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.

Sleep, cytokines and immune function

Bi-directional communication pathways exist between the brain and the cytokine-immune-endocrine systems. The hypothalamic-pituitary axis, the efferent neuronal hypothalamus-autonomic nervous system axis, and the direct drainage of macromolecules from the brain into the blood and the lymphatic system provide a network by which the sleeping/waking brain influence bodily functions. Similarly, changes in cytokine levels in the periphery modulate the central nervous system either directly or via the vagal nerve and influence the sleeping/waking brain. In humans, circadian nocturnal sleep-daytime wakefulness is associated with changes in peripheral cytokines, cellular immune functions, and endocrines. Progesterone levels influence sleep and cellular immune functions during the menstrual cycle. The interaction between the circadian sleeping/waking brain and the cytokine-immune-endocrine system are integral to preserving homeostasis. Disorganization or loss of sleep disrupts the harmonious integration of the circadian cytokine-immune-endocrine system. However, the mechanisms of circadian sleep/wakefulness-related cytokine-immune-endocrine functions in host defence against disease remain to be determined.

Insomnia and health problems in Canadians

STUDY OBJECTIVES

The objective of this study was to determine the prevalence of, and to identify the relative contribution of selected factors associated with insomnia in the Canadian population age 15 and older.

DESIGN

Weighted analysis of cross-sectional data from the Canadian General Social Survey, Cycle 6, 1991. Prevalence estimates were calculated for the total and age-specific Canadian population age 15 and older. Multiple logistic regression techniques were employed to study the contribution of an array of sociodemographic, lifestyle, stress, and physical health factors to the experience of insomnia.

SETTING

N/A.

PARTICIPANTS

A representative sample of the Canadian household population age 15+ (n=11,924).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Twenty-four percent of the Canadian population age 15+ report insomnia. The following factors were associated with insomnia in multivariate logistic regression: female gender, being widowed or single, low education, low income, not being in the labor force, ever having smoked, life stress, specific chronic physical health problems (circulatory, digestive and respiratory disease, migraine, allergy and rheumatic disorders), pain, activity limitation and health dissatisfaction. Age was not significantly associated with insomnia.

CONCLUSIONS

Insomnia was highly prevalent among the non-institutionalized Canadian population age 15 and older. A very stressful life, severe pain and dissatisfaction with one's health demonstrated the highest odds ratios associated with insomnia. Increasing age per se and lifestyle factors were not significantly associated with insomnia.

Seasonal symptom severity in patients with rheumatic diseases: a study of 1,424 patients

OBJECTIVE

To examine the nature of seasonal symptoms, their prevalence, and differences among rheumatic disorders by examining longitudinal data over a period of up to 24 years.

METHODS

We used a questionnaire assessment of seasonal symptoms using the Seasonal Pattern Assessment Questionnaire (SPAQ) in 1,424 patients with rheumatoid arthritis (RA), osteoarthritis (OA), and fibromyalgia (FM). Clinical status was evaluated with standard assessment measures, and reported symptoms were compared with actual seasonal differences measured for periods of up to 24 years.

RESULTS

About 50% of patients with rheumatic disease reported exacerbation of rheumatic symptoms (pain, global severity, and fatigue) by seasonal changes. The presence of seasonal symptoms was not related to diagnosis or to seasonal affective disorder (SAD) symptoms, and symptoms were less common in older patients and in men. The number of symptoms and the severity of allied factors (depression, anxiety, pain, global severity, number of months with seasonal symptoms) were increased in persons with FM and/or complete SAD symptoms. Using circular statistics, the modal months for worse symptoms were December and January, and for best symptoms was July. Bimodal patterns of seasonality were identified for global severity, joint pain, fatigue, and socialization. Seasonal symptoms differed as to the degree at which they were dispersed around the 12 month circle. When pain and global severity measurements obtained over a 24 year period were analyzed, pain was slightly increased in the summer and global severity was not related to season at all. Even when patients who specifically reported worse symptoms in winter and best symptoms in summer were examined, no effect of season could be found.

CONCLUSION

Seasonal rheumatic symptoms are commonly reported across all rheumatic diseases, but appear to reflect perception rather than reality since reported symptoms do not agree with measured clinical scores. In addition, regardless of seasonal complaints, measured pain and global severity scores are not worse in winter. Although patients with FM and Season (+) patients report more severe symptoms, their pattern of reporting and their actual scores do not differ according to season compared to persons without FM or positive seasonality.

Actigraphy and parental ratings of sleep in children with attention-deficit/hyperactivity disorder (ADHD)

STUDY OBJECTIVES

To assess various sleep parameters in latency-aged children with ADHD and their normally developing peers through the use of multiple sleep measures.

DESIGN

Six sleep parameters were evaluated for two groups of children, ADHD and normal comparison. Each group consisted of 25 children (20 males, 5 females) who ranged in age from 7 to 11 years. All children underwent rigorous diagnostic procedures and the ADHD subjects were selected only if they displayed pervasiveness in their symptomatology and were medication naive. Parents completed a retrospective questionnaire which evaluated sleep problems over the past six months. Additionally, each child wore an actigraph for seven consecutive nights, and the child's parents completed a sleep diary during this time period.

SETTING

N/A.

PATIENTS OR PARTICIPANTS

N/A.

INTERVENTIONS

N/A.

RESULTS

Based on the findings from the questionnaire, parents of children with ADHD reported significantly more sleep problems than parents of normally developing children. However, the majority of these sleep differences were not verified through actigraphy or sleep diary data, with the exception of longer sleep duration for children with ADHD and parent reports that describe increased bedtime resistence. It was also found that child-parent interactions during bedtime routines were more challenging in the ADHD group.

