Alpha-like EEG activity in non-REM sleep and the fibromyalgia (fibrositis) syndrome

Non-inflammatory pain in inflammatory arthritis

'Non-inflammatory' pain, pain that is not associated with measures of inflammation, is common in patients with inflammatory arthritis including RA. One important cause of non-inflammatory pain is concomitant fibromyalgia. Systematic review has shown that fibromyalgia is common in inflammatory arthritis including RA affecting 1 in 5 patients and is associated with higher disease activity scores due to inflated tender joint count and patient global assessment. Consequently, many patients with RA and concomitant fibromyalgia may fail to reach treatment target and switch to alternate disease modifying drugs frequently. European Alliance of Association for Rheumatology has highlighted that concomitant fibromyalgia is an important consideration in assessing difficult-to-treat RA. The incidence and prevalence of fibromyalgia are higher in RA than the general population, raising the possibility that fibromyalgia may be 'secondary' to RA rather than a concomitant disease. The precise mechanisms whereby patients with RA develop fibromyalgia are unknown. In this review, we discussed fibromyalgia in RA, its clinical impact and epidemiology as well as data suggesting fibromyalgia might be 'secondary'. Lastly, we reviewed potential pathogenic mechanisms which included inflammatory cytokines sensitizing nociceptive neurones, temporal summation, also known as windup, from chronic pain and impaired coping from poor quality sleep and mental well-being. Deciphering the exact mechanisms may lead to treatment strategies that prevent development of secondary fibromyalgia and will address a common factor associated with difficult-to-treat RA.

Characteristics and Reproducibility of Novel Sleep EEG Biomarkers and their Variation with Sleep Apnea and Insomnia in a Large Community-Based Cohort

STUDY OBJECTIVES

New EEG features became available for use in polysomnography and have shown promise in early studies. They include a continuous index of sleep depth (Odds-Ratio-Product; ORP), agreement between right and left sleep depth (R/L coefficient), dynamics of sleep recovery following arousals (ORP-9), general EEG amplification (EEG Power), alpha intrusion and arousal intensity. This study was undertaken to establish ranges and reproducibility of these features in subjects with different demographics and clinical status.

METHODS

We utilized data from the two phases of the Sleep-Heart-Health-Study (SHHS1 and SHHS2). Polysomnograms of 5804 subjects from SHHS1 were scored to determine the above features. Feature values were segregated according to clinical status of Obstructive Sleep Apnea (OSA), insomnia, insomnia plus OSA, no clinical sleep disorder, and demographics (age, gender and race). Results from SHHS visit2 were compared with SHHS1 results.

RESULTS

All features varied widely among clinical groups and demographics. Relative to participants with no sleep disorder, wake ORP was higher in participants reporting insomnia symptoms and lower in those with OSA (p<0.0001 for both), reflecting opposite changes in sleep pressure, while NREM ORP was higher in both insomnia and OSA (p<0.0001), reflecting lighter sleep in both groups. There were significant associations with age, gender, and race. EEG Power, and REM ORP were highly reproducible across the two studies (ICC>0.75).

CONCLUSIONS

The reported results serve as bases for interpreting studies that utilize novel sleep EEG biomarkers and identify characteristic EEG changes that vary with age, gender and may help distinguish insomnia from OSA.

Protocol for the impact of CBT for insomnia on pain symptoms and central sensitisation in fibromyalgia: a randomised controlled trial

INTRODUCTION

Approximately 50% of individuals with fibromyalgia (a chronic widespread pain condition) have comorbid insomnia. Treatment for these comorbid cases typically target pain, but growing research supports direct interventions for insomnia (eg, cognitive behavioural treatment for insomnia (CBT-I)) in these patients. Previous research suggests sustained hyperarousal mediated by a neural central sensitisation mechanism may underlie insomnia and chronic pain symptoms in fibromyalgia. We hypothesise CBT-I will improve insomnia symptoms, improve clinical pain and reduce central sensitisation. The trial will be the first to evaluate the short-term and long-term neural mechanisms underlying insomnia and pain improvements in fibromyalgia. Knowledge obtained from this trial might allow us to develop new or modify current treatments to better target pain mechanisms, perhaps reversing chronic pain or preventing it.

METHODS AND ANALYSIS

Female participants (n=130) 18 years of age and older with comorbid fibromyalgia (with pain severity of at least 50/100) and insomnia will be recruited from the University of Missouri in Columbia, Missouri, and surrounding areas. Participants will be randomised to 8 weeks (plus 4 bimonthly booster sessions) of CBT-I or a sleep hygiene control group (SH). Participants will be assessed at baseline, post-treatment, 6 and 12 months follow-ups. The following assessments will be completed: 2 weeks of daily diaries measuring sleep and pain, daily actigraphy, insomnia severity index, pain-related disability, single night of polysomnography recording, arousal (heart rate variability, cognitive affective arousal), structural and functional MRI to examine pain-related neural activity and plasticity and mood (depression, anxiety).

ETHICS AND DISSEMINATION

Ethics approval was obtained in July 2018 from the University of Missouri. All data are expected to be collected by 2022. Full trial results are planned to be published by 2024. Secondary analyses of baseline data will be subsequently published.

TRIAL REGISTRATION NUMBER

NCT03744156.

