II. Indices of Pain Intensity Derived From Ecological Momentary Assessments and Their Relationships With Patient Functioning: An Individual Patient Data Meta-analysis

Pain intensity is a complex and dynamic experience. A focus on assessing patients’ average pain levels may miss important aspects of pain that impact functioning in daily life. In this second of 3 articles investigating alternative indices of pain intensity derived from Ecological Momentary Assessments (EMA), we examine the indices’ associations with physical and psychosocial functioning. EMA data from 10 studies (2,660 patients) were reanalyzed to construct indices of Average Pain, Maximum Pain, Minimum Pain, Pain Variability, Time in High Pain, Time in Low Pain, Pain after Wake-up. Three sets of individual patient data meta-analyses examined 1) the test-retest reliability of the pain indices, 2) their convergent validity in relation to physical functioning, fatigue, depression, mental health, and social functioning, and 3) the incremental validity of alternative indices above Average Pain. Reliabilities approaching or exceeding a level of .7 were observed for all indices, and most correlated significantly with all functioning domains, with small to medium effect sizes. Controlling for Average Pain, Maximum Pain and Pain Variability uniquely predicted all functioning measures, and Time in High Pain predicted physical and social functioning. We suggest that alternative pain indices can provide new perspectives for understanding functioning in chronic pain.PerspectiveAlternative summary measures of pain intensity derived from EMA have the potential to help better understand patients’ pain experience. Utilizing EMA for the assessment of Maximum Pain, Pain Variability, and Time in High Pain may provide an enhanced window into the relationships between pain and patients’ physical and psychosocial functioning.     

III. Detecting Treatment Effects in Clinical Trials With Different Indices of Pain Intensity Derived From Ecological Momentary Assessment

Pain intensity represents the primary outcome in most pain clinical trials. Identifying methods to measure aspects of pain that are most sensitive to treatment may facilitate discovery of effective interventions. In this third of 3 articles examining alternative indices of pain intensity derived from ecological momentary assessments (EMA), we compare treatment effects based on Average Pain, Maximum Pain, Minimum Pain, Pain Variability, Time in High Pain, Time in Low Pain, and Pain After Wake-Up. We also examine which indices contribute to Patient Global Impressions of Change (PGIC). Data came from 2 randomized, double-blind, placebo-controlled trials examining the efficacy of milnacipran for fibromyalgia treatment; 2,084 patients provided >1 million EMA pain intensity ratings over 24 (Study 1) or 26 (Study 2) treatment weeks. Pain Variability and Time in High Pain produced significantly smaller treatment effects than Average Pain; other pain indices showed effects that were numerically smaller, but not significantly different from Average Pain. Changes in all pain indices were significantly associated with PGIC, with improvements in Maximum Pain and in Pain Variability offering small incremental contributions to understanding PGIC over Average Pain. Results suggest that different pain indices could be used to detect treatment effects in pain clinical trials.PerspectiveAlternative summary measures of pain intensity derived from EMA may broaden the scope of outcomes useful in pain clinical trials. In this analysis of a pharmacological treatment for fibromyalgia, most pain summary measures indicated similar effects; improvements in Maximum Pain and Pain Variability contributed to understanding PGIC over Average Pain.     

Reliabilities of Intra-Individual Mean and Intra-Individual Variability of Self-Reported Pain Derived From Ecological Momentary Assessments: Results From the Einstein Aging Study

An individual's pain experiences vary substantially over time. Though variability in pain may be an important metric which usually predicts health consequences, research on the measurement of pain variability estimates is lacking among older adults. We aimed to examine the reliabilities of both intra-individual mean (IIM) and intra-individual variability (IIV) of pain assessed using ecological momentary assessments (EMA) among racially diverse, systematically recruited community dwelling cohort of older adults. Participants (N = 311, age = 70–91) completed a 14-day EMA protocol which included self-reports of pain intensity, pain interference with activities, and pain interference with concentration multiple times a day. Over a 2-week period, we found excellent reliabilities for both pain IIM (.99), and pain IIV (≥.90). We also found that we need 5 to 6 days to achieve good reliability (.8) for pain IIV, suggesting that a shorter protocol may be used to reduce participants’ burden among the current sample, although caution is required when using this result to determine EMA study designs among different samples. Future studies are required to examine the associations of various EMA pain metrics with different health outcomes among older adults to facilitate the detection of underlying mechanisms linking pain to health as a prelude to interventions.PerspectiveMean levels and variability in pain intensity, pain interference with activities, and pain interference with concentration can be reliably measured to be linked with various health outcomes in older adults. Future studies including these pain metrics will assess the natural history, the consequences, and effects of intervention of pain.     

