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 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Information which has emerged thus far relates to the overall transmitter mechanisms of sleep. The data, while conflicting, point to the involvement of many neuroregulators at numerous integrative levels of the process. However the long term question still remain: what triggers and maintain sleep, what stops sleep, what occurs to the body and brain during sleep--in essence, why sleep? These questions are now problems for behavioral neurochemists, whereas in a previous era, they were problems for philosophers. Unfortunately, our answers to date, while in another idiom, have hardly been more complete or satisfying. To answer these questions, it will be necessary to understand, in detail, the manner in which neurobiochemical processes relate to the functional physiology of sleep. Although existing studies have given invaluable insight into the neurochemical anatomy of sleep, we have only recently acquired the technical and biochemical expertise necessary to investigate sleep as it occurs normally. Future research must focus on the dynamic changes associated with the regulatory mechanisms of neurotransmitters. Many questions can be asked. With sleep transitions, what changes occur in transmitter content, synthesis, or release? Are there changes in metabolic pathways, reflecting a shift from intra- to interneuronal metabolism? What changes occur in pre- and postsynaptic neurotransmitter receptors to affect sensitivity? What constraints do genetic (245) and environmental (246) factors impose upon these mechanisms? Knowledge of such parameters will allow us to construct more complete models of the neuroregulatory basis of sleep and waking. However, as we acquire this knowledge, we must avoid the temptation of assuming causation when the evidence merely shows correlation. Neuroregulation are involved in the control of number different behaviors; and, at present, we have few, if any, methods of establishing causative links between a specific neuroregulator and a specific behavioral state. Yet, even without an understanding of what "causes" sleep, we may be able to develop pharmacological agents which permits discrete alteration of sleep mechanisms in a more physiological and specific manner. This potential for manipulation of sleep is of obvious importance in illnesses such as insomnia, narcolepsy, and sleep apnea (247, 248). In addition, it may be valuable in the treatment of such conditions as psychosis and depression, where sleep disturbances are an important component of the illness. For example, delirium tremens might be best understood as a psychotic episode which is the result of an aspect of sleep emerging into wakefulness. The range and breadth of both the basic questions and the potential application of sleep research portend an exciting future for this field.
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PMID:Neuroregulators and sleep mechanisms. 16 54

Primary sleep disorders include narcolepsy, the Pickwickian syndrome, sleep apnea in infants and other rare conditions. Secondary sleep disorders occur in depression, alcoholism, endocrinopathies, heart failure and pregnancy. Medical symptomatology often increases during rapid-eye-movement (REM) sleep, when physiologic activity is high. Insomnia, the most common sleep disorder, requires careful work-up, attempts at environmental manipulation and judicious short-term pharmacotherapy. Pharmacologic manipulation of sleep is beset with complications. A basic understanding of properties and side effects of the sleep-inducing drugs is needed in order to select the optimal agent.
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PMID:Sleep disorders and insomnia. 62 43

Periodic sleep apnea may be due to repeated episodes of upper airway obstruction in patients who have a short thick neck and/or large jowls. Apnea due to complete cessation of breathing may occur to a lesser extent. Anaylsis of the sleep electroencephalogram shows that these patients rarely achieve deep sleep and have less stage 1-REM sleep than normal subjects of comparable age. They are chronically sleep-deprived, a manifestation expressed by daytime somnolence, chronic fatigue and often by personality disturbances marked by paranoia, agitated depression and hostility. The definitive diagnosis of this syndrome may be established by monitoring during sleep, the electroencephalogram, measuring abdominal excursions through a mercury-in-Silastic-strain gauge and recording air flow at the nose by means of a thermocouple. As demonstrated by other investigators, chronic hypoventilation during sleep leads to both pulmonary and systemic arterial hypertension, which may produce generalized cardiac enlargement and congestive heart failure. The abnormalities in the periodic sleep apnea syndrome are abolished by establishing a patent airway either through tracheostomy or weight reduction.
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PMID:Periodic sleep apnea: chronic sleep deprivation related to intermittent upper airway obstruction and central nervous system disturbance. 111 91