Comparison of sleep structure in patients with fibromyalgia and healthy controls

BACKGROUND

Sleep disturbances such as nonrestorative sleep and nighttime awakenings play a crucial role in fibromyalgia (FMS). Pain and sleep disturbances show a bidirectional relationship which affect outcomes in FMS. This study aims to compare sleep structures between patients with fibromyalgia and healthy controls.

METHODS

We evaluated subjective and objective sleep structures of 33 patients with fibromyalgia and 34 healthy controls using the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and polysomnography. Student's T test, chi-square, discriminant analysis, the Kruskal-Wallis, and Mann-Whitney U test were used for statistical analysis.

RESULTS

Patients with FMS reported poorer sleep quality than controls (p = 0.003). Polysomnography data showed patients with FMS exhibited a greater number of awakenings (p = 0.01), more arousals (p = 0.00), higher arousal index (p = 0.00), greater apnea hypopnea index (p = 0.03), and less N1 sleep (p = 0.02) than healthy controls. The discriminant analysis revealed that number of arousals, arousal index, and N1 sleep were able to distinguish patients with FMS from healthy controls with 78.5% accuracy. Twelve of the 33 patients with FMS were diagnosed with obstructive sleep apnea syndrome (OSAS). When we excluded patients with OSAS, a statistically significant difference was maintained.

CONCLUSIONS

Our findings may explain the deterioration of subjective sleep, symptoms as unrefreshing sleep, fatigue, and pain in patients with FMS. Despite similar clinical manifestations, patients with FMS should be evaluated for OSAS due to treatment differences. The role of sleep alterations in the clinical manifestation and severity of FMS suggest that effective treatments to improve sleep quality may lead to more effective management of FMS.

Learning Using Concave and Convex Kernels: Applications in Predicting Quality of Sleep and Level of Fatigue in Fibromyalgia

Fibromyalgia is a medical condition characterized by widespread muscle pain and tenderness and is often accompanied by fatigue and alteration in sleep, mood, and memory. Poor sleep quality and fatigue, as prominent characteristics of fibromyalgia, have a direct impact on patient behavior and quality of life. As such, the detection of extreme cases of sleep quality and fatigue level is a prerequisite for any intervention that can improve sleep quality and reduce fatigue level for people with fibromyalgia and enhance their daytime functionality. In this study, we propose a new supervised machine learning method called Learning Using Concave and Convex Kernels (LUCCK). This method employs similarity functions whose convexity or concavity can be configured so as to determine a model for each feature separately, and then uses this information to reweight the importance of each feature proportionally during classification. The data used for this study was collected from patients with fibromyalgia and consisted of blood volume pulse (BVP), 3-axis accelerometer, temperature, and electrodermal activity (EDA), recorded by an Empatica E4 wristband over the courses of several days, as well as a self-reported survey. Experiments on this dataset demonstrate that the proposed machine learning method outperforms conventional machine learning approaches in detecting extreme cases of poor sleep and fatigue in people with fibromyalgia.

Objective measures of sleep in fibromyalgia syndrome: Relationship to clinical, psychiatric, and immunological variables

We aimed to investigate the changes in the objective and subjective sleep variables during painful episodes of fibromyalgia and post-episode period, and to evaluate the impact of the sleep variables on the current clinical, psychological, and immunologic parameters. Thirty-one consecutive patients who were referred to the Erenköy Physical Therapy and Rehabilitation Polyclinic with a diagnosis of fibromyalgia were evaluated before and in the sixth week of the acute pain treatment. The sleep variables were measured by polysomnography, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale. The clinical and psychiatric assessment of patients was performed by using Fibromyalgia Impact Questionnaire; Patient Health Questionnaire-Somatic, Anxiety, and Depressive Symptoms; and Visual Analog Scale. Serum pro-inflammatory molecules were measured to evaluate the immunological status. The pain treatment significantly affected subjective sleep variables, psychiatric variables, clinical variables, and IL-6 levels. The subjective sleep parameters, clinical and psychiatric variables, and IL-6 levels were improved with pain treatment in fibromyalgia. The objective sleep variables, IL-1 and TNF-alpha levels were not significantly improved with the pain treatment, and they were not related to clinical presentation of patients with fibromyalgia. Subjective variability of sleep contributes to the clinical presentation, suggesting that the objective structure is trait-specific with IL-1 and TNF-alpha.

The sleep EEG spectrum is a sexually dimorphic marker of general intelligence

The shape of the EEG spectrum in sleep relies on genetic and anatomical factors and forms an individual "EEG fingerprint". Spectral components of EEG were shown to be connected to mental ability both in sleep and wakefulness. EEG sleep spindle correlates of intelligence, however, exhibit a sexual dimorphism, with a more pronounced association to intelligence in females than males. In a sample of 151 healthy individuals, we investigated how intelligence is related to spectral components of full-night sleep EEG, while controlling for the effects of age. A positive linear association between intelligence and REM anterior beta power was found in females but not males. Transient, spindle-like "REM beta tufts" are described in the EEG of healthy subjects, which may reflect the functioning of a recently described cingular-prefrontal emotion and motor regulation network. REM sleep frontal high delta power was a negative correlate of intelligence. NREM alpha and sigma spectral power correlations with intelligence did not unequivocally remain significant after multiple comparisons correction, but exhibited a similar sexual dimorphism. These results suggest that the neural oscillatory correlates of intelligence in sleep are sexually dimorphic, and they are not restricted to either sleep spindles or NREM sleep.

