Neurobiological mechanisms underlying the sleep-pain relationship in adolescence: A review

Adolescent Girls' Musculoskeletal Pain is More Affected by Insomnia Than Boys, and Through Different Psychological Pathways

Prior research has established that insomnia is predictive of pain in adolescents and that psychological mechanisms have a crucial role in this relationship. Adolescent girls report more insomnia and pain than boys, yet little is known of gender differences in how insomnia influences pain. This study assessed gender differences in levels and trajectories of insomnia and pain during adolescence, and whether rumination and negative mood mediated the effect of insomnia on pain. Longitudinal survey data measured on 5 annual occasions (Nbaseline = 2,767) were analyzed in a multigroup longitudinal serial mediation model. A final model was generated with insomnia as the predictor, rumination and depressed mood as mediators, pain as the outcome, and gender as the grouping variable. The results showed that insomnia predicted pain in adolescents, with an effect 3.5 times larger in girls than boys. Depressed mood was the main mediator in boys. In girls, rumination was the only significant mediator. There were significant gender differences in the effects of insomnia on rumination and pain, and in the effects of rumination on depressed mood and pain, with stronger effects in girls. These results highlight that girls and boys should be considered separately when studying the relationship between insomnia and pain. PERSPECTIVE: Levels of insomnia and pain are progressively higher in adolescent girls than boys, across adolescence. The predictive strength of insomnia symptoms for future pain is 3.5 times greater in girls, with distinct gender-specific underlying pathways: rumination partially mediates this effect in girls, while depressed mood does so in boys.

Sleep disturbances, altered brain microstructure and chronic headache in youth

Chronic headache (persistent or recurrent headache for 3-months or longer) is highly prevalent among youth. While sleep disturbances have been associated with headache, their inter-relationship with brain connectivity remains unknown. This observational study examined whether self-report and actigraphy measures of sleep were associated with alterations to white matter tracts (i.e., uncinate fasciculus and cingulum) in youth with chronic headache versus healthy controls. Thirty youth aged 10-18 years with chronic headache and thirty controls underwent an MRI. Diffusion tensor images were obtained and mean fractional anisotropy values of the cingulum and uncinate were extracted. One-week prior to their MRI, youth wore an actigraph to obtain sleep duration, wake after sleep onset and sleep efficiency measures. Moreover, they completed questionnaires regarding their sleep quality and pain symptomatology. Linear regression was applied to examine the relationships between sleep (self-report and actigraphy), fractional anisotropy, and number of headache days per month. Self-report and actigraphy measures of sleep did not differ between patients and controls. However, poorer self-reported sleep quality was associated with lower fractional anisotropy values in the left uncinate (P = 0.05). Lower left uncinate fractional anisotropy was related to increased headache frequency (P = 0.002) in youth with chronic headache. Therefore, alterations to connectivity may be associated with the relationship between altered perceptions of sleep and headache chronicity.

Increases in Sleep Difficulties and Psychological Symptoms are Associated With the Increase of Chronic Back Pain in Adolescents: The HBSC Study 2002 to 2018

Cross-national research using data from the Health Behavior in School-aged Children (HBSC) survey showed an increase in the prevalence of chronic back pain from 2002 to 2014. However, it is unknown if this trend has persisted beyond 2014. The aims of this study were to 1) determine if the prevalence of chronic back pain in girls and boys aged 11, 13, and 15 continued to increase from 2014 to 2018 and if this was the case, 2) examine whether this increase in the prevalence of chronic back pain between 2002 and 2018 was explained indirectly by increases in sleep difficulties and psychological symptoms. Data from 7,89,596 adolescents retrieved from 5 waves of the HBSC survey conducted in 2002, 2006, 2010, 2014, and 2018 in 32 countries/regions were used. Logistic regressions and path analyses were conducted. Results showed an overall increase of .5% in the prevalence of chronic back pain between 2014 and 2018, ranging from .4% for 15-year-old girls to 1.3% for 11-year-old boys, indicating a continued overall increase in chronic back pain in adolescents beyond 2014. For 13-year-old girls and for 15-year-old girls and boys, the increase in the prevalence of chronic back pain between 2002 and 2018 was partially mediated by increases in sleep difficulties, which in turn were associated with increases in psychological symptoms. The findings provide important information that may aid stakeholders in enhancing public health initiatives to prevent or reduce the increasing trend in the prevalence of chronic back pain in adolescents. PERSPECTIVE: This study shows that chronic back pain prevalence continues to increase among adolescents, with sleep difficulties and psychological symptoms contributing significantly to this trend. The findings provide insights that may inform strategies to prevent or reduce the increasing trend of chronic back pain in adolescents.