CONCLUSIONS

Despite the possibility of intrinsic sleep problems such as longer sleep duration, results indicate that many of the sleep problems of children with ADHD may be due to challenging behaviours during bedtime routines. The reason for discrepancies among sleep studies employing objective measures as well as between retrospective and prospective measures are discussed.

Alpha sleep characteristics in fibromyalgia

OBJECTIVE

To characterize the patterns of alpha electroencephalographic sleep and their associations with pain and sleep in patients with fibromyalgia.

METHODS

Pain and sleep symptoms of 40 female patients with fibromyalgia and 43 healthy control subjects were studied before and after overnight polysomnography. Blinded analyses of alpha activity in non-rapid eye movement (non-REM) sleep were performed using time domain, frequency domain, and visual analysis techniques.

RESULTS

Three distinct patterns of alpha sleep activity were detected in fibromyalgia: phasic alpha (simultaneous with delta activity) in 50% of patients, tonic alpha (continuous throughout non-REM sleep) in 20% of patients, and low alpha activity in the remaining 30% of patients. Low alpha activity was exhibited by 83.7% of control subjects (P < 0.01). All fibromyalgia patients who displayed phasic alpha sleep, activity reported worsening of pain after sleep, compared with 58.3% of patients with low alpha activity (P < 0.01) and 25.0% of patients with tonic alpha activity (P < 0.01). Postsleep increase in the number of tender points occurred in 90.0% of patients with phasic alpha activity, 41.7% of patients with low alpha activity, and 25.0% of patients with tonic alpha activity (P < 0.01). Self ratings of poor sleep were reported by all patients with phasic alpha activity, 58.3% of patients with low alpha activity (P < 0.01), and 12.5% of patients with tonic alpha activity (P < 0.01). Patients with phasic alpha activity reported longer duration of pain than patients in other subgroups (P < 0.01). Additionally, patients with phasic alpha sleep activity exhibited less total sleep time than patients in other subgroups (P < 0.05), as well as lower sleep efficiency (P < 0.05) and less slow wave sleep (P < 0.05) than patients with a tonic alpha sleep pattern.

CONCLUSION

Alpha intrusion during sleep can be of different patterns. Phasic alpha sleep activity was the pattern that correlated better with clinical manifestations of fibromyalgia.

The contribution of sleep medicine to the assessment of the tired patient

Tiredness is one of the most common complaints that confront the clinician. Yet the nature of the symptom and its implications for sleep-related disorders is poorly understood. This review provides the clinician with an understanding of the difficulties inherent in assessing the tired patient. The complaint of tiredness is commonly an expression of sleepiness and fatigue that arises as the result of sleep-wake-related disorders. Behavioural and physiological procedures are described in the assessment and management of sleepiness and fatigue in primary sleep disorders and sleep-related medical and psychiatric disorders. Improvement in the diagnosis and management of the fatigued or sleepy patient requires that residents in psychiatry and neurology be exposed to the behavioural and physiological techniques of sleep medicine as part of their post-graduate training programs.

Brain-blood permeability: TNF-alpha promotes escape of protein tracer from CSF to blood

The objective of this study was to determine the effect of tumor necrosis factor (TNF)-alpha on the efflux of protein from the central nervous system to blood based on assessing the clearance of radiolabeled albumin from the cerebrospinal fluid (CSF) to blood in rats. (125)I-labeled human serum albumin ((125)I-HSA) was injected into a lateral ventricle, and venous blood was sampled hourly to determine the basal CSF protein clearance into the blood. After this, rats were intraventricularly infused with 10 microliter TNF-alpha and 10 microliter (131)I-HSA (n = 6) or 10 microliter saline and 10 microliter (131)I-HSA (n = 6). Venous blood was sampled hourly for 3 h. (131)I-HSA tracer recovery increased threefold in the venous blood and was significantly higher in the spleen, muscles, and skin in animals treated with TNF-alpha. No significant changes were observed in control animals treated with saline. The data suggest that TNF-alpha promotes the clearance of protein macromolecules from the CSF to the venous blood.

The relationship of lymphocytes in blood and in lymph to sleep/wake states in sheep

Based on evidence of a role for immune-associated cytokines in sleep induction, we investigated the possibility that lymphocyte distribution between blood and lymphatics could be altered as a function of sleep/wakefulness. Blood and lymph sample were obtained from 5 sheep during periods of slow-wave sleep and wake. Blood and lymph lymphocytes were phenotyped using monoclonal antibodies against CD4, CD8, gd T-cell receptors and a surface marker on ovine B cells. Lymph flow rates and efferent lymph cell output were measured. Lymph flow and prescapular efferent lymphocyte output were reduced during sleep compared to wakefulness (p<0.0005). There were no differences in lymphocyte subsets in the blood and in the lymph during sleep/wake brain states. These data indicate that migration of cells in the peripheral lymphatic system is altered during sleep compared to wakefulness.

Sleep problems in children with attention-deficit/hyperactivity disorder: impact of subtype, comorbidity, and stimulant medication

OBJECTIVE

To determine the relationship of sleep problems to attention-deficit/hyperactivity disorder (ADHD), diagnostic subtype, comorbid disorders, and the effects of stimulant treatment.

METHOD

On the basis of clinical diagnostic interviews, children aged 6 to 12 years were assigned to 4 groups: unmedicated ADHD (n = 79), medicated ADHD (n = 22), clinical comparison (n = 35), and healthy nonclinical comparison (n = 36). These groups were compared on 2 sleep questionnaires completed by the parents that assessed current sleep problems and factors associated with sleep difficulties (i.e., sleep routines, sleep practices, child and family sleep history).

