One night of total sleep deprivation promotes a state of generalized hyperalgesia: a surrogate pain model to study the relationship of insomnia and pain

Gut Bless Your Pain—Roles of the Gut Microbiota, Sleep, and Melatonin in Chronic Orofacial Pain and Depression

Background. Increased attention has been paid to the gut–brain axis recently, but little is known so far regarding how this translates into pain susceptibility. Aim. The aim of this review is to determine whether gastroenterological disorders and sleep disorders (directly or indirectly) contribute to an increased susceptibility to depression and chronic orofacial pain. Method. A search was performed in the U.S. National Library of Medicine (PubMed) database in order to find studies published before 19 December 2021. We used the following terms: gut microbiome, OR sleep quality, OR melatonin, OR GERD, OR IBS, AND: depression OR chronic pain, in different configurations. Only papers in English were selected. Given the large number of papers retrieved in the search, their findings were described and organized narratively. Results. A link exists between sleep disorders and gastroenterological disorders, which, by adversely affecting the psyche and increasing inflammation, disturb the metabolism of tryptophan and cause excessive microglial activation, leading to increased susceptibility to pain sensation and depression. Conclusions. Pain therapists should pay close attention to sleep and gastrointestinal disorders in patients with chronic pain and depression.

Chronic Musculoskeletal Pain Moderates the Association between Sleep Quality and Dorsostriatal-Sensorimotor Resting State Functional Connectivity in Community-Dwelling Older Adults

Aging is associated with poor sleep quality and greater chronic pain prevalence, with age-related changes in brain function as potential underlying mechanisms. Objective. The following cross-sectional study aimed to determine whether self-reported chronic musculoskeletal pain in community-dwelling older adults moderates the association between sleep quality and resting state functional brain connectivity (rsFC). Methods. Community-dwelling older individuals (mean age = 73.29 years) part of the NEPAL study who completed the Pittsburg Sleep Quality Index (PSQI) and a rsFC scan were included (n = 48) in the present investigation. To that end, we tested the effect of chronic pain-by-PSQI interaction on rsFC among atlas-based brain regions-of-interest, controlling for age and sex. Results and Discussion. A significant network connecting the bilateral putamen and left caudate with bilateral precentral gyrus, postcentral gyrus, and juxtapositional lobule cortex, survived global multiple comparisons (FDR; q < 0.05) and threshold-free network-based-statistics. Greater PSQI scores were significantly associated with greater dorsostriatal-sensorimotor rsFC in the no-pain group, suggesting that a state of somatomotor hyperarousal may be associated with poorer sleep quality in this group. However, in the pain group, greater PSQI scores were associated with less dorsostriatal-sensorimotor rsFC, possibly due to a shift of striatal functions toward regulation sensorimotor aspects of the pain experience, and/or aberrant cortico-striatal loops in the presence of chronic pain. This preliminary investigation advances knowledge about the neurobiology underlying the associations between chronic pain and sleep in community-dwelling older adults that may contribute to the development of effective therapies to decrease disability in geriatric populations.

Impact of coronavirus disease 2019 on patients with chronic pain: multicenter study in Korea

Background

The coronavirus disease 2019 (COVID-19) pandemic has caused significant changes. This study aimed to investigate the impact of COVID-19 on patients with chronic pain.

Methods

Patients with chronic pain from 23 university hospitals in South Korea participated in this study. The anonymous survey questionnaire consisted of 25 questions regarding the following demographic data, diagnosis, hospital visit frequency, exercise duration, time outside, sleep duration, weight change, nervousness and anxiety, depression, interest or pleasure, fatigue, daily life difficulties, and self-harm thoughts. Depression severity was evaluated using the Patient Health Questionnaire-9 (PHQ-9). Logistic regression analysis was used to investigate the relationship between increased pain and patient factors.

Results

A total of 914 patients completed the survey, 35.9% of whom had decreased their number of visits to the hospital, mostly due to COVID-19. The pain level of 200 patients has worsened since the COVID-19 outbreak, which was more prominent in complex regional pain syndrome (CRPS). Noticeable post-COVID-19 changes such as exercise duration, time spent outside, sleep patterns, mood, and weight affected patients with chronic pain. Depression severity was more significant in patients with CRPS. The total PHQ-9 average score of patients with CRPS was 15.5, corresponding to major depressive orders. The patients’ decreased exercise duration, decreased sleep duration, and increased depression were significantly associated with increased pain.

Conclusions

COVID-19 has caused several changes in patients with chronic pain. During the pandemic, decreased exercise and sleep duration and increased depression were associated with patients’ increasing pain.

Predictive factors of sleep quality in patients with chronic migraine

INTRODUCTION

One of the factors contributing to transformation of migraine are sleep disorders, which can act as a trigger and/or perpetuating factor in these patients. This study's primary objective was to identify predictive factors related to sleep quality in patients with chronic migraine (CM); the secondary objective was to identify any differences in psychological variables and disability between patients with CM with better or poorer sleep quality.

METHODS

A total of 50 patients with CM were included in an observational, cross-sectional study. We recorded data on demographic, psychological, and disability variables using self-administered questionnaires.

RESULTS

A direct, moderate-to-strong correlation was observed between the different disability and psychological variables analysed (P < .05). Regression analysis identified depressive symptoms, headache-related disability, and pain catastrophising as predictors of sleep quality; together, these factors explain 33% of the variance. Statistically significant differences were found between patients with better and poorer sleep quality for depressive symptoms (P = .016) and pain catastrophising (P = .036).

CONCLUSIONS

The predictive factors for sleep quality in patients with CM were depressive symptoms, headache-related disability, and pain catastrophising. Patients with poorer sleep quality had higher levels of pain catastrophising and depressive symptoms.

Predictive factors of sleep quality in patients with chronic migraine

INTRODUCTION

One of the factors contributing to transformation of migraine are sleep disorders, which can act as a trigger and/or perpetuating factor in these patients. This study's primary objective was to identify predictive factors related to sleep quality in patients with chronic migraine (CM); the secondary objective was to identify any differences in psychological variables and disability between patients with CM with better or poorer sleep quality.

METHODS

A total of 50 patients with CM were included in an observational, cross-sectional study. We recorded data on demographic, psychological, and disability variables using self-administered questionnaires.

RESULTS

A direct, moderate-to-strong correlation was observed between the different disability and psychological variables analysed (P<.05). Regression analysis identified depressive symptoms, headache-related disability, and pain catastrophising as predictors of sleep quality; together, these factors explain 33% of the variance. Statistically significant differences were found between patients with better and poorer sleep quality for depressive symptoms (P=.016) and pain catastrophising (P=.036).

CONCLUSIONS

The predictive factors for sleep quality in patients with CM were depressive symptoms, headache-related disability, and pain catastrophising. Patients with poorer sleep quality had higher levels of pain catastrophising and depressive symptoms.

Profiling and Association over Time between Disability and Pain Features in Patients with Chronic Nonspecific Neck Pain: A Longitudinal Study

OBJECTIVES

To longitudinally investigate the relationships between neck/arm disability and pain profile measures in individuals with chronic nonspecific neck pain (NSNP) at baseline, one month, and six months after a standardized physiotherapy intervention. A secondary aim was to compare pain sensitivity of individuals with chronic NSNP at baseline to healthy controls.

METHODS

A total of sixty-eight individuals with chronic NSNP and healthy controls were recruited. Neck disability index (NDI), the 11-item disabilities of the arm, shoulder, and hand questionnaire (QuickDASH), temporal summation (TS), pressure pain thresholds (PPTs), pain intensity and pain extent were assessed in individuals with chronic NSNP. For the cross-sectional assessment, TS and PPTs were compared to healthy controls.

RESULTS

After following a standardized physiotherapy intervention, local and distal PPTs to the neck region decreased at one and six month follow-ups, respectively. Pain extent decreased at one and six months. Furthermore, a positive correlation between neck/arm disability and pain intensity was found at baseline, whereas moderate positive correlations (e.g., between NDI and pain extent) at baseline, one and six month follow-ups and negative correlations at six months (e.g., between arm disability and PPTs) were found.