Preliminary investigation of the interactive role of physiological arousal and insomnia complaints in gray matter volume alterations in chronic widespread pain

STUDY OBJECTIVES

Brain regions involved in insomnia and chronic pain are overlapping and diffuse. The interactive role of physiological arousal in associations between insomnia symptoms and neural regions is unknown. This preliminary study examined whether arousal interacted with sleep in associations with gray matter volume of frontal (dorsolateral prefrontal cortex, anterior cingulate cortex) and temporal (right/left hippocampus) regions in adults with chronic widespread pain and insomnia complaints.

METHODS

Forty-seven adults with chronic widespread pain and insomnia (mean age = 46.00, standard deviation = 13.88, 89% women) completed 14 daily diaries measuring sleep onset latency (SOL), wake time after sleep onset, and total sleep time (TST), as well as Holter monitor assessments of heart rate variability (measuring physiological arousal), and magnetic resonance imaging. Multiple regressions examined whether average SOL, wake time after sleep onset, or TST were independently or interactively (with arousal/heart rate variability) associated with dorsolateral prefrontal cortex, anterior cingulate cortex, and left/right hippocampus gray matter volumes.

RESULTS

Shorter TST was associated with lower right hippocampus volume. TST also interacted with arousal in its association with right hippocampal volume, Specifically, shorter TST was associated with lower volume at highest and average arousal levels. SOL interacted with arousal in its association with anterior cingulate cortex volume, such that, among individuals with lowest arousal, longer SOL was associated with lower volume.

CONCLUSIONS

Preliminary findings highlight the interactive roles of physiological arousal and insomnia symptoms in associations with neural structure in chronic widespread pain and insomnia. Individuals with the highest physiological arousal may be particularly vulnerable to the impact of shorter TST on hippocampal volume loss. Reducing SOL may only impact anterior cingulate cortex volume in those with lower physiological arousal.

CITATION

Curtis AF, Nair N, Hayse B, et al. Preliminary investigation of the interactive role of physiological arousal and insomnia complaints in gray matter volume alterations in chronic widespread pain. J Clin Sleep Med. 2024;20(2):293-302.

Repeat mild traumatic brain injuries (RmTBI) modify nociception and disrupt orexinergic connectivity within the descending pain pathway

Repeat mild traumatic brain injuries (RmTBI) result in substantial burden to the public health system given their association with chronic post-injury pathologies, such as chronic pain and post-traumatic headache. Although this may relate to dysfunctional descending pain modulation (DPM), it is uncertain what mechanisms drive changes within this pathway. One possibility is altered orexinergic system functioning, as orexin is a potent anti-nociceptive neuromodulator. Orexin is exclusively produced by the lateral hypothalamus (LH) and receives excitatory innervation from the lateral parabrachial nucleus (lPBN). Therefore, we used neuronal tract-tracing to investigate the relationship between RmTBI and connectivity between lPBN and the LH, as well as orexinergic projections to a key site within the DPM, the periaqueductal gray (PAG). Prior to injury induction, retrograde and anterograde tract-tracing surgery was performed on 70 young-adult male Sprague Dawley rats, targeting the lPBN and PAG. Rodents were then randomly assigned to receive RmTBIs or sham injuries before undergoing testing for anxiety-like behaviour and nociceptive sensitivity. Immunohistochemical analysis identified distinct and co-localized orexin and tract-tracing cell bodies and projections within the LH. The RmTBI group exhibited altered nociception and reduced anxiety as well as a loss of orexin cell bodies and a reduction of hypothalamic projections to the ventrolateral nucleus of the PAG. However, there was no significant effect of injury on neuronal connectivity between the lPBN and orexinergic cell bodies within the LH. Our identification of structural losses and the resulting physiological changes in the orexinergic system following RmTBI begins to clarify acute post-injury mechanistic changes that drive may drive the development of post-traumatic headache and the chronification of pain.

The complexities of the sleep-pain relationship in adolescents: A critical review

Chronic pain is a common and disabling condition in adolescents. Disturbed sleep is associated with many detrimental effects in adolescents with acute and chronic pain. While sleep and pain are known to share a reciprocal relationship, the sleep-pain relationship in adolescence warrants further contextualization within normally occurring maturation of several biopsychological processes. Since sleep and pain disorders begin to emerge in early adolescence and are often comorbid, there is a need for a comprehensive picture of their interrelation especially related to temporal relationships and mechanistic drivers. While existing reviews provide a solid foundation for the interaction between disturbed sleep and pain in youth, we will extend this review by highlighting current methodological challenges for both sleep and pain assessments, exploring the recent evidence for directionality in the sleep-pain relationship, reviewing potential mechanisms and factors underlying the relationship, and providing direction for future investigations. We will also highlight the potential role of digital technologies in advancing the understanding of the sleep and pain relationship. Ultimately, we anticipate this information will facilitate further research and inform the management of pain and poor sleep, which will ultimately improve the quality of life in adolescents and reduce the risk of pain persisting into adulthood.

