Total Sleep Deprivation and Pain Perception during Cold Noxious Stimuli in Humans

The Impacts of Poor Sleep Quality on Knee Pain and Quality of Life in Young Adults: Insights From a Population-based Cohort

OBJECTIVES

Poor sleep is common among young adults and is often associated with pain. This study investigates the relationship between pain-related outcomes, sleep quality, and quality of life (QoL) in young adults with and without knee pain.

METHODS

This study is a secondary analysis of the 5-year follow-up of a prospective cohort study. Five hundred twenty-three young adults were surveyed for knee pain in 2011 and followed up 5 years later. Respondents reporting knee pain at both points were categorized as having knee pain (n = 177), while controls did not report knee pain (n = 85). Five-year follow-up data assessed clinical pain intensity, pain-related outcomes, QoL, and physical activity. In addition, respondents were scored as having good, moderate, or poor sleep quality.

RESULTS

Respondents in the knee pain group with poor sleep had worse Knee injury and Osteoarthritis Outcome Score (Knee Outcome and Osteoarthritis Score) across all domains ( P < 0.05), decreased QoL ( P < 0.001), impacted mood ( P < 0.05), and impacted everyday life ( P < 0.001) compared with those with good sleep. Respondents with poor sleep in both the knee pain and control group reported more pain sites per month ( P < 0.01) compared with those with good sleep. Finally, respondents in the knee pain group with poor sleep had increased pain medication usage compared with those with good sleep ( P < 0.05).

CONCLUSION

This study emphasizes the negative association between poor sleep quality and knee pain in young adults. The results indicate a need for strategies to address sleep disturbances in young adults to alleviate pain-related suffering and to increase HRQoL.

Sleep as a prognostic factor in low back pain: a systematic review of prospective cohort studies and secondary analyses of randomized controlled trials

Sleep problems are common in individuals with low back pain (LBP) and sleep restriction seems to be associated with impaired pain processing. Our objective was to investigate whether sleep is associated with future LBP outcomes (i.e. pain intensity, disability, and recovery) in adults. We conducted a systematic review of prospective cohort studies and secondary analyses of randomized controlled trials (registration-PROSPERO CRD42022370781). In December 2022, we searched the MEDLINE, Embase, CINAHL, and PsycINFO databases. Fourteen studies, totaling 19 170 participants were included. Thirteen studies were rated as having high risk of bias (QUIPS tool). We used vote-counting and meta-analysis approaches to synthesize the data. We found associations between baseline sleep with future pain intensity, recovery, and between changes in sleep with changes in pain intensity, changes in disability, and recovery. We further synthesized outcomes as "overall LBP improvement" outcomes. Baseline poor sleep was moderately associated with non-improvement in LBP in the long-very long term (OR 1.55, 95% CI: 1.39 to 1.73; three studies providing unadjusted effect sizes), and non-improvement in sleep was largely associated with non-improvement in LBP in the short-moderate term (OR 3.45, 95% CI: 2.54 to 4.69; four studies providing unadjusted effect sizes). We found no association between baseline sleep with future disability and overall LBP improvement in the short-moderate term. Therefore, sleep may be a prognostic factor for pain intensity and recovery from LBP. All findings were supported by low to very low-quality evidence. Better-conducted studies are needed to strengthen our certainty about the evidence.

The impact of sleep disturbance on pain perception: A systematic review examining the moderating effect of sex and age

Females have increased pain sensitivity and are more vulnerable to chronic pain conditions. Sleep disturbances are comorbid with chronic pain and exacerbate pain symptoms. Different types of sleep disturbance affect pain perception distinctly, but it is not clear if these effects are equal in men and women. This systematic review investigated potential differences in how sleep disturbance affects pain in males and females. We searched EBSCO, MEDLINE, Psych INFO, Science Direct, and Web of Science from January 2001 to November 2022 and found 38 studies with 978 participants. Separate random-effects models were used to estimate the pooled effect sizes based on standardized mean differences (SMDs) of experimental sleep disturbance paradigms on various pain outcomes. Sex moderated the effect of sleep disturbance on pain facilitation (SMD = 0.13; 95%CI: 0.004 to 0.022; p=.009) and pain inhibition (SMD = 0.033; 95%CI: 0.011 to 0.054; p=.005), with increased facilitation and decreased inhibition in females, but the opposite effect in males. Further, age moderated the effects of total sleep deprivation (SMD = -0.194; 95%CI -0.328 to -0.060; p=.008) on pain sensitivity and fragmented sleep (SMD = -0.110; 95%CI: 0.148 to -0.072; p<.001) on pain threshold. While the moderating effect of sex and age on the sleep-pain relationship was small, these factors need to be considered in future sleep-pain research.