DISCUSSION

Overall, these findings indicate that pain sensitivity can worsen following treatment despite reduced pain extent and unchanged neck disability and pain intensity scores over a six-month period in individuals with chronic NSNP.

Prevalence and predictors of low back pain among the Iranian population: Results from the Persian cohort study

Background and objectives

Low back pain (LBP) is a common health condition in populations. Limited large-scale population-based studies evaluated the prevalence and predictors of LBP in developing countries. This study aimed to evaluate the prevalence and factors associated with LBP among the Iranian population.

Methods

We used baseline information from the Prospective Epidemiological Research Studies in Iran (PERSIAN), including individuals from 16 provinces of Iran. LBP was defined as the history of back pain interfering with daily activities for more than one week during an individual's lifetime. Various factors hypothesized to affect LBP, such as age, sex, marital status, educational status, ethnicity, living area, employment status, history of smoking, body mass index (BMI), physical activity, sleep duration, wealth score, history of joint pain, and history of morning stiffness in the joints were evaluated.

Results

In total, 163770 Iranians with a mean age of 49.37 (SD = 9.15) were included in this study, 44.8% of whom were male. The prevalence of LBP was 25.2% among participants. After adjusting for confounders, the female gender [OR:1.244(1.02–1.50)], middle and older ages [OR:1.23(1.10–1.33) and OR:1.13(1.07–1.42), respectively], being overweight or obese [OR:1.13(1.07–1.19) and OR:1.21(1.16–1.27), respectively], former and current smokers (OR:1.25(1.16–1.36) and OR:1.28(1.17–1.39), respectively], low physical activity [OR:1.07(1.01–1.14)], and short sleep duration [OR: 1.09(1.02–1.17)] were significantly associated with LBP.

Conclusion

In this large-scale study, we found the lifetime prevalence of LBP to be lower among the Iranian population in comparison to the global prevalence of LBP; further studies are warranted to evaluate the causality of risk factors on LBP.

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The lifetime prevalence of low back pain in the Iranian population is 25.2%.

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Our survey includes 163770 people from 16 Iranian provinces.

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We used PERSIAN Cohort data which is the largest study conducted in Iran population.

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For analysis, we used both unadjusted and adjusted logistic regression models.

Progress on the Mechanism of Visceral Hypersensitivity in Nonerosive Reflux Disease

Nonerosive reflux disease (NERD) is the most common type of gastroesophageal reflux disease (GERD). Its clinical symptoms can recur, and clinical treatment is often ineffective, causing patients severe economic and psychological burden. In recent years, studies that have explored in-depth the pathogenesis of NERD have found that visceral hypersensitivity (VH) plays an important role. VH refers to the phenomenon that viscera react strongly to nociceptive stimuli or produce a negative reaction to physiological stimuli due to the decrease of one’s visceral pain threshold. Studies have found that the VH mechanism in NERD primarily includes abnormal neurotransmitters, the activation of acid-sensitive receptors, and abnormal psychological factors—all of which we review in this article.

Simultaneous measurement of intra-epidermal electric detection thresholds and evoked potentials for observation of nociceptive processing following sleep deprivation

Sleep deprivation has been shown to increase pain intensity and decrease pain thresholds in healthy subjects. In chronic pain patients, sleep impairment often worsens the perceived pain intensity. This increased pain perception is the result of altered nociceptive processing. We recently developed a method to quantify and monitor altered nociceptive processing by simultaneous tracking of psychophysical detection thresholds and recording of evoked cortical potentials during intra-epidermal electric stimulation. In this study, we assessed the sensitivity of nociceptive detection thresholds and evoked potentials to altered nociceptive processing after sleep deprivation in an exploratory study with 24 healthy male and 24 healthy female subjects. In each subject, we tracked nociceptive detection thresholds and recorded central evoked potentials in response to 180 single- and 180 double-pulse intra-epidermal electric stimuli. Results showed that the detection thresholds for single- and double-pulse stimuli and the average central evoked potential for single-pulse stimuli were significantly decreased after sleep deprivation. When analyzed separated by sex, these effects were only significant in the male population. Multivariate analysis showed that the decrease of central evoked potential was associated with a decrease of task-related evoked activity. Measurement repetition led to a decrease of the detection threshold to double-pulse stimuli in the mixed and the female population, but did not significantly affect any other outcome measures. These results suggest that simultaneous tracking of psychophysical detection thresholds and evoked potentials is a useful method to observe altered nociceptive processing after sleep deprivation, but is also sensitive to sex differences and measurement repetition.

Are Changes in Sleep Quality/Quantity or Baseline Sleep Parameters Related to Changes in Clinical Outcomes in Patients With Nonspecific Chronic Low Back Pain?: A Systematic Review

OBJECTIVES

Sleep disturbance is prevalent among patients with chronic low back pain (CLBP). This systematic review aimed to summarize the evidence regarding the: (1) temporal relations between changes in sleep quality/quantity and the corresponding changes in pain and/or disability; and (2) role of baseline sleep quality/quantity in predicting future pain and/or disability in patients with CLBP.

METHODS

Four databases were searched from their inception to February 2021. Two reviewers independently screened the abstract and full text, extracted data, assessed the methodological quality of the included studies, and evaluated the quality of evidence of the findings using the Grading of Recommendations Assessment Development and Evaluation (GRADE).

RESULTS

Of 1995 identified references, 6 articles involving 1641 participants with CLBP were included. Moderate-quality evidence substantiated that improvements in self-reported sleep quality and total sleep time were significantly correlated with the corresponding LBP reduction. Low-quality evidence showed that self-reported improvements in sleep quality were related to the corresponding improvements in CLBP-related disability. There was conflicting evidence regarding the relation between baseline sleep quality/quantity and future pain/disability in patients with CLBP.

DISCUSSION

This is the first systematic review to accentuate that improved self-reported sleep quality/quantity may be associated with improved pain/disability, although it remains unclear whether baseline sleep quality/quantity is a prognostic factor for CLBP. These findings highlight the importance of understanding the mechanisms underlying the relation between sleep and CLBP, which may inform the necessity of assessing or treating sleep disturbance in people with CLBP.

Headache outcomes of a sleep behavioral intervention in breast cancer survivors: Secondary analysis of a randomized clinical trial

BACKGROUND

Breast cancer survivors often have persisting headache. In a secondary analysis of the Brief Behavioral Therapy for Cancer-Related Insomnia (BBT-CI) clinical trial (ClinicalTrials.gov identifier NCT02165839), the authors examined the effects of BBT-CI on headache outcomes in patients with breast cancer.

METHODS

Patients with breast cancer who were receiving chemotherapy were randomly assigned to receive either the BBT-CI intervention or the Healthy EAting Education Learning for healthy sleep (HEAL) control intervention, and both were delivered over 6 weeks by trained staff. Headache outcomes and heart rate variability (HRV) were measured at baseline, 6 weeks, 6 months, and 12 months. Mixed-effects models were used to examine longitudinal headache outcomes in the groups according to the intention to treat. Principal component analysis and agglomerative hierarchical clustering were conducted to reduce 16 variables for data-driven phenotyping.

RESULTS

Patients in the BBT-CI arm (n = 73) exhibited a significant reduction in headache burden over time (P = .02; effect size [Cohen d] = 0.43), whereas the reduction was not significant among those in the HEAL arm (n = 66). The first principal component was positively loaded by headache, sleep, fatigue, and nausea/vomiting and was negatively loaded by cognitive, physical, and emotional functioning. Agglomerative hierarchical clustering revealed 3 natural clusters. Cluster I (n = 58) featured the highest burden of headache, insomnia, and nausea/vomiting; cluster II (n = 50) featured the lowest HRV despite a low burden of headache and insomnia; and cluster III (n = 31) showed an inverse relation between HRV and headache-insomnia, signifying autonomic dysfunction.