Sleep disturbances in fibromyalgia: A meta-analysis of case-control studies

OBJECTIVE

Sleep disturbances are common in fibromyalgia, but the features of sleep disturbances are not well understood. We performed a systematic review and meta-analysis of case-control studies to compare the sleep outcomes of individuals with fibromyalgia and healthy controls.

METHODS

We systematically searched eight databases (PubMed, Ovid MEDLINE, Embase, CINAHL, PsycINFO, Web of Science, Airiti Library and Wanfang Data) for articles published before April 2016.

RESULTS

Twenty-five case-controlled studies and a total of 2086 participants were included in the meta-analysis. Sleep was assessed using polysomnography and the Pittsburgh Sleep Quality Index. When sleep was assessed using polysomnography (19 studies), significant differences were observed in wake time after sleep onset (g=0.81, 95% confidence interval [CI] 0.21-1.41), total sleep time (g=-0.78, 95% CI=-1.34 to -0.15), sleep efficiency (g=-0.78, 95% CI=-1.23 to -0.32), percentage of stage 1 sleep (g=0.55, 95% CI=0.15-0.95), and percentage of slow-wave sleep (g=-0.66, 95% CI=-1.21 to -0.12) between participants with fibromyalgia and healthy controls. When sleep was assessed using the Pittsburgh Sleep Quality Index (7 studies), significant differences were observed in global scores (g=2.19, 95% CI 1.58-2.79), sleep onset latency (g=1.75, 95% CI 0.80-2.70), and sleep efficiency (g=-1.08, 95% CI -1.65 to -0.51) between participants with fibromyalgia and healthy controls.

CONCLUSION

Individuals with fibromyalgia experience lower sleep quality and sleep efficiency; longer wake time after sleep onset, short sleep duration, and light sleep when objectively assessed and more difficulty in initiating sleep when subjectively assessed. Sleep difficulties in fibromyalgia appear to be more when reported subjectively than when assessed objectively.

COMPLIANCE WITH ETHICAL STANDARDS

This study received no funding from any source. All authors declare that they have no conflict of interest. This article does not contain any studies with human participants performed by any of the authors.

Regional Patterns of Elevated Alpha and High-Frequency Electroencephalographic Activity during Nonrapid Eye Movement Sleep in Chronic Insomnia: A Pilot Study

STUDY OBJECTIVES

To examine nonrapid eye movement (NREM) sleep in insomnia using high-density electroencephalography (EEG).

METHODS

All-night sleep recordings with 256 channel high-density EEG were analyzed for 8 insomnia subjects (5 females) and 8 sex and age-matched controls without sleep complaints. Spectral analyses were conducted using unpaired t-tests and topographical differences between groups were assessed using statistical non-parametric mapping. Five minute segments of deep NREM sleep were further analyzed using sLORETA cortical source imaging.

RESULTS

The initial topographic analysis of all-night NREM sleep EEG revealed that insomnia subjects had more high-frequency EEG activity (> 16 Hz) compared to good sleeping controls and that the difference between groups was widespread across the scalp. In addition, the analysis also showed that there was a more circumscribed difference in theta (4-8 Hz) and alpha (8-12 Hz) power bands between groups. When deep NREM sleep (N3) was examined separately, the high-frequency difference between groups diminished, whereas the higher regional alpha activity in insomnia subjects persisted. Source imaging analysis demonstrated that sensory and sensorimotor cortical areas consistently exhibited elevated levels of alpha activity during deep NREM sleep in insomnia subjects relative to good sleeping controls.

CONCLUSIONS

These results suggest that even during the deepest stage of sleep, sensory and sensorimotor areas in insomnia subjects may still be relatively active compared to control subjects and to the rest of the sleeping brain.

Polysomnographic characteristics in nonmalignant chronic pain populations: A review of controlled studies

Sleep and pain are critical homeostatic systems that interact in a bidirectional manner. Complaints of sleep disturbance are ubiquitous among patients with chronic pain disorders, and conversely, patients with persistent insomnia symptoms commonly report suffering from chronic pain. Sleep deprivation paradigms demonstrate that partial or complete sleep loss induce hyperalgesia, possibly due to shared mechanistic pathways including neuroanatomic and molecular substrates. Further, chronic pain conditions and sleep disturbances are intertwined through comorbidities, which together cause detrimental psychological and physical consequences. This critical review examines 29 polysomnography studies to evaluate whether nonmalignant chronic pain patients, as compared to controls, show differences in objective measures of sleep continuity and sleep architecture. Whereas these controlled studies did not reveal a consistent pattern of objective sleep disturbances, alterations of sleep continuity were commonly reported. Alterations of sleep architecture such as increases in light sleep or decreases in slow-wave sleep were less commonly reported and findings were mixed and also inconsistent. Methodological flaws were identified, which complicated interpretation and limited conclusions; hence, recommendations for future research are suggested. Knowledge of abnormalities in the sleep process has implications for understanding the pathophysiology of chronic pain conditions, which might also direct the development of novel intervention strategies.

