Fibromyalgia, sleep disorder and chronic fatigue syndrome

Reduced heart rate variability predicts poor sleep quality in a case-control study of chronic fatigue syndrome

Parasympathetic function is important in the induction and maintenance of sleep. We examined whether nocturnal vagal modulation of heart rate is related to the poor sleep quality commonly reported in chronic fatigue syndrome (CFS). Heart rate (HR, as R-R intervals) was continuously monitored during sleep in 20 patients with CFS and 20 matched control subjects. Questionnaires assessed demographic information, symptoms, functional impairment, and subjective sleep quality. CFS was associated with more sleep problems in general and poorer subjective sleep quality on the study night (all p < 0.003), and reports of repeated awakening during the night were 7 times more likely compared to healthy subjects (p = 0.017). Time and frequency-domain parameters of HR variability during sleep were significantly lower in patients with CFS (all p < 0.006). Multiple regression analyses revealed that heart rate variability (HRV) parameters were the best predictors of subjective sleep measures. This study identified significant reductions in vagal modulation of heart rate during sleep in CFS. Low HRV strongly predicted sleep quality-suggesting a pervasive state of nocturnal sympathetic hypervigilance in CFS.

Electroencephalographic correlates of Chronic Fatigue Syndrome

BACKGROUND

Unremitting fatigue and unrefreshing sleep, hallmark traits of Chronic Fatigue Syndrome (CFS), are also pathognomonic of sleep disorders. Yet, no reproducible perturbations of sleep architecture, multiple sleep latency times or Epworth Sleepiness Scores are found to be associated consistently with CFS. This led us to hypothesize that sleep homeostasis, rather than sleep architecture, may be perturbed in CFS. To probe this hypothesis, we measured and compared EEG frequencies associated with restorative sleep between persons with CFS and matched controls, both derived from a population-based sample.

METHODS

We evaluated overnight polysomnography (PSG) in 35 CFS and 40 control subjects. PSG records were manually scored and epochs containing artifact removed. Fast Fourier Transformation was utilized to deconstruct individual EEG signals into primary frequency bands of alpha, delta, theta, sigma, and beta frequency domains. The spectral power of each frequency domain for each sleep state was compared between persons with CFS and matched controls.

RESULTS

In persons with CFS, delta power was diminished during slow wave sleep, but elevated during both stage 1 and REM. Alpha power was reduced during stage 2, slow wave, and REM sleep. Those with CFS also had significantly lower theta, sigma, and beta spectral power during stage 2, Slow Wave Sleep, and REM.

DISCUSSION

Employing quantitative EEG analysis we demonstrate reduced spectral power of cortical delta activity during SWS. We also establish reduced spectral power of cortical alpha activity, with the greatest reduction occurring during REM sleep. Reductions in theta, beta, and sigma spectral power were also apparent.

CONCLUSION

Unremitting fatigue and unrefreshing sleep, the waking manifestations of CFS, may be the consequence of impaired sleep homeostasis rather than a primary sleep disorder.

Management of insomnia in patients with chronic pain conditions

The management of insomnia in patients experiencing chronic pain requires careful evaluation, good diagnostic skills, familiarity with cognitive-behavioural interventions and a sound knowledge of pharmacological treatments. Sleep disorders are characterised by a circular interrelationship with chronic pain such that pain leads to sleep disorders and sleep disorders increase the perception of pain. Sleep disorders in individuals with chronic pain remain under-reported, under-diagnosed and under-treated, which may lead--together with the individual's emotional, cognitive and behavioural maladaptive responses--to the frequent development of chronic sleep disorders. The moderately positive relationship between pain severity and sleep complaints, and the specificity of pain-related arousal and mediating variables such as depression, illustrate that insomnia in relation to chronic pain is multifaceted and poorly understood. This may explain the limited success of the available treatments. This article discusses the evaluation of patients with chronic pain and insomnia and the available pharmacological and nonpharmacological interventions to manage the sleep disorder. Non-pharmacological interventions should not be considered as single interventions, but in association with one another. Some non-pharmacological interventions especially the cognitive and behavioural approaches, can be easily implemented in general practice (e.g. stimulus control, sleep restriction, imagery training and progressive muscle relaxation). Hypnotics are routinely prescribed in the medically ill, regardless of their adverse effects; however, their long-term efficacy is not supported by robust evidence. Antidepressants provide an interesting alternative to hypnotics, since they can improve pain perception as well as sleep disorders in selected patients. Sedative antipsychotics can be considered for sleep disturbances in those patients exhibiting psychotic features, or for those with contraindications to benzodiazepines. Low doses of sedative antipsychotics may improve chronic insomnia in the elderly. However, no intervention is likely to be effective unless a good physician-patient relationship is developed.

Chronic fatigue syndrome: probable pathogenesis and possible treatments

Chronic fatigue syndrome (CFS) belongs in the medically unexplained illnesses. It affects approximately 0.2-0.7% of the population in Western countries. It is characterised by unexplained fatigue, lasting 6 months or more, impairment of neurocognitive functions and quality of sleep, and of somatic symptoms, such as recurrent sore throat, muscle aches, arthralgias, headache and postexertional malaise. No link between infections and CFS has been clearly established but the immune system is activated, there are aberrations in several hypothalamic-pituitary axes and involvement of other parts of the central nervous system. No specific treatment has been found. Cognitive behavioural therapy is established to be of value to improve quality of life. More effective treatment should result, as advances in biomedical as well as psychological research continue.

Sensory and affective components of orofacial pain: is it all in your brain?

In this paper, we shall review several chronic orofacial pain conditions with emphasis on those that are essentially refractory to treatment. We shall present a review of current and past literature that describes the various pain phenomena as well as their underlying central mechanisms. New data concerning refractory pain will be used to underscore the importance of central processing of pain, with particular emphasis on neuropsychological and cognitive function and capacity that may play important roles in pain processing and maintenance of the pain state. Further, neurophysiological data showing that the anterior cingulate cortex (ACC) and other structures in the brain may play key roles in modulation of chronic pain will also be discussed. Although peripheral triggering events surely play an important role in initiating pain, the development of chronic and, in particular, refractory pain may depend on changes or malfunctions in the central nervous system. These changes may be quite subtle and require sophisticated approaches, such as functional MRI, to study them, as is now being done. New findings obtained therefore may lead to more rational and reliable treatment for orofacial pain.

Chronic fatigue syndrome: new insights and old ignorance

Chronic fatigue syndrome (CFS) is a condition characterized by impairment of neurocognitive functions and quality of sleep and of somatic symptoms such as recurrent sore throat, muscle aches, arthralgias, headache, and postexertional malaise. A majority of patients describe an infectious onset but the link between infections and CFS remains uncertain. Findings show an activation of the immune system, abberations in several hypothalamic-pituitary axes and involvement of other parts of the central nervous system. The origin is bound to be complex and it may well be that the solution will come together with a more generally altered view about mind-body dualism, and the concept of illness and disease.