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

Sleep problems and fatigue as predictors for the onset of chronic widespread pain over a 5- and 18-year perspective

BACKGROUND

Previous research suggests that sleep problems may be an important predictor for chronic widespread pain (CWP). With this study we investigated both sleep problems and fatigue as predictors for the onset of CWP over a 5-year and an 18-year perspective in a population free from CWP at baseline.

METHODS

To get a more stable classification of CWP, we used a wash-out period, including only individuals who had not reported CWP at baseline (1998) and three years prior baseline (1995). In all, data from 1249 individuals entered the analyses for the 5-year follow-up and 791 entered for the 18-year follow-up. Difficulties initiating sleep, maintaining sleep, early morning awakening, non-restorative sleep and fatigue were investigated as predictors separately and simultaneously in binary logistic regression analyses.

RESULTS

The results showed that problems with initiating sleep, maintaining sleep, early awakening and non-restorative sleep predicted the onset of CWP over a 5-year (OR 1.85 to OR 2.27) and 18-year (OR 1.54 to OR 2.25) perspective irrespective of mental health (assessed by SF-36) at baseline. Also fatigue predicted the onset of CWP over the two-time perspectives (OR 3.70 and OR 2.36 respectively) when adjusting for mental health. Overall the effect of the sleep problems and fatigue on new onset CWP (over a 5-year perspective) was somewhat attenuated when adjusting for pain at baseline but remained significant for problems with early awakening, non-restorative sleep and fatigue. Problems with maintaining sleep predicted CWP 18 years later irrespective of mental health and number of pain regions (OR 1.72). Reporting simultaneous problems with all four aspects of sleep was associated with the onset of CWP over a five-year and 18-yearperspective, irrespective of age, gender, socio economy, mental health and pain at baseline. Sleep problems and fatigue predicted the onset of CWP five years later irrespective of each other.

CONCLUSION

Sleep problems and fatigue were both important predictors for the onset of CWP over a five-year perspective. Sleep problems was a stronger predictor in a longer time-perspective. The results highlight the importance of the assessment of sleep quality and fatigue in the clinic.

Higher habitual dietary caffeine consumption is related to lower experimental pain sensitivity in a community-based sample

RATIONALE

Caffeine is the most widely consumed psychoactive substance in the world. Caffeine administered acutely in a laboratory environment or as a medication adjuvant has known properties that help alleviate pain. However, much less is known about the potential impact of habitual dietary caffeine consumption on the experience of pain.

OBJECTIVES

The primary objective of this observational study was to determine whether caffeine consumed habitually as part of a daily diet was associated with experimental pain sensitivity using noxious stimuli in a non-clinical sample of 62 community-dwelling adults between 19 and 77 years old.

METHODS

Study participants monitored their daily dietary caffeine consumption (e.g., coffee, tea, soda, energy drinks, and chocolate) across a period of seven consecutive days using a caffeine consumption diary. On the seventh day of caffeine consumption monitoring, participants presented to the laboratory to complete experimental pain sensitivity testing. Noxious thermal and mechanical stimuli were used to obtain threshold and tolerance for painful heat and pressure, respectively.

RESULTS

Data analysis revealed that greater self-reported daily caffeine consumption was significantly associated with higher heat pain threshold (β = .296, p = .038), higher heat pain tolerance (β = .242, p = .046), and higher pressure pain threshold (β = .277, p = .049) in multiple regression models adjusted for covariates.

CONCLUSIONS

Results of this study completed with community-dwelling adults revealed that individuals who habitually consume greater amounts of caffeine as part of their daily diets demonstrate diminished sensitivity to painful stimuli in a laboratory setting.

Effects of Sleep Fragmentation and Induced Mood on Pain Tolerance and Pain Sensitivity in Young Healthy Adults

Background: Experimental research exploring the sleep/pain-relationship has typically focused on total or partial sleep deprivation, hereby failing to reproduce the mere fragmented sleep pattern typically observed in patients with chronic pain. Further, little research is done on how affect moderates the sleep–pain relationship after sleep fragmentation. The present study sought to clarify the relationship between pain, sleep and positive and negative affect.

Methods: In an experimental counterbalanced crossover design, 35 healthy young adults were subjected to several pain measures after one night of fragmented sleep, compared to one control night of normal sleep, both conducted in their own homes, and respectively, positive and negative affect induction using validated film clips and facial feedback procedures. Sleep was monitored using sleep diaries.

Results: Increased pain sensitivity after one night of experimentally induced sleep fragmentation was found, compared to after one control night of undisturbed sleep. No main effects of induced affect on pain were found, and sleep x induced affect interaction was not significant.

Conclusion: The present study supports the adverse effect of sleep fragmentation on pain sensitivity, however, affect was not found to be a moderator in the sleep–pain relationship. The results underline the need for further research within this field.

Paradoxical Sleep Deprivation Aggravates and Prolongs Incision-Induced Pain Hypersensitivity via BDNF Signaling-Mediated Descending Facilitation in Rats

The mechanisms underlying the pronociceptive effect of paradoxical sleep deprivation (PSD) are not fully established. The modulation of BDNF signaling-mediated descending facilitation from the rostral ventromedial medulla (RVM) of brain stem has been demonstrated in persistent pain models of inflammatory pain, but not in incisional pain model. Recent study has shown that PSD increases the expression of brain-derived neurotrophic factor (BDNF) in the brainstem structure. Therefore, in the current study, we asked whether the BDNF signaling-mediated descending facilitation was involved in the PSD-induced pronociceptive effect on incisional pain and delay the recovery period of postoperative pain in rats. Our results found that a preoperative 24 h PSD significantly aggravated the pain hypersensitivity after incision and prolonged the duration of postoperative pain. The lesions of ipsilateral dorsolateral funiculus partly reversed the PSD-induced pronociceptive effect on incisional pain. Interestingly, the 24 h PSD, but not incision significantly enhanced the levels of BDNF protein expression in the RVM areas of rats. Furthermore, at 1 day or 4 days after incision, intra-RVM microinjection of a BDNF antibody partly reversed the PSD-induced pronociceptive effects in incisional rats, while it did not change the cumulative pain scores and paw withdrawal thresholds in rats receiving only plantar incision. These findings suggest that the preoperative PSD may aggravate and prolong the incision-induced pain hypersensitivity via BDNF signaling-mediated descending facilitation.

Psychological Interventions for Late-life Insomnia: Current and Emerging Science

Purpose of Review

Late-life insomnia is a serious medical condition associated with many untoward consequences. The high prevalence of late-life insomnia, along with the concomitant risks inherent in the use of hypnotic medications in older adults necessitates non-pharmacological (i.e., psychological) treatment options. We aim to summarize and evaluate the state-of-the-science of psychological treatment options for late-life insomnia.

Recent Findings

Cumulative scientific evidence suggests the efficacy of psychological treatment of late-life insomnia. During the previous decade, trials of psychological treatments for insomnia have begun to test various modifications to treatments that have the potential to improve access for older adults, along with expanding their focus to include individuals with comorbid conditions that are common to older adults. While these modifications represent positive advances in the science of treatment for late-life insomnia, the evidence is still largely explanatory/efficacious in nature.

Summary

Psychological strategies represent the best approaches for the treatment of late-life insomnia. Future investigations would be wise to progressively move towards increasingly pragmatic/effectiveness investigations, adding to the literature base regarding the treatment of late-life insomnia under usual/real-world conditions as opposed to ideal/artificial conditions.