Nonrestorative Sleep, Musculoskeletal Pain, Fatigue in Rheumatic Disorders, and Allied Syndromes: A Historical Perspective

This chapter provides a historical perspective of the notion that the sleeping–waking brain is intimately related to complaints of unrefreshing sleep, widespread musculoskeletal pain, fatigue, and suffering. Such a constellation of symptoms extend from the remote biblical past, and involve various religious and cultural belief systems up to the recent evolution in Western medicine application of scientific methods for classification of illness. The contemporary application of scientific principles is directed to the etiology of diseases and to derive procedures for the management of such ill-understood illnesses. Historically, this constellation of rheumatic pain and fatigue symptoms have been given ever-changing medical and psychiatric labels that have been devoid of satisfactory medical understanding. In this chapter, the hypothesis that the sleeping/waking brain is integral to the somatic and behavioral symptoms of these disabling rheumatic chronic illness, termed fibromyalgia and various allied disorders, that are being examined and treated by a variety of health care professionals. Contemporary advances in mechanisms of how the sleeping–waking brain connects to these somatic and behavioral symptoms are reviewed. Potential avenues for further scientific understanding are described. Advances in such understanding are influencing current pharmacological and behavioral management of these suffering patients.

Relationship between sleep and pain in adolescents with juvenile primary fibromyalgia syndrome

STUDY OBJECTIVES

To investigate sleep quality in adolescents with juvenile primary fibromyalgia syndrome (JPFS) and determine whether sleep abnormalities, including alpha-delta sleep (ADS), correlate with pain intensity. We hypothesized that successful treatment for pain with exercise therapy would reduce ADS and improve sleep quality.

DESIGN

Single-center preintervention and postintervention (mean = 5.7 ± 1.0 weeks; range = 4.0-7.3 weeks) observational study.

PATIENTS

Ten female adolescents (mean age = 16.2 ± 0.65 SD yr) who met criteria for JPFS and completed treatment.

INTERVENTIONS

Multidisciplinary pain treatment, including intensive exercise therapy.

MEASUREMENTS AND RESULTS

Pain and disability were measured by a pain visual analog scale (VAS) and the functional disability inventory. Subjective sleep measures included a sleep VAS, an energy VAS, and the School Sleep Habits Survey. Objective sleep measures included actigraphy, polysomnography (PSG), and the Multiple Sleep Latency Test. Baseline PSG was compared with that of healthy age- and sex-matched control patients. At baseline, patients had poorer sleep efficiency, more arousals/awakenings, and more ADS (70.3% of total slow wave sleep [SWS] versus 21.9% SWS, P = 0.002) than controls. ADS was unrelated to pain, disability, or subjective sleep difficulty. After treatment, pain decreased (P = 0.000) and subjective sleep quality improved (P = 0.008). Objective sleep quality, including the amount of ADS, did not change.

CONCLUSIONS

Although perceived sleep quality improved in adolescents with JPFS after treatment, objective measures did not. Our findings do not suggest exercise therapy for pain improves sleep by reducing ADS, nor do they support causal relationships between ADS and chronic pain or subjective sleep quality.

Passive body heating improves sleep patterns in female patients with fibromyalgia

OBJECTIVE

To assess the effect of passive body heating on the sleep patterns of patients with fibromyalgia.

METHODS

Six menopausal women diagnosed with fibromyalgia according to the criteria determined by the American College of Rheumatology were included. All women underwent passive immersion in a warm bath at a temperature of 36 ±1 °C for 15 sessions of 30 minutes each over a period of three weeks. Their sleep patterns were assessed by polysomnography at the following time-points: pre-intervention (baseline), the first day of the intervention (acute), the last day of the intervention (chronic), and three weeks after the end of the intervention (follow-up). Core body temperature was evaluated by a thermistor pill during the baseline, acute, chronic, and follow-up periods. The impact of this treatment on fibromyalgia was assessed via a specific questionnaire termed the Fibromyalgia Impact Questionnaire.

RESULTS

Sleep latency, rapid eye movement sleep latency and slow wave sleep were significantly reduced in the chronic and acute conditions compared with baseline. Sleep efficiency was significantly increased during the chronic condition, and the awakening index was reduced at the chronic and follow-up time points relative to the baseline values. No significant differences were observed in total sleep time, time in sleep stages 1 or 2 or rapid eye movement sleep percentage. The core body temperature and Fibromyalgia Impact Questionnaire responses did not significantly change over the course of the study.

CONCLUSION

Passive body heating had a positive effect on the sleep patterns of women with fibromyalgia.

Effect of pregabalin on sleep in patients with fibromyalgia and sleep maintenance disturbance: a randomized, placebo-controlled, 2-way crossover polysomnography study

OBJECTIVE

To assess the effect of pregabalin on polysomnographic (PSG) measures of sleep and patient-rated sleep, tiredness, and pain in fibromyalgia patients.

METHODS

We performed a randomized, double-blind, placebo-controlled, 2-period crossover PSG study. Patients ages ≥18 years with fibromyalgia satisfied subjective and objective sleep disturbance criteria prior to randomization. Eligible patients were randomized (1:1) to pregabalin (300-450 mg/day) or placebo for crossover period 1, and vice versa for period 2. Each crossover period comprised a dose-adjustment and dose-maintenance phase, with a 2-week taper/washout between periods. In-laboratory PSGs were recorded during 2 consecutive nights at screening and at the end of each crossover period. The primary end point was the difference in sleep maintenance defined by PSG-recorded wake after sleep onset (WASO; minutes) between 4 weeks of treatment with pregabalin and with placebo. Other PSG measures; patient-rated sleep, tiredness, and pain; and tolerability were assessed.