CONCLUSIONS

BBT-CI is efficacious in reducing headache burden in breast cancer survivors. Patient phenotyping demonstrates a headache type featuring sleep disturbance, nausea/vomiting, and low physical functioning-revealing similarities to migraine.

LAY SUMMARY

Breast cancer survivors often have persisting headache symptoms. In patients with cancer, treatment of chronic headache disorders using daily medications may be challenging because of drug interactions with chemotherapy and other cancer therapies as well as patients' reluctance to add more drugs to their medicine list. Headache and sleep disorders are closely related to each other. This study demonstrates that a sleep behavioral therapy reduced headache burden in breast cancer survivors. In addition, the majority of headache sufferers had a headache type with similarities to migraine-featuring sleep disturbance, nausea/vomiting, and low physical functioning.

Association between peripheral neuropathy and sleep quality among colorectal cancer patients from diagnosis until 2-year follow-up: results from the PROFILES registry

PURPOSE

Studies on the association between peripheral neuropathy (PN) and patient-reported outcomes have mostly overlooked sleep quality. Therefore, we aimed to assess the association between PN and sleep quality in a population-based sample of colorectal cancer (CRC) patients up 2 years after diagnosis.

METHODS

All newly diagnosed CRC patients from four Dutch hospitals were eligible for participation. Patients (N = 340) completed questionnaires about PN (EORTC QLQ-CIPN20) and sleep (PSQI) before initial treatment (baseline) and 1 and 2 years after diagnosis.

RESULTS

Patients who developed sensory PN (n = 76) or motor PN (n = 79) after treatment more often reported poor sleeping scores (PSQI > 5) compared with those who did not develop SPN or MPN at 1-year (SPN: 38% vs. 261%, MPN: 37% vs. 14%) and 2-year follow-up (SPN: 38 vs. 23%, MPN: 37% vs. 18%) (all p < 0.05). Overall, results showed that among patients who did not develop SPN or MPN, sleep quality improved after baseline, while among patients with SPN or MPN, sleep quality did not improve at one and two years after diagnosis.

CONCLUSIONS

Both SPN and MPN were significantly associated with the course of sleep quality among CRC patients up to 2 years after diagnosis. Clinicians should be encouraged to discuss sleep quality with their patients who either report PN or are at risk of developing PN.

IMPLICATIONS FOR CANCER SURVIVORS

Improving sleep quality among survivors with PN is important, either by reducing PN symptoms or directly targeting sleep.

The association between sleep quality, preoperative risk factors for chronic postoperative pain and postoperative pain intensity 12 months after knee and hip arthroplasty

BACKGROUND

Chronic postoperative pain following total joint replacement (TJA) is a substantial clinical problem, and poor sleep may affect predictive factors for postoperative pain, such as pain catastrophizing. However, the magnitude of these associations is currently unknown. This exploratory study investigated (1) the relationship between preoperative sleep quality, clinical pain intensity, pain catastrophizing, anxiety, and depression and (2) their associations with chronic postoperative pain following TJA.

METHODS

This secondary analysis from a larger randomized controlled trial included rest pain intensity (preoperative and 12 months postoperative; visual analogue scale, VAS), preoperative Pittsburgh Sleep Quality Index (PSQI), Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Scale (HADS) data from 74 knee and 89 hip osteoarthritis (OA) patients scheduled for TJA. Poor sleepers were identified based on preoperative PSQI scores higher than 5.

RESULTS

Poor sleepers demonstrated higher preoperative VAS, pain catastrophizing, anxiety, and depression compared with good sleepers (all p < 0.003). Preoperative PSQI (β = 0.23, p = 0.006), PCS (β = 0.44, p < 0.005), and anxiety (β = 0.18, p = 0.036) were independent factors for preoperative VAS. Preoperative VAS (β = 0.32, p < 0.005), but not preoperative sleep quality (β = -0.06, p = 0.5), was an independent factor for postoperative VAS.

CONCLUSION

The OA patients reporting poor preoperative sleep quality show higher preoperative pain, pain catastrophizing, anxiety, and depression. High preoperative pain intensity, but not poor sleep quality, was associated with higher chronic postoperative pain intensity. Future studies are encouraged to explore associations between sleep and chronic postoperative pain.

The association of sleep disturbances with burning mouth syndrome: An overlooked relationship-A qualitative systematic review

OBJECTIVES

To review the relevant literature to assess whether patients with burning mouth syndrome (BMS) are more prone to have sleep disturbances than general population.

METHODS

The literature search for relevant articles was from July 2020 to March 2021. A systematic search of PubMed, Embase, Google Scholar, Cochrane library, Dentistry & Oral Sciences Source, and Scopus was conducted to search for relevant studies. The quality of studies was assessed in accordance with the Joanna Briggs Institute's guidelines and using the software SUMARI-The System for the Unified Management, Assessment and Review of Information. Confidence in the findings was assessed using the GRADE-CERQual approach.

RESULTS

A total of 1064 studies were initially identified from the search; six studies, two cross-sectional and four case-control, met the inclusion criteria and were selected for this systematic review. Sleep disturbances were a required outcome measured in selected studies evaluating symptoms of BMS. For studies that were included in the final analyses, BMS was found to relate to several dimensions of sleep including sleep disturbance and duration (n = 6), sleep affecting daytime function (n = 4), sleep quality (n = 6), sleep efficiency (n = 4), and ability to fall asleep (n = 4). Consistent evidence of moderate confidence found that BMS was associated with greater sleep disturbance, reduced sleep quality, increased time taken to fall asleep, reduced sleep efficiency, and poor daytime function, whereas evidence of low confidence was found regarding the association of BMS with reduced sleep duration.

CONCLUSIONS

Although the presented studies could not establish a direct causal relationship between BMS and sleep disturbances, it supports the evidence that sleep disturbance is associated with symptoms of BMS. Management strategies to improve sleep may be considered in future research for managing BMS patients.

Why It Is Important to Consider the Effects of Analgesics on Sleep: A Critical Review

We review the known physiological mechanisms underpinning all of pain processing, sleep regulation, and pharmacology of analgesics prescribed for chronic pain. In particular, we describe how commonly prescribed analgesics act in sleep-wake neural pathways, with potential unintended impact on sleep and/or wake function. Sleep disruption, whether pain- or drug-induced, negatively impacts quality of life, mental and physical health. In the context of chronic pain, poor sleep quality heightens pain sensitivity and may affect analgesic function, potentially resulting in further analgesic need. Clinicians already have to consider factors including efficacy, abuse potential, and likely side effects when making analgesic prescribing choices. We propose that analgesic-related sleep disruption should also be considered. The neurochemical mechanisms underlying the reciprocal relationship between pain and sleep are poorly understood, and studies investigating sleep in those with specific chronic pain conditions (including those with comorbidities) are lacking. We emphasize the importance of further work to clarify the effects (intended and unintended) of each analgesic class to inform personalized treatment decisions in patients with chronic pain. © 2021 American Physiological Society. Compr Physiol 11:1-31, 2021.

Cluster Headache Pathophysiology—A Disorder of Network Excitability?

Patients’ accounts of cluster headache attacks, ictal restlessness, and electrophysiological studies suggest that the pathophysiology involves Aδ-fibre nociceptors and the network processing their input. Continuous activity of the trigeminal autonomic reflex throughout the in-bout period results in central sensitization of these networks in many patients. It is likely that several factors force circadian rhythmicity upon the disease. In addition to sensitization, circadian changes in pain perception and autonomic innervation might influence the excitability of the trigeminal cervical complex. Summation of several factors influencing pain perception might render neurons vulnerable to spontaneous depolarization, particularly at the beginning of rapid drops of the pain threshold (“summation headache”). In light of studies suggesting an impairment of short-term synaptic plasticity in CH patients, we suggest that the physiologic basis of CH attacks might be network overactivity—similarly to epileptic seizures. Case reports documenting cluster-like attacks support the idea of distinct factors being transiently able to induce attacks and being relevant in the pathophysiology of the disorder. A sustained and recurring proneness to attacks likely requires changes in the activity of other structures among which the hypothalamus is the most probable candidate.