RESULTS

Factor analysis revealed 3 sleep problem categories: dyssomnias, parasomnias, and sleep-related involuntary movements. Linear regression analyses showed that (1) dyssomnias were related to confounding factors (i.e., comorbid oppositional defiant disorder and stimulant medication) rather than ADHD; (2) parasomnias were similar in clinical and nonclinical children; and (3) the DSM-IV combined subtype of ADHD was associated with sleep-related involuntary movements. However, sleep-related involuntary movements were more highly associated with separation anxiety.

CONCLUSIONS

The results suggest that the relationship between sleep problems and ADHD is complex and depends on the type of sleep problem assessed as well as confounding factors such as comorbid clinical disorders and treatment with stimulant medication.

Adenosine: a mediator of interleukin-1beta-induced hippocampal synaptic inhibition

Interleukin-1 (IL-1) is a pleotrophic cytokine implicated in a variety of central activities, including fever, sleep, ischemic injury, and neuromodulatory responses, such as neuroimmune, and neuroendocrine interactions. Although accumulating evidence is available regarding the expression pattern of this cytokine, its receptors in the CNS, and its mechanistic profile under pathological levels, it is unclear whether this substance modulates central neurons under physiological concentrations. Further, in light of the functional and spatial overlap between the adenosine and IL-1 systems, it is not known whether these two systems are coupled. We report here that, in rat brain slices, brief application of sub-femtomolar IL-1beta causes a profound decrease of glutamate transmission, but not GABAergic inhibition, in hippocampal CA1 pyramidal neurons. This decrease by IL-1beta is prevented by pharmacological blockade of adenosine A1 receptors. In addition, we show that IL-1beta failed to suppress glutamate transmission at room temperature. Because the production and release of adenosine in the CNS is thought to be metabolically dependent, this observation suggests that one of the functions of IL-1beta is to increase the endogenous production of adenosine. Together, these data suggest for the first time that sub-femtomolar levels of IL-1 can effectively modulate glutamate excitation in hippocampal neurons via an adenosine-dependent mechanism.

Intracerebroventricular injection of TNF-alpha promotes sleep and is recovered in cervical lymph

Recent studies have shown that the central nervous system (CNS) communicates with the periphery by the drainage of cerebrospinal fluid and brain interstitial fluid into blood and lymph. We hypothesized that tumor necrosis factor (TNF)-alpha would not only influence the CNS by promoting sleep but also would be directly transmitted into the peripheral immune system. Five hundred nanograms of 125I-labeled TNF-alpha were injected into the lateral ventricles of the brain of six sheep and sampled in venous blood and cervical and prescapular lymph every 30 min for 6 h. 125I-TNF-alpha was measured in lymph nodes and control fat, skin, and muscle tissues 6 h postinjection. 125I-TNF-alpha was detected in the cervical lymphatics within the first 30 min and peaked within 2-3 h. 125I-TNF-alpha counts were elevated in the nodes of the head and neck region. Polysomnographic recordings of four animals showed that TNF-alpha induced a significant increase in slow-wave sleep at postinjection hours 4 and 5. CNS TNF-alpha and its direct drainage into the lymphatic system may influence both the sleeping/waking brain and peripheral immune functions.

Determinants of disability after a work related musculetal injury

OBJECTIVE

Musculoskeletal soft tissue injuries consume considerable resources in personal suffering, medical care, work absenteeism, and compensation benefits. Our aim was to determine specific clinical and behavioral factors that prognostically influence return to work following musculoskeletal work related injuries.

METHODS

A longitudinal cohort study was conducted on 148 randomly selected workers who had not returned to work in 3 months following musculoskeletal soft tissue injury. The cohort was identified from the files of the Workers' Compensation Board of Ontario, Canada. The workers were interviewed and assessed at 3, 9, 15, and 21 months after injury. The WHO Classification of Impairment, Disabilities and Handicap was used as the conceptual framework. The analysis employed a proportional hazards regression model with allowance for time dependent covariates.

RESULTS

The rate of return to work for men was 1.5 times that for women, and 20% less for every 10 year increase in age. Controlling for sex and age, psychological distress and functional disability were associated with a slower rate of return to work. The rate of return to work for workers who were provided with modified jobs was 2 times higher than for those with no such accommodation in employment.

CONCLUSION

The negative effect of psychological distress and functional disability on return to work rates must be considered in the design and delivery of rehabilitation programming for workers with musculoskeletal soft tissue injuries. The employer's provision of a "modified job" is important in the prevention of continued disability.

Comparative effects of nefazodone and fluoxetine on sleep in outpatients with major depressive disorder

BACKGROUND

Sleep disturbances are common in major depressive disorder. In previous open-label trials, nefazodone improved sleep continuity and increased rapid eye movement (REM) sleep, while not affecting stage 3/4 sleep or REM latency: in contrast, fluoxetine suppressed REM sleep. This study compared the objective and subjective effects of nefazodone and fluoxetine on sleep.

METHODS

This paper reports combined results of three identical, multisite, randomized, double-blind, 8-week, acute-phase trials comparing nefazodone (n = 64) with fluoxetine (n = 61) in outpatients with nonpsychotic major depressive disorder and insomnia. Sleep electroencephalographic (EEG) recordings were gathered at baseline and weeks 2, 4, and 8. Clinical ratings were obtained at weeks 1-4, 6, and 8.

RESULTS

Nefazodone and fluoxetine were equally effective in reducing depressive symptoms; however, nefazodone differentially and progressively increased (while fluoxetine reduced) sleep efficiency and reduced (while fluoxetine increased) the number of awakenings in a linear fashion over the 8-week trial. Fluoxetine, but not nefazodone, prolonged REM latency and suppressed REM sleep. Nefazodone significantly increased total REM sleep time. Clinical evaluations of sleep quality were significantly improved with nefazodone compared with fluoxetine.