Ecological Momentary Assessment Methodology in Chronic Pain Research: A Systematic Review

Self-reported pain intensity assessments are central to chronic pain research. Ecological momentary assessment (EMA) methodologies are uniquely positioned to collect these data, and are indeed being used in the field. However, EMA protocols are complex, and many decisions are necessary in the design of EMA research studies. A systematic literature review identified 105 articles drawing from 62 quantitative EMA research projects examining pain intensity in adult chronic pain patients. Study characteristics were tabulated to summarize and describe the use of EMA, with an emphasis placed on various dimensions of decision-making involved in executing EMA methodologies. Most identified studies considered within-person relationships between pain and other variables, and a few examined interventions on chronic pain. There was a trend toward the use of smartphones as EMA data collection devices more recently, and completion rates were not reported in nearly one third of studies. Pain intensity items varied widely with respect to number of scale points, anchor labels, and length of reporting period; most used numeric rating scales. Recommendations are provided for reporting to improve reproducibility, comparability, and interpretation of results, and for opportunities to clarify the importance of design decisions.

Establishing the Reliability,Validity, and Prognostic Utility of the Momentary Pain Catastrophizing Scale for Use in Ecological Momentary Assessment Research

Despite the marked increase in ecological momentary assessment research, few reliable and valid measures of momentary experiences have been established. The goal of this preregistered study was to establish the reliability, validity, and prognostic utility of the momentary Pain Catastrophizing Scale (mPCS), a 3-item measure developed to assess situational pain catastrophizing. Participants in 2 studies of postsurgical pain outcomes completed the mPCS 3 to 5 times per day prior to surgery (N = 494, T = 20,271 total assessments). The mPCS showed good psychometric properties, including multilevel reliability and factor invariance across time. Participant-level average mPCS was strongly positively correlated with dispositional pain catastrophizing as assessed by the Pain Catastrophizing Scale (r = .55 and .69 in study 1 and study 2, respectively). To establish prognostic utility, we then examined whether the mPCS improved prediction of postsurgical pain outcomes above and beyond one-time assessment of dispositional pain catastrophizing. Indeed, greater variability in momentary pain catastrophizing prior to surgery was uniquely associated with increased pain immediately after surgery (b = .58, P = .005), after controlling for preoperative pain levels and dispositional pain catastrophizing. Greater average mPCS score prior to surgery was also uniquely associated with lesser day-to-day improvement in postsurgical pain (b = .01, P = .003), whereas dispositional pain catastrophizing was not (b = −.007, P = .099). These results show that the mPCS is a reliable and valid tool for ecological momentary assessment research and highlight its potential utility over and above retrospective measures of pain catastrophizing.PerspectiveThis article presents the psychometric properties and prognostic utility of a new measure to assess momentary pain catastrophizing. This brief, 3-item measure will allow researchers and clinicians to assess fluctuations in pain catastrophizing during individuals’ daily lives, as well as dynamic relationships between catastrophizing, pain, and related factors.     

An Ecological Momentary Assessment Study of Pain Intensity Variability: Ascertaining Extent,Predictors, and Associations With Quality of Life,Interference and Health Care Utilization Among Individuals Living With Chronic Low Back Pain

This ecological momentary assessment (EMA) study examined the extent of pain intensity variability among 140 individuals with chronic low back pain and explored predictors of such variability and psychosocial and health care utilization outcomes. Individuals completed momentary pain intensity reports (0–10 numeric rating scale) several times daily for two periods of seven consecutive days, one month apart. Participants also completed online questionnaires at baseline which tapped into pain characteristics, pain-related catastrophization, kinesiophobia, activity patterns, and depression and anxiety symptoms. Questionnaires assessing quality of life and health care utilization were administered online one month after completion of the last EMA report. Data were analyzed using linear hierarchical location-scale models. Results showed that pain intensity fluctuated over the course of a week as shown by an average standard deviation of 1.2. The extent of variability in pain intensity scores was heterogeneous across participants but stable over assessment periods. Patients’ baseline characteristics along with psychosocial and health care utilization outcomes were not significantly associated with pain intensity variability. We conclude that pain intensity variability differs across patients yet correlates remain elusive. There is an important gap in our knowledge of what affects this variability. Future EMA studies should replicate and extend current findings.PerspectiveThis study provides evidence indicating that there is substantial variability in momentary reports of pain intensity among individuals living with chronic low back pain. However, risk and protective factors for greater lability of pain are elusive as is evidence that greater pain intensity variability results in differential health care utilization.     

