The association of sleep and pain: an update and a path forward

Sleep disturbances and back pain : Systematic review and meta-analysis

BACKGROUND

In today's society, sleep disturbances and back pain are both common problems which threaten health. Although some studies have focused on the effects of sleep disturbances on back pain, no meta-analysis has been done. The purpose of this study is to systematically review and perform a meta-analysis on the effects of sleep disturbances on back pain.

METHODS

A literature search in PubMed, Scopus and EMBASE with keywords until June 2019 was performed. The eligible articles were evaluated qualitatively and the results were pooled using random effects. The publication bias and the degree of heterogeneity were examined.

RESULTS

In all, 21 studies were included in the meta-analysis. Sleep disturbances were associated with back pain (odds ratio 1.52; confidence interval [CI] 1.37-1.68; P < 0.001). In men, the odds ratio was 1.49 (CI 1.34-1.65; P < 0.001). In women, the odds ratio was 1.56 (CI 1.33-1.81; P < 0.001). Begg's test (P = 0.856) and Egger test (P = 0.188) did not show any publication bias. A funnel plot and trim-and-fill method showed publication bias, and heterogeneity was also high.

CONCLUSIONS

Sleep disturbance is associated with risk of back pain. Improving sleep can be a deterrent against back pain. Therefore, interventions to reduce sleep disturbances can help to improve health. On the other hand, the relationship between sleep disturbances and back pain can be two-sided, and back pain can also lead to sleep disturbances. Not only in view of the lifetime prevalence and the multifactorial impairments of those affected, but also in consideration of social and economic burdens, this issue will remain of considerable importance.

Sleep and Sleep Disruption in Amyotrophic Lateral Sclerosis

PURPOSE OF REVIEW

In amyotrophic lateral sclerosis (ALS), sleep disruption is frequently present and substantially adds to disease burden. This review aims to summarize current knowledge on causes, pathophysiology, and treatment of sleep disturbances in ALS.

RECENT FINDINGS

Motor neuron degeneration and muscle weakness may lead to muscle cramps, pain, spasticity, immobilization, restless legs, sleep-disordered breathing, and difficulties to clear secretions. Furthermore, existential fears and depression may promote insomnia. Sleep-disordered breathing, and nocturnal hypoventilation in particular, requires ventilatory support which meaningfully prolongs survival and improves health-related quality of life albeit respiratory failure is inevitable. Early indication for non-invasive ventilation can be achieved by inclusion of capnometry in diagnostic sleep studies. Sleep disruption is extremely common in ALS and may arise from different etiologies. The absence of causative therapeutic options for ALS underlines the importance of symptomatic and palliative treatment strategies that acknowledge sleep-related complaints.

Work- and stress-related musculoskeletal and sleep disorders among health professionals: a cross-sectional study in a hospital setting in Switzerland

Background

Musculoskeletal and sleep disorders have been reported to be very common among health care and hospital workers and particularly nurses. They are assumed or found to be a result of psychological stress and/or physical strain or pain. However, no other study so far – at least in a hospital setting and for Switzerland – has considered and investigated musculoskeletal as well as sleep disorders in consequence of or rather in association with both physical workload and psychological stress.

Methods

Cross-sectional survey data of 1232 health professionals were used and analysed. Data were collected in 2015/16 among the health care workforces of three public hospitals and two rehabilitation clinics in the German-speaking part of Switzerland. Musculoskeletal and sleep disorders were assessed by three items taken from the Swiss Health Survey, a 2-item measure of accumulated low back, back, neck and shoulder pain and a single-item measure of problems in getting to sleep or sleeping through. Stratified and adjusted bivariate logistic and multivariate linear regression analyses were performed to calculate measures of association (adjusted odds ratios, z-standardized beta coefficients), to control for potential confounders, and to compare different health professions (nurses, physicians, therapists, other).

Results

Almost every fourth of the studied health professionals reported severe or even very severe musculoskeletal disorders (MSDs) and nearly every seventh severe sleep disorders (SDs). These prevalence rates were significantly or at least slightly higher among nurses than among physicians and other health care workers. General stress, work stress, physical effort at work, and particularly a painful or tiring posture at work were found to be clear and strong risk factors for MSDs, whereas only general and work-related stress were found to be significantly associated with SDs. There was no or only weak association between MSDs and SDs.

Conclusions

This study found MSDs to be largely a result of physical workload or rather poor posture at work and only secondarily a consequence of (general) stress, whereas SDs were revealed to be primarily a consequence of stress on and particularly off the job. Preventive strategies therefore have to differentiate and combine measures for the reduction of both psychological stress and physical strain.

Less Pain, Better Sleep? The Effect of a Multidisciplinary Back Pain App on Sleep Quality in Individuals Suffering from Back Pain - a Secondary Analysis of App User Data

Purpose

Mobile health solutions are finding their way into health systems. The Kaia app has been shown to be able to reduce back pain in two studies. Since pain often comes along with disturbed sleep and both symptoms are strongly related we investigated whether the Kaia app training is associated with improved sleep quality.

Methods

User data of individuals with back pain were collected in two app versions (cohort 1: N = 180; cohort 2: N = 159). We analyzed the ratings of sleep quality and pain intensity on a 11-point numeric ratings scale (NRS; 0–10) both at the beginning of usage (baseline: BL) and on the individual last day of usage (follow-up: LU) within a 3-month training program.

Results

In both cohorts, we found a significant reduction in pain intensity from BL to LU (cohort 1: M_BL = 4.80; SD = 1.59 to M_LU = 3.75; SD = 1.76, Δ_pain = –1.04; SD = 2.12; t(158) = 6.207; p<.001/cohort 2: M_BL = 4.20; SD = 1.98 to M_LU = 3.65; SD = 1.78; Δ_pain = –0.50; SD = 2.04; t(147) = 3.001; p = 0.003) and a significant improvement of sleep quality (cohort 1: M_BL = 5.76; SD = 2.12 to M_LU = 6.56; SD = 1.72; Δ_sleep = t(158) = 4.310; p < 0.001/cohort 2: M_BL = 6.08; SD = 2.08 to M_LU = 6.76; SD = 1.55; Δ_sleep = 0.67; SD = 2.13; sleep: t(147) = 3.825; p < 0.001). Interestingly, improvement of sleep quality was not fully mediated by pain reduction.

Conclusion

Our analysis underlines the relationship between pain and sleep in the clinical context. Improvement of sleep quality came along with pain reduction and vice versa. Further study should explain the exact mechanisms of action which are associated with the improvement of both symptom parameters.

Convergent and Discriminant Validity of the Serbian Version of the Central Sensitization Inventory

OBJECTIVES

The goal of the present study was to explore additional evidence of validity of the Serbian version of the Central Sensitization Inventory (CSI), a patient-reported outcome measure of symptoms that have been found to be associated with central sensitization (CS). The CSI has been found to be psychometrically sound, and has demonstrated evidence of convergent and discriminant validity in numerous published studies and in multiple languages.

METHODS

CSI data were collected from 399 patients with chronic pain who had various diagnoses and from 146 pain-free controls. In addition, the patient sample completed a battery of validated patient-reported outcome measures of sleep problems, cognitive problems, pain catastrophizing, pain-related fear-avoidance, decreased quality of life, and decreased perception of social support. Six patient subgroups were formed, with presumably different levels of CS (including those with fibromyalgia, multiple pain sites, and localized pain sites).

RESULTS

Significant differences were found in total CSI scores among the controls and patient subgroups. Those with fibromyalgia and multiple pathologies scored highest and the control subjects scored lowest. Other patient-reported CS-related symptom dimensions were significantly correlated with total CSI scores. When the patients were divided into CSI severity subgroups (from subclinical to extreme), the severity of these other symptom dimensions increased with the severity of CSI scores.