Relationships of sleep disturbance, intestinal microbiota, and postoperative pain in breast cancer patients: a prospective observational study

PURPOSE

Our study was designed to examine the possible relationship between gut microbiota, sleep disturbances, and acute postoperative pain.

METHODS

Using 16S rRNA sequencing, we analyzed preoperative fecal samples from women undergoing breast cancer surgery. Preoperative sleep disturbance was evaluated with the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Peak and average pain at rest and movement were evaluated 24 h after surgery, using a numerical rating scale (NRS). Preoperative symptoms of depression and anxiety were assessed with the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7), respectively. Inflammation was measured using white blood cell and neutrophil counts, together with platelet-lymphocyte ratio, and neutrophil-lymphocyte ratio.

RESULTS

Preoperative sleep disturbance was associated with more severe acute postoperative pain. At the phylum level, women with poor sleep quality had higher relative abundance of Firmicutes (p = 0.021) and lower relative abundance of Bacteroidetes (p = 0.013). At the genus level, women with poor sleep quality harbored higher relative abundance of Acidaminococcus and lower relative abundance of several genera. The genus Alloprevotella was negatively associated with peak pain at movement during the first 24 h (r = - 0.592, p < 0.001). The genus Desulfovibrio was negatively associated with symptoms of anxiety (r = - 0.448, p = 0.006). However, partial correlations suggested that the relationship between Alloprevotella and peak pain at movement during the first 24 h was not statistically significant after controlling for sleep (r = - 0.134, p = 0.443).

CONCLUSION

These findings suggest that the changed gut microbiota may be involved in sleep-pain interaction and could be applied as a potential preventive method for postoperative pain.

TRIAL REGISTRATION

The present clinical study has been registered on Chinese Clinical Trial Registry ( www.chictr.org.cn ); the clinical trial registration number is ChiCTR1900021730; the date of registration is March 7, 2019.

The Association between Sleep and Chronic Spinal Pain: A Systematic Review from the Last Decade

Chronic spinal pain, including both neck and low back pain, is a common disabling disorder in which sleep problems are frequently reported as a comorbidity. The complex processes of both sleep and chronic pain seem to have overlapping mechanisms, which may explain their often established bidirectional relationship. This systematic review aims to investigate the assumed association between sleep and chronic spinal pain by providing an overview of the literature from the last decade. Eligible studies were obtained by searching four databases (PubMed, Embase, Web of Science, and PsycARTICLES). Articles were found relevant if they included a human adult population and investigated the possible association between sleep parameters and chronic spinal pain. Only studies published after January 2009 were included, as this review aimed to provide an update of a previous literature overview on this topic. The quality of the studies was assessed by risk of bias and level of evidence. A total of twenty-seven studies (6 cohort, 5 case-control, and 16 cross-sectional studies) were included in this systematic review. The methodological quality of these studies was low to moderate. The majority of studies reported weak to moderate evidence for an association between sleep parameters and chronic spinal pain, with more severe pain accompanied by more disturbed sleep. Addressing frequently reported sleep problems in chronic spinal pain patients therefore appears to be a necessary complement to pain management to achieve optimal treatment outcomes.

Poor Sleep Predicts Increased Pain Perception Among Adults With Mild Cognitive Impairment

BACKGROUND

Older adults with mild cognitive impairment are at an increased risk for dementia of the Alzheimer's type. These older adults also report poorer sleep and more pain than their cognitively intact adult counterparts. Poor sleep and pain are both symptoms associated with an increased risk for dementia in later life. Symptom science research in the direction of how poor sleep affects pain among older adults, especially those with mild cognitive impairment, is needed for the development of targeted sleep interventions to reduce pain and potentially delay/reduce the risk for Alzheimer's disease in this population.

OBJECTIVE

The aim of the study was to examine a predictive model of the relationship between poor sleep and pain perception among community-dwelling older adults with mild cognitive impairment.

METHODS

A longitudinal prospective design with 58 continuous matched sleep-pain observations of 15 older adults with mild cognitive impairment for up to 6 months was used. Multilevel, mixed-modeling, statistical techniques were used to examine the effects of prior-week sleep on subsequent pain perception. Pain perception (pain intensity, pain interference, and pain behavior) is measured by the Patient-Reported Outcomes Measurement Information System during monthly in-person visits. The ActiGraph GT3X+ was used to measure sleep (total sleep time, sleep efficiency, awakenings after sleep onset) objectively and continuously for up to 6 months, along with other covariates (e.g., physical activity).

RESULTS

Increased awakenings after sleep onset in the prior week is associated with increased pain intensity, pain interference, and pain behavior. There was a trend toward sleep efficiency, and increased pain intensity and sleep efficiency predicted increased pain interference and pain behavior. There was no relationship between prior-week total sleep time and subsequent pain perception.

DISCUSSION

In this study, poor sleep in the prior week increased pain intensity, pain interference, and pain behavior. Interventions designed to decrease awakening after sleep onset and increase sleep efficiency specifically may effectively reduce pain in this population. Given that these symptoms are prevalent among older adults with mild cognitive impairment, sleep and pain interventions may also ameliorate some of the risk for Alzheimer's disease in this population.

Sensitization in office workers with chronic neck pain in different pain conditions and intensities

OBJECTIVES

Office workers with chronic neck pain demonstrates signs of widespread hyperalgesia, less efficient descending pain modulation, which could indicate sensitization of central pain pathways. No studies have assessed a wide variety of office workers with different chronic neck pain disorders and assessed the impact of pain intensity on assessments of central pain pathways. This study aimed to assessed pressure pain thresholds (PPTs), temporal summation of pain (TSP) and conditioned pain modulation (CPM) and to associate these with pain intensity and disability in subgroups of office workers.

METHODS

One hundred-and-seventy-one office workers were distributed into groups of asymptomatic and chronic neck pain subjects. Chronic neck pain was categorized as chronic trapezius myalgia and chronic non-specific neck pain and as 'mild-pain' (Visual Analog Scale [VAS]≤3) and 'moderate-pain' (VAS>3) groups. PPTs, TSP, CPM, and Copenhagen Psychosocial Questionnaire II were assessed in all subjects. Neck Disability Index and Pain Catastrophizing Scale were assessed in all the symptomatic office workers.

RESULTS

PPTs were lower in moderate pain (n=49) and chronic trapezius myalgia (n=56) compared with asymptomatic subjects (n=62, p<0.05). TSP was facilitated in moderate pain group compared with mild pain (n=60, p<0.0001) group and asymptomatic subjects (p<0.0001). No differences were found in CPM comparing the different groups (p<0.05). Multiple regression analysis identified Neck Disability Index and TSP as independent factors for prediction of pain intensity in chronic trapezius myalgia (R²=0.319) and chronic non-specific neck pain (R²=0.208). Somatic stress, stress and sleep as independent factors in chronic non-specific neck pain (R²=0.525), and stress in moderate pain group (R²=0.494) for the prediction of disability.

CONCLUSIONS

Office workers with chronic trapezius myalgia and moderate pain intensity showed significant signs of widespread pressure hyperalgesia. Moreover, the moderate pain group demonstrated facilitated TSP indicating sensitization of central pain pathways. Neck Disability Index and TSP were independent predictors for pain intensity in pain groups. Sleep and stress were independent predictors for disability.