CONCLUSIONS

Nefazodone and fluoxetine were equally effective antidepressants. Nefazodone was associated with normal objective, and clinician- and patient-rated assessments of sleep when compared with fluoxetine. These differential sleep EEG effects are consistent with the notion that nefazodone and fluoxetine may have somewhat different modes and spectra of action.

Sleep disturbances in children with attention-deficit/hyperactivity disorder

OBJECTIVE

To evaluate the relationship between sleep disturbances and attention-deficit/hyperactivity disorder (ADHD).

METHOD

Empirical research published since 1970 on sleep disturbances in children with ADHD was systematically reviewed. A "box-score" approach was used to examine consistency of findings across the studies, which used different outcome measures.

RESULTS

Although subjective accounts of sleep disturbances in ADHD were prevalent, objective verification of these disturbances was less robust. The only consistent objective findings were that children with ADHD displayed more movements during sleep but did not differ from normal controls in total sleep time. An additional finding was that stimulant medication led to changes in the children's sleep (e.g., prolonged sleep latency, increased length of onset to first rapid eye movement cycle), but these changes were believed to be nonpathological.

CONCLUSIONS

The exact nature of the sleep problems in children with ADHD remains to be determined. Many of the relevant issues have not been adequately addressed. Factors such as poorly defined diagnostic groups, small sample sizes, few studies, and methodological and procedural limitations make it difficult to determine the relationship between ADHD and sleep problems.

Sleep, daytime symptoms, and cognitive performance in patients with fibromyalgia

OBJECTIVE

To assess sleep, daytime symptoms, and cognitive performance in patients with fibromyalgia (FM).

METHODS

Ten female patients with FM (mean age 32 yrs) and a matched, noncomplaintive comparison group (n = 9; mean age 30 yrs) spent 2 nights in the sleep laboratory. After the 2nd night, subjects completed a computerized 20 min battery of self-assessment and performance tests at hourly intervals from 07:00 to 20:00 h.

RESULTS

Patients with FM spent more time in stage 1 sleep; however, there were no group differences on any other sleep measures. They reported greater sleepiness, more fatigue, more pain, more negative mood, and lower accuracy on performance tasks across a 14 h day. The FM group was slower in speed, but not impaired in accuracy, on performance of complex tasks, i.e., grammatical reasoning, serial addition/subtraction, and a simulated multi-task office procedure.

CONCLUSION

Patients with FM have diurnal impairment in speed of performance on complex cognitive tasks, which accompany light stage 1 electroencephalographic (EEG) sleep and their experience of diffuse pain and nonrestorative sleep symptoms of sleepiness, fatigue, and negative mood.

Randomized, double-blind, placebo-controlled crossover trial of modafinil in the treatment of excessive daytime sleepiness in narcolepsy

Seventy-five patients meeting international diagnostic criteria for narcolepsy enrolled in a 6-week, three-period, randomized, crossover, placebo-controlled trial. Patients received placebo, modafinil 200 mg, or modafinil 400 mg in divided doses (morning and noon). Evaluations occurred at baseline and at the end of each 2-week period. Compared with placebo, modafinil 200 and 400 mg significantly increased the mean sleep latency on the Maintenance of Wakefulness Test by 40% and 54%, with no significant difference between the two doses. Modafinil, 200 and 400 mg, also reduced the combined number of daytime sleep episodes and periods of severe sleepiness noted in sleep logs. The likelihood of falling asleep as measured by the Epworth Sleepiness Scale was equally reduced by both modafinil dose levels. There were no effects on nocturnal sleep initiation, maintenance, or architecture, nor were there any effects on sleep apnea or periodic leg movements. Neither dose interfered with the patients' ability to nap voluntarily during the day nor with their quantity or quality of nocturnal sleep. Modafinil produced no changes in blood pressure or heart rate in either normotensive or hypertensive patients. The only significant adverse effects were seen at the 400-mg dose, which was associated with more nausea and more nervousness than either placebo or the 200-mg dose. As little as a 200-mg daily dose of modafinil is therefore an effective and well-tolerated treatment of excessive daytime somnolence in narcoleptic persons.

Regional differences in technetium-99m-ECD clearance on brain SPECT in healthy subjects

The aim of this study was to evaluate the in vivo stability of ECD brain SPECT.

METHODS

Twenty normal volunteers (35.4 +/- 9.1 yr) each had six ECD scans at 30, 60, 120, 240, 360 and 480 min postinjection. Each scan was acquired for 24 min using a triple-head SPECT system. Average counts per pixel were measured from frontal, temporal, parietal, occipital, cerebellum, basal ganglia, thalamus and white matter regions. ECD clearance rates were calculated by fitting regional time activity data to a monoexponential equation. Regional gray-to-white matter (G/W) and gray-to-cerebellum (G/C) ratios were calculated for each scan. Analysis of variance was used to compare regional ECD clearance and ratio measurements.

RESULTS

The average ECD clearance was 4.3%/hr. There was a significant regional variation in the ECD clearance, being higher for occipital (6.34%/hr) but lower for both white matter (2.39%/hr) and thalamus (2.45%/hr). Both G/W and G/C ratios showed a significant regional variation with time. The overall G/W ratio was 2.13 at 30 min and became progressively lower after 2 hr, reaching 1.78 at 8 hr. All regional G/W ratios declined with time except for thalamus where it remained constant at 2.15. The overall G/C ratio was 0.984 at 30 min but it declined after 4 hr, reaching 0.955 at 8 hr. All regional G/C ratios declined with time except for thalamus where it increased progressively from 0.955 to 1.120 at 8 hr.

CONCLUSION

ECD clears from normal brain slowly and shows a significant regional variation. As a result, G/W contrast begins to decrease after 2 hr and the gray-matter activity pattern becomes significantly different after 4 hr. Therefore, the optimal imaging time may be between 30-120 min. However, images obtained up to 4 hr still maintain the initial gray-matter activity pattern.