A Novel Approach for Sleep Arousal Disorder Detection Based on the Interaction of Physiological Signals and Metaheuristic Learning

The vast majority of sleep disturbances are caused by various types of sleep arousal. To diagnose sleep disorders and prevent health problems such as cardiovascular disease and cognitive impairment, sleep arousals must be accurately detected. Consequently, sleep specialists must spend considerable time and effort analyzing polysomnography (PSG) recordings to determine the level of arousal during sleep. The development of an automated sleep arousal detection system based on PSG would considerably benefit clinicians. We quantify the EEG-ECG by using Lyapunov exponents, fractals, and wavelet transforms to identify sleep stages and arousal disorders. In this paper, an efficient hybrid-learning method is introduced for the first time to detect and assess arousal incidents. Modified drone squadron optimization (mDSO) algorithm is used to optimize the support vector machine (SVM) with radial basis function (RBF) kernel. EEG-ECG signals are preprocessed samples from the SHHS sleep dataset and the PhysioBank challenge 2018. In comparison to other traditional methods for identifying sleep disorders, our physiological signals correlation innovation is much better than similar approaches. Based on the proposed model, the average error rate was less than 2%-7%, respectively, for two-class and four-class issues. Additionally, the proper classification of the five sleep stages is determined to be accurate 92.3% of the time. In clinical trials of sleep disorders, the hybrid-learning model technique based on EEG-ECG signal correlation features is effective in detecting arousals.

Dehydrocorydaline alleviates sleep deprivation-induced persistent postoperative pain in adolescent mice through inhibiting microglial P2Y12 receptor expression in the spinal cord

During adolescence, a second period of central nervous system (CNS) plasticity that follows the fetal period, which involves sleep deprivation (SD), becomes apparent. SD during adolescence may result in abnormal development of neural circuits, causing imbalance in neuronal excitation and inhibition, which not only results in pain, but increases the chances of developing emotion disorders in adulthood, such as anxiety and depression. The quantity of surgeries during adolescence is also consistently on the rise, yet the impact and underlying mechanism of preoperative SD on postoperative pain remain unexplored. This study demonstrates that preoperative SD induces upregulation of the P2Y12 receptor, which is exclusively expressed on spinal microglia, and phosphorylation of its downstream signaling pathway p38Mitogen-activated protein/Nuclear transcription factor-κB (p38MAPK/NF-κB)in spinal microglia, thereby promoting microglia activation and microglial transformation into the proinflammatory M1 phenotype, resulting in increased expression of proinflammatory cytokines that exacerbate persisting postoperative incisional pain in adolescent mice. Both intrathecal minocycline (a microglia activation inhibitor) and MRS2395 (a P2Y12 receptor blocker) effectively suppressed microglial activation and proinflammatory cytokine expression. Interestingly, supplementation with dehydrocorydaline (DHC), an extract of Rhizoma Corydalis, inhibited the P2Y12/p38MAPK/NF-κB signaling pathway, microglia activation, and expression of pro-inflammatory cytokines in the model mice. Taken together, the results indicate that the P2Y12 receptor and microglial activation are important factors in persistent postoperative pain caused by preoperative SD in adolescent mice and that DHC has analgesic effects by acting on these targets.

Sleep deprivation and NLRP3 inflammasome: Is there a causal relationship?

In the modern era, sleep deprivation (SD) is one of the most common health problems that has a profound influence on an individual's quality of life and overall health. Studies have identified the possibility that lack of sleep can stimulate inflammatory responses. NLRP3 inflammasome, a key component of the innate immune responses, initiates inflammatory responses by enhancing proinflammatory cytokine release and caspase-1-mediated pyroptosis. In this study, NLRP3 modification, its proinflammatory role, and potential targeted therapies were reviewed with regard to SD-induced outcomes. A growing body of evidence has showed the importance of the mechanistic connections between NLRP3 and the detrimental consequences of SD, but there is a need for more clinically relevant data. In animal research, (i) some animals show differential vulnerability to the effects of SD compared to humans. (ii) Additionally, the effects of sleep differ depending on the SD technique employed and the length of SD. Moreover, paying attention to the crosstalk of all the driving factors of NLRP3 inflammasome activation such as inflammatory responses, autonomic control, oxidative stress, and endothelial function is highly recommended. In conclusion, targeting NLRP3 inflammasome or its downstream pathways for therapy could be complicated due to the reciprocal and complex relationship of SD with NLRP3 inflammasome activation. However, additional research is required to support such a causal claim.

Pediatric sleep and pain: etiologies, consequences, and clinical considerations

STUDY OBJECTIVES

To examine current evidence of the relationship between sleep and pain from the neonatal period through adolescence. This review serves as a critical review of the literature and of the needs for future research on pediatric sleep and pain.

METHODS

The PubMed online database was queried from January 1, 1960, to March 1, 2020, producing 149 articles applicable to pain and sleep in the pediatric population. Of those, 97 articles were cited in this review with the key articles including over 3800 participants.

