• Sleep Medicine and Psychophysiology
• /
• v.18 no.2
• /
• pp.67-71
• /
• 2011

Schizophrenia is a chronic, currently incurable, and devastating syndrome. Although sleep disturbances are not primary symptoms of schizophrenia, they are important aspects of schizophrenia. Difficulties initiating or maintaining sleep are frequently encountered in patients with schizophrenia. Many schizophrenics report low subjective sleep quality. Measured by polysomnography, increased sleep latency as well as reduced total sleep time, sleep efficiency, slow wave sleep, and rapid eye movement sleep latency (REM latency), are found in most patients with schizophrenia and appear to be an important aspect of the pathophysiology of this disorder. Some literatures suggest that worsening sleep quality precedes schizophrenic exacerbations. Co-morbid sleep disorders such as obstructive sleep apnea (OSA) and restless legs syndrome (RLS), and sleep-disrupting behaviors associated with schizophrenia may lead to sleep disturbances. Clinicians should screen the patient with sleep complaints for primary sleep disorders like OSA and RLS, and carefully evaluate sleep hygiene behaviors of all patients with schizophrenia who complain of sleep disturbances.

• Korean Journal of Clinical Laboratory Science
• /
• v.39 no.3
• /
• pp.264-270
• /
• 2007

Obstructive sleep apnea syndrome (OSAS) is defined by sleep apnea with decreased oxygen saturation, excessive snoring with daytime sleepiness, and frequent awakening during the night time sleep. The present study was performed to investigate how apnea-hypopnea, that possibly causes breathing disturbance during sleep, can affect sleep pattern in patients with OSAS. We included 115 patients (92 men, 23 women) who underwent a polysomnography from January 2006 to May 2007. As the frequency of sleep apnea-hypopnea increases, the proportion of non-rapid eye movement (REM) sleep (p<0.001), and stage I sleep (p<0.001) increased, while that of stage II sleep (p<0.001), stage III and IV sleep (p<0.01), and REM sleep (p<0.05) decreased. Furthermore, sleep apnea-hypopnea was closely correlated with REM sleep (r=0.314, p<0.001), stage I sleep (r=0.719, p<0.001), stage II sleep (p=-0.342, p<0.05), stage III and IV sleep (r=-0.414, p<0.001), and REM sleep (r=-0.342, p<0.05). Stage I sleep could account for the 51% of the variance of apnea-hyponea. Our study shows sleep apnea-hypopnea affects sleep pattern in pattern with OSAS significantly, and the change of stage I sleep is the most important factor in estimating the disturbance of sleep pattern.

• Sleep Medicine and Psychophysiology
• /
• v.7 no.2
• /
• pp.79-83
• /
• 2000

Sleep disturbances are frequently associated with neurological disorders. Sleep disorders interfere with rehabilitation of patients with neurological disorders such as stroke and may increase the severity of their symptoms and recurrence rate of stroke. The treatment of sleep apnea syndrome is particularly important in managing patients with cerebral infarction of whom 50-80% have moderate to severe sleep apnea. Sleep apnea produces not only poor quality sleep but also excessive daytime sleepiness, fatigue and lack of energy. Sleep problems frequently found in patients with dementia are sleep-wake cycle abnormality, fragmentation of sleep, nocturnal insomnia, decreased slow wave sleep and REM sleep, and sleep disordered breathing. The management of sleep disturbances is very important for controlling symptoms such as nocturnal wandering and sundowning syndrome in patients with dementia. Parkinson's disease and epilepsy are other neurological disorders that may have sleep disturbances.

• Sleep Medicine and Psychophysiology
• /
• v.19 no.2
• /
• pp.63-67
• /
• 2012

The reciprocal interaction between sleep and pain has been reported by numerous studies. Patients with acute or chronic pain often complain of difficulty falling asleep, frequent awakenings, shorter sleep duration, unrefreshing sleep, and poor sleep quality in general. According to the majority of the experimental human studies, sleep deprivation may produce hyperalgesic changes. The selective disruption of slow wave sleep has shown this effect more consistently, while results after selective REM sleep deprivation remain unclear. Patients with chronic pain have a marked alteration of sleep structure and continuity, such as frequent sleep-stage shifts, increased nocturnal awakenings, decreased slow wave sleep (SWS), decreased rapid eye movement (REM) sleep, and alpha-delta sleep. Many analgesic medications can alter sleep architecture in a manner similar to the effects of acute and chronic pain, suppressing SWS and REM sleep.