Dopamine D2 receptors quantified in vivo in human narcolepsy

Assays in brain tissues from humans suffering from narcolepsy, and from genetically narcoleptic dogs have suggested that dopamine function may be disturbed in this condition. We have used the specific D2 receptor ligand N-(3-[18F]fluoropropyl)-spiperone and positron tomography to study a group of 6 well-characterized medication-free, HLA-DR2 DRW15 DW6-positive narcoleptic patients and a group of age- and sex-matched control individuals during life. We found no difference in striatal D2 receptor binding between these two groups. These results suggest that narcolepsy is not associated with alterations in D2 receptor density and affinity.

The clinical course of musculoskeletal pain in empirically derived groupings of injured workers

The purpose of this paper is to examine the clinical course of musculoskeletal, soft tissue, work-related injury. An analysis of empirically derived sub-groupings of workers based on prognostically important pain and disability variables assessed on enrollment into the study is described. Multidimensional time-dependent profiles are used to characterize stages in the development of pain, impairment, disability and handicap. The clinical course over the 18 months of study of the three subgroups is examined. The conceptual model, used to examine the workers' changing responses over time, is based on the World Health Organization Classification of Impairments, Disabilities and Handicaps (1980). Methodologically, the study employed a prospective longitudinal design. A randomly selected cohort of workers who had not returned to work by 3 months post-injury were identified from the files of the Workers' Compensation Board of Ontario. The workers were interviewed and examined on enrollment into the study at 3 months and subsequently at 9 months, 15 months and 21 months after injury. The outcomes were return to work or continued work disability. The results are based on those 104 workers who attended all four assessment periods. K means clustering was used to identify homogenous subgroups of workers. Repeated measures ANOVAs were used to characterize the stages of development of pain, impairment, disability and handicap. Duncan's multiple range test was used to compare pairs of means at each assessment period. Cluster groupings, based on three prognostically important clinical variables, number of pain sites, pain behavior and functional disability, obtained at the initial assessment were valid predictors of the number of days to return to work and total number of days on work disability. Prognostic stratification can enhance confidence in predictive decisions of clinical practice and improve clinical trials of therapy.

The effects of bright light treatment on the symptoms of fibromyalgia

OBJECTIVE

To investigate the effects of bright light treatment on the symptoms of pain, mood, and sleep in patients with fibromyalgia (FM) reporting seasonality of symptoms on the Seasonal Pattern Assessment Questionnaire (SPAQ).

METHODS

A randomized 10 week crossover study compared the effects of 4 weeks of "visible electromagnetic fields" (EMF) (light condition; mean 4750 lux, SD 2337 lux) to 4 weeks of "nonvisible EMF" (no light condition) in 14 patients with FM having a minimum SPAQ score of 11. The light visor system (Bio-Brite) was fitted with an opaque filter for the "nonvisible EMF" control condition.

RESULTS

No significant differences were found between treatment conditions on tenderness measured with dolorimetry, self-ratings of sleep, pain, mood, and global measures. Mood was not related to pain or sleep. There was significant reduction in depression scores and subjective pain, but increased tenderness and nocturnal awakenings related to time.

CONCLUSION

The were no significant differences between the light and no light conditions on pain, mood, or sleep in patients with FM reporting seasonality of symptoms. No relationship was found between mood and the symptoms of FM (i.e., pain, sleep, and fatigue).

Periodic K-alpha sleep EEG activity and periodic limb movements during sleep: comparisons of clinical features and sleep parameters

The K-alpha sleep electroencephalographic (EEG) phenomenon is characterized by periodic (approximately 20-40 seconds) K-complexes, immediately followed by alpha-EEG activity (7.5-11 Hz) of 0.5- to 5.0-second duration. A group of 14 subjects with the periodic K-alpha anomaly was found to have a similar distribution pattern of interevent intervals as compared with previously published data for sleep-related periodic limb movements during sleep (PLMS). Sleep parameters and somatic symptoms of 30 patients with K-alpha were compared with 30 patients with PLMS. The periodic K-alpha group was predominantly female, younger, exhibiting more slow-wave sleep, gastrointestinal symptoms and muscular complaints and fewer movement arousals on overnight polysomnography. The K-alpha group presented uniformly with complaints of unrefreshing sleep, often associated with fibromyalgia and chronic fatigue syndrome. The PLMS group was predominantly male, showed greater sleep disruption and presented with a variety of sleep-related symptoms.

The effect of zolpidem in patients with fibromyalgia: a dose ranging, double blind, placebo controlled, modified crossover study

OBJECTIVE

This dose ranging, double blind, placebo controlled, modified crossover study examined whether zolpidem would improve the disturbed sleep, fatigue, mood and pain symptoms in patients with fibromyalgia (FM).

METHODS

All symptoms were rated over 4 nights and 4 conditions for 16 consecutive nights during which 19 patients (mean age 42 years) randomly received placebo or zolpidem 5 mg, 10 mg, or 15 mg at bedtime.

RESULTS

The 16 patients who completed the study reported no significant differences in ratings of pain, number of tender points, mood, sleep quality, morning fatigue, morning sleepiness or ability to concentrate. Compared to the placebo group, patients treated with zolpidem recorded significantly reduced time to fall asleep, increased sleep time, reduced awakenings, overall improvement in sleep and daytime energy, but a lower rating for evening energy. Zolpidem at the 10 mg dose was rated most acceptable for sleep. Adverse incidence rates were highest in the placebo group and lowest in the zolpidem 10 mg group. One person withdrew because of migraine while taking zolpidem 10 mg.

CONCLUSION

Short term treatment with zolpidem (5 to 15 mg) does not affect the pain of FM, but is useful for sleep and daytime energy in this patient population.