RESULTS

The pediatric literature supports the relationship between poor sleep (both sleep efficiency and nighttime awakenings) and subsequent risk for pain, especially among children with chronic disease. The reverse effect of pain on sleep is not yet well delineated. The key moderating factors explored in the literature are pharmacologic and nonpharmacologic therapies, psychologic health, and the etiology of pain. There is evidence that both altered sleep and pain early in life impact neurodevelopment, as seen by changes in sleep structure in clinical studies and alterations in brain development in animal models.

CONCLUSIONS

The complicated relationship between sleep and pain is critically important during pediatric development when alterations to a normal sleep structure can have a lifelong impact. It is becoming clear that sleep deprivation and poor sleep quality exacerbate pain. Further research is needed into the complex alterations of sleep in chronic pain conditions as well as treatments to improve sleep in pediatric care.

CITATION

Morris EE, Howell MJ, Pickup E, Iber C, Wang SG. Pediatric sleep and pain: etiologies, consequences, and clinical considerations. J Clin Sleep Med. 2022;18(9):2281-2289.

Chronic Pain, Insomnia and their Mutual Maintenance: A Call for Cognitive Bias Research

Chronic pain and insomnia are highly comorbid: Approximately 50% of those with chronic pain experience insomnia or clinically significant sleep disturbances, and 50% of those with insomnia experience chronic pain. Further, these conditions can be extremely disabling, particularly when they co-occur. There is increasing recognition of the need to tackle both chronic pain and insomnia together, as evidenced by growing empirical research in this area. Cognitive processing biases have been independently implicated in both chronic pain and in insomnia. Given their trans-diagnostic status, cognitive biases may therefore have a role in explaining the co-occurrence and mutual maintenance of these conditions. These biases also represent novel, potentially modifiable targets for treatment. However, the role of cognitive biases has not been adequately explored in comorbid chronic pain and insomnia. Here, we describe the state of cognitive bias research in chronic pain and insomnia, considering evidence for the roles of attentional bias, interpretation bias, expectancy bias, and memory bias. In reviewing the literature, it is apparent that similar cognitive biases operate in insomnia and chronic pain, with preliminary, albeit sparse, evidence of pain-related cognitive biases influencing sleep-related outcomes. On the basis of current findings and separate theoretical models, we present a novel, testable cognitive model of comorbid chronic pain and insomnia, to guide future research in this area. Key recommendations for the future of this relatively new field are provided. PERSPECTIVE: Chronic pain and insomnia are highly co-morbid, suggesting an overlap in causal mechanisms. Empirical research, although sparse, suggests that cognitive biases may play a role in their development and mutual maintenance. Our novel cognitive model generates research avenues of clinical importance for treating co-morbid chronic pain and insomnia.

New insight into the neural mechanisms of migraine in adolescents: Relationships with sleep

OBJECTIVE

This case-control study examines if measures of subjective and objective (actigraphic) sleep difficulties mediate alterations in amygdalar connectivity in adolescents with migraine compared to healthy adolescents.

BACKGROUND

Adolescents with migraine have different functional connectivity of the amygdala compared to individuals without migraine. Sleep is often disturbed in adolescents with migraine, and could contribute to the alterations in functional connectivity.

METHODS

Twenty adolescents with migraine and 20 healthy controls were recruited from Cincinnati Children's Hospital. Participants completed surveys about their headaches and overall sleep quality, sleep hygiene, and perceived sleep difficulties (Insomnia Severity Scale [ISI]); completed wrist-worn actigraphy; and underwent a magnetic resonance imaging scan.

RESULTS

Adolescents with migraine differed from healthy controls only in perceived difficulty in sleep initiation and maintenance (ISI: 8.5 ± 4.7 and 4.5 ± 3.7 [mean ± standard deviation], -4.00 [95% confidence: -6.7 to -1.3], p = 0.005) and had greater functional connectivity between the amygdala and the posterior cingulate cortex, precuneus, dorsolateral prefrontal, sensorimotor, and the occipital cortexes. The differences in functional connectivity of the amygdala were not mediated by the subjective/objective sleep measures (ISI/wake minutes after sleep onset).

CONCLUSIONS

Adolescents with migraine have greater connectivity between the amygdala and areas involved in sensory, affective, and cognitive aspects of pain. These alterations may not be due to higher levels of sleep difficulties in adolescents with migraine, suggesting that both amygdala and sleep alterations may play an independent role in migraine pathophysiology. This advances the understanding of the mechanisms underlying pediatric migraine and can potentially advance migraine management.