• Sleep Medicine and Psychophysiology
• /
• v.14 no.1
• /
• pp.5-12
• /
• 2007

Sleep changes substantially with age. There is a phase advance in the circadian sleep cycle and increased waking after sleep onset. The elderly people wake more frequently during the night and experience fragmented sleep and excessive daytime sleepiness. The prevalence of sleep disorders increases with age, and the composition of sleep disorders in the elderly differs from that in the young. The most frequently encountered sleep disorders are psychophysiologic insomnia, sleep disturbance due to dementia, sleeprelated respiratory disorder, restless legs syndrome and periodic limb movement disorder, and REM sleep behavior disorder. To treat the elderly sleep problem appropriately, it is important to know how sleep pattern changes as we age and to understand the cause of sleep-related symptoms. This article will review the sleep physiology and common sleep disorders in the elderly.

• Clinical and Experimental Pediatrics
• /
• v.50 no.8
• /
• pp.711-717
• /
• 2007

Sleep is a vital, highly organized process regulated by complex systems of neuronal networks and neurotransmitters. Normal sleep comprises non-rapid eye movement (NREM) and REM periods that alternate through the night. Sleep usually begins in NREM and progresses through deeper NREM stages (2, 3, and 4 stages), but newborns enter REM sleep (active sleep) first before NREM (quiet sleep). A period of NREM and REM sleep cycle is approximately 90 minutes, but newborn have a shorter sleep cycle (50 minutes). As children mature, sleep changes as an adult pattern: shorter sleep duration, longer sleep cycles and less daytime sleep. REM sleep is approximately 50% of total sleep in newborn and dramatically decreases over the first 2 years into adulthood (20% to 25%). An initial predominant of slow wave sleep (stage 3 and 4) that peaks in early childhood, drops off abruptly after adolescence by 40% from preteen years, and then declines over the life span. The hypothalamus is recognized as a key area of brain involved in regulation of sleep and wakefulness. The basic function of sleep largely remains elusive, but it is clear that sleep plays an important role in the regulation of CNS and body physiologic processes. Understanding of the architecture of sleep and basic mechanisms that regulate sleep and wake cycle are essential to evaluate normal or abnormal development of sleep pattern changes with age. Reduction or disruption of sleep can have a significant impact on daytime functioning and development, including learning, growth, behavior, and emotional regulation.

• Sleep Medicine and Psychophysiology
• /
• v.3 no.1
• /
• pp.47-55
• /
• 1996

Narcolepsy is characterized by sleep attack with excessive daytime sleepiness(EDS), cataplexy, sleep paralysis, and hypnagogic hallucination. Paradoxically, narcoleptics tend to complain of frequent arousals and shallow sleep during the night time despite their excessive sleepiness. However, nocturnal sleep fragmentation in narcoleptics is relatively ignored in treatment strategies, compared with sleep attack/EDS and cataplexy. In our paper, we attempted to investigate further on the poor nocturnal sleep in narcoleptics and to discuss possible treatment interventions. Out of consecutively seen patients at Seoul National University Sleep Disorders Clinic and Division of Sleep Studies, we recruited 57 patients, clinically assessed as having sleep attack and/or EDS. Nocturnal polysomnography and multiple sleep latency test(MSLT) were done in each of the subjects. We selected 19 subjects finally diagnosed as narcolepsy(mean age $26.0{\pm}18.3$ years, 16 men and 3 women) for this study, depending on the nocturnal polysomnographic and MSLT findings as well as clinical history and symptomatology. Any subject co-morbid with other hypersomnic sleep disorders such as sleep apnea or periodic limb movements during sleep was excluded. Sleep staging was done using Rechtschaffen and Kales criteria. Sleep parameters were calculated using PSDENT program(Stanford Sleep Clinic, version 1.2) and were compared with the age-matched normal values provided in the program. In narcoleptics, compared with the normal controls, total wake time was found to be significantly increased with significantly decreased sleep efficiency(p<.01, p<.05, respectively), despite no difference of sleep period time and total sleep time between the two groups. Stage 2 sleep%(p<.05), slow wave sleep%(p<.05), and REM sleep%(p<.01) were found to be significantly decreased in narcoleptics compared with normal controls, accompanied by the significant increase of stage 1 sleep%(p<.01). Age showed negative correlation with slow wave sleep%(p<.05). The findings in the present study indicate significant fragmentation of nocturnal sleep in narcoleptics. Reduction of REM sleep% and the total number of REM sleep periods suggests the disturbance of nocturnal REM sleep distribution in narcoleptics. No significant correlations between nocturnal polysomnographic and MSLT variables in narcoleptics suggest that nocturnal sleep disturbance in narcoleptics may be dealt with, in itself, in diagnosing and managing narcolepsy. With the objective demonstration of qualitative and quantitative characteristics of nocturnal and daytime sleep in narcoleptics, we suggest that more attention be paid to the nocturnal sleep fragmentation in narcoleptics and that appropriate treatment interventions such as active drug therapy and/or circadian rhythm-oriented sleep hygiene education be applied as needed.