A 34-year-old female was admitted on June 25, 1990, for the evaluation of alveolar hypoventilation which worsened after her second delivery. She showed impairment of both hypercapnic and hypoxic ventilatory responses, and marked desaturation due to hypopnea and apnea during sleep. Although administration of methylxanthine and medroxyprogesterone was not very effective, after treatment with low flow oxygen, there was a marked decrease in the frequency and duration of desaturation during sleep and improvement of arterial daytime blood gases, which suggested the existence of hypoxic ventilatory depression in the pathophysiology of her nocturnal desaturation. Furthermore, the use of a negative pressure ventilator for 3 hours in the daytime for 10 days resulted in marked improvement of symptoms, arterial blood gases, respiratory muscle strength, and the frequency and duration of sleep desaturation. These findings suggest that both low flow oxygen therapy during sleep, and daytime negative pressure ventilation may be beneficial in patients with primary alveolar hypoventilation and central sleep apnea syndrome.
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PMID:[A case of primary alveolar hypoventilation syndrome with a good response to nocturnal low-flow oxygen inhalation and negative pressure ventilation]. 128 38

Very few epidemiological surveys have specifically studied relationships between sleep disturbances and psychiatric diseases. In this review, we preferred to use the classification proposed in 1979 by the Association of Sleep Disorders Centers. It includes four main categories: insomnias, excessive sleepiness, troubles of the wake/sleep schedule and parasomnias. Evaluating psychiatric disorders among general populations is easier owing to DSM III and DSM III-R criteria, but there are not equivalent criteria in evaluating sleep disorders. It is almost impossible to realize polysomnographic recordings in large samples, therefore sleep disorders are to be detected by questionnaires. It has been shown that there is a good correlation between self-reports and polysomnographic recordings among clinical and general samples. The prevalence of insomnia, defined as difficulties of initiating and maintaining sleep, is estimated between 9 and 31%. It is higher among women, elderly people, separated and divorced subjects, and low educational levels' groups. It has to be noticed that polysomnographic records of some subjective insomniacs are not different from those of good sleepers, sleep latency excepted. These subjective (and not objective) insomniacs have high scores in anxiety scale, depression scale, or psychologic distress. Insomnia is more frequently noted amongst subjects with psychiatric diagnoses, especially major depressive disorders and anxiety disorders. Depressive disorders are present in 21-40% of insomniacs versus 0-1% of non-insomniacs, and anxiety disorders in 13-24% of insomniacs versus 3-10% of non-insomniacs. In depressive disorders, sleep alterations are frequently noted: they are difficulties of initiating and maintaining sleep, decreasing proportion of slow-wave sleep, decreasing time of REM (rapid eye movement) sleep and REM sleep latency, and increasing density of REM sleep. Of these modifications, the last two ones seem to be specific for depression. The relationships between sleep, aging and depression are more complex than previously noted. For example, differences between depressed and non-depressed subjects depend on the age of the population. The prevalence of hypersomnia is lower than the insomnia's. It varies between 2 and 4%. It is more frequently noted among young people, and never married subjects. Two specific aetiologies must be looked for: sleep apnea syndrome and narcolepsy. These diagnoses are respectively found in 45% and 24% of hypersomniacs examined in American Sleep Centers. Hypersomnias are objectived by the Multiple Sleep Latency Test, which measures the physiologic sleep tendency.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Sleep disorders in psychiatric diseases. Epidemiological aspects]. 129 83

We investigated whether or not the adaptation of peripheral chemoreceptor (PCR) activity can contribute to hypoxic ventilatory depression (HVD) during sustained hypoxia for 20 min in both healthy subjects and patients with sleep apnea. Effects of HVD on diaphragm (DIA) and genioglossal muscle (GG) were also assessed. Withdrawal test, which is well established to solely represent the function of PCR, was repeatedly conducted at 5 and 20 min during sustained hypoxic condition. The results suggested that PCR did not play an important role in the development of HVD. When HVD ensued during sustained hypoxia, minute ventilation and EMGDIA were suppressed to the same extent in both groups. On the other hand, EMGGG was strongly and consistently attenuated in OSAS, whereas it was not always the case in healthy subjects. We speculate that treatment for hypoxic conditions can induce improvement of impaired regulation of breathing via central mechanisms, and it can be an important factor reducing the incidence and the severity of upper airway occlusion or collapse.
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PMID:[Hypoxic ventilatory response and hypoxic depression]. 130 12