Associates of Insomnia in People with Chronic Spinal Pain: A Systematic Review and Meta-Analysis

Insomnia is a major problem in the chronic spinal pain (CSP) population and has a negative impact on health and well-being. While insomnia is commonly reported, underlying mechanisms explaining the relation between sleep and pain are still not fully understood. Additionally, no reviews regarding the prevention of insomnia and/or associated factors in people with CSP are currently available. To gain a better understanding of the occurrence of insomnia and associated factors in this population, we conducted a systematic review of the literature exploring associates for insomnia in people with CSP in PubMed, Web of Science and Embase. Three independent reviewers extracted the data and performed the quality assessment. A meta-analysis was conducted for every potential associate presented in at least two studies. A total of 13 studies were found eligible, which together identified 25 different potential associates of insomnia in 24,817 people with CSP. Twelve studies had a cross-sectional design. Moderate-quality evidence showed a significantly higher rate for insomnia when one of the following factors was present: high pain intensity, anxiety and depression. Low-quality evidence showed increased odds for insomnia when one of the following factors was present: female sex, performing no professional activities and physical/musculoskeletal comorbidities. Higher healthcare use was also significantly related to the presence of insomnia. One study showed a strong association between high levels of pain catastrophizing and insomnia in people with chronic neck pain. Last, reduced odds for insomnia were found in physically active people with chronic low back pain compared to inactive people with chronic low back pain. This review provides an overview of the available literature regarding potential associates of insomnia in people with CSP. Several significant associates of insomnia were identified. These findings can be helpful to gain a better understanding of the characteristics and potential origin of insomnia in people witch CSP, to identify people with CSP who are (less) likely to have insomnia and to determine directions of future research in this area.

The effect of sleep deprivation and restriction on mood, emotion, and emotion regulation: three meta-analyses in one

STUDY OBJECTIVES

New theory and measurement approaches have facilitated nuanced investigation of how sleep loss impacts dimensions of affective functioning. To provide a quantitative summary of this literature, three conceptually related meta-analyses examined the effect of sleep restriction and sleep deprivation on mood, emotion, and emotion regulation across the lifespan (i.e. from early childhood to late adulthood).

METHODS

A total of 241 effect sizes from 64 studies were selected for inclusion, and multilevel meta-analytic techniques were used when applicable.

RESULTS

There was a moderate, positive effect of sleep loss on negative mood (g = 0.45), which was stronger for studies with younger samples, as well as a large, negative effect of sleep loss on positive mood (g = -0.94). For negative mood only, studies that used total sleep deprivation had larger effect sizes than studies that restricted sleep. After correcting for publication bias, a modest but significant negative effect for sleep loss on emotion (g = -0.11) was found; the valence of emotional stimuli did not change the direction of this effect, and type of sleep manipulation was also not a significant moderator. Finally, sleep restriction had a small, negative effect on adaptive emotion regulation (g = -0.32), but no significant impact on maladaptive emotion regulation (g = 0.14); all studies on adaptive emotion regulation were conducted with youth samples.

CONCLUSIONS

Sleep loss compromises optimal affective functioning, though the magnitude of effects varies across components. Findings underscore the importance of sleep for healthy affective outcomes.

Factors associated with low back pain among construction workers in Nepal: A cross-sectional study

BACKGROUND

Low back pain (LBP) is the commonest cause of disability throughout the world. This study aimed to determine the prevalence and factors associated with LBP among the construction workers in Nepal.

METHODS

A community-based cross-sectional study was conducted among the construction workers working in Banepa and Panauti municipalities of Kavre district, from September 2019 to February 2020. Data was collected purposively by face-to-face interview from 402 eligible participants from the both municipalities using semi-structured questionnaire. Mobile-based data collection was done using KoboCollect. Data were exported to and analysed using R-programming software (R-3.6.2). Univariate and multivariate logistic regressions were performed. All tests were two tailed and performed at 95% confidence interval (CI).

RESULT

One-year prevalence of LBP among construction workers were 52.0% (95%CI: 47.0-57.0). The higher odds of LBP was reported among females [adjusted odds ratio (aOR) = 2.42; 95%CI: 1.12-5.23], those living below poverty-line (aOR = 2.35; 95%CI: 1.32-4.19), participants with more than five years of work experience (aOR = 1.66; 95%CI: 1.01-2.73) and those with intermediate sleep quality (aOR = 2.06; CI: 1.03-4.11). About 80.0% of construction workers with LBP never seek healthcare services due to: a) time constraints (90.9%), b) financial constraints (18.1%) and c) fear of losing wages on seeking healthcare services (40.9%). The majority of the participants (94.8% among those without LBP and 72.3% among those with LBP) did nothing to prevent or manage LBP.

CONCLUSION

The prevalence of LBP in the past one year was high among construction workers where majority of workers never did anything to prevent or manage LBP. Therefore, the public health professionals should set up the health promotion, education, and interventions aimed at increasing awareness on preventive techniques and predisposing factors of LBP.

Pinprick and Light Touch Are Adequate to Establish Sensory Dysfunction in Patients with Lumbar Radicular Pain and Disc Herniation

BACKGROUND

The frequency with which sensory disturbances occur in patients with radicular leg pain and disc herniation is not well known, and the efficacy of tests to identify such changes are not firmly established. The presence of sensory disturbances is a key sign of nerve root involvement and may contribute to the diagnosis of a lumbar disc herniation, identify patients for referral to spinal imaging and surgery, and improve disease classification.

QUESTIONS/PURPOSES

In this study, we sought: (1) to determine the frequency with which abnormal sensory findings occur in patients with lumbar disc herniation-related radicular pain, using a standard neurological sensory examination; (2) to determine what particular standard sensory test or combination of tests is most effective in establishing sensory dysfunction; and (3) to determine whether a more detailed in-depth sensory examination results in more patients being identified as having abnormal sensory findings.

METHODS

Between October 2013 and April 2016, 115 patients aged 18 to 65 years referred to secondary health care with radicular leg pain and disc herniation were considered potentially eligible for inclusion in the study. Based on these inclusion criteria, 79% (91) were found eligible. Ten percent (11) were excluded because of other illness that interfered with the study purpose, 3% (3) because of cauda equina syndrome, 2% (2) because of spinal stenosis, 2% (2) because of prior surgery at the same disc level, and 2% (2) because of poor Norwegian language skills. Three percent (4) of the patients did not want to participate in the study. Of the 91 eligible patients, 56% (51) consented to undergo a comprehensive clinical examination and were used for analysis here. The sample for the purposes of the present study was predetermined at 50. These patients were first examined by a standard procedure, including sensory assessment of light touch, pinprick, vibration, and warmth and cold over the back and legs. Second, an in-depth semiquantitative sensory testing procedure was performed in the main pain area to assess sensory dysfunction and improve the detection of potential positive sensory signs, or sensory gain of function more precisely. Sensory loss was defined as sensations experienced as distinctly reduced in the painful side compared with the contralateral reference side. In contrast, sensory gain was defined as sensations experienced as abnormally strong, unpleasant, or painful and distinctly stronger than the contralateral side. Ambiguous test results were coded as a normal response to avoid inflating the findings. The proportions of abnormal findings were calculated for each sensory modality and for all combinations of the standard examination tests.

RESULTS

The standard examination identified at least one abnormal finding in 88% (45 of 51) of patients. Sensory loss was present in 80% (41), while sensory gain was present in 35% (18). The combination of pinprick and light touch identified all patients who were classified as having abnormal findings by the full standard examination. The semiquantitative procedure identified an additional three patients with an abnormal finding.

CONCLUSION

We suggest that the combination of pinprick and light touch assessment is an adequate minimal approach for diagnostic and classification purposes in patients with lumbar radicular pain.

LEVEL OF EVIDENCE

Level I, diagnostic study.

Pain matters for central sensitization: sensory and psychological parameters in patients with fibromyalgia syndrome

Sensory abnormalities through quantitative sensory testing in fibromyalgia were not substantially influenced by psychological comorbidities. A significant subgroup showed signs of central sensitization, influenced by pain intensity.

Introduction:

Patients suffering from fibromyalgia syndrome (FMS) are heterogenous. They often present with sensory abnormalities and comorbidities.

Objectives:

We aimed to answer the following questions: (1) Is there a specific somatosensory profile in our patient cohort? (2) Can we detect subgroups characterized by a specific combination of sensory and psychological features? and (3) Do psychological parameters influence sensory signs?