CONCLUSIONS

The current study successfully demonstrated additional evidence of the convergent and discriminant validity of the Serbian version of the CSI.

Sleep quality and chronic neck pain: a cotwin study

STUDY OBJECTIVES

Sleep quality and chronic neck pain (NP) are associated. However, the genetic influences on this association have not been explored. This study investigated the genetic and environmental influences on the association between sleep quality and chronic NP.

METHODS

The sample comprised 2,328 individual twins from the Murcia Twin Registry (Spain). A bidirectional cotwin logistic regression analysis was performed (sleep quality assessed as the exposure and chronic NP as the outcome and vice versa). Analysis included 2 sequential stages: total sample analysis and within-pair twin case-control analysis.

RESULTS

Sleep quality was significantly associated with chronic NP in the total sample analysis (adjusted odds ratio [OR]: 1.09; 95% confidence interval [CI]: 1.06, 1.12; P < .001); in the cotwin case-control analysis, including both monozygotic and dizygotic twin pairs (adjusted OR: 1.10; 95% CI: 1.04, 1.17; P = .001); in dizygotic pairs (Adjusted OR: 1.11; 95% CI: 1.03, 1.19; P = .005); but not in monozygotic pairs (adjusted OR: 1.08; 95% CI: 0.98, 1.19; P = .118). Chronic NP was significantly associated with poor sleep quality in the total sample analysis (adjusted OR: 1.80; 95% CI: 1.43, 2.26; P < .001); in the cotwin case-control analysis, including both monozygotic and dizygotic twin pairs (Adjusted OR: 1.63; 95% CI: 1.07, 2.47; P = .023); in dizygotic pairs (Adjusted OR: 1.80; 95% CI: 1.05, 3.09; P = .031), but not in monozygotic pairs (adjusted OR: 1.67; 95% CI: 0.80, 3.48; P = .170).

CONCLUSIONS

The association between sleep quality and chronic NP is partially confounded by genetic factors.

Linking Nonrestorative Sleep and Activity Interference Through Pain Catastrophizing and Pain Severity: An Intraday Process Model Among Individuals With Fibromyalgia

Nonrestorative sleep is a key diagnostic feature of the musculoskeletal pain disorder fibromyalgia and is robustly associated with poor physical functioning, including activity interference. However, the mechanisms through which nonrestorative sleep elicits activity interference among individuals with fibromyalgia at the within-person level remain unclear. The present study tested the following 3-path mediation model, using data gathered from a 21-day electronic daily diary in 220 individuals with fibromyalgia: previous night nonrestorative sleep → morning pain catastrophizing → afternoon pain severity → end-of-day activity interference. Results of multilevel structural equation modeling supported the 3-path mediation model. Previous night's nonrestorative sleep and morning pain catastrophizing were also directly related to end-of-day activity interference. Previous night nonrestorative sleep did not significantly predict afternoon pain severity while controlling for the effect of morning pain catastrophizing. Greater nonrestorative sleep during the previous night and a higher level of morning pain catastrophizing appear to serve as risk factors for experiencing greater daily pain and activity interference later in the day. These findings point to the potential utility of targeted interventions that improve both sleep quality and pain catastrophizing to help individuals with chronic pain engage in important daily activities despite experiencing pain. PERSPECTIVE: This study provides a better understanding of how nonrestorative sleep is associated with daily activity interference among individuals with fibromyalgia. An intervention that targets attenuating nonrestorative sleep and pain catastrophizing may help improve daily physical functioning of this population.

Sex Differences in Interleukin-6 Responses Over Time Following Laboratory Pain Testing Among Patients With Knee Osteoarthritis

Epidemiological studies suggest that women are not only at a higher risk for developing knee osteoarthritis (KOA), but also report greater symptom severity compared to men. One potential underlying mechanism of these sex differences may be exaggerated inflammatory responses to pain among women compared to men. The present study examined sex differences in interleukin-6 (IL-6) response over time following experimental pain testing. We hypothesized that women, when compared to men, would show greater IL-6 reactivity when exposed to acute pain in a human laboratory setting. Eighty-four participants (36 men and 48 women) with KOA scheduled for total knee arthroplasty underwent a quantitative sensory testing (QST) battery. A total of seven IL-6 measurements were taken, twice at baseline, once immediately after QST, and every 30 minutes up to 2 hours after QST. Consistent with our hypothesis, women, when compared to men, showed accelerated increases in IL-6 levels following laboratory-evoked pain, even after controlling for body mass index, marital status, clinical pain, evoked pain sensitivity, and situational pain catastrophizing. Given that KOA is a chronic condition, and individuals with KOA frequently experience pain, these sex differences in IL-6 reactivity may contribute to the maintenance and/or exacerbation of KOA symptoms. PERSPECTIVES: The present study demonstrates that women, when compared to men, exhibit greater IL-6 reactivity after exposure to laboratory-evoked pain. Such sex differences may explain the mechanisms underlying women's higher chronic pain risk and pain perception, as well as provide further insight in developing personalized pain interventions.

Association between work productivity and sleep health: A cross-sectional study in Japan

OBJECTIVES

To examine the impact of sleep health on work in Japan and to investigate the relationship between presenteeism and sleep health.

DESIGN

Cross sectional analysis of a questionnaire survey.

SETTING

Seventeen offices in Tokyo, Japan.

PARTICIPANTS

The study included 2897 participants, of which 1835 were men and 1062 women, aged between 18 and 76 years.

MEASUREMENTS

Productivity loss was measured using the Short Form of the Work Limitations Questionnaire (WLQ-SF).

RESULTS

The decline in productivity due to presenteeism of people with short sleep duration, between 5 and 6 h (β = 0.068, p = 0.004) and less than 5 h (β = 0.105, p < 0.001), was significantly greater compared with those with long sleep duration (7-8 h). Subjective sleep quality (β = 0.124, p < 0.001), sleep latency (β = 0.073, p < 0.001), sleep disturbance (β = 0.123, p < 0.001), use of sleep medication (β = 0.044, p = 0.007), and daytime dysfunction (β = 0.359, p = 0.001) significantly affected presenteeism. When adjusting for confounding factors, sleep duration on workdays, sleep duration on free days, mid-sleep on free days corrected for sleep debt on workdays (MSFsc), and social jet lag were not associated with presenteeism in the multiple regression analysis.

CONCLUSIONS

Sleep health is associated with presenteeism in Japan. Subjective sleep quality, daytime dysfunction, sleep disturbance, and use of sleep medicine are associated with presenteeism. Good sleep hygiene may be important for workers' productivity.

Musculoskeletal pain among offshore wind industry workers: a cross-sectional study

Objective

To assess whether there are differences in musculoskeletal pain among different types of occupations offshore and their relationship to ergonomic demands.

Methods

We conducted a web-based cross-sectional survey among workers from offshore wind energy companies operating within the German exclusive economic zone. We selected workers with regular offshore commitments and at least 28 days spent offshore in the past year (n = 268). Musculoskeletal pain was assessed using the Subjective Health Complaints inventory (SHC), which considers the past month.

Results

Of the 268 male participants eligible for analysis, 54% reported back pain 50.4% neck pain, 40.3% lower back pain, 35.5% shoulder, 23.3% arm and 22.1% leg pain, all of them during the past month. Compared to other offshore occupations, technicians reported more frequently arm (OR 3.13; 95% CI 1.58–6.19), back (OR 1.97; 95% CI 1.15–3.39), shoulder (OR 1.94; 95% CI 1.11–3.40) and neck pain (OR 1.89; 95% CI 1.11–3.22). After adjusting for age and nationality, lifting and carrying heavy loads were associated with all types of pain except leg pain. Overhead work, work in awkward postures, and the use of personal protection equipment and heavy tools was associated with shoulder, back and arm pain.