Potential for the development of light therapies in mild traumatic brain injury

Light affects almost all aspects of human physiological functioning, including circadian rhythms, sleep-wake regulation, alertness, cognition and mood. We review the existing relevant literature on the effects of various wavelengths of light on these major domains, particularly as they pertain to recovery from mild traumatic brain injuries. Evidence suggests that light, particularly in the blue wavelengths, has powerful alerting, cognitive and circadian phase shifting properties that could be useful for treatment. Other wavelengths, such as red and green may also have important effects that, if targeted appropriately, might also be useful for facilitating recovery. Despite the known effects of light, more research is needed. We recommend a personalized medicine approach to the use of light therapy as an adjunctive treatment for patients recovering from mild traumatic brain injury.

Sleep Environment and Insomnia in Elderly Persons Living at Home

The aim of this study was to draw a portrait of the sleep environment of elderly persons living in private households and to determine its relationship with the presence of insomnia. A sample of 599 individuals aged 70 years and older responded to questions about the comfort of their pillow and mattress and the noise level and brightness of their bedroom at night and in the morning. They were also asked whether or not they shared their bed or bedroom with a sleep partner. The Insomnia Severity Index was used to assess insomnia severity. Over 40% of the study participants were using a pillow that was not very comfortable, and almost 30% said that their bedroom was not completely quiet. Binomial logistic regression results revealed that two variables were significantly associated with insomnia symptoms: a pillow rated as moderately comfortable to very uncomfortable and a bedroom that was not completely quiet. No other sleep environment characteristics considered in this study were associated with the risk of insomnia. These results indicate that a nonnegligible proportion of the elderly population endures a suboptimal sleep environment. Although it is difficult to predict the real impact of changes to the sleep environment, this study supports the proposal that simple, minor changes to the bedroom can promote sleep in the elderly.

Undercover Dogs: Pet Dogs in the Sleep Environment of Patients with Chronic Pain

(1) Background: Chronic pain is a significant and prevalent condition in many industrialized nations. Pain and sleep’s reciprocal nature suggests that interventions to improve sleep may decrease pain symptoms. Little attention has been paid to the influence that owning a pet dog has on the pain/sleep relationship. Typical advice to remove pets from the bedroom negates the possible positive benefit of human-animal co-sleeping. Aim: To investigate pain patients’ perceived impact of pet dog ownership on sleep. (2) Methods: We carried out a content analysis of interview data focused on the impact of pet dog ownership on sleep. The qualitative dataset comes from a subgroup of participants in a larger study examining the pain patient/canine relationship. This subgroup of participants from the larger study was asked, “Does your dog have a positive or negative impact on your sleep?” The data were thematically coded using an iterative approach. (3) Findings: Codes included: companionship; physical presence/’cuddles’; routine/schedule; distraction from anxiety/worry at night; reassuring/protective presence; active intervention to keep participant safe; daytime activity to promote sleeping at night; and reciprocal concern for the sleep of the pet dog. (4) Conclusions: Pet dogs may play important roles in helping people with chronic pain achieve sleep onset and maintenance. Removing the dog to improved sleep could be counter-productive and lead to additional sleep-related issues.

Impact of Poor Sleep on Physical and Mental Health in Older Women

Many aspects of sleep and circadian rhythms change as people age. Older adults usually experience decrease in sleep duration and efficiency, increase in sleep latency and fragmentation, high prevalence of sleep disorders, and weakened rest-activity rhythms. Research evidence suggests that women are more likely to report aging-related sleep problems. This review presents epidemiologic and clinical evidence on the relationships between sleep deficiency and physical and mental outcomes in older women, explores potential mechanisms underlying such relationships, points out gaps in the literature that warrant future investigations, and considers implications in clinical and public health settings.

Burning mouth syndrome in postmenopausal women with self-reported sleep problems

OBJECTIVE

The aim of this study was to investigate possible relationships among hematologic factors, psychological dimensions, the presence of self-reported sleep problems, and clinical characteristics in patients with burning mouth syndrome (BMS).

METHODS

Twenty-five postmenopausal female patients with primary BMS (aged 55.2 ± 9.6 years) were included. All participants underwent clinical and psychological evaluations and blood sampling. The patients were subdivided according to the absence or presence of the self-reported sleep problems.

RESULTS

Pain intensity of BMS patients with sleep problems was significantly higher than those without sleep problems, and the severity of oral complaints was correlated with the presence of depression, anxiety, hostility, phobia, and psychosis. Estradiol levels were significantly lower, and FSH and LH levels were higher in BMS patients with sleep problems than those without sleep problems.

DISCUSSION

BMS patients with sleep problems may suffer inharmonious psychoneuroendocrinological interactions that might worsen oral BMS symptoms.

Sleep Biomarkers, Health Comorbidities, and Neurocognition in Obstructive Sleep Apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is associated with cognitive impairment but the relationships between specific biomarkers and neurocognitive domains remain unclear. The present study examined the influence of common health comorbidities on these relationships. Adults with suspected OSA (N=60; 53% male; M age=52 years; SD=14) underwent neuropsychological evaluation before baseline polysomnography (PSG). Apneic syndrome severity, hypoxic strain, and sleep architecture disturbance were assessed through PSG.

METHODS

Depression (Center for Epidemiological Studies Depression Scale, CESD), pain, and medical comorbidity (Charlson Comorbidity Index) were measured via questionnaires. Processing speed, attention, vigilance, memory, executive functioning, and motor dexterity were evaluated with cognitive testing. A winnowing approach identified 9 potential moderation models comprised of a correlated PSG variable, comorbid health factor, and cognitive performance.

RESULTS

Regression analyses identified one significant moderation model: average blood oxygen saturation (AVO2) and depression predicting recall memory, accounting for 31% of the performance variance, p<.001. Depression was a significant predictor of recall memory, p<.001, but AVO2 was not a significant predictor. The interaction between depression and AVO2 was significant, accounting for an additional 10% of the variance, p<.001. The relationship between low AVO2 and low recall memory performance emerged when depression severity ratings approached a previously established clinical cutoff score (CESD=16).

CONCLUSIONS

This study examined sleep biomarkers with specific neurocognitive functions among individuals with suspected OSA. Findings revealed that depression burden uniquely influence this pathophysiological relationship, which may aid clinical management. (JINS, 2018, 28, 864-875).

Improve postoperative sleep: what can we do?

Purpose of review

We reviewed evidences regarding occurrence, risk factors, harmful effects, prevention, and management of sleep disturbances in patients after surgery.

Recent findings

Normal sleep is important to maintain physical and mental health. Sleep disturbances frequently occur in patients after surgery. Factors associated with the development of postoperative sleep disturbances include old age, preoperative comorbidity, type of anesthesia, severity of surgical trauma, postoperative pain, environment stress, as well as other factors leading to discomfort of patients. Development of sleep disturbances produces harmful effects on postoperative patients, that is, leading to higher risk of delirium, increased sensitivity to pain, more cardiovascular events, and poorer recovery. Both nonpharmacological and pharmacological measures (such as zolpidem, melatonin, and dexmedetomidine) can be used to improve postoperative sleep. Recent evidences show that sleep promotion may improve patients’ outcome, but requires further evidences.

Summary

Sleep disturbances are common in patients after surgery and produce harmful effects on postoperative recovery. Sleep-promotion therapy may be helpful to improve postoperative recovery, but long-term effects deserve further study.