RESULTS

Of 119 patients randomized (103 women [86.6%], mean age 48.4 years), 102 (85.7%) completed both periods. Patients treated with pregabalin showed a reduction in PSG-determined WASO versus treatment with placebo (week 4 difference: -19.2 minutes [95% confidence interval (95% CI) -26.7, -11.6]; P < 0.0001). Pain score improved (decreased) with pregabalin versus placebo treatment at all 4 weeks (week 4 difference: -0.52 [95% CI -0.90, -0.14]; P = 0.0084). Modest (ρ = <0.3) but significant correlations were found between PSG sleep assessments and ratings of pain and sleep quality. Frequently reported all-causality adverse events (pregabalin versus placebo) were: dizziness (30.4% versus 9.9%), somnolence (20.5% versus 4.5%), and headache (8.9% versus 8.1%).

CONCLUSION

Patients with fibromyalgia treated with pregabalin had statistically significant and meaningful improvements in sleep, as assessed by PSG. Patients with fibromyalgia also reported decreased daily pain. Pregabalin was well tolerated.

Predictors of clinical pain in fibromyalgia: examining the role of sleep

Understanding individual differences in the variability of fibromyalgia pain can help elucidate etiological mechanisms and treatment targets. Past research has shown that spatial extent of pain, negative mood, and aftersensation (pain ratings taken after experimental induction of pain) accounts for 40 to 50% of the variance in clinical pain. Poor sleep is hypothesized to have a reciprocal relationship with pain, and over 75% of individuals with fibromyalgia report disturbed sleep. We hypothesized that measures of sleep would increase the predictive ability of the clinical pain model. Measures of usual pain, spatial extent of pain, negative mood, and pain aftersensation were taken from 74 adults with fibromyalgia. Objective (actigraph) and subjective (diary) measures of sleep duration and nightly wake time were also obtained from the participants over 14 days. Hierarchical regression indicated that greater spatial extent (R(2) = .26), higher aftersensation ratings (R(2) = .06), and higher negative mood (R(2) = .04) accounted for 36% of the variance in clinical pain (average of 14 daily pain ratings). None of the sleep variables were significant predictors of clinical pain. Results replicate previous research and suggest that spatial extent of pain, pain aftersensation, and negative mood play important roles in clinical pain, but sleep disturbance did not aid in its prediction.

PERSPECTIVE

This study suggests that measures of sleep duration and nightly wake time do not predict fibromyalgia pain at the group level. Fibromyalgia patients may benefit from a 3-pronged approach to pain management: reducing pain's spatial extent, normalization of central nervous system hypersensitivity, and psychobehavioral therapies for negative mood.

Neurobiology underlying fibromyalgia symptoms

Fibromyalgia is characterized by chronic widespread pain, clinical symptoms that include cognitive and sleep disturbances, and other abnormalities such as increased sensitivity to painful stimuli, increased sensitivity to multiple sensory modalities, and altered pain modulatory mechanisms. Here we relate experimental findings of fibromyalgia symptoms to anatomical and functional brain changes. Neuroimaging studies show augmented sensory processing in pain-related areas, which, together with gray matter decreases and neurochemical abnormalities in areas related to pain modulation, supports the psychophysical evidence of altered pain perception and inhibition. Gray matter decreases in areas related to emotional decision making and working memory suggest that cognitive disturbances could be related to brain alterations. Altered levels of neurotransmitters involved in sleep regulation link disordered sleep to neurochemical abnormalities. Thus, current evidence supports the view that at least some fibromyalgia symptoms are associated with brain dysfunctions or alterations, giving the long-held “it is all in your head” view of the disorder a new meaning.

Fibromialgia: nível de atividade física e qualidade do sono

O objetivo foi identificar o nível de atividade física e sua relação com sonolência excessiva diurna e qualidade de sono em 15 mulheres com fibromialgia, com idade média de 58±7 anos. Foi utilizado o Questionário Internacional de Atividade Física, o Índice de Qualidade de Sono de Pittsburgh e a Escala de Sonolência de Epworth. O programa SPSS Statistics versão 17 foi utilizado para as analises estatísticas e o valor para significância foi de α < 0,05. Os resultados evidenciaram que 33,3% das pacientes classificaram-se inativas e 66,7% minimamente ativas. Observou-se sonolência excessiva diurna em 60% das pacientes. A qualidade ruim de sono foi observada em 55,6% das pacientes minimamente ativas e em 60% das inativas. O tempo médio para adormecer foi 34,3 minutos, a eficiência do sono foi 81% e o tempo total de sono foi 5,9 horas. O baixo nível de atividade física parece ser um dos fatores capazes de piorar a qualidade do sono de mulheres com fibromialgia.

Can neuroimaging help us to understand and classify somatoform disorders? A systematic and critical review

OBJECTIVE

Debate about the nature of somatoform disorders and their current diagnostic classification has been stimulated by the anticipation of new editions of Diagnostic and Statistical Manual of Mental Disorders and International Statistical Classification of Diseases and Related Health Problems diagnostic classifications. In the current paper, we review systematically the literature on the neuroimaging of somatoform disorders and related conditions with the aim of addressing two specific questions: Is there evidence of altered neural function or structure that is specifically associated with somatoform disorders? What conclusions can we draw from these findings about the etiology of somatoform disorders?