Methods:

In 87 patients with FMS quantitative sensory testing was performed on the hand and evaluated in combination with questionnaire results regarding pain, psychological comorbidities, sleep, and functionality.

Results:

Patients presented different somatosensory patterns, but no specific subgroups regarding sensory signs and psychological features were detected. Hypersensitivity for noxious mechanical and thermal stimuli and hyposensitivity for nonnoxious mechanical stimuli were the most prominent features. Thirty-one percent of patients showed signs of central sensitization as indicated by abnormally increased pinprick hyperalgesia or dynamic mechanical allodynia. Central sensitization was associated with higher pain intensities (P < 0.001). Only a small influence of psychiatric comorbidities on mechanical pain sensitivity (P = 0.044) and vibration detection (P = 0.028) was found, which was partly associated with high pain intensities. A small subgroup of patients (11.4%) demonstrated thermal hyposensitivity (loss of small-fiber function).

Conclusion:

Patients with FMS showed various somatosensory abnormalities. These were not significantly influenced by psychological comorbidities. Signs for central sensitization were detected in about one-third of patients and associated with higher pain intensities. This supports the notion of central sensitization being a major pathophysiological mechanism in FMS, whereas small-fiber loss may be less important.

Experimental sleep restriction increases latency jitter in pain elicited cortical responses

Objective

Previous studies have shown increased pain scores to painful stimulation after experimental sleep restriction, but reduced or unchanged magnitude of the event related potentials (ERPs) when averaged in the time-domain. However, some studies found increased response magnitude when averaging in the time-frequency domain. The aim of this study was to determine whether ERP-latency jitter may contribute to this discrepancy.

Methods

Ninety painful electrical stimuli were given to 21 volunteers after two nights of 50% sleep restriction and after two nights of habitual sleep. ERPs were analyzed in the time-domain (N2-and P2-peaks) and time-frequency domain (power spectral density). We quantified latency jitter by the mean consecutive difference (MCD) between single-trial peak latencies and by phase locking value (PLV) across trials.

Results

P2-MCD increased from 20.4 ± 2.1 ms after habitual sleep to 24.3 ± 2.2 ms after sleep restriction (19%, p = 0.038) and PLV decreased from 0.582 ± 0.015 after habitual sleep to 0.536 ± 0.015 after sleep restriction (7.9%, p = 0.009). We found no difference for N2-MCD.

Conclusions

Our results indicate that partial sleep restriction increase latency jitter in cortical responses to experimental pain.

Significance

Latency jitter may contribute to the discrepancies between ERP-responses in the time-frequency domain and time-domain. Latency jitter should be considered when ERPs are analyzed.

Naringenin Ameliorates Chronic Sleep Deprivation-Induced Pain via Sirtuin1 Inhibition

Growing experimental evidences have suggested the reciprocal correlation between sleep deprivation and pain. Inflammation and oxidative stress are among the key pathways underlying this correlation. Therefore, the present study was aimed to assess the effect of antioxidant and anti-inflammatory compound naringenin (NGN) against chronic sleep deprivation (CSD)-induced mechanical and thermal hyperalgesia in female Swiss albino mice. In this study, mice were chronically sleep-deprived for 8 h a day for five days a week with the weekend as a free sleep period and continued for nine weeks using a modified multiple platform method. The pain behavioral tests were conducted at the end of the fourth week to assess the development of hyperalgesia followed by the administration of NGN and a combination of NGN with Sirtinol (SIR, a sirtuin1 inhibitor) till the end of the study. After nine weeks, pain behavioral tests, along with oxidative stress and inflammatory parameters in cortex and striatum, were assessed. Results indicated that CSD-induced hyperalgesia in mice accompanied by increased oxidative stress and inflammatory markers in cortex and striatum of the brain. NGN combatted the hyperalgesic response and also decreased levels of oxidative stress and inflammatory markers. Furthermore, the pharmacological effect of NGN was mitigated with SIR. Thus, the findings of the present study reveal that NGN is acting via sirtuin1 to exert its antinociceptive activity against CSD-induced hyperalgesia.

Impact of Sleep Deprivation in the Neurological Intensive Care Unit: A Narrative Review

Sleep is fundamental for everyday functioning, yet it is often negatively impacted in critically ill patients by the intensive care setting. With a focus on the neurological intensive care unit (NeuroICU), this narrative review summarizes methods of measuring sleep and addresses common causes of sleep disturbance in the hospital including environmental, pharmacological, and patient-related factors. The effects of sleep deprivation on the cardiovascular, pulmonary, immune, endocrine, and neuropsychological systems are discussed, with a focus on short-term deprivation in critically ill populations. Where evidence is lacking in the literature, long-term sleep deprivation studies and the effects of sleep deprivation in healthy individuals are also referenced. Lastly, strategies for the promotion of sleep in the NeuroICU are presented.

MicroRNA-19b predicts widespread pain and posttraumatic stress symptom risk in a sex-dependent manner following trauma exposure

Posttraumatic widespread pain (PTWP) and posttraumatic stress symptoms (PTSS) are frequent comorbid sequelae of trauma that occur at different rates in women and men. We sought to identify microRNA (miRNA) that may contribute to sex-dependent differences in vulnerability to these outcomes. Monte Carlo simulations (x10,000) identified miRNA in which predicted targeting of PTWP or PTSS genes was most enriched. Expression of the leading candidate miRNA to target PTWP/PTSS-related genes, miR-19b, has been shown to be influenced by estrogen and stress exposure. We evaluated whether peritraumatic miR-19b blood expression levels predicted PTWP and PTSS development in women and men experiencing trauma of motor vehicle collision (n = 179) and in women experiencing sexual assault trauma (n = 74). A sex-dependent relationship was observed between miR-19b expression levels and both PTWP (β = -2.41, P = 0.034) and PTSS (β = -3.01, P = 0.008) development 6 months after motor vehicle collision. The relationship between miR-19b and PTSS (but not PTWP) was validated in sexual assault survivors (β = -0.91, P = 0.013). Sex-dependent expression of miR-19b was also observed in blood and nervous tissue from 2 relevant animal models. Furthermore, in support of increasing evidence indicating a role for the circadian rhythm (CR) in PTWP and PTSS pathogenesis, miR-19b targets were enriched in CR gene transcripts. Human cohort and in vitro analyses assessing miR-19b regulation of key CR transcripts, CLOCK and RORA, supported the potential importance of miR-19b to regulating the CR pathway. Together, these results highlight the potential role that sex-dependent expression of miR-19b might play in PTWP and PTSS development after trauma/stress exposure.

Using Nonlinear Dynamics and Multivariate Statistics to Analyze EEG Signals of Insomniacs with the Intervention of Superficial Acupuncture

Objective

As a noninvasive and nonpharmacological therapeutic approach, superficial acupuncture (SA) is a special method of acupuncture. In this study, using nonlinear dynamics and multivariate statistics, we studied the electroencephalography (EEG) of primary insomnia under SA intervention to investigate how brain regions change.

Method

This study included 30 adults with primary insomnia. They underwent superficial acupuncture at the Shangen acupoint. The EEG signals were collected for 10 minutes at each state, including the resting state, the intervention state, and the postintervention state. The data were conducted using nonlinear dynamics (including approximate entropy (ApEn) and correlation dimension (CD)) and multivariate statistics.

Result

The repeated-measures ANOVA results showed that both ApEn and CD values were not significantly different at the three states (p > 0.05). The paired t-test results showed that the ApEn values of electrodes O2 (the right occipital lobe) at the postintervention state have decreased, compared with the resting state (p < 0.05), and no difference was detected in CD (p > 0.05). The cluster analysis results of ApEn showed that patients' EEG has changed from the right prefrontal lobe (electrode Fp2) to the right posterior temporal lobe (electrode T6) and finally to the right occipital lobe (electrode O2), before, during, and after the SA intervention. In addition, the factor analysis results of CD revealed that patients' EEG of all brain regions except for the occipital lobes has changed to the frontal lobes and anterior temporal and frontal lobes from pre- to postintervention.