Sleep phase and pre-sleep arousal predicted co-developmental trajectories of pain and insomnia within adolescence

The onset of both chronic pain and insomnia is high during adolescence. Although a bidirectional relationship between pain and insomnia has support, how pain and sleep co-develop throughout adolescence remains unknown. Sleep–wake patterns, pre-sleep behavior and pre-sleep arousal may influence the co-development of pain and insomnia. Four waves of longitudinal self-report data were used (N^baseline = 2767, Age^baseline M = 13.65 years, SD = 0.65). Multidimensional growth mixture modeling was used to identify four subgroups of adolescents with different concurrent trajectories of pain and insomnia. The trajectories followed each other across time in all classes: one class of consistently low pain and insomnia (68.7%), one class with persistent high symptoms (4.9%), as well as one class of increasing (13.9%), and one of decreasing (12.5%), trajectories. Later sleep–wake patterns and more pre-sleep cognitive-emotional arousal predicted both increasing and decreasing trajectories of concurrent pain and insomnia. The current study showed that developmental trajectories of pain and insomnia follow each other within adolescents and across adolescence. Both sleep-phase focused interventions as well as psychological interventions that focus on pre-sleep cognitive-emotional arousal may prove beneficial for adolescents with comorbid pain and insomnia.

Longitudinal, bidirectional relationships of insomnia symptoms and musculoskeletal pain across adolescence: the mediating role of mood

ABSTRACT

Previous studies have established a bidirectional relationship between sleep and pain, and mood has been proposed as a mediator of this relationship. There are only a limited number of longitudinal studies examining the mediational role of mood, and the directionality of effects between sleep, pain, and mood is uncertain. In addition, despite the high prevalence of pain and sleep problems during adolescence, these relationships have rarely been examined in a longitudinal sample of adolescents. Here, longitudinal survey data with 5 yearly measurements were used to examine the bidirectional relationship between insomnia symptoms and pain across adolescence (Mbaseline age = 13.65 years, Nbaseline = 2767). We also explored if depressed mood, positive affect, and anxious mood are mediators in both directions of the sleep-pain relationship. Using latent variables for insomnia, pain, and mood at multiple time points, the data were analyzed with cross-lagged panel models for longitudinal data with structural equation modeling. Current results confirmed a bidirectional relationship between insomnia symptoms and pain, where the effect of insomnia symptoms on pain was stronger than vice versa. Depressed mood and anxious mood mediated the effect of insomnia symptoms on pain, but not the reverse effect of pain on insomnia symptoms. Positive affect did not serve as a mediator in either direction. These findings add novel insights into the temporal directionality of sleep, pain, and mood during adolescence, suggesting a temporal path from sleep to pain, through mood, rather than a reciprocal relationship between the constructs.

2022 Society of Critical Care Medicine Clinical Practice Guidelines on Prevention and Management of Pain, Agitation, Neuromuscular Blockade, and Delirium in Critically Ill Pediatric Patients With Consideration of the ICU Environment and Early Mobility

RATIONALE

A guideline that both evaluates current practice and provides recommendations to address sedation, pain, and delirium management with regard for neuromuscular blockade and withdrawal is not currently available.

OBJECTIVE

To develop comprehensive clinical practice guidelines for critically ill infants and children, with specific attention to seven domains of care including pain, sedation/agitation, iatrogenic withdrawal, neuromuscular blockade, delirium, PICU environment, and early mobility.

DESIGN

The Society of Critical Care Medicine Pediatric Pain, Agitation, Neuromuscular Blockade, and Delirium in critically ill pediatric patients with consideration of the PICU Environment and Early Mobility Guideline Taskforce was comprised of 29 national experts who collaborated from 2009 to 2021 via teleconference and/or e-mail at least monthly for planning, literature review, and guideline development, revision, and approval. The full taskforce gathered annually in-person during the Society of Critical Care Medicine Congress for progress reports and further strategizing with the final face-to-face meeting occurring in February 2020. Throughout this process, the Society of Critical Care Medicine standard operating procedures Manual for Guidelines development was adhered to.

METHODS

Taskforce content experts separated into subgroups addressing pain/analgesia, sedation, tolerance/iatrogenic withdrawal, neuromuscular blockade, delirium, PICU environment (family presence and sleep hygiene), and early mobility. Subgroups created descriptive and actionable Population, Intervention, Comparison, and Outcome questions. An experienced medical information specialist developed search strategies to identify relevant literature between January 1990 and January 2020. Subgroups reviewed literature, determined quality of evidence, and formulated recommendations classified as "strong" with "we recommend" or "conditional" with "we suggest." Good practice statements were used when indirect evidence supported benefit with no or minimal risk. Evidence gaps were noted. Initial recommendations were reviewed by each subgroup and revised as deemed necessary prior to being disseminated for voting by the full taskforce. Individuals who had an overt or potential conflict of interest abstained from relevant votes. Expert opinion alone was not used in substitution for a lack of evidence.

RESULTS

The Pediatric Pain, Agitation, Neuromuscular Blockade, and Delirium in critically ill pediatric patients with consideration of the PICU Environment and Early Mobility taskforce issued 44 recommendations (14 strong and 30 conditional) and five good practice statements.