METHODS

Studies reporting neuroimaging findings in patients with a somatoform disorder or a functional somatic syndrome (such as fibromyalgia) were found using Pubmed, PsycINFO, and EMBASE database searches. Reported structural and functional neuroimaging findings were then extracted to form a narrative review.

RESULTS

A relatively mature literature on symptoms of pain and less developed literatures on conversion and fatigue symptoms were identified. The available evidence indicates that, when compared with nonclinical groups, somatoform diagnoses are associated with increased activity of limbic regions in response to painful stimuli and a generalized decrease in gray matter density; however, methodological considerations restrict the interpretation of these findings.

CONCLUSIONS

Whereas the neuroimaging literature has provided evidence about the possible mechanisms underlying somatoform disorders, this is not yet sufficient to provide a basis for classification. By adopting a wider variety of experimental designs and a more dynamic approach to diagnosis, there is every reason to be hopeful that neuroimaging data will play a significant role in future taxonomies.

Light sleep and sleep time misperception - relationship to alpha-delta sleep

OBJECTIVE

We investigated the association of alpha-delta sleep (A-DS) with: (1) perception of light sleep and (2) discrepancy between subjective and objective sleep duration.

METHODS

We analyzed data from 5764 individuals who underwent polysomnography (PSG) and replied questions about quantity and quality of sleep, including sleep depth. The difference between objectively recorded sleep time and subjectively estimated sleep time was calculated. Alpha-delta sleep (A-DS) was visually scored in a scale from 1 to 4, based on the density and overnight duration of alpha activity and confirmed using spectral array of the electroencephalographic activity.

RESULTS

A-DS scores 1-4 occurred in, respectively, 37.9%; 31.3%; 20.5%; and 6.2% of the cases. ANOVA showed significant difference of light sleep sensation (p<0.001) and sleep time underestimation (p<0.001) among the four A-DS categories. Regression to explain both light sleep and sleep time underestimation, controlling for confounders, confirmed A-DS as a significant regressor.

CONCLUSIONS

This study of a large prospective sample provides evidence for the association of alpha-delta sleep with subjective sensation of light sleep and with sleep time underestimation.

SIGNIFICANCE

Alpha-delta sleep may be a marker of the physiological disorder underlying light sleep and sleep state misperception.

Delta sleep instability in children with chronic arthritis

The objective of the present study was to evaluate the expression of a cyclic alternating pattern (CAP) in slow wave sleep (SWS) in children with the well-defined chronic syndrome juvenile idiopathic arthritis (JIA). Twelve patients (9-17 years of age), 7 girls, with JIA were compared to matched controls by age, pubertal stage and gender. After one night of habituation in the sleep laboratory, sleep measurements were obtained by standard polysomnography with conventional sleep scoring and additional CAP analyses. The sleep parameters of the JIA and control groups were similar for sleep efficiency (91.1 +/- 6.7 vs 95.8 +/- 4.0), sleep stage in minutes: stage 1 (16.8 +/- 8.5 vs 17.8 +/- 4.0), stage 2 (251.9 +/- 41 vs 262.8 +/- 38.1), stage 3 (17.0 +/- 6.0 vs 15.1 +/- 5.7), stage 4 (61.0 +/- 21.7 vs 77.1 +/- 20.4), and rapid eye movement sleep (82.0 +/- 27.6 vs 99.0 +/- 23.9), respectively. JIA patients presented nocturnal disrupted sleep, with an increase in short awakenings, but CAP analyses showed that sleep disruption was present even during SWS, showing an increase in the overall CAP rate (P < 0.01). Overall CAP rate during non-rapid eye movement sleep was significantly higher in pediatric patients who were in chronic pain. This is the first study of CAP in pediatric patients with chronic arthritis showing that CAP analyses can be a powerful tool for the investigation of disturbance of SWS in children, based on sleep EEG visual analysis.

Power spectral analysis of sleep EEG in twins discordant for chronic fatigue syndrome

OBJECTIVE

The purpose of the study was to evaluate quantitative sleep electroencephalogram (EEG) frequencies in monozygotic twins discordant for chronic fatigue syndrome.

METHODS

Thirteen pairs of female twins underwent polysomnography. During the first night, they adapted to the sleep laboratory, and during the second night, their baseline sleep was assessed. Visual stage scoring was conducted on sleep electroencephalographic records according to standard criteria, and power spectral analysis was used to quantify delta through beta frequency bands, processed in 6-s blocks. Data were averaged across sleep stage within each twin and coded for sleep stage and the presence or absence of chronic fatigue syndrome (CFS). A completely within-subjects repeated measure multivariate analysis of variance evaluated twin pairs by frequency band by sleep stage interactions and simple effects. The relationship between alpha and delta EEG was also assessed across twin pairs.

RESULTS

No significant differences in spectral power in any frequency band were found between those with CFS and their nonfatigued cotwins. Phasic alpha activity, coupled with delta was noted in five subjects with CFS but was also present in 4/5 healthy twins, indicating this finding likely reflects genetic influences on the sleep electroencephalogram rather than disease-specific sleep pathology.

CONCLUSIONS

The genetic influences on sleep polysomnography and microarchitecture appear to be stronger than the disease influence of chronic fatigue syndrome, despite greater subjective sleep complaint among the CFS twins. EEG techniques that focus on short duration events or paradigms that probe sleep regulation may provide a better description of sleep abnormalities in CFS.

