body, at least for women.

Effect of Electroacupuncture vs Sham Treatment on Change in Pain Severity Among Adults With Chronic Low Back Pain: A Randomized Clinical Trial.

Importance: Chronic low back pain has high societal and personal impact but remains challenging to treat. Electroacupuncture has demonstrated superior analgesia compared with placebo in animal studies but has not been extensively studied in human chronic pain conditions. Objective: To evaluate the treatment effect of real electroacupuncture vs placebo in pain and disability among adults with chronic low back pain and to explore psychophysical, affective, and demographic factors associated with response to electroacupuncture vs placebo in treating chronic low back pain. Design, Setting, and Participants: This double-blind randomized clinical trial was conducted between August 2, 2016, and December 18, 2018, at a single center in Stanford, California. Primary outcomes were collected at approximately 2 weeks before and after intervention. Participants included English-speaking adults with at least 6 months of chronic low back pain, pain intensity of at least 4 on a scale of 0 to 10, and no radiculopathy. Data analyses for this intent-to-treat study were conducted from June 2019 to June 2020. Interventions: Twelve sessions of real or placebo (sham) electroacupuncture administered twice a week over 6 weeks. Main Outcomes and Measures: The main outcome was change in pain severity from baseline to 2 weeks after completion of treatment, measured by the National Institutes of Health PROMIS pain intensity scale. A secondary outcome was change in the Roland Morris Disability Questionnaire (RMDQ). Baseline factors potentially associated with these outcomes included psychophysical testing (ie, thermal temporal summation, conditioned pain modulation, pressure pain threshold), participant's self-report (ie, widespread pain, coping strategies, expectations, self-efficacy, and pain catastrophizing), and demographic characteristics (eg, age, sex, and race). Results: A total of 121 adults were recruited to the study, among whom 59 participants (mean [SD] age, 46.8 [11.9] years; 36 [61.0%] women) were randomized to real electroacupuncture and 62 participants (mean [SD] age, 45.6 [12.8] years; 33 [53.2%] women) were randomized to sham electroacupuncture. At baseline, the mean (SD) PROMIS T-score was 50.49 (3.36) in the real electroacupuncture group and 51.71 (4.70) in the sham acupuncture group, and the mean (SD) RMDQ score was 10.16 (4.76) in the real electroacupuncture group and 10.03 (5.45) in the sham acupuncture group. After adjusting for baseline pain scores, there was no statistically significant difference between groups in change in T-scores 2 weeks after completion of treatment (real electroacupuncture: -4.33; 95% CI, -6.36 to -2.30; sham acupuncture: -2.90; 95% CI, -4.85 to -0.95; difference: -2.09; 95% CI, -4.27 to 0.09; P = .06). After adjusting for baseline RMDQ, there was a significantly greater reduction in RMDQ in the real electroacupuncture group (-2.77; 95% CI, -4.11 to -1.43) compared with the sham electroacupuncture group (-0.67; 95% CI, -1.88 to 0.55; difference: -2.11; 95% CI, -3.75 to -0.47; P = .01). Within the real electroacupuncture group, effective coping at baseline was associated with greater RMDQ reduction (r = -0.32; 95% CI, -0.54 to -0.05; P = .02), and White race was associated with worse outcomes in PROMIS score (ß = 3.791; 95% CI, 0.616 to 6.965; P = .02) and RMDQ (ß = 2.878; 95% CI, 0.506 to 5.250; P = .02). Conclusions and Relevance: This randomized clinical trial found no statistically significant difference in change in PROMIS pain score in real electroacupuncture vs sham electroacupuncture. There was a statistically significant treatment effect for the secondary outcome of RMDQ compared with sham electroacupuncture. Effective coping skills and non-White race were associated with response to electroacupuncture. Trial Registration: ClinicalTrials.gov Identifier: NCT02890810.

Central mechanisms of real and sham electroacupuncture in the treatment of chronic low back pain: study protocol for a randomized, placebo-controlled clinical trial.