Sleep disorders in chronic pain and its neurochemical mechanisms: a narrative review

Chronic pain (CP) is a prevalent problem, and more than half of patients with CP have sleep disorders. CP comorbidity with sleep disorders imposes immense suffering and seriously affects the patient's quality of life, which is a challenging issue encountered by clinicians. Although the reciprocal interactions between pain and sleep have been studied to some degree, there is still a lack of awareness and comprehensive description of CP comorbidity with sleep disorders. In this narrative review article, we summarize the current knowledge about the present estimates of the prevalence of comorbid sleep disorders in CP patients, sleep detection methods, sleep characterization in CP, and the effect of sleep disorders on CP and current therapies. We also summarize current knowledge of the neurochemical mechanisms of CP comorbidity with sleep disorders. In conclusion, insufficient attention has been paid to the role of sleep disorders in CP patients, and CP patients should be screened for sleep disorders in the clinic. Special attention should be given to a possible risk of drug-drug interaction when using two types of drugs targeting pain and sleep simultaneously. The current insight into the neurobiological mechanisms underlying CP comorbidity with sleep disorders is still rather limited.

Temporomandibular Disorders Within the Context of Sleep Disorders

This paper provided an overview of the knowledge on the relationship between temporomandibular disorders (TMDs) and the main sleep conditions and disorders of dental interest, namely, sleep bruxism (SB), sleep apnea, and gastroesophageal reflux disease (GERD). It emerged that although the topic of SB as a possible detrimental factor for the stomatognathic structures has been the most studied, evidence is growing that SB, obstructive sleep apnea, and GERD, all belong to a circle of mutually interacting sleep disorders and conditions that, in turn, may be associated with TMDs. The pathophysiology of the cause-and-effect relationships, if existing, has to be elucidated yet.

A crossover study evaluating the sex-dependent and sensitizing effects of sleep deprivation using a nociceptive test battery in healthy subjects

AIM

We assessed whether total sleep deprivation (TSD) in combination with pain tests yields a reliable method to assess altered pain thresholds, which subsequently may be used to investigate (novel) analgesics in healthy subjects.

METHODS

This was a two-part randomized crossover study in 24 healthy men and 24 women. Subjects were randomized 1:1 to first complete a day of nonsleep-deprived nociceptive threshold testing, followed directly by a TSD night and morning of sleep-deprived testing, or first complete the TSD night and morning sleep-deprived testing, returning 7 days later for a day of nonsleep-deprived testing. A validated pain test battery (heat, pressure, electrical burst and stair, cold pressor pain test and conditioned pain modulation [CPM] paradigm) and sleep questionnaires were performed.

RESULTS

Subjects were significantly sleepier after TSD as measured using sleepiness questionnaires. Cold pressor pain tolerance (PTT, estimate of difference [ED] -10.8%, 95% CI -17.5 to -3.6%), CPM PTT (ED -0.69 mA, 95% CI -1.36 to -0.03 mA), pressure PTT (ED -11.2%, 95% CI -17.5% to -4.3%) and heat pain detection thresholds (ED -0.74 °C, 95% CI -1.34 to -0.14 °C) were significantly decreased after TSD compared to the baseline morning assessment in the combined analysis (men + women). Heat hyperalgesia was primarily driven by an effect of TSD in men, whereas cold and pressure hyperalgesia was primarily driven by the effects of TSD observed in women.

CONCLUSIONS

TSD induced sex-dependent hyperalgesia on cold, heat and pressure pain, and CPM response. These results suggest that the TSD model may be suitable to evaluate (novel) analgesics in early-phase drug studies.