CONCLUSIONS

The current guidelines represent a comprehensive list of practical clinical recommendations for the assessment, prevention, and management of key aspects for the comprehensive critical care of infants and children. Main areas of focus included 1) need for the routine monitoring of pain, agitation, withdrawal, and delirium using validated tools, 2) enhanced use of protocolized sedation and analgesia, and 3) recognition of the importance of nonpharmacologic interventions for enhancing patient comfort and comprehensive care provision.

[Better Sleep and Less Pain? Sleep Training in Orthopedic Rehabilitation]

PURPOSE

There is high comorbidity between chronic pain and insomnia. Not only does chronic pain impair sleep, poor sleep quality can also exacerbate the sensation of pain. However, usually, the respective symptoms are treated separately. We evaluate a new cognitive behavioral sleep-pain-training aiming at improving symptoms of both insomnia and chronic pain in the setting of ambulant orthopedic rehabilitation.

METHODS

N=41 patients participated in the study (with 15 participants being enrolled in the control group). The training consists of 4 modules á 90min and was explicitly developed for patients suffering from chronic pain and comorbid insomnia. It includes several methods of cognitive behavioral therapy for the treatment of insomnia and pain (e. g., sleep hygiene, sleep restriction, sleep-pain-protocol, cognitive restructuring) and specifically addresses the relationship between the two. Sleep quality, sleep related thoughts (focusing, rumination), internal health locus of control, pain intensity (day and night) as well as pain related thoughts (pain related anxiety, pain related depression/helplessness) were assessed pre and post training by means of a questionnaire.

RESULTS

Mixed ANOVAS revealed small (η²=: 0,010) to medium (η²=: 0,068) interaction effects for most dependent variables (sleep quality, sleep efficiency, focusing, rumination, internal health locus of control, average day and night pain, maximum night pain, pain related anxiety and pain related depression/helplessness) for the interaction of time and group. However, effects for rumination and average day pain were not significant. There was no interaction effect for maximum day pain. Effect sizes for single group analyses revealed medium (internal sleep locus of control: d=0,52) to large (sleep quality: d=1,73) significant effects for the training group and no (focusing: d=0,00) to small (maximum day pain: d=-0,43) and non-significant effects for the control group.

CONCLUSION

The training analyzed in this study may constitute a complement to existing treatment possibilities for patients suffering from chronic pain and should be further evaluated in larger samples.

Prospective Association between Dysmenorrhea and Chronic Pain Development in Community-Dwelling Women

Despite emerging evidence of associations between dysmenorrhea, enhanced pain sensitivity, and functional neuroimaging patterns consistent with chronic pain, it is unknown whether dysmenorrhea is prospectively associated with chronic pain development. Gaining a better understanding of this relationship could inform efforts in prevention of chronic pain. Using data from the national Midlife in the United States cohort, we examined the prospective association between dysmenorrhea and chronic pain development during a 10-year follow-up (starting 10 years after dysmenorrhea was measured) among 874 community-dwelling women aged 25-74 at baseline (when dysmenorrhea was measured). We fit modified Poisson regression models adjusting for sociodemographic, lifestyle and psychosocial factors. Among women who were menstruating at baseline, self-reported dysmenorrhea was associated with a 41% greater (95% confidence interval [CI] = 6%-88%) risk of developing chronic pain. Women with dysmenorrhea also developed chronic pain in more body regions (≥3 regions vs 1-2 regions vs none, odds ratio [OR] = 1.77, 95% CI = 1.18-2.64) and experienced greater pain interference (high-interference vs low-interference vs none, OR = 1.73, 95% CI = 1.15-2.59). Among women who had stopped menstruation at baseline, we did not find evidence of an association between their history of dysmenorrhea and subsequent risk of chronic pain development. Results suggest dysmenorrhea may be a general risk factor for chronic pain development among menstruating women. PERSPECTIVE: This study supports the temporality of dysmenorrhea and chronic pain development in a national female sample. Dysmenorrhea was also associated with developing more widespread and disabling pain among women who were still menstruating. Early management of dysmenorrhea may reduce the development and severity of chronic pain in women, although further research is required to determine whether dysmenorrhea is a causal risk factor or a risk marker of chronic pain.

The Role of Sleep in the Transition from Acute to Chronic Musculoskeletal Pain in Youth-A Narrative Review

Musculoskeletal pain is common in the general pediatric population and is a challenge to youth, their parents, and society. The majority of children experiencing musculoskeletal pain will recover; however, a small subgroup of youth develops chronic pain. There is limited understanding of the factors that affect the transition from acute to chronic pain in youth. This review introduces sleep deficiency in the acute to chronic pain transition, exploring the potential mediational or mechanistic role and pathways of sleep in this process, including the interaction with sensory, psychological, and social components of pain and highlighting new avenues for treatment. Biological mechanisms include the increased production of inflammatory mediators and the effect on the hypothalamus-pituitary-adrenal (HPA) axis and on the dopaminergic signaling. Psychological and social components include the effect of sleep on the emotional-affective and behavioral components of pain, the negative impact on daily and social activities and coping strategies and on the reward system, increased pain catastrophizing, fear of pain, pain-related anxiety, hypervigilance, and social isolation. Future longitudinal studies are needed to elucidate these mechanistic pathways of the effect of sleep on the transition from acute to chronic pain, which may lead to the development of new treatment targets to prevent this transition.