Higher Incidence of Sleep Disturbance among Survivors with Musculoskeletal Pain after the Great East Japan Earthquake: A Prospective Study

Sleep disturbance is a common symptom after natural disasters. Although musculoskeletal pain also increases after natural disasters, its relation to sleep disturbance is not clear. The purpose of this study was to determine the influence of musculoskeletal pain on new-onset sleep disturbance among survivors after the Great East Japan Earthquake (GEJE). A prospective cohort study was conducted with the survivors of the GEJE at two and three years after the earthquake. New-onset sleep disturbance was defined as sleep disturbance absent at two years and present at three years after the earthquake. The sites of musculoskeletal pain included low back, shoulder, knee, and hand or foot. The number of musculoskeletal pain sites at two years after the earthquake was divided into three categories (0, 1, and 2 or more). Univariate and multivariate logistic regression models were used to calculate the odds ratio (OR) and 95% confidence interval (95%CI) for new-onset sleep disturbance according to the number of musculoskeletal pain sites. A total of 1,102 survivors were included in this study and 14.6% of the participants reported new-onset sleep disturbance. Using "0" as a reference, the adjusted ORs (95% CI) for new-onset sleep disturbance were 2.43 (1.55-3.80) in "1" and 2.96 (1.88-4.64) in "2 or more", respectively (P for trends < 0.001). In conclusion, this is the first study showing higher incidence of sleep disturbance among survivors with musculoskeletal pain after the GEJE. Care for musculoskeletal pain is important to prevent sleep disturbance after natural disasters.

Effects of Mindfulness Training on Sleep Problems in Patients With Fibromyalgia

Fibromyalgia syndrome (FMS) is a complex psychosomatic pain condition. In addition to generalized pain and various cognitive difficulties, new FMS diagnostic criteria acknowledge fatigue and sleep problems as core aspects of this condition. Indeed, poor sleep quality has been found to be a significant predictor of pain, fatigue, and maladaptive social functioning in this patient group. While there is promising evidence supporting the role of mindfulness as a treatment for FMS, to date, mindfulness intervention studies have principally focused on dimensions of pain as the primary outcome with sleep problems either not being assessed or included as a secondary consideration. Given the role of sleep problems in the pathogenesis of FMS, and given that mindfulness has been shown to improve sleep problems in other clinical conditions, the present study explored the effects of a mindfulness-based intervention known as Flow Meditation (Meditación-Fluir) on a range of sleep-related outcomes (subjective insomnia, sleep quality, sleepiness, and sleep impairment) in individuals with FMS. Adult women with FMS (n = 39) were randomly assigned to the 7 weeks mindfulness treatment or a waiting list control group. Results showed that compared to the control group, individuals in the mindfulness group demonstrated significant improvements across all outcome measures and that the intervention effects were maintained at a 3 month follow-up assessment. The Meditación-Fluir program shows promise for alleviating sleep problems relating to FMS and may thus have a role in the treatment of FMS as well as other pain disorders in which sleep impairment is a central feature of the condition.

Sleep Deprivation Related Changes of Plasma Oxytocin in Males and Female Contraceptive Users Depend on Sex and Correlate Differentially With Anxiety and Pain Hypersensitivity

Disturbed sleep is known to substantially aggravate both the pain condition and the affective state of pain patients. The neurobiological mechanisms underlying these adverse effects are unknown. Oxytocin (OT), being largely involved in social and emotional behavior, is considered to also play a modulatory role in nociception. We hypothesized a pathophysiological role of OT for the hyperalgesic and anxiogenic effects of sleep loss. An established human model of one night of total sleep deprivation (TSD) was used to test this hypothesis. Twenty young healthy students (n = 10 male and n = 10 female) were investigated in a balanced cross-over design, contrasting TSD with a night of habitual sleep (HS). All females took monophasic oral contraceptives (OC) and were investigated during their ‘pill-free’ phase. Plasma OT concentrations were correlated with (1) pain thresholds, (2) descending pain inhibition, and (3) state-anxiety scores. Compared to the HS condition, the plasma OT concentration was significantly increased in sleep deprived females (p = 0.02) but not males (p = 0.69). TSD resulted in pain hypersensitivity to noxious cold (p = 0.05), noxious heat (p = 0.023), and pricking stimuli (p = 0.013) and significantly increased state-anxiety (p = 0.021). While, independent of sex, lower heat pain thresholds correlated with higher plasma OT (p = 0.036), no such associations were found for cold/mechanical pain. In sleep-deprived females, higher plasma OT showed a mild (but insignificant) association with lower pain inhibition (p = 0.093). We found a positive correlation between anxiety-scores and OT (p = 0.021), which was enhanced when respecting “sex” (p = 0.008) and “sleep” (p = 0.001) in a hierarchical regression analysis. Altogether, our study revealed a complex and partially sex-dependent correlation between plasma OT and TSD-induced changes of experimental pain and anxiety. The minor role of OT for TSD-induced changes of evoked pain, and its major involvement in anxiety, argues against a specific role of OT for linking the adverse effects of TSD on pain sensitivity and anxiety with each other. Future investigations are needed in order to dissect out the effect of OC on the sex-dependent effects of TSD observed in our study.

A prospective study of work-private life conflict and number of pain sites: moderated mediation by sleep problems and support

The objective of the current study was to elucidate how work-private life conflict prospectively affects musculoskeletal pain complaints by exploring possible mediation through sleep problems. In addition, the study determined whether support from coworkers and superior moderate this mediated relationship. The study incorporated a two-wave full panel design and participants included 4681 Norwegian working men and women. Path analyses were performed to study direct and indirect effects of work-private life conflict on sleep problems and multisite musculoskeletal pain, moderated by support. This study suggested time-lagged relationships of work-private life conflict with number of pain sites. Furthermore, sleep problems may mediate the effects of work-private life conflict on number of pain sites. While support has been found to affect the direct relationship between work-private life conflict and number of pain sites, it does not significantly moderate the indirect mediation effect, i.e. no moderated mediation effect of support was established. Findings from the present study suggest sleep may be one explaining factor in the complex work-pain mechanism, and this may aid the development of theories on work-private life conflict and pain. Since both work-private life conflict and support are modifiable work factors, primary workplace interventions by the employer aiming to reduce sleep problems and musculoskeletal pain in employees could target these specific work factors, and help prevent work-related pain complaints.

Sleep quality with WHO Step III opioid use for cancer pain

OBJECTIVE

Sleep is often disturbed in patients with advanced cancer. There is limited knowledge about sleep in patients with cancer treated with strong opioids. This study examines sleep quality in patients with advanced cancer who are treated with a WHO Step III opioid for pain.

METHODS

An international, multicentre, cross-sectional study with 604 adult patients with cancer pain using WHO Step III opioids. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI) global score (range; 0-21; score >5 indicates poor sleep). PSQI includes sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbances, use of sleep medications and daytime dysfunction. Pain and quality of life were assessed by Brief Pain Inventory and European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core30.

RESULTS

The median age was 62 years, 42% were female, mean Karnofsky performance score (KPS) was 62.5 (±14.2) and mean oral daily morphine equivalent dose was 303 mg/24 hours (±543.8 mg). The mean PSQI global score was 8.8 (±4.2) (range 0-20). Seventy-eight per cent were poor sleepers. All PSQI components were affected, and 44% reported trouble sleeping caused by pain. In the multiple regression model, predictors of PSQI global scores were pain intensity, emotional function, constipation, financial difficulties and KPS (adjusted R²=0.21).

CONCLUSION

The majority (78%) of these patients with cancer treated with Step III opioids experienced poor sleep quality. Pain intensity, emotional function, constipation, financial difficulties and KPS predicted poor PSQI global scores. The clinical implication is that healthcare personnel should routinely assess and treat sleep disturbance in patients with advanced cancer disease.

Pain and severe sleep disturbance in the general population: Primary data and meta-analysis from 240,820 people across 45 low- and middle-income countries

OBJECTIVE

Pain and sleep disturbances are widespread, and are an important cause of a reduced quality of life. Despite this, there is a paucity of multinational population data assessing the association between pain and sleep problems, particularly among low- and middle-income countries (LMICs). Therefore, we investigated the relationship between pain and severe sleep disturbance across 45 LMICs.

