• Sleep Medicine and Psychophysiology
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• v.24 no.2
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• pp.106-117
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• 2017

Objectives: Obstructive sleep apnea (OSA) is a sleep-related breathing disorder that is characterized by repetitive collapse or partial collapse of the upper airway during sleep in spite of ongoing effort to breathe. It is believed that OSA is usually worsened in REM sleep, because muscle tone is suppressed during REM sleep. However, many cases showed a higher apnea-hypopnea index (AHI) during NREM sleep than during REM sleep. We aimed here to determine the characteristics of REM sleep-dependent OSA (REM-OSA) and NREM sleep-dependent OSA (NREM-OSA). Methods: Five hundred sixty polysomnographically confirmed adult OSA subjects were studied retrospectively. All patients were classified into 3 groups based on the ratio between REM-AHI and NREM-AHI. REM-OSA was defined as REM-AHI/NREM-AHI > 2, NREM-OSA as NREM-AHI/REM-AHI > 2, and the rest as sleep stage-independent OSA (IND-OSA). In addition to polysomnography, questionnaires related to subjective sleep quality, daytime sleepiness, and emotion were completed. Chi-square test, ANOVA, and ANCOVA were performed. Results: There was no age difference among subgroups. The REM-OSA group was comprised of large proportions of mild OSA and female OSA patients. These patients experienced poor sleep and more negative emotions than other two groups. The AHI and oxygen desaturation index (ODI) were lowest in REM-OSA. Sleep efficiency and N3 percentage of REM-OSA were higher than in NREM-OSA. The percentage of patients who slept in a supine position was higher in REM-OSA than other subgroups. IND-OSA showed higher BMI and larger neck circumference and abdominal circumference than REM-OSA. The patients with IND-OSA experienced more sleepiness than the other groups. AHI and ODI were highest in IND-OSA. NREM-OSA presented the shortest total sleep time and the lowest sleep efficiency. NREM-OSA showed shorter sleep latency and REM latency and higher percentage of N1 than those of REM-OSA and the highest proportion of those who slept in a lateral position than other subgroups. NREM-OSA revealed the highest composite score on the Horne and ${\ddot{O}}stberg$ questionnaire. With increased AHI severity, the numbers of apnea and hypopnea events during REM sleep decreased, and the numbers of apnea and hypopnea events during NREM sleep increased. The results of ANCOVA after controlling age, sex, BMI, NC, AC, and AHI showed the lowest sleep efficiency, the highest AHI in the supine position, and the highest percentage of waking after sleep onset in NREM-OSA. Conclusion: REM-OSA was associated with the mild form of OSA, female sex, and negative emotions. IND-OSA was associated with the severe form of OSA. NREM-OSA was most closely related to position and showed the lowest sleep efficiency. Sleep stage-dependent characteristics could provide better understanding of OSA.

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

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.190-195
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• 1997

Medilog SAC847 수면종합분석시스템을 이용하여 침대와 온돌에서 성인 남 자가 수면시 피험자의 뇌전도, 턱근전도, 다리근전도, 심전도, 안전도(눈) 등의 생리신호를 동시 측정하여수면단계기록국제기준에 근거하여 NREM 4단 계와 REM 단계의 수면시간을 산정 하였다. 수면감을 평가하기 위하여 침대 와 온돌에서 수면시 입면지연시간과 NREM 단계4의 수면시간 비중을 고찰한 결과 침대수면이 온돌수면보다 입면지연 시간이 더짧게 나타났으며 나머지 NREM 4단계와 REM 단계에 소요된 수면시간은 서로 비슷하게 나타났다. 본 연구를 통한 수면생리신호 분석연구는 쾌적침대개발에 활용하고자 한다.