Treatment of Complex Regional Pain Syndrome Type I With Oral Phenoxybenzamine: Rationale and Case Reports

▪ Abstract:   The nonselective α-adrenergic antagonist, phenoxybenzamine, has been used in the treatment of neuropathic pain syndromes, specifically, complex regional pain syndrome (CRPS) types I and II. This agent has also previously been used in intravenous regional peripheral blocks for treatment of CRPS I; however, an intravenous preparation of phenoxybenzamine is not currently available in the U.S.A. In this case series, systemic administration was more appropriate for three of the four patients, as their syndromes had spread beyond the initial area of surgery or trauma. We report an apparent clinical benefit in three of the four patients following oral administration. We postulate that this may be due to the noncompetitive (irreversible) blockade of α₁- and α₂-adrenergic receptors. We further hypothesize that this blockade could reduce stimulation of an increased population of adrenergic receptors in hyperalgesic skin, blunt the stimulation by norepinephrine of α₂-adrenergic receptors on macrophages, and ultimately reduce the release of proinflammatory cytokines from cellular elements. ▪     

Ecological Momentary Assessment of Social Interactions: Associations With Depression,Anxiety, Pain,and Fatigue in Individuals With Mild Stroke

ObjectivesTo examine real-time relationships between social interactions and poststroke mood and somatic symptoms in participants’ daily environments.DesignProspective observational study using smartphone-based ecological momentary assessment (EMA) surveys 5 times a day for 2 weeks. Multilevel models were used to analyze data for concurrent and lagged associations.SettingCommunity.ParticipantsAdults (N=48) with mild stroke.InterventionsNot applicable.Main Outcome MeasuresEMA measures of self-appraisal of social interactions (confidence, satisfaction, and success), as well as mood (depression and anxiety) and somatic (pain and fatigue) symptoms.ResultsIn concurrent associations, increased depressed mood was associated with reduced ratings of all aspects of social interactions. Fatigue was associated with reduced ratings of social satisfaction and success. In lagged associations, increased anxious mood preceded increased subsequent social confidence. Higher average social satisfaction, confidence, and success were related to lower momentary fatigue, anxious mood, and depressed mood at the next time point. Regarding clinicodemographic factors, being employed was concurrently related to increased social interactions. An increased number of comorbidities predicted higher somatic, but not mood, symptoms at the next time point.ConclusionsThis study provides preliminary evidence of dynamic relationships between social interactions and somatic and mood symptoms in individuals with mild stroke. Interventions to not only address the sequelae of symptoms, but also to promote participation in social activities in poststroke life should be explored.     

Can End-of-Day Reports Replace Momentary Assessment of Pain and Fatigue?

This study evaluated the ability of end-of-day (EOD) ratings to accurately reflect momentary (EMA) ratings on 10 widely used pain and fatigue items. Rheumatology patients (n = 105) completed ≥5 randomly scheduled EMA assessments of each item per day as well as EOD ratings. Correlations were high between EOD and EMA ratings of the 5 pain items (r = .90 to .92) and somewhat lower for the 5 fatigue/energy items (r = .71 to .86). To examine the ability of EOD ratings to represent 1 week of EMA ratings, 7 EOD ratings were averaged and correlated with EMA (r ≥ .95 for pain items, r = .88 to .95 for fatigue/energy items). Further, averaging only 3 to 5 EOD ratings achieved very high correlations with 1 week of EMA ratings. Within-subject correlations of EOD with mean daily EMA across 7 days confirmed patients' ability to provide daily ratings that accurately reflect their day-to-day variation in symptom levels. These EOD results were compared to traditional recall ratings collected in the same protocol. It was concluded (1) that EOD ratings were a better representation of EMA than were recall ratings, and (2) that EOD ratings across a reporting period can replace EMA for studies targeting average levels of pain or fatigue.PerspectiveThis study in chronic pain patients demonstrated that end-of-day ratings of pain are highly accurate representations of average levels of pain experience across a day; ratings of fatigue were somewhat less accurate, though still at a level that would be valid.     