Sleep-related violence

We hypothesized that sleep-related violent behavior associated with parasomnias occurs as the result of a diathesis and is precipitated by stressors and mediated by disturbed nonrapid eye movement (NREM) sleep physiology. Sixty-four consecutive adult patients (mean age 30 years) who were investigated for sleepwalking or sleep terrors were categorized according to clinical history into three groups: serious violence during sleep to other people or to property or self (n = 26); harmful, but not destructive behavior (n = 12); and nonviolent behavior (n = 26). Log linear analysis showed that a diathesis (childhood parasomnia and/or family history of parasomnia) and a stressor (psychologic distress, substance abuse and sleep schedule disorder) predicted the presence of sleepwalking or night terror. Serious violent acts were more likely to occur with males (p < 0.004) who showed sleep schedule disorder (p < 0.03). Both harmful and serious violent sleep behavior occurred with drug abuse (p < 0.009). In comparison to all other groups, those who were violent to other people were males who experienced more stressors (p < 0.02), drank excessive caffeinated beverages, abused drugs (p < 0.03) and showed less stage 4 sleep (p < 0.02) and less alpha (7.5-11 Hz) electroencephalogram NREM sleep (p < 0.02) on polysomnography. Being male and having < 2% stage 4 sleep provided 89% sensitivity, 80% specificity and 81% diagnostic accuracy for individuals who were violent to others. The forensic implications of these findings are discussed.

Diurnal sleep/wake-related immune functions during the menstrual cycle of healthy young women

Animal and human studies have related the sleeping/waking brain to the immune system. Because women are more susceptible to certain immunological illnesses, and sex steroids regulate immune functions, it was investigated whether the diurnal sleep/wake pattern of aspects of cellular immune functions and interleukin-1 (IL-1) and IL-2-like activities differed during low and high progesterone phases of the menstrual cycle. Eleven healthy women, mean age 24 y, were assessed over 24 h with serial venous blood samples. Peripheral blood monocytes were assayed for mitogen responses, i.e. phytohemagglutin (PHA) and pokeweed (PWM) and natural killer (NK) cell activities. Plasma was assayed for IL-1 and IL-2-like activities, cortisol and progesterone. Data were standardized by Z transformation and analysed by repeated-measures analysis of variance by comparing high (N = 5) vs. low (N = 6) progesterone phases. During the high progesterone phase, delayed slow-wave sleep (SWS) onset time and reduced amount of SWS was accompanied by a delay in the decline of NK cell activity, but rise in PHA activity following sleep onset. With the low progesterone phase, the pattern was similar to men with an early sleep decline in NK cell and late sleep rise in PHA activities. PWM rose during the night and plasma IL-1-like activity peaked during midday and during nocturnal sleep irrespective of the amount of progesterone. Slow-wave sleep and sleep-related NK cell and PHA activities differed over the menstrual cycle, but not PWM response. Increases in plasma IL-1 functions during midday and night are consistent with predisposition to sleepiness during these times.

Sleep and the immune system

Recent animal and human studies show that the immune-neuroendocrine-thermal operations of the body are intimately linked to the sleeping-waking brain. In humans, the diurnal pattern of aspects of both peripheral cellular immune functions, e.g. natural killer cell cytotoxicity, and of cytokines, e.g. interleukin-1, are related to sleep. The harmonious interrelationships of the circadian patterns of the immune, neuroendocrine, thermal and brain functional activities are important for the cause and function of sleep. Disorganization or loss of the sleep-wake system is accompanied by alteration of the immunological, neuroendocrine and thermal functions of the body, and contributes to pathological processes such as infectious disease.

Sleep, neuroimmune and neuroendocrine functions in fibromyalgia and chronic fatigue syndrome

The justification for disordered chronobiology for fibromyalgia and chronic fatigue syndrome (CFS) is based on the following evidence: The studies on disordered sleep physiology and the symptoms of fibromyalgia and CFS; the experimental studies that draw a link between interleukin-1 (IL-1), immune-neuroendocrine-thermal systems and the sleep-wake cycle; studies and preliminary data of the inter-relationships of sleep-wakefulness, IL-1, and aspects of peripheral immune and neuroendocrine functions in healthy men and in women during differing phases of the menstrual cycle; and the observations of alterations in the immune-neuroendocrine functions of patients with fibromyalgia and CFS (Moldofsky, 1993b, d). Time series analyses of measures of the circadian pattern of the sleep-wake behavioural system, immune, neuroendocrine and temperature functions in patients with fibromyalgia and CFS should determine whether alterations of aspects of the neuro-immune-endocrine systems that accompany disordered sleep physiology result in nonrestorative sleep, pain, fatigue, cognitive and mood symptoms in patients with fibromyalgia and CFS.

Fibromyalgia and disability. Report of the Moss International Working Group on medico-legal aspects of chronic widespread musculoskeletal pain complaints and fibromyalgia

The present article is the result of a working group conference held in Moss, Norway, in June 1993, financed by the Royal Norwegian Ministry of Health and Social Affairs. Its purpose was to review and focus upon problems and needs related to the medico-legal aspects of fibromyalgia and chronic widespread musculoskeletal complaints: thus to define directions for future work on issues which have generally not been addressed within the medical community. Our report describes specific problems in this area in regard to definition, evaluation and recommendation, and in currently available work and disability statistics. We have recommended international efforts to establish research programs through organizations such as the International Social Security Association and the World Health Organization. While our recommendations call for research into medico-legal interactions, causes and pathogenic mechanisms, prevention and treatment are also key and relevant concerns in the medico-legal setting.