• Journal of Ginseng Research
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• v.32 no.3
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• pp.220-225
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• 2008

The present investigation was performed to evaluate the homeostatic regulation of sleep architecture by the ethanol extract of Korea red ginseng (KRG), since the available data were often controversial. In addition, it was also interested in whether the sleep-wake stages were differently affected by low and high doses of KRG. Each adult Wistar male rat was implanted with a transmitter for recording EEG and activity via telemetry. After one week of surgery, polygraphic signs of undisturbed sleep-wake activities were recorded for 12 h (between 9:00 am and 9:00 pm) after KRG administration. KRG (10 and 100 mg/kg) increased non-rapid eye movement (NREM) sleep as well as total sleep. The total percentages of wakefulness were decreased comparably. KRG (10 mg/kg) decreased the power density of the ${\delta}-wave$ (0.75-4.5 Hz) and increased ${\alpha}-wave$ (8.0-13.0 Hz) in the NREM and rapid eye movement (REM) sleep. KRG also decreased ${\delta}-wave$ power density in wake time. However, KRG (100 mg/kg) increased ${\delta}-wave$ and decreased ${\theta}-wave$ (5.0-9.0 Hz) power density in wake time, while showed little effect on the power density in NREM and REM sleep. In conclusion, low and high doses of KRG increase spontaneous sleep and NREM sleep and differently regulate the EEG spectra in REM and NREM sleep.

• Journal of Ginseng Research
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• v.34 no.1
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• pp.30-40
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• 2010

The present investigation was conducted to evaluate the regulation of sleep architecture by the red ginseng water extract (RGE) in acutely and chronically restraint stressed rats. Adult rats were fitted with sleep.wake recording electrodes. Following post-surgical recovery, rats were extensively habituated for freely moving polygraphic recording conditions. Polygraphic signs of sleep-wake activities were recorded for 24 h after RGE administration and induction of stress and were analyzed to understand the regulation of sleep architecture. Acute stress decreased wakefulness and increased total sleep, non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep in both the daytime and nighttime recording. RGE shortened the daytime NREM and REM sleep, without changing the wakefulness and total sleep. RGE increased nighttime wakefulness, and decreased total, NREM and REM sleep. Chronic stress increased wakefulness and decreased total sleep in the daytime recording, and increased REM and decreased NREM sleep in both the day and night time recording. RGE ameliorated chronic stress and induced alterations of REM and NREM sleep in the day and night time sleep architecture. Acute and chronic stress could also induce alternations in cortex electroencephalogram (EEG) recording during NREM, REM sleep and wakefulness. These findings suggest that RGE may modulate the sleep behavior in acutely and chronically stressed rats and the ameliorating effect of RGE on the sleep architecture may involve in modulation of $\alpha$-, $\theta$- and $\delta$- wave activities of the cortical EEG.

• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.107-118
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• 2007

Background : It is well known that non-rapid eye movement(NREM) sleep activates the occurrence of interictal epileptiform discharges(IED) in many epileptic syndromes. We performed this study to assess the effect of NREM sleep on IED in epileptic patients with organic brain lesions. Materials and Methods : We analyzed awake and sleep electroencephalopathy(EEG) recorded simultaneously after partial sleep deprivation in 50 patients. We calculated the awake and sleep spike index (ASI and SSI, spikes/epoch), and the percentage increase of ASI and SSI during sleep. Results : In the 50 patients, the IEDs were recorded exclusively during the awake state in 1 (2%) patient, and during the sleep state in 13(26%) patients. The SSI was higher in 44 (88%) patients, and the ASI was higher in 5 (10%) patients. The mean ASI and the SSI in patients with organic brain lesions were $0.058{\pm}0.121$ and $0.148{\pm}0.187$, and it was $0.081{\pm}0.150$ and $0.174{\pm}0.226$ in patients without organic brain lesions. There were significant increases in the spike index (P<0.05) during NREM sleep in both groups (n=36), but no significant difference in the percent increase of spike index (P>0.05). Conclusion : The IEDs were activated significantly during NREM sleep both in patients with and without organic brain lesions, but there were no differences in the degree of activation in both groups. The activating effect of NREM sleep was not correlated with clinical factors such as, frequent nocturnal seizures, frequent generalized tonic clonic seizures, type of epilepsy and taking anticonvulsants. We conclude that the routine EEG used to evaluate epileptiform discharges in epileptic patients should include sleep recordings after partial sleep deprivation.