BACKGROUND: Chronic low back pain (CLBP) is the most common chronic pain condition and is often resistant to conventional treatments. Acupuncture is a popular alternative for treating CLBP but its mechanisms of action remain poorly understood. Evidence suggests that pain regulatory mechanisms (particularly the ascending and secondarily the descending pain modulatory pathways) and psychological mechanisms (e.g., expectations, pain catastrophizing and self-efficacy) may be involved in the pathogenesis of CLBP and its response to treatments. We will examine these mechanisms in the treatment of CLBP by electroacupuncture (EA). METHODS: We present the aims and methods of a placebo-controlled, participant-blinded and assessor-blinded mechanistic study. Adult patients with CLBP will be randomized to receiving 16 sessions of real (active) or sham (placebo) EA over the course of 8 weeks. The primary pain regulatory measure for which the study was powered is temporal summation (TS), which approximates ascending pain facilitation. Conditioned pain modulation (CPM), representing a descending pain modulatory pathway, will be our secondary pain regulatory measure. The primary psychological measure is expectations of benefit, and the secondary psychological measures are pain catastrophizing and self-efficacy in managing pain. Main clinical outcomes are back pain bothersomeness on a 0-100 visual analog scale (primary), Roland Morris Disability Questionnaire (secondary), and relevant items from the National Institutes of Health (NIH) Patient-Reported Outcome Measures Information System (secondary). We hypothesize that compared to sham, real EA will lead to greater reduction in TS after 8 treatment sessions (4 weeks); and that reduction in TS (and secondarily, increase in CPM) after 8 treatment sessions will mediate reduction in back pain bothersomeness from baseline to week 10 (clinical response) to EA. We also hypothesize that the three psychological factors are moderators of clinical response. With 100 treatment completers, the study is designed to have 80% power to detect a medium-sized between-group effect (d = 0.5) on temporal summation. DISCUSSION: To the best of our knowledge, this is the first appropriately powered, placebo-controlled clinical trial evaluating mechanisms of EA in the treatment of CLBP. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02503475 . Registered on 15 July 15 2015. Retrospectively registered.

Effects of salience-network-node neurofeedback training on affective biases in major depressive disorder.

Neural models of major depressive disorder (MDD) posit that over-response of components of the brain's salience network (SN) to negative stimuli plays a crucial role in the pathophysiology of MDD. In the present proof-of-concept study, we tested this formulation directly by examining the affective consequences of training depressed persons to down-regulate response of SN nodes to negative material. Ten participants in the real neurofeedback group saw, and attempted to learn to down-regulate, activity from an empirically identified node of the SN. Ten other participants engaged in an equivalent procedure with the exception that they saw SN-node neurofeedback indices from participants in the real neurofeedback group. Before and after scanning, all participants completed tasks assessing emotional responses to negative scenes and to negative and positive self-descriptive adjectives. Compared to participants in the sham-neurofeedback group, from pre- to post-training, participants in the real-neurofeedback group showed a greater decrease in SN-node response to negative stimuli, a greater decrease in self-reported emotional response to negative scenes, and a greater decrease in self-reported emotional response to negative self-descriptive adjectives. Our findings provide support for a neural formulation in which the SN plays a primary role in contributing to negative cognitive biases in MDD.

Acute Pain Medicine in the United States: A Status Report.

BACKGROUND: Consensus indicates that a comprehensive,multimodal, holistic approach is foundational to the practice of acute pain medicine (APM),but lack of uniform, evidence-based clinical pathways leads to undesirable variability throughout U. S. healthcare systems. Acute pain studies are inconsistently synthesized to guide educational programs. Advanced practice techniques involving regional anesthesia assume the presence of a physician-led, multidisciplinary acute pain service,which is often unavailable or inconsistently applied.This heterogeneity of educational and organizational standards may result in unnecessary patient pain and escalation of healthcare costs. METHODS: A multidisciplinary panel was nominated through the APM Shared Interest Group of the American Academy of Pain Medicine. The panel met in Chicago, IL, in July 2014, to identify gaps and set priorities in APM research and education. RESULTS: The panel identified three areas of critical need: 1) an open-source acute pain data registry and clinical support tool to inform clinical decision making and resource allocation and to enhance research efforts; 2) a strong professional APM identity as an accredited subspecialty; and 3) educational goals targeted toward third-party payers,hospital administrators, and other key stake holders to convey the importance of APM. CONCLUSION: This report is the first step in a 3-year initiative aimed at creating conditions and incentives for the optimal provision of APM services to facilitate and enhance the quality of patient recovery after surgery, illness, or trauma. The ultimate goal is to reduce the conversion of acute pain to the debilitating disease of chronic pain.

