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

Sleep disturbances linked to fibromyalgia

Fibromyalgia (FM) is a chronic muscle disorder characterized by muscle aches and pain of varying intensities. Sleep disturbances have been recognized as one of the probable causes of this disorder. Pharmacological and nonpharmacological approaches are often used to manage the symptoms of sleep disturbances. This article provides a brief background on FM, discusses the physiology of sleep, reviews the current literature on sleep disturbances associated with FM, provides insight to interventions that might be beneficial given the data available, and recommends ongoing research.

Sleep and pain

Noxious stimuli and painful disorders interfere with sleep, but disturbances in sleep also contribute to the experience of pain.Chronic paroxysmal hemicrania and possibly cluster headaches are related to REM sleep. Whereas headache is associated with snoring and sleep apnea, morning headaches are not specific for any primary sleep disorder. Nevertheless, the management of the sleep disorder ameliorates both morning headache and migraine.Noxious stimuli administered into muscles during slow-wave sleep (SWS) result in decreases in delta and sigma but an increase in alpha and beta EEG frequencies during sleep. Noise stimuli that disrupt SWS result in unrefreshing sleep, diffuse musculoskeletal pain, tenderness, and fatigue in normal healthy subjects. Such symptoms accompany alpha EEG sleep patterns that often occur in patients with fibromyalgia. The alpha EEG patterns include phasic and tonic alpha EEG sleep as well as periodic K alpha EEG sleep or frequent periodic cyclical alternating pattern. Moreover, alpha EEG sleep, as well as sleep-related breathing disorder and periodic limb movement disorder, occur in some patients with fibromyalgia, rheumatoid arthritis and osteoarthritis. Depression and not alpha EEG sleep are features of somatoform pain disorder. Disturbances in sleep, pain behaviour and psychological distress influence return to work in workers who have suffered a soft tissue injury, e.g. low back pain. Patients with irritable bowel disorder have disturbed sleep and have increased REM sleep. In conclusion, there is a reciprocal relationship between sleep quality and pain. The recognition of disturbed or unrefreshing sleep influences the management of painful medical disorders.

[Sleep in fibromyalgia: review of clinical and polysomnographic data]

Fibromyalgia syndrome is a common chronic pain syndrome that is often associated with sleep disturbances characterized by subjective experience of non-restorative sleep. The complaints of sleep disturbances are correlated with polysomnographic features showing clear abnormalities in the continuity of sleep as well as in the sleep architecture. Sleep-recording abnormalities are characterized by a reduced sleep efficiency with increased number of awakenings, a reduced amount of slow wave sleep and an abnormal alpha wave intrusion in non rapid eye movement, termed alpha-delta sleep. These data were confirmed by spectral analysis of sleep showing an increased EEG power density in the higher frequency band and a reduced EEG power density in the lower frequency bands. Moreover, other microstructural aspects of sleep were modified with high frequency of arousals and alpha-K complex reported, both indicators of fragmented sleep. The fibromyalgia symptoms may relate to a non-restorative sleep disorder associated with the alpha-EEG sleep anomalies. However, alpha-EEG sleep anomaly is non-specific for fibrositis, also seen in normal controls during stage 4 sleep deprivation. Moreover, fibromyalgia patients may also experience primary sleep disorder such as sleep apnea or periodic leg movements. The etiology of this common condition is incompletely understood and the existence of a specific entity of fibromyalgia is still a matter of debate. However, several studies have found abnormal brain metabolism of substances such as serotonin implicated in sleep arousal and pain mechanisms and administration of tricyclic antidepressants and selective serotonin reuptake inhibitors may be useful in fibromyalgia. Pain, poor sleep quality and anxiety may contribute to the clinical picture. Several factors such as psychological, environmental, genetic factor, altered serotonin metabolism and altered sleep physiology are involved in the pathogenesis of fibromyalgia.

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.