Conclusions

Our findings suggest that occupational health counselling, health promotion and preventive interventions of offshore wind energy workers needs to consider the specific tasks of the employee and be particularly tailored to the ergonomic needs of technicians.

Intraindividual variability in sleep and comorbid medical and mental health conditions

STUDY OBJECTIVES

Intraindividual variability (IIV) in sleep may be a risk factor for disease above the influence of mean sleep. Associations between IIV in sleep and risk for a comprehensive set of common medical and mental health conditions have not been assessed in a representative sample.

METHODS

This study examined mean and IIV in total sleep time (TST), sleep quality (SQ), sleep efficiency (SE), and circadian midpoint (CM) in 771 adults recruited for an epidemiological study. Participants completed 14 days of sleep diaries to assess TST, SQ, SE, and CM, after which they reported on medical conditions and mental health symptoms. Data were analyzed using logistic regression, and models controlled for gender, body mass index, age, and race.

RESULTS

Lower mean TST, SQ, and SE were related to increased odds of having gastrointestinal problems, depression, and anxiety. IIV in TST was related to increased odds of having neurological, breathing, and gastrointestinal problems, as well as pain and depression; all results held controlling for mean sleep and adjusting for false discovery rate. IIV in SQ and SE was not associated with odds of having any medical or mental health conditions after adjusting for false discovery rate, nor was IIV in CM or mean CM.

CONCLUSIONS

Confirming previous research, mean TST, SQ, and SE are related to risk for gastrointestinal problems, depression, and anxiety. IIV in TST may be a unique facet of disturbed sleep that is associated with increased risk for a diverse cluster of medical and mental health conditions.

Neuropathic pain after thoracotomy: Tracking signs and symptoms before and at monthly intervals following surgery

BACKGROUND

As the development of neuropathic symptoms contributes to pain severity and chronification after surgery, their early prediction is important to allow targeted treatment.

OBJECTIVES

We longitudinally investigated trajectories of signs and symptoms in patients undergoing thoracotomy and assessed whether and at which time they were related to the development of neuropathic pain symptoms 6 months after surgery.

METHODS

Presurgical and 6 monthly postsurgical assessments included questionnaires for mental and physical well-being (e.g., depression/anxiety, pain catastrophizing, sleep quality, neuropathic pain symptoms), and quantitative sensory testing (QST).

RESULTS

QST trajectories indicated nerve impairment of the surgery site with predominant loss of function. Signs of recovery towards the end of the assessment period were observed for some tests. Unsupervised cluster analysis with NPSI scores 6 months after surgery as clustering variable identified one group with no/low levels of neuropathic symptoms and one with moderate levels. The two groups differed w.r.t. several signs and symptoms already at early time points. Notably, neuropathic pain anywhere in the body differed already preoperatively and sleep impairment differentiated the two groups at all time points. Regression analysis revealed three factors that seemed particularly suited to predicted 6 months NPSI scores, namely preoperative neuropathic pain symptoms, with contributions from sleep impairment 1 month after surgery and the presence of dynamic mechanical allodynia 3 months after surgery.

CONCLUSIONS

Clinical routine should focus on the individual's physiological state, including pre-existing neuropathic pain and sleep quality to identify patients early who might be at risk to develop chronic post-surgical neuropathic pain.

SIGNIFICANCE

Development of neuropathies contributes to pain severity and pain chronification after surgery. Here we demonstrate trajectories of quantitative sensory tests (assessed at monthly intervals for 6 months after surgery) that reveal accurate time courses of gain/loss of nerve function following thoracotomy. Independent of the degree of neuropathic signs after surgery, the main predictors for post-surgical neuropathic pain are self-reported neuropathic pain before surgery and sleep quality shortly after surgery.

The effects of recovery sleep on pain perception: A systematic review

Experimental studies highlight profound effects of sleep disruptions on pain, showing that sleep deprivation (SD) leads to hyperalgesic pain changes. On the other hand, given that sleep helps normalizing bodily functions, a crucial role of restorative sleep in the overnight restoration of the pain system seems likely. Thus, a systematic review of experimental studies on effects of recovery sleep (RS; subsequently to SD) on pain was performed with the aim to check whether RS resets hyperalgesic pain changes occurring due to SD. Empirical animal and human studies including SD-paradigms, RS and pain assessments were searched in three databases (PubMed, Web of Science, PsycINFO) using a predefined algorithm. 29 studies were included in this review. Most results indicated a reset of enhanced pain sensitivity and vulnerability following RS, especially when total SD was implemented and pressure pain or painful symptoms (human studies) were assessed. Further research should focus on whether and how recovery is altered in chronic pain patients, as this yields implications for pain treatment by enhancing or stabilizing RS.

Predictors of fatigue in rheumatoid arthritis

People with RA commonly experience fatigue. Fatigue is a key contributor to increased clinical care costs, primary care consultations and employment loss. Despite this, our understanding of the prognostic of factors of poor fatigue outcomes is lacking and fatigue is poorly managed. Examining longitudinal predictors of fatigue can identify both individuals ‘at risk’ of poor prognosis, and candidate mechanisms that are worthy of greater inspection. This review discusses the factors most commonly investigated as being implicated in the prognosis of RA fatigue. The available data appears to implicate generic factors such as pain, mental health, disability and sleep as consistent predictors of fatigue outcome, while the role of disease activity and inflammation seems less clear. However, the existing data are not without methodological limitations and there have been no specific studies primarily designed to investigate the inflammatory biomarkers of fatigue. Future studies are required to more comprehensively and robustly determine the mechanisms of fatigue.

Sex differences in measures of central sensitization and pain sensitivity to experimental sleep disruption: implications for sex differences in chronic pain

Study Objectives

Females demonstrate heightened central sensitization (CS), a risk factor for chronic pain characterized by enhanced responsivity of central nervous system nociceptors to normal or subthreshold input. Sleep disruption increases pain sensitivity, but sex has rarely been evaluated as a moderator and few experiments have measured CS. We evaluated whether two nights of sleep disruption alter CS measures of secondary hyperalgesia and mechanical temporal summation in a sex-dependent manner. We also evaluated differences in measures of pain sensitivity.

Methods

Seventy-nine healthy adults (female n = 46) participated in a randomized crossover experiment comparing two consecutive nights of eight pseudorandomly distributed forced awakenings (FA [-200 min sleep time]) against two nights of undisturbed sleep (US). We conducted sensory testing the mornings following Night 2; the heat-capsaicin pain model was used to induce secondary hyperalgesia.

Results

FA reduced total sleep time (REM and NREM Stage 3) more profoundly in males. We observed divergent, sex-dependent effects of FA on secondary hyperalgesia and temporal summation. FA significantly increased secondary hyperalgesia in males and significantly increased temporal summation in females. Sex differences were not attributable to differential sleep loss in males. FA also significantly reduced heat-pain threshold and cold pressor pain tolerance, independently of sex.

Conclusions

Sleep disruption enhances different pain facilitatory measures of CS in males and females suggesting that sleep disturbance may increase risk for chronic pain in males and females via distinct pathways. Findings have implications for understanding sex differences in chronic pain and investigating sleep in chronic pain prevention efforts.