Conclusion

SA activated the corresponding brain regions and reduced the complexity of the brain involved. It is feasible to use nonlinear dynamics analysis and multivariate statistics to examine the effects of SA on the human brain.

Symptoms of central sensitization in patients with inflammatory bowel diseases: a case-control study examining the role of musculoskeletal pain and psychological factors

OBJECTIVES

Musculoskeletal (MSK) pain is a common complaint in patients with inflammatory bowel diseases (IBD). MSK pain in IBD has previously demonstrated association with symptoms of central sensitization; however it is uncertain whether these symptoms are influenced simply by the presence of MSK pain and/or IBD. Primary aim of this study was to investigate whether symptoms of central sensitization differed across three groups: IBD patients with and without MSK pain and healthy controls. Secondary aim was to investigate between-group differences for measures of somatosensory functioning.

METHODS

Cross-sectional study was performed on adults with IBD. Assessments included: central sensitization inventory (CSI), pressure pain threshold, temporal summation, conditioned pain modulation, perceived stress, affect style, anxiety, depression, and pain catastrophizing. One-way analyses of variance and covariance were used to investigate between-group differences for measures of central sensitization and potential confounding by psychological factors.

RESULTS

Study participants (n=66) were age/gender matched across three study groups. Between-group differences were solely demonstrated for CSI scores [F(2,63)=19.835, p<0.001, r=0.62], with IBD patients with MSK pain demonstrating the highest CSI scores and healthy controls the lowest. After controlling for individual psychological features, post hoc comparisons indicated that CSI scores were significantly different between-groups (p≤0.025) after controlling for most psychological variables, with the exception of perceived stress (p=0.063) and pain catastrophizing (p=0.593).

CONCLUSIONS

IBD patients as a whole demonstrated significantly greater symptoms of central sensitization compared to healthy controls. However, IBD patients with persistent MSK pain demonstrated the greatest symptoms of central sensitization compared to patients without MSK pain and healthy controls. Between-group differences for CSI in IBD patients with MSK were not confounded by psychological features.

IMPLICATIONS

Study results indicate that persistent MSK pain in IBD represents patients with greater central sensitization symptomology. This increased symptomology is suggestive of underlying mechanisms related to central sensitization, highlighting patient potentially at risk for worse pain experiences.

The efficacy of acupuncture in postoperative sleep quality: a literature review

PURPOSE

General anesthesia may affect the quality of postoperative sleep, especially after surgery on elderly patients. The decline of postoperative sleep quality may produce harmful effects on the postoperative recovery of patients. In this review, we summarized the efficacy and potential mechanism of acupuncture on postoperative sleep quality.

METHODS

We review the effect of general anesthesia on circadian sleep rhythm. In addition, to provide evidence about the impairment of decreased postoperative sleep quality, we also emphasize the mechanism of acupuncture alleviates factors that affect sleep quality after general anesthesia.

RESULTS

The application of acupuncture technology has been helpful to improve sleep quality and alleviate postoperative complications affecting postoperative sleep quality after general anesthesia.

CONCLUSION

Acupuncture at different acupoints could effectively improve body's neurotransmitter levels and regulate biological clock genes through various mechanisms, and then improve postoperative sleep quality. Large-scale multi-center trials are needed to verify these findings.

Opioid Use Is More Common in Nonalcoholic Fatty Liver Disease Patients with Cirrhosis, Higher BMI, and Psychiatric Disease

BACKGROUND

Opioid use is a topic of growing concern among patients with nonalcoholic fatty liver disease (NAFLD). Given safety concerns of opioids, proactively identifying subgroups of patients with an increased probability of opioid use may encourage practitioners to recommend alternative therapies for pain, thus reducing the likelihood of opioid misuse. This work assessed the prevalence and patient characteristics associated with opioid use in a real-world cohort of patients with NAFLD.

METHODS

TARGET-NASH, an observational study of participants at 55 academic and community sites in the United States, includes patients with NAFLD defined by pragmatic case definitions. Opioid use was defined as any documented opioid prescriptions in the year prior to enrollment. The association between patient characteristics and the odds of opioid use were modeled with stepwise multivariable logistic regression and tree ensemble methods (Classification and regression tree/Boosted Tree).

RESULTS

The cohort included 3,474 adult patients with NAFLD including 18.0% with documented opioid use. Variables associated with opioid use included presence of cirrhosis (OR 1.51, 95% CI 1.16-1.98), BMI ≥32 kg/m2 (OR 1.29, 95% CI 1.05-1.59), depression (OR 1.87, 95% CI 1.50-2.33), and anxiety (OR 1.59, 95% CI 1.27-1.98). In the boosted tree analysis, history of back pain, depression, and fibromyalgia had the greatest relative importance in predicting opioid use.

CONCLUSION

Prescription opioids were used in nearly 1 of 5 patients with NAFLD. Given the safety concerns of opioids in patients with NAFLD, alternative therapies including low-dose acetaminophen and nonpharmacologic treatments should be considered for these patients.

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 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.

Role of Glia in the Regulation of Sleep in Health and Disease

Sleep is a naturally occurring physiological state that is required to sustain physical and mental health. Traditionally viewed as strictly regulated by top-down control mechanisms, sleep is now known to also originate locally. Glial cells are emerging as important contributors to the regulation of sleep-wake cycles, locally and among dedicated neural circuits. A few pioneering studies revealed that astrocytes and microglia may influence sleep pressure, duration as well as intensity, but the precise involvement of these two glial cells in the regulation of sleep remains to be fully addressed, across contexts of health and disease. In this overview article, we will first summarize the literature pertaining to the role of astrocytes and microglia in the regulation of sleep under normal physiological conditions. Afterward, we will discuss the beneficial and deleterious consequences of glia-mediated neuroinflammation, whether it is acute, or chronic and associated with brain diseases, on the regulation of sleep. Sleep disturbances are a main comorbidity in neurodegenerative diseases, and in several brain diseases that include pain, epilepsy, and cancer. Identifying the relationships between glia-mediated neuroinflammation, sleep-wake rhythm disruption and brain diseases may have important implications for the treatment of several disorders. © 2020 American Physiological Society. Compr Physiol 10:687-712, 2020.

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.

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.

Still too noisy - An audit of sleep quality in trauma and orthopaedic patients

INTRODUCTION

An adequate amount of sleep is fundamental to health and well-being, especially for individuals recovering from an illness or injury. Trauma patients sustain musculoskeletal and tissue injuries and require a sufficient amount of sleep to promote recovery. However, it is known that patients can face difficulties sleeping in hospitals which impacts on their recovery.

AIM

To determine the quality of sleep, influence of sleep quality and the impact of sleep quality on recovery in trauma and orthopaedic patients.

METHODOLOGY

An exploratory descriptive design was applied using a clinical audit. As no standardised sleep assessment tool was identified, a sleep audit tool was developed.

FINDINGS

A total of 40 patients were recruited from two trauma and orthopaedic wards from a London Hospital in the United Kingdom. Of these 17 patients (43%) rated the quality of sleep as 'poor' and nearly half (n = 19, 46%) reported that the quality of their night-time sleep had affected their recovery. Two-thirds of patients reported noise was the main factor that disrupted their sleep, making it the highest contributing sleep disruptor (n = 26, 65%).

CONCLUSION

A significant association between poor quality of sleep and patient recovery was identified in this small sample of trauma and orthopaedic patients. The findings suggest that nurses should try to create a suitable sleeping environment to enhance patient recovery. There is a need for a standardised sleep assessment tool and sleep audit tool so that the quality of patients' sleep can be accurately assessed and documented.

