• Sleep Medicine and Psychophysiology
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• v.3 no.1
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• pp.15-24
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• 1996

After rapid eye movement(REM) sleep was idenified in 1953, a lively interest developed concerning a possible role of this kind of sleep in memory processes. The author reviewed studies relating REM to memory/learning. Many studies in animals and humans gave substantial evidence for relating REM sleep to memory function. The evidence supporting the position taken in this paper comes from experiments showing that : (1) learning session is followed by the significant augmentation of REM sleep : (2) REM sleep deprivation, prior to learning or immediately thereafter, impairs the formation of a permanent memory/learning : (3) there is a vulnerable period of time(eg, REM sleep "window") following succussful learning, during which REM sleep deprivation results in memory impairment : (4) theta rhythm which develops during REM sleep induces long-term potentiation in hippocampus : (5) there are some evidences providing the relationship of neurotransmitter systems to the maintenance of REM sleep and memory storage processes.

• PNF and Movement
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• v.6 no.3
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• pp.19-28
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• 2008

Purpose : The objective of this study was to determine efficacy of sleep-dependent motor learning. Methods : This is a literature study with books and internet. We searched the PubMed, Science Direct, KISS and DBpia. Key words were Sleep-dependent, motor learning, RAM and LTP. Results : Procedural memory, like declarative memory, undergoes a slow, time-dependent period of consolidation. A process has recently been described wherein performance on some procedural task improves with the mere passage of time and has been termed "enhancement". Some studies have reported that the consolidation/enhancement of perceptual and motor skill is dependent on sleep. Specially, rapid-eye-movement(REM) sleep seems to benefit procedural aspects of memory. Conclusion : Motor learning is very important for CNS injury patients. And also distribution of practice sessions is important because REM sleep is to benefit procedural aspects of memory consolidation.

• Sleep Medicine and Psychophysiology
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• v.25 no.2
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• pp.92-95
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• 2018

Catathrenia is a rare sleep disease characterized by monotonous groaning sounds that appear to be related with prolonged expiration, commonly experienced during rapid eye movement (REM) sleep. Catathrenia is also known as nocturnal groaning or sleep-related groaning and is currently categorized as a sleep-related breathing disorder. We present a rare case of a 19-year-old male with nocturnal groaning during non-REM sleep. We suggest that if catathrenia is suspected, polysomnography should be utilized to differentiate it from various sleep disorders such as snoring, central sleep apnea, sleep talking, parasomnia, and sleep-related movement disorders.

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

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.05a
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• pp.209-210
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• 2009

수면단계는 수면감성을 평가하는데 있어서 중요한 생리지표로서 사용되어왔다. 그러나 수면다원검사를 이용한 전통적 수면단계 분류방법은 뇌전도, 안전도, 심전도, 근전도 등을 종합적으로 측정하므로 수면단계를 비교적 정확히 분류할 수 있지만 피험자에게 심한 구속감을 주는 문제가 있다. 본 연구에서는, 각성상태에서 교감신경계가 지배적인 반면에 수면 중에는 부교감신경계가 더 활동적인 점에 착안하여 수면단계를 간단히 분류할 수 있는 방법을 찾고자 수면단계에 따른 심박동변이도(heart rate variability: HRV)를 분석하였다. 단일채널 심전도를 이용하여 수면단계별로 HRV 의 교감신경계/부교감신경계 활성도의 비율을 분석한 결과, W(wakefulness) 단계가 NREN(non REM) 2 단계, 3 단계, 4 단계에 비하여 높게 나타났으며, NREM 4 단계는 REM(rapid eye movement) 단계와 NREM 1단계에 비하여 낮게 나타났다. 또한 교감신경계/부교감신경계 활성도 비율의 수면단계에 따라 변화하는 양상은 W, REM, NREM 1, 2, 3, 4 단계의 순으로 단조 감소하였다.

• Journal of Korean Biological Nursing Science
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• v.23 no.2
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• pp.151-158
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• 2021

Purpose: The purpose of this study was to investigate sleep quality in older adults in nursing home with objective data collection. Methods: Participants included 74 older adults in nursing homes in Korea aged 65 years or above. Data were collected using a wearable device (Fitbit), salivary melatonin level and Sleep Disorder Inventory (SDI). The Pearson correlation coefficient was calculated to examine whether there was any correlation between sleep-related variables such as Total Sleep Time (TST), Rapid Eye Movement (REM) sleep, shallow sleep, deep sleep, salivary melatonin level and SDI. Results: There were distortion of sleep structure, as TST comprised short REM sleep (15.93±5.47%), long shallow sleep (74.18±8.08%) and short deep sleep (9.89±5.03%). Also, salivary melatonin levels were low (15.06±7.77 pg/mL). Moreover, we found than melatonin was significantly associated with TST (r = .251, p= .044), REM sleep (r= .294, p= .020) and deep sleep (r= .391, p= .002). But there was no correlation between SDI and other sleeprelated variables. Conclusion: These findings highlight that insufficient sleep structure is associated with the salivary melatonin level among older adults in nursing home. We suggest developing programs to promote sleep quality of older adults in nursing homes.