Menopause symptoms and chronic pain in a national sample of midlife women veterans

OBJECTIVE

Women are more likely than men to suffer chronic pain, with the highest rates seen in midlife. The symptoms that characterize menopause broadly affect health and well-being, but their contribution to chronic pain risk during this period is poorly understood. To address this gap in knowledge, we examined relationships between indicators of menopause symptoms and chronic pain among midlife women veterans, a population with prevalent chronic pain diagnoses and elevated risk for bothersome menopause symptoms.

METHODS

This is a cross-sectional analysis of national Veterans Health Administration medical and pharmacy records. Using national medical and pharmacy records from women veterans aged 45 to 64 with at least one VA encounter during 2014 and/or 2015 (n = 200,901), we developed multivariable logistic regression models to examine associations between menopause symptoms (defined by menopause symptom-related diagnoses on ≥2 encounters and/or menopause hormone therapy use) and chronic pain outcomes, adjusting for age, race, body mass index, mental health diagnoses, and substance use disorders.

RESULTS

In this national sample of midlife women veterans (mean age 54.3 ± 5.4), 13% had menopause symptoms, 52% had chronic pain, and 22% had ≥2 distinct chronic pain diagnoses. In multivariable analyses, women with menopause symptoms had nearly two-fold odds of chronic pain (odds ratio 1.84, 95% confidence interval 1.79-1.90, P < 0.001) and multiple chronic pain diagnoses (odds ratio 1.79, 95% confidence interval 1.74-1.83, P < 0.001).

CONCLUSIONS

These findings raise the possibility within this vulnerable critical period, midlife women with a higher menopause symptom burden may be most vulnerable for chronic pain.

A Quantitative Analysis of Sleep Quality in Women with Endometriosis

Background: Endometriosis is a complex condition that can negatively affect a woman's quality of life, including her sleep. This study aims to assess the multifactorial variables associated with poorer quality of sleep in women with endometriosis. Materials and Methods: Data from the Endometriosis Pelvic Pain Interdisciplinary Cohort (EPPIC) data registry were analyzed for women who underwent surgery at the BC Women's Center for Pelvic Pain and Endometriosis with histopathological confirmation of endometriosis (June 2015 to June 2017). The primary outcome was quality of sleep preoperatively, from the Chronic Pain Sleep Inventory (0-100 VAS). Bivariate analysis and multivariable linear regression were done to determine any significant associations between preoperative patient variables and overall quality of sleep, based on p-value of 0.05. Results: Two hundred and seventy-five women met the study criteria. Poorer overall quality of sleep was independently associated with poorer functional quality of life (EHP-30) (b = -0.18, p = 0.0026), more depressive symptoms (PHQ-9) (b = -1.62, p < 0.001), and painful bladder syndrome (PBS) (b = -5.82, p = 0.035). This indicates that a 1 point increase in the EHP-30 (worsening quality of life), a 1 point increase in the PHQ-9 (worsening depression), and the presence of PBS increased the primary outcome (i.e., toward poorer quality of sleep) by 0.18, 1.62, and 5.82 points. Conclusions: Poorer quality of sleep in women with endometriosis is associated with poorer quality of life, more depressive symptoms, and bladder pain. Research into interventions that improve sleep is warranted as part of the management of some women with endometriosis.

Cross-Cultural Adaptation and Psychometric Properties of the European Portuguese Version of the Central Sensitization Inventory in Adolescents With Musculoskeletal Chronic Pain

BACKGROUND

Central sensitization (CS) is an important feature in musculoskeletal chronic pain, and associated symptoms can be assessed using the Central Sensitization Inventory (CSI).

OBJECTIVES

This study aimed to translate and cross-culturally adapt the CSI to the European Portuguese language and to assess its validity and reliability in adolescents with musculoskeletal chronic pain.

METHODS

The European Portuguese version of the CSI was established following the translation and testing processes recommended by international guidelines. Then, this version of the CSI was completed by 1,730 adolescents, who also completed the Nordic Musculoskeletal Questionnaire; the Pain Catastrophizing Scale; the Depression, Anxiety and Stress Scale; the Tampa Scale of Kinesiophobia; and the Basic Scale on Insomnia Complaints and Quality of Sleep. Test-retest reliability and measurement error, internal consistency, hypothesis testing, and factor analysis were assessed for the translated version of the CSI.

RESULTS

Cronbach's alpha was 0.91, the intraclass correlation coefficient was 0.94 (95% confidence interval: 0.90, 0.96), and the standard error of measurement and smallest detectable change were 4.15 and 11.50, respectively. Fair correlations were found between CSI and fear of movement (Spearman's correlation [r_s ] = 0.46), sleep (r_s  = 0.46), and catastrophizing (r_s  = 0.49). Moderate to good correlations were found between CSI and depression (r_s  = 0.60), anxiety (r_s  = 0.59), and stress (r_s  = 0.65).

CONCLUSION

The European Portuguese version of the CSI was considered easy to understand and showed very good internal consistency, excellent test-retest reliability, and excellent construct validity in a community sample of adolescents with musculoskeletal chronic pain.

Machine-learned identification of psychological subgroups with relation to pain interference in patients after breast cancer treatments

Background

Persistent pain in breast cancer survivors is common. Psychological and sleep-related factors modulate perception, interpretation and coping with pain and may contribute to the clinical phenotype. The present analysis pursued the hypothesis that breast cancer survivors form subgroups, based on psychological and sleep-related parameters that are relevant to the impact of pain on the patients’ life.

Methods

We analysed 337 women treated for breast cancer, in whom psychological and sleep-related parameters as well as parameters related to pain intensity and interference had been acquired. Data were analysed by using supervised and unsupervised machine-learning techniques (i) to detect patient subgroups based on the pattern of psychological or sleep-related parameters, (ii) to interpret the detected cluster structure and (iii) to relate this data structure to pain interference and impact on life.

Results

Artificial intelligence-based detection of data structure, implemented as self-organizing neuronal maps, identified two different clusters of patients. A smaller cluster (11.5% of the patients) had comparatively lower resilience, more depressive symptoms and lower extraversion than the other patients. In these patients, life-satisfaction, mood, and life in general were comparatively more impeded by persistent pain.

Conclusions

The results support the initial hypothesis that psychological and sleep-related parameter patterns are meaningful for subgrouping patients with respect to how persistent pain after breast cancer treatments interferes with their life. This indicates that management of pain should address more complex features than just pain intensity. Artificial intelligence is a useful tool in the identification of subgroups of patients based on psychological factors.

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Pain interference with daily life is relevant for post-surgery breast cancer patients.

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11.5% of 337 patients belonged to a subgroup with high life interference of pain.

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Life interference was not a function of pain intensity.

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Risk factors were lower resilience, more depressive symptoms and lower extraversion.

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Life-satisfaction, mood, and life in general were impeded by persistent pain.

Poor Sleep Is a Risk Factor for Low-Back Pain among Healthcare Workers: Prospective Cohort Study

This study aimed to investigate the association between poor sleep and risk of low-back pain (LBP) in healthcare workers. Using a prospective cohort design with 1-year follow-up, a total of 1955 healthcare workers (60% nurses) from 389 departments at 19 hospitals responded to questionnaires containing items related to lifestyle, health, and working environment. Associations between sleep scores (0-100) at baseline and LBP intensity (0-10) at follow-up were modelled using cumulative logistic regression accounting for clustering at the department level and adjusted for lifestyle and psychosocial confounders. In the full population of healthcare workers, 43.9% and 24.4% experienced moderate and poor sleep, respectively. In the fully adjusted model with good sleep as reference, moderate, and poor sleep increased the risk of LBP at follow-up, with odds ratios (OR's) of 1.66 (95% confidence interval (CI) 1.35-2.04) and 2.05 (95% CI 1.57-2.69), respectively. Three sensitivity analyses including healthcare workers free from LBP, nurses, and nurses free from LBP at baseline, respectively, yielded similar results. In conclusion, poor sleep constitutes a potent risk factor for LBP among healthcare workers. The presented results provide strong incentives to evaluate and weigh current prevention policies against an updated biopsychosocial framework.