Nighttime sleep and daytime functioning (sleepiness and fatigue) in less well-defined chronic rheumatic diseases with particular reference to the 'alpha-delta NREM sleep anomaly'

For the past 25 years, the 'alpha-delta NREM sleep abnormality' has been used by some as a defining or legitimizing marker for poorly defined rheumatic diseases such as fibromyalgia and chronic fatigue syndrome. Comprehensive review of the literature reveals no support for such a conclusion. Most studies involve small numbers of patients. The lack of control subjects, non-standardized recording techniques, and confusion between tonic and phasic alpha frequency activity patterns make comparison difficult. There is much evidence that this sleep EEG pattern is not only non-specific, but may actually reflect a sleep maintaining process. The 'sleep fragmentation' theory of the complaint of non-restorative sleep in this patient population is invalidated by the fact that conditions characterized by severe sleep fragmentation, such as obstructive sleep apnea, are not associated with musculoskeletal symtoms. It is difficult to attribute musculoskeletal symptoms to disorders of sleep in view of the fact that the only organ of the body known to benefit from sleep, or to be adversely affected by lack of sleep, is the brain. It is concluded that fibromyalgia and chronic fatigue syndrome are associated with subjective sleep complaints, but do not represent sleep disorders.

Sleep disturbances in clinic patients with functional bowel disorders

OBJECTIVE

Sleep deprivation can lower visceral perception thresholds and nonregenerative sleep has been implicated as an etiological factor in chronic hyperalgesia syndromes. The aims of our study were to quantify the self-reported prevalence and type of sleep disturbances in patients with different functional bowel disorders (FBD) and to determine if this prevalence is related to involvement of the upper or lower gastrointestinal (GI) tract, perceived disease severity, or psychological comorbidity.

METHODS

We enrolled 505 new FBD patients from an academic referral center specializing in functional GI disorders and 247 community based healthy controls. All patients and controls were prospectively evaluated by validated bowel symptom and sleep questionnaires. A psychological profile was obtained by SCL-90R.

RESULTS

We found that 68% of functional dyspepsia (FD), 71.2% of irritable bowel syndrome (IBS)+FD, 50.2% of IBS, and 55.1% of the normal subjects reported having sleep disturbances. Waking up repeatedly during the night and waking up in the morning feeling tired or not rested were the most commonly reported sleep patterns; 57.2% of the patients reported that their abdominal ache awakened them from sleep during the night. Self-reported sleep disturbance was directly related to the perceived intensity of GI symptoms. Self-reported sleep disturbances were equally common in both male (57%) and female (58.4%) FBD patients. There was no significant difference between the mean anxiety and depression scores between patients with and without sleep dysfunction.

CONCLUSIONS

FD patients, but not IBS patients, reported sleep disturbances more frequently than healthy control subjects. Abdominal pain or discomfort that awaken FBD patients from sleep during the night were common, and thus a poor discriminating factor between organic and functional disorders.

Is fibromyalgia a distinct clinical entity? Historical and epidemiological evidence

Most medical specialities have defined medically unexplained syndromes such as fibromyalgia, to categorize patients with prominent but unexplained symptoms. Other such syndromes include irritable bowel syndrome, chronic fatigue syndrome and atypical chest pain. In this chapter we present evidence to suggest that fibromyalgia is not a unique clinical entity, but shares much with these other syndromes. We use historical, clinical and epidemiological evidence to illustrate this idea. The historical data emphasize the essentially arbitrary way in which fibromyalgia developed. The clinical evidence shows the considerable overlap between patients with fibromyalgia and those with other unexplained syndromes. From an epidemiological perspective we emphasize the strong associations between symptoms such as myalgia and fatigue. We conclude by suggesting that fibromyalgia is one of many medically unexplained syndromes which have more similarities than differences between them.