• Natural Product Sciences
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• v.15 no.4
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• pp.213-221
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• 2009

Longanae Arillus (the rind of fruits of Dimocarpus longan) has been consumed for the treatment of insomnia and anxiety in Asia. To provide further scientific basis to traditional uses of this fruit on insomnia, we evaluated the effects of methanol extract of Longanae Arillus (MELA) on the alteration of sleep architecture and electroencephalogram (EEG) power spectra in acutely and chronically restraint-stressed rats. Following postsurgical recovery, Polygraphic signs of sleep-wake activities were recorded for 24 h after MELA administration in rats. Rats in the acute stress and chronic stress were administered with MELA for 10 days. On the $8^{th},\;9^{th}\;and\;10^{th}$ day of MELA administration, the rats were stressed for 3 h once per day. On the $10^{th}$ day and 1 h after MELA administration, the rats were stressed once for 22 h in the chronic stress group. Acute and chronic stress induced alternations in cortex EEG recordings during non-rapid eye movement (NREM), rapid eye movement (REM) sleep and wakefulness. MELA shortened the total and REM sleep and increased the wakefulness in night time recording without changing daytime recordings. Chronic stress increased wakefulness and REM sleep, decreased total and NREM sleep in the daytime recording, and increased REM and decreased NREM sleep without changing total sleep and wakefulness in night time recording. These findings suggest that MELA ameliorated the alterations in REM and NREM sleep of acutely and chronically stressed rats via modulation of cortical ${\alpha}-$, ${\theta}-$ and ${\delta}-$ wave activity.

• Journal of Ginseng Research
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• v.36 no.4
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• pp.403-410
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• 2012

The current inquiry was conducted to assess the change in sleep architecture after long periods of administration to determine whether ginseng can be used in the therapy of sleeplessness. Following post-surgical recovery, red ginseng extract (RGE, 200 mg/kg) was orally administrated to rats for 9 d. Data were gathered on the 1st, 5th, and 9th day, and an electroencephalogram was recorded 24 h after RGE administration. Polygraphic signs of unobstructed sleep-wake activities were simultaneously recorded with sleep-wake recording electrodes from 11:00 a.m. to 5:00 p.m. for 6 h. Rodents were generally tamed to freely moving polygraphic recording conditions. Although the 1st and 5th day of RGE treatment showed no effect on power densities in nonrapid eye movement (NREM) and rapid eye movement (REM) sleep, the 9th day of RGE administration showed augmented ${\alpha}$-wave (8.0 to 13.0 Hz) power densities in NREM and REM sleep. RGE increased total sleep and NREM sleep. The total percentage of wakefulness was only decreased on the 9th day, and the number of sleep-wake cycles was reduced after the repeated administration of RGE. Thus, the repeated administration of RGE increased NREM sleep in rats. The ${\alpha}$-wave activities in the cortical electroencephalograms were increased in sleep architecture by RGE. Moreover, the levels of both ${\alpha}$- and ${\beta}$-subunits of the ${\gamma}$-aminobutyric acid $(GABA)_A$ receptor were reduced in the hypothalamus of the RGE-treated groups. The level of glutamic acid decarboxylase was over-expressed in the hypothalamus. These results demonstrate that RGE increases NREM sleep via $GABA_A$ergic systems.

• Sleep Medicine and Psychophysiology
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• v.8 no.2
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• pp.83-89
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• 2001

In all ages and countries, dreaming has always been a topic that has interested people. Throughout history, theories about dreaming have been heavily dependent on concurrent theories in related domains. Many researchers have claimed that dreaming occurs during REM and NREM sleep and have rejected the strict association between REM sleep mechanisms and dreams. Although dreams may occur in both REM and NREM periods, they are likely to be produced by different mechanisms during REM and NREM sleep. All physicians managing dreaming-related problems in clinical practice need to understand the multidimensional aspects of dreaming. Therefore, I have reviewed the literature on mechanisms generating and the meaning of dreaming in the neurobiological and psychophysiological perspectives.

• 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.