How is psychological stress linked to sleep quality? The mediating role of functional connectivity between the sensory/somatomotor network and the cingulo-opercular control network

How the functional connectivity of brain networks affects the relationship between psychological stress and sleep quality remains unclear. To better understand the associations between psychological stress, resting-state functional connectivity (RSFC), and sleep quality, we used the RSFC, Pittsburgh Sleep Quality Index (PSQI), and Psychosomatic Tension Relaxation Inventory (PSTRI) to investigate the relationship between psychological stress, sleep quality, and RSFC in four brain networks, the sensory/somatomotor (SM) network, cigulo-opercular control (CO) network, default mode (DM) network, and dorsal attention (DA) network, in a large healthy sample of 315 college students from Southwest University. Results showed that the brain functional connectivity in the SM, CO, DM, and DA networks was significantly correlated to sleep quality. Meanwhile, we also found that the brain functional connectivity between the SM and CO networks partially mediated the relationship between psychological stress and sleep quality, suggesting that psychological stress has an important effect on individuals' sleep quality, and increased functional connectivity between the SM and CO networks provides a neural basis for the association between psychological stress and poor sleep quality.

Is the glymphatic system the missing link between sleep impairments and neurological disorders? Examining the implications and uncertainties

Until recently, both the purpose of the biological need for sleep and the mechanism by which the central nervous system eliminated metabolic waste products were unknown. The glymphatic system is the recently discovered macroscopic waste clearance system for the CNS, which predominantly functions during sleep states. Important implications for the glymphatic system exist for a significant proportion of neurological disorders, including traumatic brain injury, epilepsy, stroke, migraine, and Alzheimer's disease. Within the limited amount of research pertaining to this novel system there exists controversy regarding several of the key structural and functional aspects of the glymphatic system. In this review we address evidence from both standpoints regarding the prominent debates surrounding the glymphatic system, including the functional differences in wakefulness vs. sleep, the role of glial aquaporin-4 water channels, and whether it reflects a convective flow or a passive diffusion process. The answers that underlie these questions will have crucial and distinct outcomes for the future of the glymphatic system and the disorders it has been implicated in. However, this review also summarizes the potential role of the glymphatic system in the development and progression of the aforementioned neurological disorders. Furthermore, the possible contribution of the orexinergic system to this relationship between the glymphatic system, sleep, and these neurological disorders is also explored. Overall, in order to develop and utilize therapeutic interventions centred around the glymphatic system we must first dedicate further investigation to elucidating these discrepancies and unanswered questions.

Association between dysmenorrhea and chronic pain: a systematic review and meta-analysis of population-based studies

OBJECTIVE

The objective of the study was to synthesize the epidemiological findings for the associations between dysmenorrhea, including primary dysmenorrhea and endometriosis-associated dysmenorrhea and any chronic pain conditions, including chronic pelvic pain, and chronic nonpelvic pain.

DATA SOURCES

The data sources included PubMed, Embase, and CINAHL from inception to December 2019.

STUDY ELIGIBILITY CRITERIA

The study criteria included observational population-based studies in which the relationship between dysmenorrhea and the presence or severity of chronic pain was examined.

STUDY APPRAISAL AND SYNTHESIS METHODS

Each study was double coded and evaluated for bias based on the modified Newcastle and Ottawa Scale. Random-effect meta-analyses were conducted to quantify the associations between dysmenorrhea and the presence of chronic pelvic and nonpelvic pain.

RESULTS

Out of 9452 records, 32 studies were included, with 14 reporting associations between dysmenorrhea and chronic pelvic pain, and 20 for dysmenorrhea and chronic nonpelvic pain. Primary dysmenorrhea and endometriosis-associated dysmenorrhea were examined in 7 studies, respectively. More than 30% of the studies were categorized as poor quality, 56% as moderate, and 12.5% as high. Dysmenorrhea was positively associated with both the presence and severity of chronic pelvic and nonpelvic pain conditions. Based on 6689 women from 8 studies, those with chronic pelvic pain had 2.43 (95% confidence interval, 1.98-2.99, I², 42%) times the odds of having dysmenorrhea compared with those without. Based on 3750 women from 11 studies, those with chronic nonpelvic pain had 2.62 (95% confidence interval, 1.84-3.72, I², 72%) times the odds of having dysmenorrhea compared with those without. Overall, dysmenorrhea was associated with 2.50 (95% confidence interval, 2.02-3.10) times the odds of chronic pain, which did not differ by chronic pelvic vs chronic nonpelvic pain, community vs clinical populations, or different geographical regions.