Sleep stage dynamics in fibromyalgia patients and controls

OBJECTIVE

To determine whether previously described sleep stage dynamics, reflecting the mean duration of specific sleep stages, may have clinical utility in a sample of patients with fibromyalgia syndrome (FMS) and controls.

METHODS

Women with FMS (n=15, screened to exclude other sleep disorders) and age-matched women in good health (n=15) were studied with nocturnal polysomnography, multiple sleep latency tests, 2-week pain diaries, and a measure of current pain intensity.

RESULTS

The FMS subjects, in comparison to controls, did not show differences in several common polysomnographic measures, except for increased numbers of stage shifts (126+/-27 vs. 107+/-22, p=.042). Mean durations for episodes of total sleep, stage 1 sleep, stage 3/4 sleep, and rapid eye movement sleep failed to distinguish FMS and control subjects (Wilcoxon rank sum tests, p>.10 for each), but those for stage 2 sleep were shorter in the FMS subjects (p=.006), possibly because transitions to stage 3/4 sleep occurred more quickly (p=.036). Shorter stage 2 sleep durations predicted higher pain diary scores (Spearman rho=-.56, p=.0014) and current pain intensity (rho=-.71, p<0.0001).

CONCLUSIONS

Sleep stage dynamic, and, more specifically, shorter durations of sleep stage 2 periods, distinguish FMS and control female subjects and may predict pain levels experienced in FMS. Analysis of the lengths of individual sleep stages, in addition to the usual sleep stage amounts and percentages listed in standard polysomnogram reports, may have clinical utility.

Did ‘the Princess on the Pea— Suffer from Fibromyalgia Syndrome?

Fibromyalgia syndrome (FMS) is a chronic pain syndrome characterised by central sensitisation resulting in hypersentivity of the skin and deeper tissues as well as fatigue. Possibly the princess in Hans Christian Andersen's ‘The Princess and the Pea’ suffered from FMS since chronic sleep disturbances are typical in FMS. These sleep disturbances have been attributed to a dysfunction in the systems regulating sleep and wakefulness resulting in loss of deep sleep. In addition, many patients with FMS experience cognitive dysfunction, characterised by impaired concentration and short term memory consolidation, a complaint also commonly reported in other sleep disorders.

In recent reviews evaluating the efficacy of acupuncture in FMS it has been concluded that acupuncture has no specific effect. A prerequisite for this conclusion is that all the major symptoms in the syndrome have been assessed. However, previous studies have generally focused on the pain alleviating effect of acupuncture in FMS. We have observed that not only pain but also sleep and cognitive dysfunction may be ameliorated in response to acupuncture, suggesting that these variables should be taken into account when evaluating the effects of acupuncture in FMS. Furthermore, the results demonstrated great individual variability apart from the systematic effects related to the group, indicating that individually performed treatment strategies are required. Our suggestion is supported by experimental and clinical studies showing that acupuncture may affect in somnia and alertness, and that there may be neurophysiologic bases for these specific effects.

Fibromyalgia, sleep disorder and chronic fatigue syndrome

Various research studies show that the amalgam of disordered sleep physiology, chronic fatigue, diffuse myalgia, and cognitive and behavioural symptoms constitutes a non-restorative sleep syndrome that may follow a febrile illness, as in the chronic fatigue syndrome. Where rheumatic complaints are prominent such a constellation of disturbed sleep physiology and symptoms also characterizes the fibromyalgia disorder. In contrast to the chronic fatigue syndrome, fibromyalgia is associated with a variety of initiating or perpetuating factors such as psychologically distressing events, primary sleep disorders (e.g. sleep apnoea, periodic limb movement disorder) and inflammatory rheumatic disease, as well as an acute febrile illness. The chronic fatigue syndrome and fibromyalgia have similar disordered sleep physiology, namely an alpha rhythm disturbance (7.5-11 Hz) in the electroencephalogram (EEG) within non-rapid eye movement (NREM) sleep that accompanies increased nocturnal vigilance and light, unrefreshing sleep. Aspects of cytokine and cellular immune functions are shown to be related to the sleep-wake system. The evidence suggests a reciprocal relationship of the immune and sleep-wake systems. Interference either with the immune system (e.g. by a viral agent or by cytokines such as alpha-interferon or interleukin 2) or with the sleeping-waking brain system (e.g. by sleep deprivation) has effects on the other system and will be accompanied by the symptoms of the chronic fatigue syndrome.

Comparison of sleep variables between chronic widespread musculoskeletal pain, insomnia, periodic leg movements syndrome and control subjects in a clinical sleep medicine practice

BACKGROUND

Between 50% and 89% of chronic pain patients report unrefreshing sleep. The aim of this retrospective analysis was to compare the sleep of normal subjects with the sleep of a clinical population presenting musculoskeletal chronic widespread pain (CWP), psychophysiological insomnia and restless legs syndrome/periodic limb movements during sleep (RLS/PLMS) in order to identify sleep variables that may explain the poor sleep complaints of CWP patients.

METHODS

Sleep data from 10 normal subjects and 37 patients (mean age 55+/-3 yo), matched for age and sex, were retrieved from our sleep data bank. Sub-analysis controlled for the effects of medication.