METHOD

Community-based data on 240,820 people recruited via the World Health Survey were analyzed. Multivariable logistic regression analyses adjusted for multiple confounders were performed to quantify the association between pain and severe sleep problems in the last 30 days. A mediation analysis was conducted to explore potential mediators of the relationship between pain and severe sleep disturbance.

RESULTS

The prevalence of mild, moderate, severe, and extreme levels of pain was 26.0%, 16.2%, 9.1%, and 2.2% respectively, whilst 7.8% of adults had severe sleep problems. Compared to those with no pain, the odds ratio (OR, 95% CI) for severe sleep problems was 3.65 (3.24-4.11), 9.35 (8.19-10.67) and 16.84 (13.91-20.39) for those with moderate, severe and extreme pain levels respectively. A country wide meta-analysis adjusted for age and sex demonstrated a significant increased OR across all 45 countries. Anxiety, depression and stress sensitivity explained 12.9%, 3.6%, and 5.2%, respectively, of the relationship between pain and severe sleep disturbances.

CONCLUSION

Pain and sleep problems are highly co-morbid across LMICs. Future research is required to better understand this relationship. Moreover, future interventions are required to prevent and manage the pain and sleep disturbance comorbidity.

Role of the Prefrontal Cortex in Pain Processing

The prefrontal cortex (PFC) is not only important in executive functions, but also pain processing. The latter is dependent on its connections to other areas of the cerebral neocortex, hippocampus, periaqueductal gray (PAG), thalamus, amygdala, and basal nuclei. Changes in neurotransmitters, gene expression, glial cells, and neuroinflammation occur in the PFC during acute and chronic pain, that result in alterations to its structure, activity, and connectivity. The medial PFC (mPFC) could serve dual, opposing roles in pain: (1) it mediates antinociceptive effects, due to its connections with other cortical areas, and as the main source of cortical afferents to the PAG for modulation of pain. This is a ‘loop’ where, on one side, a sensory stimulus is transformed into a perceptual signal through high brain processing activity, and perceptual activity is then utilized to control the flow of afferent sensory stimuli at their entrance (dorsal horn) to the CNS. (2) It could induce pain chronification via its corticostriatal projection, possibly depending on the level of dopamine receptor activation (or lack of) in the ventral tegmental area-nucleus accumbens reward pathway. The PFC is involved in biopsychosocial pain management. This includes repetitive transcranial magnetic stimulation, transcranial direct current stimulation, antidepressants, acupuncture, cognitive behavioral therapy, mindfulness, music, exercise, partner support, empathy, meditation, and prayer. Studies demonstrate the role of the PFC during placebo analgesia, and in establishing links between pain and depression, anxiety, and loss of cognition. In particular, losses in PFC grey matter are often reversible after successful treatment of chronic pain.

Bidirectional association between disturbed sleep and neuropathic pain symptoms: a prospective cohort study in post-total joint replacement participants

Background

Disturbed sleep is strongly correlated with chronic pain. The aim of this study was to examine the association between sleep disturbance and incident joint pain focusing on neuropathic-like pain symptoms.

Methods

A total of 423 individuals who had undergone total joint replacement (TJR) for osteoarthritis were assessed at the mean time of 3.6 years post-surgery and again at 5.9 years post-TJR, using the Medical Outcomes Survey sleep subscale, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and painDETECT questionnaire instruments. Cox hazard ratios (HRs) and 95% confidence intervals (CIs) were computed adjusting for age, body mass index, sex, and use of hypnotic and analgesic medication.

Results

The presence of neuropathic pain symptoms predicted incidence of disturbed sleep after adjustment for covariates and pain severity (adjusted HR [aHR] 2.01, 95% CI: 1.00–4.10; p<0.05). There was no association between joint pain and incidence of disturbed sleep when individuals with neuropathic pain symptoms at the baseline visit were excluded (aHR 1.11, 95% CI: 0.47–2.67). Disturbed sleep at baseline predicted incident neuropathic joint pain symptoms (aHR 2.75, 95% CI: 1.21–6.26; p<0.016) but had no effect on incidence of joint pain when all types of pain were considered together (aHR 0.63, 95% CI: 0.30–1.39).

Conclusion

These data suggest a causal bidirectional link between sleep disturbance and joint pain with neuropathic features but not with other types of joint pain.

Pain and quality of life of children and adolescents with osteogenesis imperfecta over a bisphosphonate treatment cycle

The objective was to describe the pain and quality of life among children and adolescents with any osteogenesis imperfecta (OI) type over one intravenous bisphosphonate treatment cycle from a child and parental perspective. A prospective, observational study was conducted, where children and adolescents evaluated their pain intensity, location, and quality, as well as quality of life before, 1 week after treatment, and 6 months later. Quality of life was also evaluated from the parental perspective at the same three time points. Thirty-three child/parent dyads participated. The results showed that pain intensity on the 0-10 self-report scale after the Zoledronate infusion (median = 0, range = 0-6) was not different from pre (median = 2, range = 0-10) and 6-months post-scores (median = 2, range = 0-8) (p = 0.170). Children and adolescents with OI reported experiencing pain mainly in the ankles and the anterior and posterior shoulders. They selected evaluative pain descriptors such as uncomfortable (n = 16, 48%) and annoying (n = 13, 39%). Children and adolescents' functioning and quality of life did not change significantly across the bisphosphonate treatment cycle (p = 0.326), parents perceived an improvement immediately after the treatment compared to before (p = 0.016).

CONCLUSION

Children and adolescents with OI experience mild, yet complex pain localized across several body areas. There is little fluctuation in the pain intensity and functioning of children with OI undergoing bisphosphonate treatment. What is Known: • Acute and chronic musculoskeletal pain remains a major issue in OI. • Pain has a negative impact on quality of life. What is New: • New and unpublished methods and findings describing the pain and quality of life of children and adolescents with OI over one intravenous bisphosphonate treatment cycle from a child- and parental-proxy perspective. • Children and adolescents with OI experience pain intensity that is mild, yet complex in quality and localized across several body areas.

Dynamic daily associations between insomnia symptoms and alcohol use in adults with chronic pain

Individuals with chronic pain are at risk for sleep disruption and heavy alcohol use, yet the daily associations between these behaviours are not well characterized. This study aimed to determine the extent to which alcohol use affects insomnia symptoms and vice versa in adults reporting symptoms of chronic pain. Participants were 73 individuals (93% women) reporting alcohol use in addition to symptoms of insomnia and chronic pain. They completed daily diaries assessing insomnia symptoms and alcohol use for 14 days. Multilevel modelling was used to evaluate the bidirectional associations between alcohol use and insomnia symptoms at the daily level. Consistent with laboratory-based research, alcohol use was associated with decreased sleep-onset latency the same night but increased sleep-onset latency 2 nights later. Specifically, for every alcoholic drink consumed, time to sleep onset decreased by 5.0 min in the same night but increased by 4.3 min 2 nights later. Alcohol use was not significantly associated with subsequent wake after sleep onset or total sleep time, and insomnia symptoms were not significantly associated with subsequent alcohol use. To our knowledge, these data provide the first evidence that alcohol use negatively affects insomnia symptoms up to 2 days post-consumption in patients reporting symptoms of insomnia and chronic pain. Findings suggest that one drink will have minimal impact on sleep, but heavier drinking (e.g. four-five drinks) may have a clinically significant impact (16-25-min increase in sleep-onset latency). Future studies may assess alcohol use as a point of intervention within this population.