Sleep apnoea (OSA), a common sleep disorder, is well recognised as a cause of morbidity including psychiatric disorders. There is increasing recognition of the link between OSA and depression. Sleep changes are intrinsic to depressive disorders, most notably disturbances of REM sleep; OSA causes predominantly REM sleep disturbances. The neuro-vegetative features of depression are similar or identical to the symptoms of OSA-an issue which has not achieved wide clinical recognition. A growing number of studies confirm the statistical link between the two conditions. The implications are twofold: OSA needs to be excluded in cases of chronic or resistant depression and treatment of OSA will make it easier to treat the primary depressive disorder. A new method of treatment for OSA, the Sullivan continuous positive airway pump (CPAP), raises the theoretical possibility of treating depression by this means as well.
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PMID:Obstructive sleep apnoea and depression--diagnostic and treatment implications. 848 Nov 62

Patients with sleep apnea/hypopnea syndrome commonly demonstrate impaired daytime performance. In a prospective study, 29 patients with sleep apnea/hypopnea syndrome were assessed polysomnographically to determine the relationship of cognitive performance and daytime sleepiness with sleep disruption, hypoxemia, and mood. Deterioration of cognitive performance correlated significantly with increasing severity of nocturnal breathing irregularity, magnitude of nocturnal hypoxemia, and extent of sleep disruption. Multiple regression analysis identified frequency of apneas plus hypopneas and of arousal and the extent of nocturnal hypoxemia as the variables most strongly associated with cognitive deficits. Anxiety and depression also contributed to this impairment. Objective daytime sleepiness was not significantly associated with nocturnal variables. This study showed that the frequency of breathing irregularities and the extent of both sleep disruption and nocturnal hypoxemia are important in determining daytime function in patients with sleep apnea/hypopnea syndrome. All of these factors should be considered when deciding which patients require treatment.
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PMID:Factors impairing daytime performance in patients with sleep apnea/hypopnea syndrome. 154 16

Sleep apnea is characterized by transient hypoxemias which are thought to affect mental functioning. Accordingly, speculation and research have focussed on relationships between sleep apnea and dementia. We studied 235 nursing home (ie institutionalized) patients (152 women with a median age of 83.5; 83 men with a median age of 79.7) with portable sleep recording equipment. The Mattis Dementia Rating Scale and the Geriatric Depression Scale were given to each. Seventy percent of the patients had five or more respiratory disturbances per hour of sleep and 96 percent showed some dementia. Sleep apnea was significantly correlated with all subscales on the dementia rating scale. There were trivial differences in dementia ratings between those with mild-moderate apnea and those with no apnea. There were significant differences, however, between the latter two groups and those with severe apnea. In particular, items reflecting attention, initiation and perseveration, conceptualization, and memory tasks on the DRS distinguished between those with and without severe sleep apnea. Among those patients with no depression, all patients with severe sleep apnea were also severely demented. Our data suggest that there is a strong relationship between dementia and sleep apnea when the sleep apnea and dementia are severe. Although causality cannot be inferred from associations, our hypothesis for study is that sleep apnea causes deficits in brain function, possibly due to global effects rather than any particular cortical or subcortical structure.
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PMID:Dementia in institutionalized elderly: relation to sleep apnea. 200 39

Holter recordings of subjects apparently free from cardiovascular disease have demonstrated a moderate sinusal and nodal depression during sleep. This depression does not seem to be sufficient to create overt cardiovascular disorders in apparently healthy subjects, but it may aggravate or even reveal an underlying disorder of rhythm or conduction in elderly people or in patients taking drugs that potentiate its effects. In sleep apnea syndrome prolonged episodes of apnea may produce a paroxysmal, then permanent increase in pulmonary arterial pressure, which may lead to right heart failure. These episodes also increase the pre- and after-load and decrease myocardial contractility, thus facilitating the occurrence of left ventricular failure, potentiated by systemic arterial hypertension, overweight or even coronary disease, all conditions that are often present in these subjects. Arterial hypertension is so frequent in sleep apnea syndrome that some authors advocate a systematic search for the syndrome by Holter recordings before the hypertension is pronounced "essential". All studies confirm the existence of rhythm and conduction disorders directly related to apneic episodes. These disorders decrease or regress after a well-conducted treatment of the sleep apnea syndrome. They are mainly of the "hypokinetic" type, created by depression of sinus activity and conduction pathways. Their frequency, their severity and, in particular, the risk of sudden death they carry seem to have been overestimated, especially since no evidence has ever been produced of a potentially lethal rhythm disorder occurring during sleep apnea. Nevertheless, there is no certainty that these patients are not at risk of sudden death related to their sleep apnea syndrome.
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PMID:[Cardiovascular disorders during sleep]. 214 78


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