Effect of sleep loss on pain-New conceptual and mechanistic avenues

Introduction

Sleep disturbances increase pain sensitivity in clinical and preclinical settings, but the precise mechanisms are unknown. This represents a major public health issue because of the growing sleep deficiency epidemic fueled by modern lifestyle. To understand the neural pathways at the intersection between sleep and pain processes, it is critical to determine the precise nature of the sleep disruptions that increase pain and the specific component of the pain response that is targeted.

Methods

We performed a review of the literature about sleep disturbances and pain sensitivity in humans and rodents by taking into consideration the targeted sleep stage (REMS, non-NREMS, or both), the amount of sleep lost, and the different types of sleep disruptions (partial or total sleep loss, duration, sleep fragmentation or interruptions), and how these differences might affect distinct components of the pain response.

Results

We find that the effects of sleep disturbances on pain are highly conserved among species. The major driver for pain hypersensitivity appears to be the total amount of sleep lost, while REMS loss by itself does not seem to have a direct effect on pain sensitivity. Sleep loss caused by extended wakefulness preferentially increases pain perception, whereas interrupted and limited sleep strongly dysregulates descending controls such as DNIC, especially in women.

Discussion

We discuss the possible mechanisms involved, including an increase in inflammatory processes, a loss of nociceptive inhibitory pathways, and a defect in the cognitive processing of noxious input.

Orexin, Sleep, Sympathetic Neural Activity, and Cardiovascular Function

Inadequate sleep duration and quality are associated with reduced cardiovascular health and increased mortality. Experimental evidence points to the sympathetic nervous system as a key mediator in the observed relationship between poor sleep and cardiovascular dysfunction. However, brain mechanisms underpinning the impaired sympathetic function associated with poor sleep remain unclear. Recent evidence suggests the central orexin system, particularly orexins A and B and their receptors, have a key regulatory role for sleep in animal and human models. While orexin system activity has been observed to significantly impact sympathetic regulation in animals, the extension of these findings to humans has been difficult due to an inability to directly assess orexin system activity in humans. However, direct measures of sympathetic activity in populations with narcolepsy and chronic insomnia, 2 sleep disorders associated with deficient and excessive orexin neural activity, have allowed indirect assessment of the relationships between orexin, sleep, and sympathetic regulation. Further, the recent pharmaceutical development of dual orexin receptor antagonists for use in clinical insomnia populations offers an unprecedented opportunity to examine the mechanistic role of orexin in sleep and cardiovascular health in humans. The current review assesses the role of orexin in both sleep and sympathetic regulation from a translational perspective, spanning animal and human studies. The review concludes with future research directions necessary to fully elucidate the mechanistic role for orexin in sleep and sympathetic regulation in humans.

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.

Circadian Variation in the Median Effective Dose of Epidural Ropivacaine for Labor Analgesia

Background: Labor pain perception has been demonstrated to exhibit a circadian rhythm with lower pain scores during the day compared with the night. This study aimed to determine and compare the median effective dose (ED₅₀) of ropivacaine in parturients having epidural labor analgesia during the day vs. during the night.

Methods: The study group consisted of 60 nulliparous healthy parturients who were assigned to one of two groups according to the time they requested labor analgesia: Day Group (7:01 am to 7:00 pm) and Night Group (7:01 pm to 7:00 am). A bolus of.15% ropivacaine was administered epidurally and effective analgesia was defined as the attainment of a visual analog scale (VAS) pain score ≤ 10 mm within 30 min. The dose of ropivacaine for the first parturient in each group was 18 mg. The dose for each subsequent parturient was varied with increments or decrements of 3 mg based on the response of the previous subject. The ED₅₀ was calculated using up-down sequential analysis. Probit regression was used to estimate the relative mean potency of ropivacaine between groups.

Results: The ED₅₀ (mean [95% CI]) of ropivacaine was lower in the Day Group (17.9 [16.5–19.4] mg) than in the Night Group (20.9 [19.2–22.7] mg) (P = 0.003). The estimate of relative potency for ropivacaine for the Night Group vs. the Day Group was 0.85 (95% CI:0.56–0.98).