Effects of sleep changes on pain-related health outcomes in the general population: A systematic review of longitudinal studies with exploratory meta-analysis

Emerging longitudinal research has highlighted poor sleep as a risk factor of a range of adverse health outcomes, including disabling pain conditions. In establishing the causal role of sleep in pain, it remains to be clarified whether sleep deterioration over time is a driver of pain and whether sleep improvement can mitigate pain-related outcomes. A systematic literature search was performed using PubMed MEDLINE, Ovid EMBASE, and Proquest PsycINFO, to identify 16 longitudinal studies involving 61,000 participants. The studies evaluated the effect of sleep changes (simulating sleep deterioration, sleep stability, and sleep improvement) on subsequent pain-related outcomes in the general population. A decline in sleep quality and sleep quantity was associated with a two- to three-fold increase in risk of developing a pain condition, small elevations in levels of inflammatory markers, and a decline in self-reported physical health status. An exploratory meta-analysis further revealed that deterioration in sleep was associated with worse self-reported physical functioning (medium effect size), whilst improvement in sleep was associated with better physical functioning (small effect size). The review consolidates evidence that changes in sleep are prospectively associated with pain-related outcomes and highlights the need for further longitudinal investigations on the long-term impact of sleep improvements.

Chronic pain prevalence and associated factors in adolescents with and without physical disabilities

AIM

Adolescents with physical disabilities may have co-occurring chronic pain, but the prevalence and specific associated factors are unknown. The aims of this study were to determine (1) the prevalence of chronic pain in adolescents with physical disabilities and (2) whether known correlates of chronic pain in the general population are also present in young people both with physical disability and with chronic pain relative to peers.

METHOD

We conducted a secondary analysis of cross-sectional nationally representative data from the National Longitudinal Study of Adolescent to Adult Health. Multivariate linear regression analysis was used to identify demographic and psychosocial factors associated with chronic pain.

RESULTS

A total of 989 (4.3%) adolescents reported physical disabilities. They had a significantly higher rate of pain (27.2%) compared with able-bodied peers (15.6%, χ² =86.3550, p<0.001). There was no significant interaction between physical disability status and chronic pain in relation to depressive symptoms, anxiety, or insomnia.

INTERPRETATION

Adolescents with physical disabilities experience chronic pain at a significantly higher rate than able-bodied peers, but the comorbidity of physical disability and chronic pain is not related to depression, anxiety, or insomnia. Evaluation of chronic pain and tailored pain interventions need to be developed for this population.

WHAT THIS PAPER ADDS

Chronic pain and its correlates are important problems for adolescents with physical disabilities. These adolescents present with higher rates of chronic pain than other young people. Chronic pain is associated with increased levels of depressive symptoms, anxiety, and insomnia regardless of disability status.

Impaired sleep predicts onset of low back pain and burnout symptoms: evidence from a three-wave study

In a three-wave questionnaire study of 405 working participants, who were initially free of low back pain (LBP) and emotional exhaustion, sleep problems were evaluated as a potential risk factor for the development of LBP and burnout up to three years later. Prospective risk paths were compared between the sexes and between two age-groups (18 to 45 years and older than 45 years). A longitudinal structural equation model showed a good fit with empirical data (RMSEA = .04, SRMR = .06, CFI = .97). Prospective risk paths between the latent constructs showed sleep problems to significantly predict self-reported LBP (β = .15, p = .011) and burnout (β = .24, p < .001) two years later. Sleep problems also predicted the occurrence of burnout three years later (β = .18, p = .002). Sleep-related risk of burnout after two years was greater in older than younger participants (β_older = .42 vs. β_younger = .13, p < .001). Sleep problems seem to precede LBP and burnout in working individuals. Health promotion initiatives should use sleep quality as an important early risk indicator, and interventions should focus on promoting better quality sleep, in an attempt to reduce the incidence of LBP and burnout.

Validation of EQ-5D and 15D in the assessment of health-related quality of life in chronic pain

Chronic pain has a significant impact on quality of life. Measurement of health-related quality of life (HRQoL) is essential in the assessment of pain management outcomes, but different instruments have produced varying results. We assessed the validity of 2 HRQoL instruments, EuroQol 5 dimensions questionnaire (EQ-5D) and 15-dimensional health-related quality of life measure (15D), in patients with challenging chronic pain. Three hundred ninety-one chronic noncancer pain patients referred to tertiary pain clinics completed EQ-5D, 15D, and a broad set of questionnaires mapping socioeconomic factors, self-rated health, pain intensity and interference, depression, pain acceptance, pain-related anxiety, and sleep. The 2 HRQoL instruments were compared with each other, and head-to-head comparisons were made with self-rated health and the symptom-specific questionnaires. 15D and EQ-5D showed moderate agreement (ρ = 0.66), but there were also considerable differences between the instruments. 15D correlated better with self-rated health than EQ-5D (ρ = -0.62 vs -0.45, P < 0.001). The EQ-5D appeared less sensitive than 15D especially in those patients with chronic pain who had a better health status. The principal component constructed from measures of pain intensity and interference, anxiety, pain acceptance, depression, and sleep had higher standardized beta coefficients with 15D than with EQ-5D (P = 0.038). The principal component explained more variance in the 15D (R = 0.65) than in the EQ-5D (R = 0.43). The study identified differences in the pain-related variables between the EQ-5D and the 15D. In patients with chronic pain, both instruments are valid, but 15D appears somewhat more sensitive than EQ-5D.

Sleep Disturbances in Chronic Pain: Neurobiology, Assessment, and Treatment in Physical Therapist Practice

Among people with chronic pain, insomnia is highly prevalent, closely related to the mechanism of central sensitization, characterized by low-grade neuroinflammation, and commonly associated with stress or anxiety; in addition, it often does not respond effectively to drug treatments. This review article applies the current understanding of insomnia to clinical practice, including assessment and conservative treatment of insomnia in people with chronic pain. Cognitive-behavioral therapy for insomnia can be efficacious for improvements in sleep initiation, sleep maintenance, perceived sleep quality, and pain interference with daily functioning in people with chronic pain. A recent systematic review concluded that with additional training, physical therapist-led cognitive-behavioral interventions are efficacious for low back pain, allowing their implementation within the field. Cognitive-behavioral therapy for insomnia, as provided to people with chronic pain, typically includes education, sleep restriction measures, stimulus control instructions, sleep hygiene, and cognitive therapy.

The association between burning mouth syndrome and sleep disturbance: A case-control multicentre study

OBJECTIVES

To investigate the quality of sleep and the psychological profiles of a large cohort of Italian patients with burning mouth syndrome (BMS) and to clarify the relationships between these variables and pain.

METHODS

In this case-control study, 200 patients with BMS vs an equal number of age- and sex-matched healthy controls, recruited in 10 universities, were enrolled. The Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Hamilton Rating Scale for Depression (HAM-D), Hamilton Rating Scale for Anxiety (HAM-A), Numeric Pain Intensity Scale (NRS) and Total Pain Rating Index (T-PRI) were administered. Descriptive statistics, including the Mann-Whitney U test and hierarchical multiple linear regression analysis, were used.

RESULTS

Poor sleep quality (PSQI ≥ 5) was present in 78.8% (160) patients with BMS. BMS patients had statistically higher scores in all items of the PSQI and ESS than the healthy controls (p < .001). A depressed mood and anxiety correlated positively with sleep disturbance. The Pearson correlations were 0.570 for the PSQI vs HAM-D (p < .001) and 0.549 for the PSQI vs HAM-A (p < .001). Pain intensity (NRS) poorly correlated to sleep quality; the Pearson correlation was 0.162 for the PSQI vs NRS (p = .021).