Report of the National Institutes of Health task force on research standards for chronic low back pain.

OBJECTIVES: Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed nonspecific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. The purpose of this article is to disseminate the report of the National Institutes of Health (NIH) task force on research standards for cLBP. METHODS: The NIH Pain Consortium charged a research task force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel developed a 3-stage process, each with a 2-day meeting. RESULTS: The panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimal data set to describe research subjects (drawing heavily on the Patient Reported Outcomes Measurement Information System methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved these recommendations, which investigators should incorporate into NIH grant proposals. CONCLUSIONS: The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of cLBP. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes. We expect the RTF recommendations will become a dynamic document and undergo continual improvement.

The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee.

INTRODUCTION: The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications. METHODS: The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar. RESULTS: Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated. CONCLUSIONS: Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

Pilot study of a compassion meditation intervention in chronic pain.

BACKGROUND: The emergence of anger as an important predictor of chronic pain outcomes suggests that treatments that target anger may be particularly useful within the context of chronic pain. Eastern traditions prescribe compassion cultivation to treat persistent anger. Compassion cultivation has been shown to influence emotional processing and reduce negativity bias in the contexts of emotional and physical discomfort, thus suggesting it may be beneficial as a dual treatment for pain and anger. Our objective was to conduct a pilot study of a 9-week group compassion cultivation intervention in chronic pain to examine its effect on pain severity, anger, pain acceptance and pain-related interference. We also aimed to describe observer ratings provided by patients' significant others and secondary effects of the intervention. METHODS: Pilot clinical trial with repeated measures design that included a within-subjects wait-list control period. Twelve chronic pain patients completed the intervention (F= 10). Data were collected from patients at enrollment, treatment baseline and post-treatment; participant significant others contributed data at the enrollment and post-treatment time points. RESULTS: In this predominantly female sample, patients had significantly reduced pain severity and anger and increased pain acceptance at post-treatment compared to treatment baseline. Significant other qualitative data corroborated patient reports for reductions in pain severity and anger. CONCLUSIONS: Compassion meditation may be a useful adjunctive treatment for reducing pain severity and anger, and for increasing chronic pain acceptance. Patient reported reductions in anger were corroborated by their significant others. The significant other corroborations offer a novel contribution to the literature and highlight the observable emotional and behavioral changes in the patient participants that occurred following the compassion intervention. Future studies may further examine how anger reductions impact relationships with self and others within the context of chronic pain.

Understanding central mechanisms of acupuncture analgesia using dynamic quantitative sensory testing: a review.

We discuss the emerging translational tools for the study of acupuncture analgesia with a focus on psychophysical methods. The gap between animal mechanistic studies and human clinical trials of acupuncture analgesia calls for effective translational tools that bridge neurophysiological data with meaningful clinical outcomes. Temporal summation (TS) and conditioned pain modulation (CPM) are two promising tools yet to be widely utilized. These psychophysical measures capture the state of the ascending facilitation and the descending inhibition of nociceptive transmission, respectively. We review the basic concepts and current methodologies underlying these measures in clinical pain research, and illustrate their application to research on acupuncture analgesia. Finally, we highlight the strengths and limitations of these research methods and make recommendations on future directions. The appropriate addition of TS and CPM to our current research armamentarium will facilitate our efforts to elucidate the central analgesic mechanisms of acupuncture in clinical populations.

