The Severity of Sleep Disordered Breathing Induces Different Decrease in the Oxygen Saturation During Rapid Eye Movement and Non-Rapid Eye Movement Sleep

OBJECTIVE: To investigate how differences in oxygen saturation between non-REM (NREM) and REM sleep in patients according to the severity of sleep apnea. METHODS: We studied 396 male patients diagnosed with simple snoring or obstructive sleep apnea syndrome (OSAS) on nocturnal polysomnography. Patients were divided into groups by the OSAS severity. We compared the average oxygen saturation between REM and NREM sleep in each group. RESULTS: In the simple snoring group, average oxygen saturation was significantly greater during REM than during NREM sleep. In the severe OSA group alone, average oxygen saturation was greater in NREM than in REM sleep. The difference of NREM-REM average oxygen saturation correlated significantly with AHI in the severe OSA group. CONCLUSION: More severe hypoxemia was seen in REM than NREM sleep in the severe OSAS group. The differential oxygen decrease between REM and NREM sleep is likely due to the differentially occurring sleep breathing events in each sleep stage according to the SDB severity. The more AHI increases in the severe OSAS patients, the more prominent the hypoxemia of REM sleep compared with NREM sleep is likely to appear. This suggests that the pressure of continuous positive airway pressure should be increased to control the hypoxemia of REM sleep in extremely severe OSAS.

Physiology of Normal Sleep: From Young to Old.

Human sleep, defined on the basis of electroencephalogram (EEG), electromyogram (EMG) and electrooculogram (EOG), is divided into rapid eye movement (REM) sleep and four stages of non–rapid eye movement (NREM) sleep. Collective monitoring and recording of physiological data during sleep is called polysomnography. Sleep which normally starts with a period of NREM alternates with REM, about 4-5 times, every night. Sleep pattern changes with increasing age. Newborns sleep for about 14-16 hours in a day of 24 hours. Although there is a wide variation among individuals, sleep of 7-8.5 hours is considered fully restorative in adults. Apart from restorative and recovery function, energy conservation could be one of the functions of sleep. The role of sleep in neurogenesis, memory consolidation and brain growth has been suggested. Though progress in medical science has vastly improved our understanding of sleep physiology, we still do not know all the functions of sleep.

Sleep spindles: validated concepts and breakthroughs: [review]

INTRODUCTION: Sleep spindles, the hallmark of sleep synchronization in stage 2 non-REM sleep, are rhythmic and monomorphic waves, between 10 and 14 Hz, with a maximum amplitude in the vertex (Cz), with bilateral irradiation to central regions (C3 and C4). OBJECTIVE: In this article we present an overview of sleep spindles ranging from well established concepts of morphology, generation mechanisms, maturational features, abnormal patterns and pathological aspects since the knowledge is important to identify the normal and abnormal patterns. CONCLUSION: Centro-parietal and frontal spindle are normal pattern and extreme spindle is abnormal, mostly found in children mentally retarded up to 5 years-old. In this review research boundaries of memory consolidation, synaptic potentiation and brain plasticity were also presented.

INTRODUÇÃO: Fusos de sono, marco da sincronização do sono no estágio 2 do sono não-REM, são ondas rítmicas e monomórficas, entre 10 e 14 Hz, com amplitude máxima no vértex (Cz), e irradiação bilateral para áreas centrais (C3 e C4). OBJETIVO: Neste artigo apresentamos uma revisão sobre fusos de sono abrangendo conceitos bem estabelecidos de morfologia, mecanismos de geração, características maturacionais, padrões anormais e aspectos patológicos, uma vez que o conhecimento se faz necessário para a identificação de padrões normais e patológicos. CONCLUSÕES: Fusos centro-parietal e frontal são padrões fisiológiocs normais do sono fase 2 enquanto fusos extremos é um padrão patológico encontrado em crianças abaixo de 5 anos com retardo mental. Fronteiras da pesquisas quanto à consolidação da memória, potenciação sináptica e plasticidade cerebral também foram revisados.

Sleep and Panic / 수면정신생리

Nocturnal panic involves sudden awakening from sleep in a state of panic characterized by various somatic sensation of sympathetic arousal and intense fear. Many(18-71%) of the spontaneous panic attacks tend to occur from a sleeping state unrelated to the situational and cognitive context. Nocturnal panickers experienced daytime panics and general somatic sensation more frequently than other panickers. Despite frequent distressing symptoms, these patients tend to exhibit little social or occupational impairment and minimal agoraphobia and have a high lifetime incidence of major depression and a good response to tricyclic antidepressants. Sleep panic attacks arise from non-REM sleep, late stage 2 or early stage 3. The pathophysiology and the similarity of nocturnal panic to sleep apnea, dream-induced anxiety attacks, night terrors, sleep paralysis, and temporal lobe epilepsy are discussed.