Pain in children and adolescents with cerebral palsy - a cross-sectional register study of 3545 individuals

Background

Pain is a common problem for individuals with cerebral palsy (CP). In Sweden, 95% of children and adolescents with CP are followed in a national follow-up programme (CPUP), which includes data on pain. The purpose of this study was to investigate the prevalence of pain based on age, sex, gross motor function and source of report (self or proxy). Pain intensity, pain site, and how much pain disturbed sleep and daily activities were also studied.

Methods

This was a cross-sectional register study based on all participants in CPUP, 4–18-years of age, with data reported in 2017–2018. Gross motor function was classified using the Gross Motor Function Classification System (GMFCS). Logistic regression was used to analyse prevalence of pain and how much pain had disturbed sleep and daily activities in the last four weeks.

Results

In total, 3545 participants (2065 boys) were included. The overall prevalence of pain was 44%. Older age and female sex were associated with higher risk of pain with odds ratios of 1.07 (95% confidence interval (CI) 1.06–1.09) and 1.28 (CI 1.12–1.47), respectively. Pain was most common in the lower extremities. There was no statistically significant difference in prevalence of pain related to source of report. Pain intensity was higher at older ages and higher GMFCS-levels. Hip/thigh pain and abdominal pain were associated with the most intense pain.

Of those who reported pain, pain disturbed sleep for 36% and daily activities for 61%.

Conclusions

Both pain frequency and pain intensity were higher at higher age. Pain intensity increased with increasing GMFCS-level. Two-thirds of all children and adolescents with CP reported that their pain disturbed their daily activities, and one-third reported that pain disturbed their sleep.

Influence of sleep problems and co-occurring musculoskeletal pain on long-term prognosis of chronic low back pain: the HUNT Study

Background

We investigated the influence of sleeplessness and number of insomnia symptoms on the probability of recovery from chronic low back pain (LBP), and the possible interplay between sleeplessness and co-occurring musculoskeletal pain on this association.

Methods

The study comprised data on 3712 women and 2488 men in the Norwegian HUNT study who reported chronic LBP at baseline in 1995–1997. A modified Poisson regression model was used to calculate adjusted risk ratios (RRs) for the probability of recovery from chronic LBP at follow-up in 2006–2008, associated with sleep problems and co-occurring musculoskeletal pain at baseline.

Results

Compared with persons without sleeplessness, persons who often/always experienced sleeplessness had a lower probability of recovery from chronic LBP (RR 0.65, 95% CI 0.57 to 0.74 in women and RR 0.81, 95% CI 0.69 to 0.95 in men). Although there was no clear evidence of statistical interaction between sleeplessness and co-occurring musculoskeletal pain, women and men who often/always experienced sleeplessness and had ≥5 additional chronic pain sites had RRs of recovery of 0.40 (95% CI 0.33 to 0.48) and 0.59 (95% CI 0.45 to 0.78), respectively, compared with persons without sleeplessness and 1–2 chronic pain sites.

Conclusion

These findings suggest that preventing or reducing sleep problems among people with chronic LBP may have the potential of improving the long-term prognosis of this condition, also among those with several additional pain sites.

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.

Does Disordered Sleep Moderate the Relationship Between Pain, Disability and Downstream Health Care Utilization in Patients With Low Back Pain?: A Longitudinal Cohort From the US Military Health System

STUDY DESIGN

Prospective cohort.

OBJECTIVE

The purpose of this study was to evaluate the influence of disordered sleep on the relationship between pain and health care utilization (HCU) and pain-related disability and HCU in individuals with low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Disordered sleep and pain influence LBP outcomes, but their relationship with health care seeking after an episode of LBP has not been investigated and could help identify who is at risk for long-term medical care.

METHODS

This study included patients with LBP participating in a self-management class at a large US military hospital between March 1, 2010 and December 4, 2012. Pain intensity, disability (Oswestry Disability Index), and sleepiness (Epworth Sleepiness Scale) were captured at baseline. Medical visits for a sleep disorder in the 12 months before the class and LBP-related healthcare utilization for the 12 months following the class were abstracted from the Military Health System Data Repository. Separate multivariate analyses evaluating pain intensity and disability as predictors of HCU were developed, with sleepiness and the presence of a sleep disorder as potential moderators. Analyses were adjusted for age, sex, history of back pain, and mental health comorbidities.

RESULTS

A total of 757 consecutive participants were included, with 195 (26.8%) diagnosed with a subsequent sleep disorder. Sleepiness was not a significant predictor of HCU. The main effects of disability, pain intensity, and presence of a sleep disorder were significant across all analyses, with higher disability, pain intensity, and presence of a sleep disorder associated with higher predicted visits and costs for LBP. The presence of a sleep disorder was not a significant moderator in any model.

CONCLUSION

Higher pain intensity and disability predicted higher pain-related HCU in the year following a LBP self-management class. The presence of a sleep disorder diagnosis, as recorded in medical records, had a significant independent effect on LBP-related health care visits and costs beyond the influences of pain intensity, disability, and other key demographic and health-related characteristics, but did not moderate these relationships.

LEVEL OF EVIDENCE

3.

The pain alarm response - an example of how conscious awareness shapes pain perception

Pain is subjective and largely shaped by context, yet, little is known about the boundaries for such influences, in particular in relation to conscious awareness. Here, we investigated processing of noxious stimuli during sleep. Four experiments were performed where participants (n = 114) were exposed to repetitions of noxious heat, either when awake or during sleep. A test-phase followed where participants were awake and exposed to painful stimuli and asked to rate pain. Two control experiments included only the test-phase, without any prior pain exposures. Participants in the awake condition rated all test-phase stimuli the same. Conversely, participants who had been sleeping, and thus unaware of getting noxious heat, displayed heightened pain during the first part of the test-phase. This heightened reaction to noxious stimuli—a pain alarm response—was further pronounced in the control conditions where participants were naïve to noxious heat. Results suggest that the pain alarm response is partly dependent on conscious awareness.

The joint effect of insomnia symptoms and lifestyle factors on risk of self-reported fibromyalgia in women: longitudinal data from the HUNT Study

OBJECTIVES

To investigate the association between insomnia symptoms and risk of self-reported fibromyalgia in women, and to explore whether leisure time physical activity and body mass index (BMI) modify this association.

DESIGN

Prospective cohort study.

SETTING

We used longitudinal data from the Norwegian Nord-Trøndelag Health Study collected in 1995-1997 (baseline) and 2006-2008 (follow-up).

PARTICIPANTS

A total of 14 172 women who reported to be free from fibromyalgia at baseline.

PRIMARY OUTCOME MEASURES

We estimated adjusted risk ratios (RRs) with 95% CI for self-reported fibromyalgia at follow-up associated with baseline insomnia symptoms, leisure time physical activity and BMI.

RESULTS

Overall, 466 incident cases of fibromyalgia were reported during the follow-up period of approximately 11 years, corresponding to a crude absolute risk (AR) of 3.3%. Compared with women without insomnia symptoms (crude AR=2.8%), women who reported one, two or three symptoms had RRs of fibromyalgia of 1.39 (95% CI: 1.08 to 1.80), 1.86 (95% CI: 1.33 to 2.59) and 2.66 (95% CI: 1.75 to 4.06), respectively. Compared with highly physically active women without insomnia symptoms (crude AR=2.7%), women with one or more insomnia symptoms had a RR of fibromyalgia of 1.90 (95% CI: 1.30 to 2.79) if they reported low physical activity and a RR of 1.55 (95% CI: 1.12 to 2.13) if they reported high physical activity. We found no synergistic effect between insomnia symptoms and BMI on risk of fibromyalgia; however, overweight and obese women with one or more insomnia symptoms had RRs of 2.35 (95% CI: 1.73 to 3.21) and 2.18 (95% CI: 1.42 to 3.35) compared with the reference group of normal weight women without insomnia symptoms (crude AR=2.3%).

CONCLUSIONS

Insomnia symptoms are strongly and positively associated with risk of fibromyalgia in adult women. Leisure time physical activity may compensate for some of the adverse effect of insomnia symptoms on risk of fibromyalgia.