Intensity of Central Pain: Analysis of Pain Scores in 18 Patients

Abstract: The aim of this clinical study was to investigate the intensity of central pain in 18 patients. Each patient systematically recorded their own pain scores a total of 700 times (ie, 7 times/day for 100 consecutiv e days) using a standard four-point scale. In all 18 patients, the intensity of pain varied considerably (ranging in grade from no pain, mild pain, moderate pain to severe pain). During the 100 days, the average number of times (percentage of total) that each grade of pain intensity was scored was: no pain 7.4 (1.1%); mild pain 570.9 (81.6%); moderate pain 93.4 (13.3%), and severe pain 28.3 (4%). The difference between mild pain and moderate, severe, or no pain was significant. Thus, in our patient group the intensity of central pain was mostly mild, not severe. In contrast to other reports, our data suggest that to state that the intensity of central pain continues to be intolerable and severe throughout the day is an exaggeration. Among our 18 patients, an exacerbation of pain intensity was observed 507 times. Of these 507 events, 392 (77.3%) were due to specifiable factors and 115 (22.7%) were due to unknown factors. The specifiable factors could be attributed to: emotional factors 261 times (66.6%), somatic stimuli 44 times (11.2%), weather 38 times (9.7%), fatigue 29 times (7.4%), visceral activity 20 times (5.1%). Since there is no universally effective treatment for central pain, the strategy to manage central pain should primarily focus (if possible) on prevention of the exacerbating factors of central pain.     

口腔癌患者癌痛水平与疼痛信念的相关性研究

目的探讨口腔癌患者癌痛水平和疼痛信念间的相关性。方法 2013年7月至2014年2月便利取样选择上海市某三级甲等综合性医院口腔颌面-头颈肿瘤科120例口腔癌住院患者,采用一般状况调查表、癌症疼痛情况调查表及疼痛信念与感知量表进行问卷调查。结果口腔癌患者当前疼痛评分均分为(3.39±2.34)分,疼痛信念总分为(1.45±5.74)分。疼痛信念的4个维度中,"认为会持续疼痛"的得分最高,其余依次为"认为疼痛不可解除"、"自责感"和"感到疼痛很神秘"。患者疼痛信念的总分、"认为疼痛会持续"、"认为疼痛不可解除"和"自责感"等维度得分与当前癌痛水平均存在正相关(均P0.05)。结论口腔癌患者的癌痛程度以轻、中度为主,患者对于疼痛的感受及认知总体上合理,不正确的疼痛信念会影响到疼痛的水平。临床护士应加强对口腔癌患者疼痛信念的关注度及健康教育,指导患者正确认识疼痛,应对疼痛,以提升其生活质量。     

Pain Acceptance Decouples the Momentary Associations Between Pain,Pain Interference,and Physical Activity in the Daily Lives of People With Chronic Pain and Spinal Cord Injury

Pain acceptance is a robust predictor of adjustment to chronic pain; however, the dynamics of pain acceptance in daily life are largely unexamined. Furthermore, research on pain acceptance in those with pain and physical disability is needed. To examine pain acceptance in daily life, we collected 7 days of ecological momentary assessments of pain intensity and pain interference (5 times per day) with continuous accelerometry (physical activity) in 128 individuals with chronic pain and spinal cord injury. Multilevel modeling revealed that pain acceptance significantly moderated the momentary association between pain intensity and pain interference; those with higher pain acceptance experienced a blunted increase in interference when pain was high. Pain acceptance also moderated the association between pain intensity and physical activity; high pain acceptance was associated with an increase and low pain acceptance with a decrease in physical activity in the context of high pain. The activities engagement component of pain acceptance was a slightly more robust driver of these interaction effects; whereas activities engagement significantly moderated the association between momentary pain and pain interference as well as physical activity, pain willingness exerted a significant moderating effect on the momentary association between pain intensity and pain interference only. These findings suggest that both components contribute to the decoupling effects of pain acceptance. Task persistence did not show the same moderating effects, indicating that pain acceptance may be unique from other types of behavioral pain coping in its ability to decouple expected associations between pain intensity, pain interference, and physical activity.

Kinesiophobia Is Associated With Pain Intensity and Disability in Chronic Shoulder Pain: A Cross-Sectional Study

ObjectiveKinesiophobia is a clinically relevant factor in the management of chronic musculoskeletal pain. The aim of this study was to explore the cross-sectional association between kinesiophobia and both pain intensity and disability among individuals with chronic shoulder pain.MethodsA total of 65 participants with chronic unilateral subacromial shoulder pain were recruited from 3 primary care centers. The Shoulder Pain and Disability Index assessed pain intensity and disability. The Tampa Scale for Kinesiophobia short form assessed the presence of kinesiophobia. A linear multivariable regression analysis evaluated the potential association between kinesiophobia and range of movement free of pain with pain intensity and disability. The analysis was adjusted for sex and age.ResultsIn the linear multivariable regression analysis, only greater kinesiophobia (standardized β = 0.35, P < .01) and sex (standardized β = -0.29, P < .01) contributed to explain 19% of the variance in shoulder pain and disability scores.ConclusionThis cross-sectional study provides preliminary evidence about the association between kinesiophobia and pain intensity and disability among individuals with chronic shoulder pain. However, our findings only contributed to explain 19% of the variance in shoulder pain and disability scores.