The probability of recovery and return to work from work disability as a function of time

This paper describes a prospective longitudinal cohort study of musculoskeletal soft tissue pain impairment following a work related injury. It focuses on specific, univariate prognostic factors indicated in previous research studies that might affect the likelihood that injured workers will return to work or remain on work disability at any point in time. These factors include gender, age, return to work attempts and site of injury. Life table analysis was used to model the probability of work disability. The results showed that different disability and return to work patterns emerged for males and females. Males were more likely to return to work; however, females had a higher probability than males of remaining at work once they returned to work. Older workers had the highest probability of being off work any given number of days after injury; were less likely to return to work, and if they did, had a higher probability of becoming disabled again. Efforts to return early to work contributed to a decrease in overall work disability. Workers with low back injuries had a greater likelihood of recurrence compared to injuries at other body sites.

Central nervous system and peripheral immune functions and the sleep-wake system

This paper reviews the relationship of aspects of the immune system to the sleep-wake system in animals and humans. In addition to the influence of certain cytokines such as interleukin-1 (IL-1) on the sleeping-waking brain, circadian measures of plasma IL-1 and peripheral immune cellular functions, for example, natural killer cell activities and cortisol are related to the sleep-wake system in humans. Changes in the circadian patterns of immune functions over the menstrual cycle are associated with the amount of progesterone and slow wave sleep. The harmonious inter-relationship of the circadian pattern of the immune, endocrine and sleep-wake systems may be important in the cause and functions of sleep.

Chronobiological influences on fibromyalgia syndrome: theoretical and therapeutic implications

A review of the evidence from diurnal physiological, seasonal environmental and prospective studies of social-behavioural functions suggest that a chronobiological theoretical model provides a comprehensive basis for the dynamics of central nervous system mechanisms, the assessment and the management of patients with fibromyalgia. The chronobiological model stresses the importance of temporal variation and the factors that influence and govern recurrent patterns of biological functions and behaviour that determine health and illness. Finally, the theory allows for an integrated study of brain, behaviour and somatic functions over time and emphasizes that such a comprehensive approach is core to any therapeutic intervention.

Litigation, sleep, symptoms and disabilities in postaccident pain (fibromyalgia)

Twenty-four patients with chronic postaccident pain were studied with self-rating symptom checklists, polysomnography and disability questionnaires. All except one had fibromyalgia. Eight had litigation resolved (R) while 16 had medicolegal claims still unresolved (UR). Patients from the R group were older, with a longer duration of symptoms and more occupation handicap compared to those from the UR group. There were no significant differences between the 2 groups in other demographic data, nature of accident, symptoms, polysomnographic findings and disability. Medicolegal claim status in these patients did not differentiate the outcome of their symptoms. Implications for litigation, treatment and further studies are discussed.

Evaluation of daytime sleepiness

In summary, the evaluation of the tired patient requires an awareness of the various meanings of tiredness. Furthermore, it is important to differentiate normal sleepiness that is a product of circadian rhythm variation in vigilance from pathologic sleepiness. Sleepiness that results from faulty habits, e.g., altered sleep scheduling, drugs, or sleep restriction, can be readily discerned with the aid of a sleep-wake diary. Because subjective sleepiness is often unappreciated, especially in patients with sleep apnea, methods that rely on self-ratings of the severity of sleepiness, e.g., visual analogue scale, 10-cm line, or SSS may not coincide with performance tasks, observer assessments, or such physiologic methods as the MSLT. Less commonly employed neurophysiologic methods include pupillometry and averaged evoked potentials. On the other hand, the MSLT is commonly used for the detection of physiologic sleepiness. Moreover, it is helpful in evaluating response to treatment. A variation of the MSLT, the MWT, which instructs the individual to remain awake, does not discriminate between sleep onset times for wakefulness and the MSLT for sleepiness in normal subjects. The MWT may be useful for the assessment of treatment responses for excessive daytime sleepiness, e.g., narcolepsy, and for determining the frequency of daytime sleep episodes. The differences that have been observed between behavioral measures and physiologic measures of sleepiness suggest that these techniques assess different aspects of sleepiness. HLA typing (DR2, DQw1) has been shown to be a useful method for corroborating narcolepsy-cataplexy, but the antigens are neither specific for the disorder nor for sleepiness alone.

Sleep, Epstein-Barr virus infection, musculoskeletal pain, and depressive symptoms in chronic fatigue syndrome

Sleep physiology, viral serology and symptoms of 14 patients with chronic fatigue syndrome (CFS) were compared with 12 healthy controls. All patients described unrefreshing sleep and showed a prominent alpha electroencephalographic nonrapid eye movement (7.5-11.0 Hz) sleep anomaly (p less than or equal to 0.001), but had no physiologic daytime sleepiness. There were no group differences in Epstein-Barr virus (EBV) antibody titers. The patient group had more fibrositis tender points (p less than 0.0001), described more somatic complaints (p less than 0.0001), and more depressive symptoms (p less than 0.0001). Patients with CFS do not show evidence for a specific chronic EBV infection, but show altered sleep physiology, numerous tender points, diffuse pain, and depressive symptoms. These features are similar to those found in fibromyalgia syndrome.

The Drosophila per gene homologs are expressed in mammalian suprachiasmatic nucleus and heart as well as in molluscan eyes

This study presents evidence for the conservation of Drosophila per gene homologs in mammalian DNA and for their expression in a number of tissues which are involved in various aspects of circadian timekeeping. Distinct 5 kb sequences, which hybridized to a non repetitive fragment of the Drosophila per gene under stringent conditions, were detected by Southern blotting. Sequences homologous to per gene of Drosophila were also amplified from rat and mouse brain cDNA libraries and from a mouse anterior hypothalamus and human hypothalamus libraries. Degenerate PCR primer design was based on conserved segments of the per protein. The per homologs were shown directly (by RT-PCR) to be expressed in hamster and mouse SCN, in hamster heart and in Aplysia and Bulla eyes.