Sleep disorders and the dental patient: an overview

This article is intended to briefly describe common sleep disorders of interest to the dental profession and to render general management guidelines. Topics include sleep-related bruxism, xerostomia, hypersalivation, gastroesophageal reflux, apnea, and the effect of orofacial pain on sleep quality. The term sleep-related is used instead of the term nocturnal because some of the activities described can occur with daytime sleep.

Sleep in fibromyalgia patients: subjective and objective findings

Fibromyalgia (FM) patients report early morning awakenings, awakening feeling tired or unrefreshed, insomnia, as well as mood and cognitive disturbances; they may also experience primary sleep disorders including sleep apnea. Longitudinal studies have demonstrated the chronic nature of these disturbances in patients with FM. A distinct relationship exists between poor sleep quality and pain intensity. Polysomnographic findings during sleep in these patients include an alpha frequency rhythm, termed alpha-delta sleep anomaly, which is also seen in normal controls during stage 4 sleep deprivation; deep pain induced during sleep in normal controls also causes this anomaly. Sleep architecture is altered in FM patients showing an increase in stage 1, a reduction in delta sleep, and an increased number of arousals. Before prescribing pharmacologic compounds aimed at modifying sleep, adequate pain control and sleep habits should be achieved; tricyclic antidepressants, trazadone, zopiclone, and selective serotonin reuptake inhibitors, however, may be required. More research is needed to elucidate the cellular and molecular mechanisms involved in the sleep disturbances occurring in patients with FM.

Alpha sleep and information processing, perception of sleep, pain, and arousability in fibromyalgia

This study examined the relationship between alpha sleep and information processing during sleep, perception of sleep, musculoskeletal pain, and arousability in patients with fibromyalgia. Patients (n = 20) were allowed to sleep undisturbed for the first 60 minutes of the study to assess amount of alpha sleep and were classified as high or low alpha generators based on quantitative analyses of alpha activity during this period. The groups were compared for performance on two memory tasks, perceptions of polysomnographically-defined sleep and EEG arousals in response to auditory stimuli. Correlations between symptoms of fibromyalgia and alpha activity were also examined. Alpha activity during sleep in fibromyalgic patients was associated with the perception of shallow sleep and an increased tendency to arouse in relation to auditory stimuli. Alpha activity was not associated with increased memory for auditory stimuli presented during sleep, sleep state misperception, or with myalgia symptoms. Alpha sleep appears to be, electrophysiologically, a shallow form of sleep. Our results suggest that it is perceived as such phenomenologically and that it is also associated with increased arousability.

The relationship between fibromyalgia and major depressive disorder

Looking at the results of the seven types of studies discussed previously, it appears that there is strong evidence for an association between fibromyalgia and major depressive disorder on the basis of (1) overlapping symptomatology, (2) similar pattern of comorbid disorders, and (3) high rates of major depressive disorder among relatives of patients with fibromyalgia. There is additional support for an association on the basis of responses to psychological tests and rating scales and the high lifetime rates of mood disorders in fibromyalgia. Two lines of evidence, (1) response to antidepressant medications and (2) response to biologic tests, offer little evidence either for or against an association. On balance, then the weight of the evidence favors an association between fibromyalgia and major depressive disorder. We therefore turn to an analysis of the nature of the association.

A reconceptualization of EEG alpha activity as an index of arousal during sleep: all alpha activity is not equal

Alpha activity occurring during sleep is generally considered to reflect arousal processes and a shift toward wakefulness. This long-standing interpretation is based on physiological and behavioural arousal correlates of alpha activity presumed to have an occipital focus. In addition to the application of this interpretation to sleep/wake state determinations, there have been reports of nonrefreshing or nonrestorative sleep in clinical populations exhibiting dramatic amounts of alpha intrusion during sleep in the absence of awakening. Reports of the presence of alpha activity during sleep in normal subjects without sleep disruption or complaints of daytime sleepiness call into question the interpretation that this activity is associated with arousal. A re-examination of this literature, incorporating the results from recent investigations employing multi-site EEG recordings, electronic processing and source dipole analyses of this activity, suggests the existence of alpha activity which differs in generation site (thalamus), scalp distribution (frontal-central), and behavioural correlates (e.g. enhancement to stimulation during wakefulness, concentration in the first-half of the night during sleep, and absence of sleep disturbance) from occipital alpha activity. Such marked differences in defining characteristics imply different functional correlates for these activities. In this context, it is proposed that this fronto-central alpha activity is associated with sleep-maintaining processes which may be enhanced in response to sleep-disturbing events.