RESULTS

In comparison to normal subjects, sleep duration was shorter in CWP patients (-71 min; p<0.01); sleep efficiency was significantly lower in CWP and insomnia patients (-10.1% and -11.1%, respectively; p<0.05). CWP and PLMS patients lost one non-rapid eye movement (REM) to REM sleep cycle (p<0.04). An intermediate level of PLM was observed during the sleep of CWP patients in comparison to normal subjects (8.8/h vs. 2.0/h) and PLMS patients (33/h). Regular use of non-narcotic analgesics did not seem to interfere with sleep variables.

CONCLUSIONS

The sleep of middle-aged patients with CWP is comparable to that of insomnia patients. The moderate level of PLM during sleep suggests that such sensory motor activity needs to be evaluated in patients suffering from chronic pain.

Prevalence and correlates of clinical insomnia co-occurring with chronic back pain

Given the suggestion of a reciprocal relationship between sleep and pain and the recognition of sleep as an important parameter in determining quality of life, there is increasing research interest in sleep disturbance linked to chronic pain. The present study aimed to provide an estimate of the prevalence of 'clinical insomnia' in patients attending a specialist pain clinic and identify factors associated with it. Seventy chronic back pain patients and 70 gender- and age-matched pain-free controls completed a set of questionnaires measuring sleep (Insomnia Severity Index; ISI), pain (Short-Form McGill Pain Questionnaire) and a selection of general and specific psychological variables (Hospital Anxiety and Depression Scale, Short Health Anxiety Inventory). Scores suggestive of clinical insomnia (ISI > or = 15) were noted in 53% of chronic pain patients, when compared with only 3% in pain-free controls. Significant positive correlations with insomnia severity were detected for all six variables of interest (pain intensity, sensory pain ratings, affective pain ratings, general anxiety, general depression and health anxiety). Affective pain ratings and health anxiety were the best predictors of insomnia severity in this sample, accounting for 30% of the total variance, even when present pain intensity was controlled for. Affective pain remained as a significant predictor of insomnia severity when both the effect of pain intensity and the effects of anxiety and depression were controlled for. Future research should consider investigating the role of pain appraisal and health anxiety in the development and manifestation of insomnia concomitant to chronic pain.

Sleep-disordered breathing among women with fibromyalgia syndrome

BACKGROUND

In clinical practice, polysomnograms ("sleep studies") are seldom ordered for patients with fibromyalgia, although sleep issues dominate the symptom complex. One reason for this is the lack of understanding how information from these studies could aid clinical decisions.

METHODS

The authors conducted a chart review of one rheumatologist's community-based practice where polysomnograms were offered routinely to all women who met the American College of Rheumatology criteria for fibromyalgia. Interpretation of these standardized protocol-based polysomnograms was performed by a board-certified neurologist using standard criteria.

RESULTS

Mean age of the study subjects (n = 23) was 45 (standard deviation, 7.8) years. Median body mass index was 27 kg/m2 (interquartile range 20-48). These women had poor sleep with many arousals (median arousal index 23), apnea-hypopneas (median apnea-hypopnea index 22, interquartile range 17-30). Desaturation was common with half the patients having nadir oxygen saturation less than 87%. Restless legs were detected in polysomnograms among many women who clinically denied it (mean leg movement index 5.8).

CONCLUSIONS

A large proportion of women with fibromyalgia in a general rheumatology practice had sleep-disordered breathing, which can be detected using sleep polysomnograms. Studies are needed to examine if treatment of the commonly detected sleep apnea will have a beneficial effect on symptoms of fibromyalgia.

Exploring the role of sleep and coping in quality of life in fibromyalgia

OBJECTIVE

The objective of this study was to explore the effect of sleep and coping on health-related quality of life in fibromyalgia syndrome (FMS).

METHODS

Patients diagnosed with FMS (N=101) completed the Positive and Negative Affect Schedule, the Pittsburgh Sleep Quality Index, the COPE, and the Medical Outcomes Study--Short-Form Health Survey for the previous month.

RESULTS

Poor sleep quality was reported by 99% of participants. Sleep quality was significantly predictive of pain, fatigue, and social functioning in patients with FMS. Active coping, planning, acceptance, and seeking instrumental and emotional social support were not predictive of health outcomes in FMS. However, the use of restraint coping was predictive of poorer physical functioning.

CONCLUSION

Sleep quality has significant implications for health-related quality of life in FMS. The use of coping strategies contributed little to the models' ability to predict health outcomes in FMS. Interventions designed to improve sleep quality may help to improve health-related quality of life for patients with FMS.

How pain and analgesics disturb sleep

OBJECTIVE

Clinical experiences as well as specific investigations show that pain and sleep disturbances are closely correlated. The aims of this review are first to describe sleep disturbances related to painful medical diseases and analgesics and secondly to propose management possibilities for these sleep disturbances.

METHOD

The viewpoints presented were based mainly on objective rest activity and sleep studies using actigraphy and polysomnography.

RESULTS

Polysomnographic and actigraphic studies have described significant sleep disturbances in patients suffering from different pain disorders. These disturbances are: reduced sleep efficiency and altered sleep architecture characterized by increased wakefulness and stage 1 non-rapid eye movement sleep, associated with diminished slow wave sleep and rapid eye movement sleep. Sleep disturbances may be related to pain and to the analgesic or sedative medications administered.

CONCLUSION

If many factors, including pain, disease process per se, as well as medication, could disturb sleep, sleep disturbances may also adversely affect the natural course of the painful disease. Improving sleep quantity and quality in patients with painful disorders may break this vicious circle and as consequence enhance the patients' overall health and quality of life.