Growth hormone and cortisol secretion in relation to sleep and wakefulness

The study investigated secretory patterns of growth hormone (GH) and cortisol in relation to sleep and wakefulness. Plasma hormone levels were monitored in 10 young men during baseline waking and sleeping, during 40 hours of wakefulness, and during sleep following deprivation. The normal nocturnal GH surge disappeared with sleep deprivation, and was intensified following sleep deprivation. Mean GH levels were higher during slow wave sleep (SWS) compared with other sleep stages. During sleep after deprivation, GH secretion was prolonged, and second GH peaks occurred in three subjects which were not associated with SWS. Average 24-hour cortisol levels were not altered by sleep deprivation or sleep following deprivation, but the nocturnal cortisol rise occurred approximately one hour earlier with sleep deprivation and one hour later with resumed sleep, compared to baseline. This effect on the timing of the rise is consistent with an initial inhibitory influence of sleep on cortisol secretion. The results demonstrate that: the nocturnal growth hormone surge is largely sleep-dependent; temporal associations between GH and SWS are not reliable after sleep deprivation; although the cortisol rhythm is not sleep-dependent, the timing of the cortisol rise may be influenced by sudden changes in the sleep-wake schedule.

Sleep physiology and psychological aspects of the fibrositis (fibromyalgia) syndrome

Fibrositis (fibromyalgia) patients were compared with normal controls in terms of electrophysiology (EEG), self-report indicants of awakening, quality of sleep, behaviourally signalled awakenings, and Symptom Check List 90R (SCL-90R) scores. The results differentiated fibrositis patients from normal controls in terms of SCL-90R scores, with fibrositis patients showing significantly more psychopathology. Fibrositis patients had more alpha EEG sleep and less REM and Stage 1 sleep. They were better able to recall their behaviourally signalled awakenings the following morning and reported qualitatively less satisfying sleep than the normal controls. The alpha EEG sleep anomaly may reflect a vigilant arousal state during nocturnal sleep and result in the daytime experience of unrefreshing sleep, psychologic distress, that re-enforces the perpetuation of the sleep-related symptoms.

The effects of cyclobenzaprine on sleep physiology and symptoms in patients with fibromyalgia

A double blind, placebo controlled, crossover design study examined overnight sleep physiology, pain, fatigue, and mood symptoms in 12 patients with fibromyalgia treated with cyclobenzaprine. Nine patients completed the study. Patients receiving cyclobenzaprine showed a decrease in evening fatigue (F = 4.7, p less than 0.05) and an increase in total sleep time (F = 4.4, p less than 0.05). Pain, including tender point count and dolorimetry, mood ratings, and alpha non-REM EEG sleep anomaly were unchanged by cyclobenzaprine.

Tourette syndrome: a follow-up study

We describe a long-term follow-up study (1-15 years) of 33 patients with Tourette syndrome who were treated with pimozide (2-18 mg), haloperidol (2-15 mg), or no drugs. Both drugs produced comparable relief of symptoms at follow up; however, significantly more patients on haloperidol (eight of 17), compared with those on pimozide (one of 13), discontinued treatment (p less than or equal to 0.05). Haloperidol produced significantly more acute dyskinesias/dystonias than pimozide (p less than or equal to 0.03); otherwise, the adverse effect profile was similar for the two drugs. In particular, we found no increased incidence of ECG abnormalities in patients treated with pimozide. A prospective, randomized, double-blind crossover trial is required to determine whether there are significant differences in efficacy between pimozide and haloperidol in treatment of Tourette's disorder.

Sleep-wake mechanisms in fibrositis

Patients with fibrositis experience chronophysiologic changes during sleep and when they are awake. A wide variety of factors contribute to this phenomenon. Chronobiologic research in the area of sleep-wake mechanisms need to be undertaken.

Nonrestorative sleep and symptoms after a febrile illness in patients with fibrositis and chronic fatigue syndromes

This review summarizes the physiologic and clinical evidence that shows nonrestorative sleep to be associated with chronic fatigue and diffuse myalgia after a flulike illness. Such a febrile illness may trigger alteration in sleep-wake brain and immune functions in patients with fibrositis or chronic fatigue syndromes.

Effects of sleep deprivation on human immune functions

The effect of 40 h of wakefulness on a variety of immunological parameters in the peripheral blood from 10 normal male subjects was studied. Sleep deprivation led to enhanced nocturnal plasma interleukin 1-like and interleukin 2-like activities. The rise in nocturnal response of lymphocytes to pokeweed mitogen stimulation during a normal 24 h sleep-wake cycle was delayed by sleep deprivation, but the response to the phytohemagglutinin mitogen was unaffected. With resumed nocturnal sleep, there was a prolonged decline in natural killer cell activity (measured as spontaneous cytolytic activity for human tumor cells) and return of an increased response to pokeweed mitogen. The altered patterns in immune functions occurred independently of the cortisol circadian rhythm, which remained unchanged.

Sleep and fibrositis syndrome

Chronic diffuse myalgia, localized areas of tenderness, fatigue, and unrefreshing sleep are related to a physiologic arousal disorder within sleep, that is, the alpha EEG NREM sleep anomaly. This sleep physiologic disorder, nonrestorative sleep, and symptoms of fibrositis syndrome are shown to occur with psychologic, environmental, and physiologic distress conditions. Pathogenic mechanisms that link nonrestorative sleep physiology to pain and fatigue may involve metabolic dysfunction of the brain with sleep-related alteration in immunologic and neurotransmitter functions (serotonin, substance P, endorphins). These sleep-related mechanisms have important implications for the understanding and treatment of fibrositis/fibromyalgia syndrome.