AAAPT Diagnostic Criteria for Acute Abdominal and Peritoneal Pain After Surgery

Abdominal and peritoneal pain after surgery is common and burdensome, yet the lack of standardized diagnostic criteria for this type of acute pain impedes basic, translational, and clinical investigations. The collaborative effort among the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks, American Pain Society, and American Academy of Pain Medicine Pain Taxonomy (AAAPT) provides a systematic framework to classify acute painful conditions. Using this framework, a multidisciplinary working group reviewed the literature and developed core diagnostic criteria for acute abdominal and peritoneal pain after surgery. In this report, we apply the proposed AAAPT framework to 4 prototypical surgical procedures resulting in abdominal and peritoneal pain as examples: cesarean delivery, cholecystectomy, colorectal surgical procedures, and pancreas resection. These diagnostic criteria address the 3 most common surgical procedures performed in the United States, capture diverse surgical approaches, and may also be applied to other surgical procedures resulting in abdominal and peritoneal pain. Additional investigation regarding the validity and reliability of this framework will facilitate its adoption in research that advances our comprehension of mechanisms, deliver better treatments, and help prevent the transition of acute to chronic pain after surgery in the abdominal and peritoneal region. PERSPECTIVE: Using AAAPT, we present key diagnostic criteria for acute abdominal and peritoneal pain after surgery. We provide a systematic classification using 5 dimensions for abdominal and peritoneal pain that occurs after surgery, in addition to 4 specific surgical procedures: cesarean delivery, cholecystectomy, colorectal surgical procedures, and pancreas resection.

Immune System Sex Differences May Bridge the Gap Between Sex and Gender in Fibromyalgia

The fibromyalgia syndrome (FMS) is characterized by chronic widespread pain, sleep disturbances, fatigue, and cognitive alterations. A limited efficacy of targeted treatment and a high FMS prevalence (2–5% of the adult population) sums up to high morbidity. Although, altered nociception has been explained with the central sensitization hypothesis, which may occur after neuropathy, its molecular mechanism is not understood. The marked female predominance among FMS patients is often attributed to a psychosocial predisposition of the female gender, but here we will focus on sex differences in neurobiological processes, specifically those of the immune system, as various immunological biomarkers are altered in FMS. The activation of innate immune sensors is compatible with a neuropathy or virus-induced autoimmune diseases. Considering sex differences in the immune system and the clustering of FMS with autoimmune diseases, we hypothesize that the female predominance in FMS is due to a neuropathy-induced autoimmune pathophysiology. We invite the scientific community to verify the autoimmune hypothesis for FMS.

Chronic Pain and Sleep Disturbances: A Pragmatic Review of Their Relationships, Comorbidities, and Treatments

Objective

The objective of this review is to answer three questions: 1) How are chronic pain severity and pain duration affected in patients with chronic pain and sleep disturbances that occur simultaneously? 2) What are common comorbidities and pain-related symptoms seen in patients with chronic pain and sleep disturbances? and 3) What are potentially effective pharmacological and nonpharmacological treatment options for both conditions?

Methods

Ovid Medline and PubMed were searched. Search terms included sleep wake disorder, chronic pain, fibromyalgia, treatment outcome, psychotherapy, complementary therapies, and therapeutics. Studies that assessed outcomes between individuals with chronic pain and those with concurrent chronic pain and sleep disturbances were included. Randomized controlled clinical trials of treatments for both conditions were included.

Results

Sixteen studies indicated that patients with both chronic pain and sleep disturbances have greater pain severity, longer duration of pain, greater disability, and are less physically active than those without sleep disturbances. Patients with both conditions are more likely to have concurrent depression, catastrophizing, anxiety, and suicidal ideation. Thirty-three randomized controlled trials assessed treatment for both chronic pain and sleep disturbances. Pregabalin was the most frequently studied medication, showing improvement in pain and sleep symptoms. Cognitive behavioral therapy for insomnia showed long-term improvement in sleep for patients with chronic pain.

Conclusions

Individuals with chronic pain and sleep disturbances have greater symptom severity, longer duration of symptoms, more disability, and additional comorbidities. Pharmacological and nonpharmacological treatments may be useful in the treatment of concurrent chronic pain and sleep disturbances, but further study is needed.

Psychosocial Variables and Sleep Associated With Neck Pain in Adolescents: A Systematic Review

Purpose: To identify and critically assess the evidence on the association between psychosocial variables and neck pain (NP) in adolescents.Methods: Searches were conducted using seven electronic databases. Two reviewers screened studies for inclusion and assessed the quality of included studies. A meta-analysis was performed for studies that measured depression and sleep.Results: Fourteen studies were included in a total of 21 comparisons. Statistically significant differences were found for depression (OR = 2.36; CI_95% = 1.26-4.42 and OR = 2.26; CI_95% = 1.06-4.84 for girls and boys), anxiety (OR = 1.43; CI_95% = 1.20-1.70), catastrophizing (WMD = 6.6; 95%CI = 3.1;10.1 points), stress (OR = 2.00; CI_95% = 1.50-2.70), and sleep (OR = 1.63; CI_95% = 1.23-2.18). Two studies on self-efficacy reported contradictory results.Conclusions: There is very limited to limited evidence that adolescents with NP have higher levels of depression, anxiety, catastrophizing, stress and report lower sleep quality, and self-efficacy than adolescents without NP. There is also conflicting evidence on whether self-efficacy differs between adolescents with and without NP.

Sleep deficiency and chronic pain: potential underlying mechanisms and clinical implications

Pain can be both a cause and a consequence of sleep deficiency. This bidirectional relationship between sleep and pain has important implications for clinical management of patients, but also for chronic pain prevention and public health more broadly. The review that follows will provide an overview of the neurobiological evidence of mechanisms thought to be involved in the modulation of pain by sleep deficiency, including the opioid, monoaminergic, orexinergic, immune, melatonin, and endocannabinoid systems; the hypothalamus-pituitary-adrenal axis; and adenosine and nitric oxide signaling. In addition, it will provide a broad overview of pharmacological and non-pharmacological approaches for the management of chronic pain comorbid with sleep disturbances and for the management of postoperative pain, as well as discuss the effects of sleep-disturbing medications on pain amplification.

Yoga, Physical Therapy, and Back Pain Education for Sleep Quality in Low-Income Racially Diverse Adults with Chronic Low Back Pain: a Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Poor sleep is common among adults with chronic low back pain (cLBP), but the influence of cLBP treatments, such as yoga and physical therapy (PT), on sleep quality is under studied.

OBJECTIVE

Evaluate the effectiveness of yoga and PT for improving sleep quality in adults with cLBP.

DESIGN

Secondary analysis of a randomized controlled trial.

SETTING

Academic safety-net hospital and 7 affiliated community health centers.

PARTICIPANTS

A total of 320 adults with cLBP.

INTERVENTION

Twelve weekly yoga classes, 1-on-1 PT sessions, or an educational book.

MAIN MEASURES

Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI) global score (0-21) at baseline, 12 weeks, and 52 weeks. Additionally, we also evaluated how the proportion of participants who achieved a clinically meaningful improvement in sleep quality (> 3-point reduction in PSQI) at 12 weeks varied by changes in pain and physical function at 6 weeks.