CONCLUSIONS

The BMS patients showed a poor sleep quality, anxiety and depression, as compared with the controls, highlighting the relationships between oral burning, sleep and mood.

Insomnia and risk of chronic musculoskeletal complaints: longitudinal data from the HUNT study, Norway

BACKGROUND

The aim of this study was to investigate the prospective association between insomnia and risk of chronic musculoskeletal complaints (CMSC) and chronic widespread musculoskeletal complaints (CWMSC). A second aim was to evaluate the association between insomnia and number of body regions with CMSC at follow-up.

METHODS

We used data from the second (HUNT2, 1995-1997) and third (HUNT3, 2006-2008) wave of the Nord-Trøndelag Health Study (the HUNT Study). The population-at-risk included 13,429 people aged 20-70 years who reported no CMSC at baseline in HUNT2 and who answered the questionnaires on insomnia in HUNT2 and CMSC in HUNT3. Insomnia was defined according to the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) with minor modification, whereas CMSC was assessed for nine different body regions. CWMSC was defined according to the 1990 criteria by the American College of Rheumatology. We used Poisson regression to estimate adjusted risk ratios (RRs) for CMSC and CWMSC at 11 years follow-up. Precision of the estimates was assessed by a 95% confidence interval (CIs).

RESULTS

Insomnia at baseline was associated with increased risk of any CMSC (RR 1.16, 95% CI 1.03-1.32) and CWMSC (RR 1.58, 95% CI 1.26-1.98) at follow-up. RR for CMSC for specific body regions ranged from 1.34 (95% CI 1.05-1.73) for the knees and 1.34 (1.10-1.63) for the neck to 1.60 (95% CI 1.19-2.14) for the ankles/ft. Further, insomnia was associated with increased risk of CMSC in 3-4 regions (RR 1.36, 95% CI 1.05-1.77), and 5 or more regions (RR 1.93, 95% CI 1.40-2.66), but not 1-2 regions (RR 0.99, 95% CI 0.80-1.24).

CONCLUSIONS

Insomnia is associated with increased risk of CMSC, CWMSC, and CMSC located in 3 or more body regions.

Preemptive Caffeine Administration Blocks the Increase in Postoperative Pain Caused by Previous Sleep Loss in the Rat: A Potential Role for Preoptic Adenosine A2A Receptors in Sleep-Pain Interactions

Sleep and pain are reciprocally related, but the precise mechanisms underlying this relationship are poorly understood. This study used a rat model of surgical pain to examine the effect of previous sleep loss on postoperative pain and tested the hypothesis that preoptic adenosinergic mechanisms regulate sleep-pain interactions. Relative to ad libitum sleep, 6 hours of total sleep deprivation prior to a surgical incision significantly enhanced postoperative mechanical hypersensitivity in the affected paw and prolonged the time to recovery from surgery. There were no sex-specific differences in these measures. There were also no changes in adrenocorticotropic hormone and corticosterone levels after sleep deprivation, suggesting that this effect was not mediated by the stress associated with the sleep perturbation. Systemic administration of the nonselective adenosine receptor antagonist caffeine at the onset of sleep deprivation prevented the sleep deprivation-induced increase in postoperative hypersensitivity. Microinjection of the adenosine A2A receptor antagonist ZM 241385 into the median preoptic nucleus (MnPO) blocked the increase in surgical pain levels and duration caused by prior sleep deprivation and eliminated the thermal hyperalgesia induced by sleep deprivation in a group of nonoperated (i.e., without surgical incision) rats. These data show that even a brief sleep disturbance prior to surgery worsens postoperative pain and are consistent with our hypothesis that adenosine A2A receptors in the MnPO contribute to regulate these sleep-pain interactions.

Understanding the different relationships between mood and sleep disorders in several groups of non-oncological patients with chronic pain

OBJECTIVE

To compare sleep dimensions in patients suffering from chronic pain of different origins, and with a group of pain-free subjects. To analyze the relationship between depression and/or anxiety and sleep disorders in musculoskeletal, neuropathic, and fibromyalgia patients.

METHODS

This cross-sectional study included patients diagnosed with neuropathic pain (NP) (n = 104), musculoskeletal pain (MSK) (n = 99), or fibromyalgia (FM) (n = 51), and pain free subjects (n = 72). Information about sleep dimensions (MOS-sleep), duration and intensity of pain (Visual Analog Scale), and anxiety and depression (Hospital Anxiety and Depression scale) was collected.

RESULTS

Of the 254 patients with chronic pain (PCP) studied, the mean pain intensity was 6.6 (SD = 1.9), with an average duration of 9 years. The scores in all sleep dimensions of the MOS-sleep were higher in CPP (more disturbances) compared to pain free patients, and differences were observed among the three groups of PCP, with FM most severely affected. Anxiety (β = 1.3), depression (β = 1.1), intensity (β = 1.7), and duration of pain (β = 0.04) were associated with more sleep problems in MSK patients. In contrast, anxiety (β = 2.5) and duration of pain (β = 0.05) were negatively related to sleep in the NP patients, and only depression (β = 1.3) affected FM patients.

CONCLUSIONS

The sleep pattern differs among groups of PCP in the presence or absence of mood disorders. Understanding these disorders in each specific group of PCP is fundamental, and it can contribute to improve the clinical situation of the patients and better orientating therapeutic strategies.

Relationships Between Sleep Quality and Pain-Related Factors for People with Chronic Low Back Pain: Tests of Reciprocal and Time of Day Effects

BACKGROUND

Poor sleep quality among people with chronic low back pain appears to be related to worse pain, affect, poor physical function, and pain catastrophizing. The causal direction between poor sleep and pain remains an open question, however, as does whether sleep quality exerts effects on low back pain differently across the course of the day.

PURPOSE

This daily diary study examined lagged temporal associations between prior night sleep quality and subsequent day pain, affect, physical function and pain catastrophizing, the reverse lagged temporal associations between prior day pain-related factors and subsequent night sleep quality, and whether the time of day during which an assessment was made moderated these temporal associations.

METHODS

Chronic low back pain patients (n = 105) completed structured electronic diary assessments five times per day for 14 days. Items included patient ratings of their pain, affect, physical function, and pain catastrophizing.

RESULTS

Collapsed across all observations, poorer sleep quality was significantly related to higher pain ratings, higher negative affect, lower positive affect, poorer physical function, and higher pain catastrophizing. Lagged analyses averaged across the day revealed that poorer prior night sleep quality significantly predicted greater next day patient ratings of pain, and poorer physical function and higher pain catastrophizing. Prior poorer night sleep quality significantly predicted greater reports of pain, and poorer physical function, and higher pain catastrophizing, especially during the early part of the day. Sleep quality × time of day interactions showed that poor sleepers reported high pain, and negative mood and low function uniformly across the day, whereas good sleepers reported relatively good mornings, but showed pain, affect and function levels comparable to poor sleepers by the end of the day. Analyses of the reverse causal pathway were mostly nonsignificant.

CONCLUSIONS

Sleep quality appears related not only to pain intensity but also to a wide range of patient mood and function factors. A good night's sleep also appears to offer only temporary respite, suggesting that comprehensive interventions for chronic low back pain not only should include attention to sleep problems but also focus on problems with pain appraisals and coping.

Current sleep disturbance in older people with a lifetime history of depression is associated with increased connectivity in the Default Mode Network

BACKGROUND

The present study investigated Default Mode Network (DMN) functional connectivity in subjects with a lifetime history of major depression, comparing those with and without current sleep disturbance. Controls were included to assess DMN abnormalities specific to depression.

