Sleep medicine reviews
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Sleep spindles are a distinctive EEG phasic feature of NREM sleep and are prevalent during stage 2 as compared to slow wave sleep. While the neurophysiological mechanisms of spindle generation, that involves thalamic and corticothalamic networks, have been recently delineated and are briefly reviewed, their definitive functional meaning still remains to be elucidated. ⋯ Moreover, specific attention has been paid to the existence of functionally and topographically distinct slow- and fast-spindles, also taking into account the presence of large inter-individual differences. Nevertheless, several fundamental issues remain to be elucidated: the physiological mechanisms controlling age-related changes in spindle parameters; the role of melatonin as a spindle-promoting agent; the relationships between plastic mechanisms (after stroke, or as a consequence of learning) and modifications in spindle activity; the possibility of using some spindle parameters as an index of the severity of developmental disorders in abnormal maturational processes.
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Sleep medicine reviews · Apr 2003
ReviewSleep in women across the life cycle from adulthood through menopause.
Studies of sleep across the life cycle in women have utilized both survey and polysomnographic techniques, but have tended to be of small sample size with diverse methodology. As a result, definitive conclusions about the impact of the menstrual cycle and use of oral contraceptives on sleep parameters cannot yet be made. Sleep disruption during pregnancy and postpartum is nearly universal, but effective and practical countermeasures are still needed. ⋯ Menopause is associated with insomnia due to several factors including hot flashes, mood disorders and increased sleep-disordered breathing. The use of hormone replacement therapy to treat sleep and other variables is an active area of investigation. In summary, much research is required to fully elucidate the impact of the life cycle on sleep parameters in women.
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Sleep medicine reviews · Feb 2003
Comment ReviewThe upper airway in sleep: physiology of the pharynx.
The upper airway is the primary conduit for passage of air into the lungs. Its physiology has been the subject of intensive study: both passive mechanical and active neural influences contribute to its patency and collapsibility. Different models can be used to explain behavior of the upper airway, including the "balance of forces" (airway suction pressure during inspiration versus upper airway dilator tone) and the Starling resistor mechanical model. ⋯ Currently SDB is thought to result from a combination of anatomical upper airway predisposition and changes in neural activation mechanisms intrinsic to sleep. Detection of SDB is based on identifying abnormal (high resistance) breaths and events, but the clinical tools used to detect these events and an understanding of their impact on symptoms is still evolving. Outcomes research to define which events are most important, and a better understanding of how events lead to physiologic consequences of the syndrome, including excessive daytime somnolence (EDS), will allow physiologic testing to objectively differentiate between "normal" subjects and those with disease.
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Sleep medicine reviews · Oct 2002
ReviewNeurobiological bases for the relation between sleep and depression.
The serotoninergic system is involved in the regulation of sleep and wakefulness, its activity being at maximum during the awake state and minimum during sleep. In particular, the production of rapid eye movement (REM) sleep depends on the decrease of serotoninergic tone in brain stem structures. Thus, serotoninergic compounds which increase this tone (such as antidepressants) induce inhibition of REM sleep. ⋯ Sleep deprivation also induces an activation of serotoninergic neurons due to prolonged wakefulness, and leads to similar serotoninergic adaptive processes. The common neurobiological mechanisms resulting from pharmacological antidepressant treatment and sleep deprivation suggest that sleep loss in some insomniac or in depressed patients might be an endogenous compensatory process which would be therapeutical rather than pathological. This proposal should open the way to new strategies in the treatment of depression.
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Sleep medicine reviews · Aug 2002
ReviewClinical symptomatology and treatment of restless legs syndrome and periodic limb movement disorder.
Patients with restless legs syndrome (RLS) suffer from sensory and motor symptoms evoked in the limbs at rest. Symptoms increase in the evening and during the night. ⋯ Dopaminergic agents such as levodopa/dopa decarboxylase inhibitor (DDI) and dopamine agonists are considered the treatment of choice for RLS and PLMS. This article gives an overview of the epidemiology, pathophysiology, clinical symptomatology and diagnosis of RLS and PLMD and focuses on treatment strategies in both disorders.