CONCLUSIONS

Dysmenorrhea may be a general risk factor for chronic pain, although whether primary dysmenorrhea increases the risk for chronic pain is unclear. Given that adolescence is a sensitive period for neurodevelopment, elucidating the role of primary dysmenorrhea in pain chronicity in future longitudinal studies is important for preventing both chronic pelvic and nonpelvic pain.

Experimental sleep restriction increases somatic complaints in healthy adolescents

Short duration sleep and somatic complaints (bodily complaints like aches/pains or GI distress) are common in adolescence and may be linked, yet no published studies have tested causation. In this study, healthy adolescents (n = 30; 14-18yrs) completed a three-week, within-subject cross-over experiment. Following a sleep stabilization week, adolescents were randomized (in counterbalanced order) to five nights of 6.5hrs in bed (Insufficient Sleep) or 9.5hrs in bed (Sufficient Sleep), each preceded by a two-night "washout." Somatic complaints were assessed via the Children's Somatic Symptoms Inventory (CSSI-24) and the Pain and Symptom Assessment Tool (PSAT) concluding each condition. Adherence to experimental condition was confirmed via actigraphy. Adolescents slept two fewer hours and reported significantly greater frequency and severity of somatic complaints during the Insufficient Sleep (vs. Sufficient Sleep) condition. Restricting sleep opportunity to a level common in adolescence causally increased somatic complaints in otherwise healthy adolescents. Findings support clinical and preventative efforts to address pervasively inadequate sleep in adolescence.

Insomnia Symptoms among African-American Older Adults in Economically Disadvantaged Areas of South Los Angeles

BACKGROUND

Although psychosocial and health factors impact insomnia symptoms, less is known about these effects in economically disadvantaged African-American older adults.

AIMS

This study investigated social and health determinants of insomnia symptoms among economically disadvantaged African-American older adults.

METHODS

This survey enrolled 398 African-American older adults (age ≥ 65 years) from economically disadvantaged areas of South Los Angeles. Gender, age, educational attainment, financial difficulty, number of chronic diseases, self-rated health, pain intensity, and depression were covariates. Total insomnia, insomnia symptoms, and insomnia impact were our outcomes. Linear regression was applied for data analysis.

RESULTS

Based on linear regression, higher financial difficulty (B = 0.48, 95% CI = 0.35-0.61), smoking status (B = 1.64, 95% CI = 0.13-3.16), higher pain intensity (B = 0.39, 95% CI = 0.11-0.67), higher number of chronic diseases (B = 0.34, 95% CI = 0.05-0.64), and more depressive symptoms (B = 0.35, 95% CI = 0.12-0.57) were associated with a higher frequency of insomnia symptoms. Based on a logistic regression model, lower age (B = 0.91, 95% CI = 0.91-1.00) and high financial difficulty (OR = 1.15, 95% CI = 1.08-1.24), pain (OR = 2.08, 95% CI = 1.14-3.80), chronic disease (OR = 1.27, 95% CI = 1.07-1.51) and depression (OR = 2.38, 95% CI = 1.22-4.65) were associated with higher odds of possible clinical insomnia. We also found specific predictors for insomnia symptoms and insomnia impact.

CONCLUSIONS

Among African-American older adults in economically disadvantaged areas of South Los Angeles, insomnia symptoms co-occur with other economic, physical, and mental health challenges such as financial difficulty, smoking, multimorbidity, pain, and depression. There is a need to address sleep as a component of care of economically disadvantaged African-American older adults who have multiple social and health challenges.

A review of psychological treatments for vomiting associated with paediatric functional gastrointestinal disorders

PURPOSE OF REVIEW

Vomiting can be a primary symptom or associated with various other functional gastrointestinal disorders (FGIDs). The purpose of this review was to discuss the evidence for psychological treatments for vomiting in pediatric FGID.

RECENT FINDINGS

Vomiting of functional origin is an increasingly recognized symptom among children and adolescents. It is highly aversive and associated with disability and poor quality of life. Cognitive behavioral therapy, lifestyle modification (especially sleep), diaphragmatic breathing, and hypnosis can be helpful in preventing vomiting episodes and reducing disability. However, no randomized clinical trials have been performed. An evidence base for psychological treatments in children with vomiting of functional origin is highly needed.

SUMMARY

Increased evidence is demonstrating value and efficacy of incorporating psychogastroenterology practices into ongoing treatment plans for digestive conditions. Current psychological treatments are focused on prevention of vomiting through stress reduction and lifestyle modification, reduction of disability by limiting avoidance behaviours, as well as counteracting biological factors. However, psychological treatments have not been shown to be helpful during an acute vomiting episode. More research is needed to build an evidence base for psychological treatments in vomiting disorders.