KEY RESULTS

Among participants (mean age = 46.0, 64% female, 82% non-white), nearly all (92%) reported poor sleep quality (PSQI > 5) at baseline. At 12 weeks, modest improvements in sleep quality were observed among the yoga (PSQI mean difference [MD] = - 1.19, 95% confidence interval [CI] - 1.82, - 0.55) and PT (PSQI MD = - 0.91, 95% CI - 1.61, - 0.20) groups. Participants who reported a ≥ 30% improvement in pain or physical function at 6 weeks, compared with those who improved < 10%, were more likely to be a sleep quality responder at 12 weeks (odds ratio [OR] = 3.51, 95% CI 1.73, 7.11 and OR = 2.16, 95% CI 1.18, 3.95, respectively). Results were similar at 52 weeks.

CONCLUSION

In a sample of adults with cLBP, virtually all with poor sleep quality prior to intervention, modest but statistically significant improvements in sleep quality were observed with both yoga and PT. Irrespective of treatment, clinically important sleep improvements at the end of the intervention were associated with mid-intervention pain and physical function improvements.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01343927.

Pain in long-term survivors of childhood cancer: A systematic review of the current state of knowledge and a call to action from the Children's Oncology Group

Survivors of childhood cancer may be at risk of experiencing pain, and a systematic review would advance our understanding of pain in this population. The objective of this study was to describe: 1) the prevalence of pain in survivors of childhood cancer, 2) methods of pain measurement, 3) associations between pain and biopsychosocial factors, and 4) recommendations for future research. Data sources for the study were articles published from January 1990 to August 2019 identified in the PubMed, PsycINFO, EMBASE, and Web of Science data bases. Eligible studies included: 1) original research, 2) quantitative assessments of pain, 3) articles published in English, 4) cancers diagnosed between birth and age 21 years, 5) survivors at 5 years from diagnosis and/or at 2 years after therapy completion, and 6) a sample size >20. Seventy-three articles were included in the final review. Risk of bias was considered using the Cochrane risk of bias tool. The quality of evidence was evaluated according to Grading of Recommendations Assessment Development and Evaluation (GRADE) criteria. Common measures of pain were items created by the authors for the purpose of the study (45.2%) or health-related quality-of-life/health status questionnaires (42.5%). Pain was present in from 4.3% to 75% of survivors across studies. Three studies investigated chronic pain according the definition in the International Classification of Diseases. The findings indicated that survivors of childhood cancer are at higher risk of experiencing pain compared with controls. Fatigue was consistently associated with pain, females reported more pain than males, and other factors related to pain will require stronger evidence. Theoretically grounded, multidimensional measurements of pain are absent from the literature.

Smartphone Use and Sleep Quality in Chinese College Students: A Preliminary Study

BACKGROUND

Chinese college students are at high risk of sleep problems, and smartphone use is common among this population. However, the relationship between smartphone use characteristics and sleep problems in Chinese college students has been inadequately studied. In this preliminary study, we examined the association of poor sleep quality with smartphone use in a sample of Chinese college students from a health vocational college in Changsha, China.

METHODS

A total of 439 college students completed a self-report questionnaire containing the Pittsburgh Sleep Quality Index (PSQI) and questions regarding demographic information, psychosocial factors, physical health, smartphone use characteristics, and mobile phone addiction (MPA).

RESULTS

The results showed that the prevalence of poor sleep quality (PSQI > 7) in Chinese college students was 9.8%. In multiple logistic regression analysis, poor sleep quality was significantly associated with male gender (OR: 2.80, P: 0.022), not having good physical health (OR: 2.61, P: 0.020), headache (OR: 2.47, P: 0.014), more severe depressive symptoms (OR: 2.17, P: 0.049), > four years of smartphone use (OR: 3.38, P: 0.001), > five hours of daily smartphone use (OR: 2.19, P: 0.049), and more severe inability to control MPA craving (OR: 2.04, P: 0.040).

CONCLUSION

Our findings suggest that excessive smartphone use and MPA are associated with poor sleep quality in a sample of Chinese college students from a health vocational college. Because of the limited sample representativeness and cross-sectional design of this study, large-scale prospective representative studies are warranted to confirm these associations.

Associations of Sleep Disturbance, Atopy, and Other Health Measures with Chronic Overlapping Pain Conditions

AIMS

To quantify the contributions of atopic disorders, sleep disturbance, and other health conditions to five common pain conditions.

METHODS

This cross-sectional analysis used data from 655 participants in the OPPERA study. The authors investigated the individual and collective associations of five chronic overlapping pain conditions (COPCs) with medically diagnosed atopic disorders and self-reported sleep disturbance, fatigue, and symptoms of obstructive sleep apnea. Atopic disorders were allergies, allergic rhinitis, atopic dermatitis, allergic asthma, urticaria, allergic conjunctivitis, and food allergy. Logistic regression models estimated odds ratios as measures of association with temporomandibular disorders, headache, irritable bowel syndrome, low back pain, and fibromyalgia. Measures of sleep and atopy disorders were standardized to z scores to determine the relative strength of their associations with each COPC. Sociodemographic characteristics and body mass index were covariates. Random forest regression analyzed all variables simultaneously, computing importance metrics to determine which variables best differentiated pain cases from controls.

RESULTS

Fatigue and sleep disturbance were strongly associated with each COPC and with the total number of COPCs. An increase of one standard deviation in fatigue or sleep disturbance score was associated with approximately two-fold greater odds of having a COPC. In random forest models, atopic disorders contributed more than other health measures to differentiating between cases and controls of headache, whereas other COPCs were best differentiated by measures of fatigue or sleep.

CONCLUSION

Atopic disorders, previously recognized as predictors of poor sleep, are associated with COPCs after accounting for sleep problems.

Exploring the Meaning of Cognitive Behavioral Therapy for Insomnia for Patients with Chronic Pain

OBJECTIVE

Insomnia is one of the most common, persistent, and distressing symptoms associated with chronic pain. Cognitive behavioral therapy for insomnia (CBT-I) is the firstline treatment for insomnia, but patient preferences and perspectives about CBT-I within the context of chronic pain are unknown. The current qualitative study sought to understand the experience of CBT-I among patients with chronic pain, including aspects of CBT-I that were found to be difficult (e.g., pain as a specific barrier to adherence/dropout), changes in sleep and pain functioning after CBT-I, and aspects of CBT-I that were appreciated.

DESIGN

Qualitative semistructured interviews.

METHODS

We conducted individual semistructured interviews with 17 veterans with chronic pain and insomnia who had recently participated in CBT-I, as well as their CBT-I therapists, and used thematic analysis to identify conceptual themes.

RESULTS

Results revealed that patients and CBT-I therapists found changing sleep habits during CBT-I challenging due to anxiety and temporary increases in fatigue, but did not identify major pain-related barriers to adhering to CBT-I recommendations; patients experienced better sleep, mood, energy, and socialization after CBT-I despite minimal changes in pain intensity; and patients highly valued CBT-I as a personalized treatment for sleep and strongly recommended it for other patients with chronic pain.

CONCLUSIONS

Findings of improved sleep and functional outcomes support efforts to incorporate CBT-I into chronic pain treatment, including educating patients and providers about the strong feasibility of improving sleep and quality of life despite ongoing pain.