Conclusions: Under the conditions of this study, the dose requirement for epidural ropivacaine for labor analgesia was ~ 15% greater during the night than during the day.

Clinical Trials Registration: Chinese Clinical Trial Registry (No.: ChiCTR1900025269. http://www.chictr.org.cn/showprojen.aspx?proj=36993).

At the intersection of sleep deficiency and opioid use: mechanisms and therapeutic opportunities

Due to the ongoing opioid epidemic, innovative scientific perspectives and approaches are urgently needed to reduce the unprecedented personal and societal burdens of nonmedical and recreational opioid use. One promising opportunity is to focus on the relationship between sleep deficiency and opioid use. In this review, we examine empirical evidence: (1) at the interface of sleep deficiency and opioid use, including hypothesized bidirectional associations between sleep efficiency and opioid abstinence; (2) as to whether normalization of sleep deficiency might directly or indirectly improve opioid abstinence (and vice versa); and (3) regarding mechanisms that could link improvements in sleep to opioid abstinence. Based on available data, we identify candidate sleep-restorative therapeutic approaches that should be examined in rigorous clinical trials.

Poor sleep and emotion dysregulation mediate the association between depressive and premenstrual symptoms in young adult women

A large portion of reproductive-aged women report experiencing distressing premenstrual symptoms. These symptoms can be exacerbated by concurrent mood problems and contribute to long-term depressive risk. However, difficulty sleeping and regulating emotional responses are also associated with the premenstrual phase and represent additional, well-established risk factors for depression. The aim of this study was to investigate whether habitual sleep problems and emotion regulation strategies serve to mediate the relationship between mood and premenstrual symptoms in non-treatment-seeking young women. Participants included 265 adult women between the ages of 18 and 25 who provided retrospective self-reports of depressive symptoms, habitual sleep quality, and premenstrual symptoms for the past month. Trait-based difficulties in regulating emotions were also assessed. Greater depressive symptoms significantly predicted greater premenstrual symptoms and both poor sleep and ineffective emotion regulation were shown to mediate this relationship. Poor sleep may enhance experience of premenstrual symptoms via its well-established impact on physical, cognitive, and/or affective functioning. Similarly, an inability to effectively regulate emotional responses in general may exacerbate experience or perception of somatic and mood symptoms during the premenstrual period, contributing to mood disturbances and risk. Findings require replication in future studies using prospective designs and more diverse samples of women.

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

Study Objectives

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

Methods

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

Results

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

Conclusions

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

Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology

The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.

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

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

Effects of prolonged paradoxical sleep deprivation with or without acute cold stress on hemodynamic perturbations in rats

Prolonged paradoxical sleep deprivation (PSD) and cold stress (CS) are known to cause sympathoexcitation and increase the risk of cardiovascular disease. The present study examined the effect of PSD with CS on hemodynamic perturbations by investigating blood pressure and heart rate variability (BPV and HRV) in conscious rats. Adult male Sprague-Dawley rats were divided into three groups (n = 10, each): normal sleep (NS), PSD of 72 h, and recovery sleep of 7 days after PSD. When compared with NS, PSD increased systolic blood pressure in all three conditions: before CS (PreCS), CS, and after CS (PostCS). The PSD also increased heart rate in both PreCS and PostCS. Furthermore, spectral power changes were observed throughout the experiment. The PSD increased very-low-frequency BPV in PreCS, decreased very-low-frequency HRV in CS, and increased low-frequency BPV in all three conditions. The PSD increased low-frequency HRV in PreCS, increased high-frequency BPV in both CS and PostCS, and also increased high-frequency HRV in both PreCS and CS but decreased that in PostCS. On the other hand, when compared with PSD, recovery sleep has reversed most cardiovascular changes in PSD toward the NS level. However, when compared with NS, spectral powers of very-low-frequency BPV in the recovery phase showed a lower level. These results showed that in the resting condition, PSD might evoke sympathoexcitation with a tendency to increase both very-low-frequency BPV and very-low-frequency HRV, as the intensified myogenic oscillations. However, in the CS condition, PSD evoked the sympathoexcitation yet might attenuate such myogenic oscillations.

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.