Real-time fMRI applied to pain management.

Current views recognize the brain as playing a pivotal role in the arising and maintenance of pain experience. Real-time fMRI (rtfMRI) feedback is a potential tool for pain modulation that directly targets the brain with the goal of restoring regulatory function. Though still relatively new, rtfMRI is a rapidly developing technology that has evolved in the last 15 years from simple proof of concept experiments to demonstrations of learned control of single and multiple brain areas. Numerous studies indicate rtfMRI feedback assisted control over specific brain areas may have applications including mood regulation, language processing, neurorehabilitation in stroke, enhancement of perception and learning, and pain management. We discuss in detail earlier work from our lab in which rtfMRI feedback was used to train both healthy controls and chronic pain patients to modulate anterior cingulate cortex (ACC) activation for the purposes of altering pain experience. Both groups improved in their ability to control ACC activation and modulate their pain with rtfMRI feedback training. Furthermore, the degree to which participants were able to modulate their pain correlated with the degree of control over ACC activation. We additionally review current advances in rtfMRI feedback, such as real-time pattern classification, that bring the technology closer to more comprehensive control over neural function. Finally, remaining methodological questions concerning the further development of rtfMRI feedback and its implications for the future of pain research are also discussed.

Randomized clinical trial of acupuncture for myofascial pain of the jaw muscles.

AIMS: To evaluate the effectiveness of acupuncture in treating symptoms associated with myofascial pain of the jaw muscles. METHODS: Twenty-eight subjects over the age of 18 and diagnosed with chronic myofascial pain of the jaw muscles were randomized to receive real (n = 16) or sham (n = 12) acupuncture. Prior to treatment, each subject clenched his or her teeth for 2 minutes. Acupuncture or sham acupuncture was then administered at the Hegu large intestine 4 (LI4) acupoint for 15 minutes. Real acupuncture was given by penetrating the needle through a sticky foam pad at the acupoint. Sham acupuncture was conducted by pricking the skin, without penetration, with a shortened, blunted acupuncture needle through a foam pad placed away from the acupoint. General head and neck pain ratings were obtained before and after treatment on a numerical rating scale. A mechanical pain stimulus on the masseter muscle was given before and after treatment and rated on a visual analog scale to measure pain tolerance level. Paired t tests were performed to detect significant changes in pain levels. RESULTS: Subjects receiving real acupuncture experienced a significant reduction in jaw pain (P = .04), jaw/face tightness (P = .04), and neck pain (P = .04), and a significant increase in pain tolerance of the masseter muscle (P = .001). Subjects were not able to determine whether they received real or sham acupuncture (P = .69). No significant pain reductions were observed in the sham acupuncture group. CONCLUSION: A single acupuncture session using one acupoint at Hegu large intestine 4 significantly reduced most myofascial pain endpoints when compared to sham acupuncture.

Control over brain activation and pain learned by using real-time functional MRI.

If an individual can learn to directly control activation of localized regions within the brain, this approach might provide control over the neurophysiological mechanisms that mediate behavior and cognition and could potentially provide a different route for treating disease. Control over the endogenous pain modulatory system is a particularly important target because it could enable a unique mechanism for clinical control over pain. Here, we found that by using real-time functional MRI (rtfMRI) to guide training, subjects were able to learn to control activation in the rostral anterior cingulate cortex (rACC), a region putatively involved in pain perception and regulation. When subjects deliberately induced increases or decreases in rACC fMRI activation, there was a corresponding change in the perception of pain caused by an applied noxious thermal stimulus. Control experiments demonstrated that this effect was not observed after similar training conducted without rtfMRI information, or using rtfMRI information derived from a different brain region, or sham rtfMRI information derived previously from a different subject. Chronic pain patients were also trained to control activation in rACC and reported decreases in the ongoing level of chronic pain after training. These findings show that individuals can gain voluntary control over activation in a specific brain region given appropriate training, that voluntary control over activation in rACC leads to control over pain perception, and that these effects were powerful enough to impact severe, chronic clinical pain.