Sleep problems increase the risk of musculoskeletal pain in boys but not girls: a prospective cohort study

Adults with sleep problems are at higher risk for onset of musculoskeletal pain, but the evidence is less clear for children. This prospective cohort study investigated whether children with sleep problems are at higher risk for onset of musculoskeletal pain and explored whether sex is a modifier of this association. In a prospective cohort study of Australian schoolchildren (n = 1239, mean age 9 years), the associations between sleep problems at baseline and new onset of both musculoskeletal pain and persistent musculoskeletal pain (pain lasting > 3 months) 1 year later were investigated using logistic regression. The potential modifying effect of sex was also assessed. One-year incidence proportion for musculoskeletal pain onset is 43% and 7% for persistent musculoskeletal pain. Sleep problems were associated with musculoskeletal pain onset and persistent musculoskeletal pain onset in boys, odds ratio 2.80 (95% CI 1.39, 5.62) and OR 3.70 (1.30, 10.54), respectively, but not girls OR 0.58 (0.28, 1.19) and OR 1.43 (0.41, 4.95), respectively.Conclusions: Rates of musculoskeletal pain are high in children. Boys with sleep problems are at greater risk of onset of musculoskeletal pain, but girls do not appear to have higher risk. Consideration of sleep health may help prevent persistent musculoskeletal pain in children. What is Known: • Sleep problems are associated with the onset of musculoskeletal pain in adults. • It is not clear if the association between sleep problems and the onset of musculoskeletal pain is present also in children and if sex plays a role in this association. What is New: • This is the first large population-based study that has prospectively investigated the relationship between sleep problems and onset of musculoskeletal pain in school-aged children. • Children, especially boys with sleep problems, were at increased risk for the development of persistent musculoskeletal pain.

I'm tired and it hurts! Sleep quality and acute pain response in a chronic pain population

OBJECTIVE/BACKGROUND

There are bidirectional links between sleep quality and pain, with recent research suggesting that sleep impairment more strongly predicts future pain than vice versa. Relatively few studies have examined the relationship between sleep quality and acute pain among chronic pain patients. The purpose of the current study is to investigate relationships among subjective sleep quality and behavioral and physiological responses to a cold pressor pain task (CPT) in chronic pain patients.

PATIENTS/METHODS

In sum, 120 individuals with chronic pain were included. Participants completed a series of questionnaires followed by the CPT. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Physiological baseline state and stress response were assessed before and during the CPT using heart rate (HR), electromyography frontalis (EMGF), galvanic skin response conductance (GSR), and skin temperature (°C). Multiple linear regressions adjusting for opioid usage were performed.

RESULTS

After adjusting for opioid use, PSQI global score explained significant variance in pain tolerance (B = -5.37, β = -0.23, p = 0.01), baseline GSR (B = -0.66, β = -0.24, p = 0.01), and HR change from baseline to CPT (B = 1.33, β = 0.25, p = 0.01).

CONCLUSIONS

Worse perceived sleep quality was associated with lower pain tolerance, lower baseline GSR conductance, and greater HR change from baseline to CPT. These findings underscore the importance of accounting for opioid usage and psychological dimensions of pain in the relationship between sleep and acute pain response in chronic pain populations.

Sleepiness comorbid to musculoskeletal pain is associated with worse quality of life and mood symptoms in a general population sample

Objectives

Musculoskeletal (MSK) pain and hypersomnolence (HPS) are very disabling conditions that may share some pathophysiological factors. This study aimed to evaluate the interaction between MSK pain and HPS and its association with mood symptoms, fatigue, quality of life, and both objective and subjective sleep quality.

Design

Cross-sectional study.

Setting

General population based sample.

Participants

510 individuals from EPISONO cohort, São Paulo (Brazil).

Measurements

All participants completed questionnaires, had clinical assessment and underwent a full-night polysomnography. HPS was defined according to Epworth Sleepiness Scale while the presence of MSK pain was defined by structured questionnaire. The sample was allocated into 4 groups: control (CTRL, n=281), HPS (n=141), MSK (n=50), and both conditions (HPS+MSK, n=38).

Results

MSK pain and HPS by themselves were associated with worse mood symptoms and quality of life. However, individuals with both associated conditions (HPS+MSK) presented higher frequencies of moderate to severe depression (44.1%) and anxiety symptoms (45.7%), as well as an additional decrease in quality of life compared to the other groups. There were no differences between HPS+MSK and MSK groups in objective sleep pattern. With regard to subjective sleep, HPS+MSK presented a higher prevalence of sleep attacks and cataplexy compared to all other groups.

Conclusions

The combination of MSK pain and HPS was associated with worse mood symptoms, quality of life and HPS-related features. This study suggests that sleepiness may be an important symptom to be investigated and treated in MSK pain-related conditions for a better quality of life.

Heart rate variability and surgical pleth index under anesthesia in poor and normal sleepers

Poor sleep quality is associated with autonomic dysfunctions and altered pain perception and tolerance. To investigate whether autonomic dysregulations related to insomnia would still exist under general anesthesia, we adopt heart rate variability (HRV) analysis to evaluate ANS activity and surgical pleth index (SPI) to compare nociceptive/anti-nociceptive balance. We enrolled 61 adult females scheduled for gynecological surgeries under general anesthesia. All the subjects were ASA Class I to III without using medicines affecting HRV. We used the Insomnia Severity Index to evaluate sleep qualities. ECG data were recorded and signals which denote four different surgical stages were extracted (baseline, incision, mid-surgery, and end of surgery). We analyzed the HRV changes across the whole surgical period and differences among good and poor sleepers. We also compared the SPI differences among groups. For baseline HRV analysis, we found significant differences in the RMSSD (p = 0.043), pNN50 (p = 0.029), VLF power (p = 0.035), LF power (p = 0.004), and HF power (p = 0.037) between the good and poor sleeper groups. However, all intergroup differences disappeared after anesthesia induction. Temporal HRV changes significantly among different perioperative stages (RMSSD, p < 0.001; pNN50, p = 0.004; LF, p < 0.001; and HF, p < 0.001). Patients with different sleep qualities did not exhibit different SPI levels in all four periods. Poor sleepers exhibited attenuated parasympathetic activities at the baseline but no differences after the induction. Nociceptive/anti-nociceptive balance seems not be altered by poor sleep condition under general anesthesia.

Sleep, Experimental Pain and Clinical Pain in Patients with Chronic Musculoskeletal Pain and Healthy Controls

Purpose

Everyday variations in night sleep in healthy pain-free subjects are at most weakly associated with pain, whereas strong alterations (eg, sleep deprivation, insomnia) lead to hyperalgesic pain changes. Since it remains unclear how substantial sleep alterations need to be in order to affect the pain system and lead to a coupling of both functions, the present study aimed at providing sufficient variance for co-variance analyses by examining a sample consisting of both healthy subjects and chronic pain patients.

Methods

A sample of 20 chronic musculoskeletal pain patients and 20 healthy controls was examined. This sample was assumed to show high inter-individual variability in sleep and pain, as pain patients frequently report sleep disturbances, whereas healthy subjects were required to be pain-free and normal sleepers. Sleep of two non-consecutive nights was measured using portable polysomnography and questionnaires. Experimental pain parameters (pressure pain thresholds (PPT), temporal summation of pain (TSP), conditioned pain modulation (CPM)) and situational pain catastrophizing (SCQ) were assessed in laboratory sessions before and after sleep. Pain patients’ clinical pain was assessed via questionnaire.

Results

As expected, both groups differed in several sleep parameters (reduced total sleep time and sleep efficiency, more time awake after sleep onset, lower subjective sleep quality in the patients) and in a few pain parameters (lower PPTs in the patients). In contrast, no differences were found in TSP, CPM, and SCQ. Contrary to our expectations, regression analyses indicated no prediction of overnight pain changes by sleep parameters.

Conclusion

Since sleep parameters were hardly apt to predict overnight pain changes, this leaves the association of both systems mainly unproven when using between-subject variance for verification.