• Sleep Medicine and Psychophysiology
• /
• v.6 no.2
• /
• pp.102-109
• /
• 1999

Headaches and sleep problems are common complaints in clinical practice. The relationship of sleep and headache has been extensively studied. Brain systems involved in the regualtion of sleep may also play a role in the initiation of vascular headache. Some of the physiological alterations in sleep, particularly REM sleep, are similar to those described in vascular headache. Clinical studies have documented an association between vascular headache and sleep, and headache is a common symptom of sleep disorders. Sleep and headache are known to be interrelated in several ways. It can be summarized as follows: 1) sleep-related headaches, 2) sleep phase-related headaches, 3) length of sleep(excess, lack, and disruption) and headaches, 4) headache related to sleep associated behavior, 5) sleep disorders and headaches, 6) effects of headaches on sleep, and 7) dreams and headaches. Several mechanisms can be proposed to explain the relationship between sleep and headaches.

• Sleep Medicine and Psychophysiology
• /
• v.12 no.2
• /
• pp.87-92
• /
• 2005

Cytokines are the main regulatory molecules of not only immune system but also sleep system. Research on the role of cytokines on sleep has greatly been expanding since the first report of sleep-promoting effects of interleukin-1, the first cytokine molecule. Interleukin-1 and tumor necrosis factor are most widely studied among various cytokines. Studies over about twenty years demonstrate that most cytokines promote sleep but several cytokines inhibit sleep. Slow wave sleep is the main part that cytokines have effects on. Besides normal sleep physiology, cytokines have more major roles on pathophysiology of various sleep disorders. Obstructive sleep apnea is the representative sleep disorder that shows how deeply cytokines are involved in their pathophysiologic mechanisms of sleep disorders. Though there are many controversial issues on this topic, more mysterious part of normal sleep physiology and sleep disorders will be revealed in near future through thorough studies on sleep and cytokine.

• Journal of mucopolysaccharidosis and rare diseases
• /
• v.1 no.2
• /
• pp.35-39
• /
• 2015

Sleep problems occur frequently among patients with Prader-Willi syndrome (PWS). The most common problem is excessive daytime sleepiness (EDS) that are closely related to of sleep-related breathing disorder (SRBD) such as obstructive sleep apnea (OSA) and congenital hypoventilation syndrome. Obesity, craniofacial dysmorphism and muscular hypotonia of patients with PWS may increase the risk of SRBD. Sleep apneas can interrupt the continuity of sleep, and these disruptions result in a decrease in both the quality and quantity of sleep. In addition to SRBD, other sleep disorders have been reported, such as hypersomnia, a primary abnormality of the rapid eye movement (REM) sleep and narcolepsy traits at sleep onset REM sleep. Patients with PWS have intrinsic abnormalities of sleep-wake cycles due to hypothalamic dysfunction. The treatment of EDS and other sleep disorders in PWS are similar to standard treatments. Correction of sleep hygiene such as sufficient amount of sleep, maintenance of regular sleep-wake rhythm, and planned naps are important. After comprehensive evaluation of sleep disturbances, CPAP or surgery should be recommended for treatment of SRBD. Remaining EDS or narcolepsy-like syndrome are controlled by stimulant medication. Bright light therapy might be beneficial for disturbed circadian sleep-wake rhythm caused by hypothalamic dysfunction.