METHODS

A total of 93 adults aged 50 years and over were recruited from the Healthy Brain Ageing Clinic at the Brain and Mind Centre, Sydney, Australia. The sample comprised two groups, including 22 controls and 71 participants with a lifetime history of DSM-IV major depression (with depressive episode current or remitted). 52 of those with a lifetime history of depression also met criteria for Mild Cognitive Impairment (MCI). Participants underwent resting-state fMRI along with comprehensive psychiatric, neuropsychological, and medical assessment. Subjective sleep quality was assessed via the Pittsburgh Sleep Quality Index (PSQI). Sleep disturbance was defined as a PSQI score > 5. A total of 68% (n = 48) of cases with a lifetime history of depression met criteria for sleep-disturbance. DMN functional connectivity was assessed via ROI-to-ROI analyses.

RESULTS

Relative to controls, those with lifetime major depression demonstrated significantly increased functional connectivity between the ventromedial prefrontal cortex and the temporal pole. Within the depression group (n = 48), those with current sleep disturbance had significantly increased connectivity between the anterior medial prefrontal cortex and both the parahippocampal cortex and the hippocampal formation, relative to those without sleep disturbance (n = 23). These results were present after controlling for MCI diagnosis.

CONCLUSIONS

Current sleep disturbance together with depression is associated with distinct abnormalities in DMN functioning incorporating regions responsible for self-reflection and declarative memory processes. Impaired sleep is associated with increased connectivity between these regions. Future studies may augment these findings with complementary imaging techniques including cortical thickness and diffusion tensor imaging, as well as high density electroencephalogram recording.

Prevalence of and characteristics associated with insomnia and obstructive sleep apnea among veterans with knee and hip osteoarthritis

BACKGROUND

Few studies have examined patterns of specific sleep problems among individuals with osteoarthritis (OA). The primary objective of this study was to examine prevalence of symptoms of insomnia and obstructive sleep apnea (OSA) among Veterans with OA. Secondary objectives were to assess proportions of individuals with insomnia and OSA symptoms who may have been undiagnosed and to examine Veterans' characteristics associated with insomnia and OSA symptoms.

METHODS

Veterans (n = 300) enrolled in a clinical trial completed the Insomnia Severity Index (ISI) and the Berlin Questionnaire (BQ) at baseline; proportions of participants with symptoms consistent with insomnia and OSA were calculated, using standard cut-offs for ISI and BQ. For Veterans with insomnia and OSA symptoms, electronic medical records were searched to identify whether there was a diagnosis code for these conditions. Multivariable linear (ISI) and logistic (BQ) regression models examined associations of the following characteristics with symptoms of insomnia and OSA: age, gender, race, self-reported general health, body mass index (BMI), diagnosis of post-traumatic stress disorder (PTSD), pain severity, depressive symptoms, number of joints with arthritis symptoms and opioid use.

RESULTS

Symptoms consistent with insomnia and OSA were found in 53 and 66% of this sample, respectively. Among participants screening positive for insomnia and OSA, diagnosis codes for these disorders were present in the electronic medical record for 22 and 51%, respectively. Characteristics associated with insomnia were lower age (β (SE) = - 0.09 (0.04), 95% confidence interval [CI] = - 0.16, - 0.02), having a PTSD diagnosis (β (SE) = 1.68 (0.73), CI = 0.25, 3.11), greater pain severity (β (SE) = 0.36 (0.09), CI = 0.17, 0.55), and greater depressive symptoms (β (SE) = 0.84 (0.07), CI = 0.70, 0.98). Characteristics associated with OSA were higher BMI (odds ratio [OR] = 1.13, CI = 1.06, 1.21), greater depressive symptoms (OR = 1.12, CI = 1.05, 1.20), and opioid use (OR = 0.51, CI = 0.26, 0.99).

CONCLUSIONS

Insomnia and OSA symptoms were very common in Veterans with OA, and a substantial proportion of individuals with symptoms may have been undiagnosed. Characteristics associated with insomnia and OSA symptoms were consistent with prior studies.

TRIAL REGISTRATION

NCT01130740 .

Sleep and Pain in Mid- to Late-Life: An Exploration of Day-to-Day Pain Inconsistency

OBJECTIVES

This study examined how different quantifications of pain (average vs. day-to-day inconsistency) are related to sleep in older adults beyond known predictors.

METHODS

Baseline measures from the Active Adult Mentoring Project were used for secondary analyses. Participants included 82 adults in mid- to late-life. Depression was assessed with the BDI-II. Pain intensity was assessed over seven days on a 11-point Likert-scale, while sleep efficiency (SE), total sleep time (TST), and total wake time (TWT) were assessed using a self-report diary.

RESULTS

Regression analyses revealed that pain inconsistency was associated with both SE and TWT and accounted for significant variance over age, gender, and depression. In contrast, average pain was not associated with SE, TST, or TWT.

CONCLUSIONS

The findings indicate that pain inconsistency may be a more meaningful predictor of sleep disturbance than average pain level, suggesting that one's ability to regulate pain may be related to one's ability to engage in optimal sleep in mid- to late-life.

CLINICAL IMPLICATIONS

Pain inconsistency appears to contribute more to sleep disturbance than average pain. Pain inconsistency in late-life warrants greater attention and may be an area of clinical intervention through activity-pacing or coping skills training.

The association between pain and sleep in fibromyalgia

OBJECTIVE

To clarify the association between pain and sleep in fibromyalgia.  Methods: Electronic databases, including PsycINFO, the Cochrane database for systematic reviews, PubMed, EMBASE, and Ovid were searched to identify eligible articles. Databases independently screened and  the quality of evidence using a reliable and valid quality assessment tool was assessed.  Results: In total, 16 quantitative studies fulfilled the inclusion criteria. According to the results, increased pain in fibromyalgia was associated with reduced sleep quality, efficiency, and duration and increased sleep disturbance and onset latency and total wake time. Remarkably, depressive symptoms were also related to both pain and sleep in patients with fibromyalgia.   Conclusion: Management strategies should be  developed to decrease pain while increasing sleep quality in patients with fibromyalgia. Future studies should also consider mood disorders and emotional dysfunction, as comorbid conditions could occur with both pain and sleep disorder in fibromyalgia.

Pharmacological targeting of the mammalian clock reveals a novel analgesic for osteoarthritis-induced pain

Environmental disruption of the circadian rhythm is linked with increased pain due to osteoarthritis (OA). We aimed to characterize the role of the clock gene in OA-induced pain more systemically using both genetic and pharmacological approaches. Genetically modified mice, (bmal1f/fNav1.8CreERT mice), generated by deleting the critical clock gene, bmal1, from Nav1.8 sensory neurons, were resistant to the development of mechanical hyperalgesia associated with OA induced by partial medial meniscectomy (PMM) of the knee. In wild-type mice, induction of OA by PMM surgery led to a substantial increase in BMAL1 expression in DRG neurons. Interestingly, pharmacological activation of the REV-ERB (a negative regulator of bmal1 transcription) with SR9009 resulted in reduction of BMAL1 expression, and a significant decrease in mechanical hyperalgesia associated with OA. Cartilage degeneration was also significantly reduced in mice treated with the REV-ERB agonist SR9009. Based on these data, we also assessed the effect of pharmacological activation of REV-ERB using a model of environmental circadian disruption with its associated mechanical hyperalgesia, and noted that SR9009 was an effective analgesic in this model as well. Our data clearly demonstrate that genetic disruption of the molecular clock, via deletion of bmal1 in the sensory neurons of the DRG, decreases pain in a model of OA. Furthermore, pharmacological activation of REV-ERB leading to suppression of BMAL1 expression may be an effective method for treating OA-related pain, as well as to reduce joint damage associated with this disease.