Sleep, its subjective perception, and daytime performance in insomniacs with a pattern of alpha sleep

Intrusion of alpha activity, an electroencephalographic (EEG) pattern typical for wakefulness, into sleep stages has repeatedly been described and investigated in various populations. Some studies suggested that it is a less deep and restorative sleep, but others did not support this interpretation. The present study was carried out to collect ample data on neurophysiology and subjective experience of sleep and on daytime cognitive performance to clarify this point. A sample of 128 primary insomniacs was investigated with polysomnography (PSG) that was submitted to a computerized, automatic analysis of alpha activity during sleep. It yielded two groups of 64 Ss each with a normal, that is, nonalpha sleep EEG and with alpha-sleep, respectively. Contrasting the two groups for PSG showed that alpha sleep Ss had significantly more stage 4 and a (nonsignificant) tendency for more awakenings. Subjectively, they largely underestimated intermittent wake time and consequently overestimated sleep duration by 50 min. The performance test battery showed a difference in one test only, that is, a better short-term memory function by alpha sleep Ss. In conclusion, there was no result supporting the assumption that alpha sleep is less restorative, but a significant lack of perception of intermittent awakenings during night sleep by alpha sleep Ss was found. The authors propose an explanation and point to the implications this misperception might have for the clinician.

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.

Nocturnal motor activity in fibromyalgia patients with poor sleep quality

Nocturnal motor activity was examined in long-term rehabilitation patients complaining of poor sleep and having fibromyalgia syndrome (N = 24) or other musculoskeletal disorders (N = 60) and compared with that in 91 healthy controls drawn from a random community sample. Self-reports on sleep complaints and habits were collected. The frequency of nocturnal body movements, the "apnoea" index and ratio of "quiet sleep" to total time in bed were measured using the Static Charge Sensitive Bed (SCSB) (BioMatt). As a group, patients with fibromyalgia syndrome did not differ from patients with other musculoskeletal disorders or from healthy controls in their nocturnal motor activity. The "apnoea" index was a little higher in the fibromyalgia group than in the healthy control group but did not differ from that of the group of other musculoskeletal patients. Further multivariate analyses adjusted for age, BMI, medication and "apnoea" index did not support the assumption that an increased nocturnal motor activity characterizes patients with fibromyalgia syndrome.

Human slow wave sleep: a review and appraisal of recent findings, with implications for sleep functions, and psychiatric illness

Recent findings concerning human slow wave sleep (hSWS-stages 3 + 4; delta EEG activity) are critically reviewed. Areas covered include the significance of the first hSWS cycle; hSWS in extended sleep; relationship between hSWS, prior wakefulness and sleep loss; hSWS influence on sleep length; problems with hSWS deprivation; influence of the circadian rhythm; individual differences in hSWS, especially, age, gender and constitutional variables such as physical fitness and body composition. Transient increases in hSWS can be produced by increasing both the quality and quantity of prior wakefulness, with an underlying mechanism perhaps relating to the waking level of brain metabolism. Whilst there may also be thermoregulatory influences on hSWS, hypotheses that energy conservation and brain cooling are major roles for hSWS are debatable. hSWS seems to offer some form of cerebral recovery, with the prefrontal cortex being particularly implicated. The hSWS characteristics of certain forms of major psychiatric disorders may well endorse this prefrontal link.