• Journal of Oral Medicine and Pain
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• v.42 no.1
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• pp.1-7
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• 2017

Purpose: The aims of this study were to evaluate the clinical characteristics and polysomnographic results of patients visited the Seoul National University Dental Hospital (SNUDH) and to suggest guidelines for the management of sleep disordered-breathing patients in a dental clinic. Methods: Five hundred sixty-two patients who visited the Snoring and Sleep Apnea Clinic of SNUDH were evaluated for clinical characteristics including associated comorbidities, age, gender, body mass index (BMI), neck circumference, and daytime sleepiness and among them 217 patients were performed nocturnal polysomnography for evaluating respiratory disturbance index, apnea-hypopnea index (AHI), oxygen saturation levels, and sleep stages. The associations among clinical characteristics, sleep parameters, and positional and rapid eye movement (REM) dependencies of the patients were analyzed. Results: The most common co-morbidities of the patients were cardiovascular (30.2%), endocrine (10.8%), and respiratory diseases (7.9%). Age (${\beta}=0.394$), total AHI (${\beta}=0.223$), and lowest $O_2$ saturation levels (${\beta}=0.205$) were significantly associated with the number of co-morbidities in patients with obstructive sleep apnea (OSA). Mean $O_2$ saturation was not significantly associated with number of co-morbidities. Non-positional OSA patients had higher BMI, longer neck circumferences, more severe AHI values, and lower mean and lowest $O_2$ saturation levels compared to positional OSA patients. Not-REM-related patients were older and had more severe AHI values compared to REM-related patients. Not-REM-related patients have longer duration of stage I sleep and shorter stage II, III, and REM sleep than REM-related patients. There were no significant differences in each sleep stage between positional and non-positional patients. Neck circumference, positional dependency, REM dependency, and percentage of supine position were significantly associated with severity of OSA. Conclusions: Age, total AHI, and lowest $O_2$ saturation level were significantly associated with the number of co-morbidities in patients with OSA. Neck circumference, positional dependency, REM dependency, and percentage of supine position were significantly associated with severity of OSA.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.3
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• pp.239-243
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• 2002

Multi-valued decision making for transitional stochastic events was newly derived based on conditional probability of knowledge database which included experts'knowledge and experience. The proposed multi-valued decision making was successfully adopted to the determination of the five levels of the vigilance of a subject during the EEG (electroencephalogram) recording; awake stage (stage W), and sleep stages (stage REM (rapid eye movement), stage 1, stage 2, stage $\sfrac{3}{4}$). Innovative feature of the proposed method is that the algorithm of decision making can be constructed only by use of the knowledge database, inspected by experts. The proposed multi-valued decision making with a mathematical background of the probability can also be applicable widely, in industries and in other medical fields for purposes of the multi-valued decision making.

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

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.1
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• pp.27-36
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• 2017

Angelicae Gigantis Radix (AGR, Angelica gigas) has been used for a long time as a traditional folk medicine in Korea and oriental countries. Decursinol angelate (DCA) is structurally isomeric decursin, one of the major components of AGR. This study was performed to confirm whether DCA augments pentobarbital-induced sleeping behaviors via the activation of $GABA_A$-ergic systems in animals. Oral administration of DCA (10, 25 and 50 mg/kg) markedly suppressed spontaneous locomotor activity. DCA also prolonged sleeping time, and decreased the sleep latency by pentobarbital (42 mg/kg), in a dose-dependent manner, similar to muscimol, both at the hypnotic (42 mg/kg) and sub-hypnotic (28 mg/kg) dosages. Especially, DCA increased the number of sleeping animals in the sub-hypnotic dosage. DCA (50 mg/kg, p.o.) itself modulated sleep architectures; DCA reduced the counts of sleep/wake cycles. At the same time, DCA increased total sleep time, but not non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. In the molecular experiments. DCA (0.001, 0.01 and $0.1{\mu}g/ml$) increased intracellular Cl- influx level in hypothalamic primary cultured neuronal cells of rats. In addition, DCA increased the protein expression of glutamic acid decarboxylase ($GAD_{65/67}$) and $GABA_A$ receptors subtypes. Taken together, these results suggest that DCA potentiates pentobarbital-induced sleeping behaviors through the activation of $GABA_A$-ergic systems, and can be useful in the treatment of insomnia.