Pain Catastrophizing, Mindfulness, and Pain Acceptance: What's the Difference?

OBJECTIVES

It is not known whether psychosocial chronic pain treatments produce benefits through the unique mechanisms specified by theory. Fundamental to gaining an accurate understanding of this issue is to first determine whether the most widely used process measures assess unique constructs and predict unique variance in pain outcomes. This study examined the associations between the Pain Catastrophizing Scale (PCS), Five-Facet Mindfulness Questionnaire (FFMQ-SF), and the Chronic Pain Acceptance Questionnaire (CPAQ-8), and determined their unique contributions to the prediction of pain intensity, pain interference, and depression.

METHODS

A cross-sectional study was conducted with undergraduate students (N=260) reporting chronic or intermittent pain. Correlations, regression models, and multiple mediation models were performed. Relevant covariates were included.

RESULTS

The PCS, FFMQ-SF scales, and CPAQ-8 were correlated in mostly expected directions, but not so highly as to indicate redundancy. The PCS significantly predicted pain intensity, interference, and depression. The FFMQ-SF Observing and Describing scales predicted pain intensity; Nonreactivity and Nonjudging significantly predicted interference and depression, respectively. The CPAQ-8 was not a significant predictor in any of the regression models. The PCS was a comparatively stronger mediator than the FFMQ-SF scales in the intensity to interference, and intensity to depression mediation models.

DISCUSSION

The findings indicate that pain catastrophizing, mindfulness, and pain acceptance are related, but unique constructs. The PCS and select FFMQ-SF scales were uniquely associated with the criterion measures. However, the PCS emerged as the most robust process, highlighting the importance of targeting this cognitive domain in streamlining pain treatments to optimize outcome.

Depressive Symptoms and Sleep Efficiency Sequentially Mediate Racial Differences in Temporal Summation of Mechanical Pain

BACKGROUND

Racial differences in endogenous pain facilitatory processes have been previously reported. Evidence suggests that psychological and behavioral factors, including depressive symptoms and sleep, can alter endogenous pain facilitatory processes. Whether depressive symptoms and sleep might help explain racial differences in endogenous pain facilitatory processes has yet to be determined.

PURPOSE

This observational, microlongitudinal study examined whether depressive symptoms and sleep were sequential mediators of racial differences in endogenous pain facilitatory processes.

METHODS

A total of 50 (26 African American and 24 non-Hispanic white) community-dwelling adults without chronic pain (mean 49.04 years; range 21-77) completed the Center for Epidemiological Studies Depression Scale prior to seven consecutive nights of sleep monitoring with actigraphy in the home environment. Participants subsequently returned to the laboratory for assessment of endogenous pain facilitation using a mechanical temporal summation protocol.

RESULTS

Findings revealed greater depressive symptoms, poorer sleep efficiency, and greater temporal summation of mechanical pain in African Americans compared to non-Hispanic whites. In a sequential mediation model, greater depressive symptoms predicted poorer sleep efficiency (t = -2.55, p = .014), and poorer sleep efficiency predicted enhanced temporal summation of mechanical pain (t = -4.11, p < .001), particularly for African Americans.

CONCLUSIONS

This study underscores the importance of examining the contribution of psychological and behavioral factors when addressing racial differences in pain processing. Additionally, it lends support for the deleterious impact of depressive symptoms on sleep efficiency, suggesting that both sequentially mediate racial differences in endogenous pain facilitation.

The Effect of Insomnia on Neuropsychological Functioning in Patients with Comorbid Symptoms of Pain, Fatigue, and Mood Disorders

OBJECTIVES

To examine if elevated symptoms of insomnia affects neuropsychological functioning in patients with concurrent symptoms of pain, fatigue, and mood disorders.

METHODS AND RESULTS

A total of seventy-six subjects participated in this (cross-sectional) study. Based on the cut-off score guidelines from The Insomnia Severity Index subjects were assigned to either a clinical insomnia group (N = 35) or a comparison group (N = 41). Factors such as age, general cognitive functioning, and symptoms of pain, fatigue, depression, and anxiety did not differ between the groups. Both groups completed a questionnaire which assessed subjective memory functioning. In addition they completed a set of neuropsychological tests measuring general cognitive functioning, spatial and verbal working memory, and inhibitory control. Although the subjects with clinical insomnia did not report more memory problems than the comparison group, they presented significant deficiencies on the tests assessing spatial and verbal working memory. There was no difference between the groups in inhibitory control.

CONCLUSIONS

This study shows that as the symptom severity of insomnia increases and become clinically significant, it has substantial effect on both spatial and verbal-numeric working memory functioning. By differentiating and testing different domains of working memory, this study provides a more detailed and nuanced characterization of working memory deficiencies than the previous studies within this field. The results need to be transferred to clinical practice so that neuropsychologists include assessments of sleep as part of their routine screenings.

Association of Stress and Musculoskeletal Pain With Poor Sleep: Cross-Sectional Study Among 3,600 Hospital Workers

Background: While acute stress and pain are part of our inherent survival mechanisms, persistent stress and pain can negatively impact health and well-being. This may also lead to poor sleep and thus a lack of recovery. This study investigated the influence of stress and musculoskeletal pain on sleep quality. Methods: A total of 3,593 Danish hospital workers replied to a questionnaire about work and health. Pain intensity was evaluated using subjective values as an average of 9 body parts. Stress was assessed using the full version of Cohen's Perceived Stress scale. Sleep quality was rated using 3 questions on sleep characteristics. Associations between stress and pain (mutually adjusted predictors) and sleep (outcome) were modeled using binary logistic regression controlling for gender, age, education, BMI and smoking. Results: The risk ratio of moderate stress (compared to no/low stress) on poor sleep was 1.27 (CI 1.26-1.29), whereas the risk ratio of high stress on poor sleep was 1.87 (CI 1.83-1.91). Similarly, for pain, the risk ratio of moderate pain (compared to no/low pain) on poor sleep was 1.18 (95% CI 1.16-1.19), whereas the risk ratio of a high pain score on poor sleep was 1.48 (95% CI 1.44-1.52). Conclusion: This study demonstrates that both stress and musculoskeletal pain are associated with poor sleep among hospital workers. Hospital management should consider implementing strategies for preventing stress and musculoskeletal pain to improve the overall health and workability among hospital workers.

Insomnia Really Hurts: Effect of a Bad Night's Sleep on Pain Increases With Insomnia Severity

Insomnia and chronic pain are highly prevalent conditions and are often comorbid. Somatic complaints other than pain are also often observed in insomnia. Poor sleep and pain are known to mutually reinforce each other. However, it is unknown whether the habitual severity of insomnia modulates the acute effect of a particularly bad night's sleep on the next day's pain severity, and whether it modulates the acute effect of pain on the following night's sleep quality. Using data from 3,508 volunteers (2,684 female, mean age 50.09 y), we addressed these questions in addition to the associations between the habitual severity of insomnia, somatic complaints, and pain. Results indicated that people suffering from more severe habitual insomnia showed stronger mutual acute within-day reactivity of pain and poor sleep quality. The same increased reactivity was found in people with more severe habitual pain. Interestingly, the acute within-day mutual reactivity of pain and sleep quality showed consistent asymmetry. Pain worsened more after a particularly bad night's sleep than it improved after a particularly good night's sleep. Likewise, sleep worsened more after a day with more-than-usual pain than it improved after a day with less-than-usual pain. Future interventions may profit from addressing this asymmetric mutual reactivity especially in people with severe comorbid insomnia and chronic pain.