Improvements in clinical pain and experimental pain sensitivity after cognitive functional therapy in patients with severe persistent low back pain

Introduction:

Multidisciplinary care is recommended for disabling persistent low back pain (pLBP) nonresponsive to primary care. Cognitive functional therapy (CFT) is a physiotherapy-led individualised intervention targeting psychological, physical, and lifestyle barriers to recovery, to self-manage pLBP.

Objectives:

This pilot study investigated clinical outcomes and pain thresholds after a 12-week CFT pathway in patients with severe pLBP referred to a University Pain Center. Exploratory analyses compared changes in clinical outcomes, opioid consumption, and costs after CFT with changes after a multidisciplinary pain management (MPM) pathway.

Methods:

In total, 47 consecutively referred pLBP patients consented to the CFT pathway. At baseline, 3 and 6 months, clinical outcomes and PPTs were assessed. Control patients (n = 99) who had completed an MPM pathway in the last 3 years were matched from the clinical pain registry used in the Pain Center in a 3:1 ratio based on propensity scores derived from relevant baseline variables of the CFT cases.

Results:

Most clinical outcomes and low back pressure pain threshold were improved at 3 and 6 months after the CFT pathway. Compared with MPM, CFT patients had significantly larger reductions in disability and improved quality of life after the interventions at a lower cost (−3688€ [confidence interval: −3063 to −4314€]). Reduction in pain intensity and proportion of patients withdrawing from opioids (18.2% vs 27.8%) were similar between CFT and MPM groups.

Conclusion:

Improvements in clinical and experimental pain were found after the CFT pathway. Fully powered randomized controlled trials comparing CFT with an MPM program in patients with disabling pLBP are warranted to control for the current limitations.

A Review of Medical Conditions and Behavioral Problems in Dogs and Cats

Not all animals behave identically when faced with the same situation. These individual differences in the expression of their behavior could be due to many factors, including medical conditions. These medical problems can change behavior directly or indirectly. The aims of this review are to describe the state of the art of the relationship among some medical and behavioral problems, and to propose new lines of investigation. The revision is focused on the relation between behavioral problems and pain, endocrine diseases, neurological problems, vomeronasal organ alterations, and cardiac disorders. These problems represent a diagnostic challenge from a practical point of view. The most common sign of pain in animals is a change in behavior. Although the relation of pain to behavioral problems has been widely studied, it is not absolutely clear. As an example, the relation between sleep disorders and pain is poorly known in veterinary medicine. New studies in humans and laboratory animals show that a reciprocal relationship does, in fact, exist. More specifically, the literature suggests that the temporal effect of sleep deprivation on pain may be stronger than that of pain on sleep. Some behavioral problems could modify the sleep-awake cycle (e.g., cognitive dysfunction). The impact of these behavioral problems on pain perception is completely unknown in dogs and cats. Thyroid hormones play an important role, regarding behavioral control. Both hypothyroidism and hyperthyroidism have been related to behavioral changes. Concerning hypothyroidism, this relationship remains controversial. Nonetheless, new neuro-imaging studies provide objective evidence that brain structure and function are altered in hypothyroid patients, both in laboratory animals and in humans. There are many neurological problems that could potentially change behavior. This paper reviews those neurological problems that could lead to behavioral changes without modifying neurological examination. The most common problems are tumors that affect central nervous system silent zones, mild traumatic brain injury, ischemic attacks, and epilepsy. Most of these diseases and their relationship to behavior are poorly studied in dogs and cats. To better understand the pathophysiology of all of these problems, and their relation to behavioral problems, may change the diagnostic protocol of behavioral problems.

Race-related differences in acute pain complaints among inner-city women: the role of socioeconomic status

Previous research has shown that African Americans (AA) report higher pain intensity and pain interference than other racial/ethnic groups as well as greater levels of other risk factors related to worse pain outcomes, including PTSD symptoms, pain catastrophizing, and sleep disturbance. Within a Conservation of Resources theory framework, we tested the hypothesis that socioeconomic status (SES) factors (i.e., income, education, employment, perception of income meeting basic needs) largely account for these racial/ethnic differences. Participants were 435 women [AA, 59.1%; Hispanic/Latina (HL), 25.3%; Non-Hispanic/White (NHW), 15.6%] who presented to an Emergency Department (ED) with an acute pain-related complaint. Data were extracted from psychosocial questionnaires completed at the participants' baseline interview. Structural equation modeling was used to examine whether racial/ethnic differences in pain intensity and pain interference were mediated by PTSD symptoms, pain catastrophizing, sleep quality, and sleep duration, and whether these mediation pathways were, in turn, accounted for by SES factors. Results indicated that SES factors accounted for the mediation relationships linking AA race to pain intensity via PTSD symptoms and the mediation relationships linking AA race to pain interference via PTSD symptoms, pain catastrophizing, and sleep quality. Results suggested that observed racial/ethnic differences in AA women's pain intensity, pain interference, and common risk factors for elevated pain may be largely due to racial/ethnic differences in SES. These findings highlight the role of social inequality in persistent health disparities facing inner-city, AA women.

Total sleep deprivation increases pain sensitivity, impairs conditioned pain modulation and facilitates temporal summation of pain in healthy participants

Chronic pain patients often suffer from insomnia or impaired sleep which has been associated with increased pain sensitivity, but a limited amount of studies have investigated the effects of total sleep deprivation on central pain mechanisms. Therefore, the aim of this study was to determine the effects of total sleep deprivation on temporal summation, conditioned pain modulation, thermal and pressure pain sensitivity in healthy participants. Twenty-four healthy participants took part in this two-session trial. The measurements were conducted after a night of habitual sleep (baseline) and following 24 hours of total sleep deprivation. Detection thresholds for cold and warmth and pain thresholds for cold and heat were assessed. Cuff induced pressure pain detection and tolerance thresholds, temporal summation and conditioned pain modulation were assessed with user-independent, computer-controlled cuff algometry. Conditioned pain modulation was significantly impaired, temporal summation was significantly facilitated and pain sensitivity to pressure and cold pain were significantly increased at follow-up compared with baseline. In conclusion, this study found that one night of total sleep deprivation impaired descending pain pathways, facilitated spinal excitability and sensitized peripheral pathways to cold and pressure pain. Future studies are encouraged to investigate if sleep therapy might normalize pain sensitivity in sleep-deprived chronic pain patients.

From being restrained to recapturing vitality: non-western immigrant women's experiences of undergoing vitamin D treatment after childbirth

Purpose: Vitamin D deficiency is a complex topic in human health and ill-health and has been studied in a variety of contexts and populations. Few studies examine Vitamin D deficiency among non-western immigrant women and even fewer examine women's perspective on daily life while living with low vitamin D levels after childbirth and undergoing vitamin D treatment. The aim was, therefore, to explore health and ill-health among non-western immigrant women living with low vitamin D levels after childbirth and reaching normalized levels after one year of vitamin D treatment. Method: An explorative qualitative study using qualitative content analysis. Six women aged 25 to 38 years, diagnosed with low 25-hydroxyvitamin D levels during pregnancy, were recruited after having undergone vitamin D treatment. Results: The women told about living a restrained life which gradually transformed into an experience of recaptured vitality. They also experienced a need for continuity in medication, as an interruption of treatment meant returning symptoms. Conclusion: In this study, non-western immigrant women described benefits in everyday life, increased strength, relieved pain and improved sleep quality. The findings can provide valuable knowledge for healthcare providers meeting women with physical weakness, musculoskeletal pain and/or poor sleep quality after childbirth. Further studies using a longitudinal design and larger samples are warranted.