• Sleep Medicine and Psychophysiology
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• v.8 no.2
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• pp.121-128
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• 2001

Objectives: In narcoleptic patients diagnosed with ICSD (international classification of sleep disorders, 1990) criteria, nocturnal polysomnography, and MSLT (multiple sleep latency test), we tried to find characteristic features of quantitative electroencephalography (QEEG) in a wakeful state. Methods: We compared eight drug-free narcoleptic patients with sex- and age-matched normal controls, using computerized electroencephalographic mapping technique and spectral analysis. Absolute power, relative power, interhemispheric asymmetry, interhemispheric and intrahemispheric coherence, and mean frequency in each frequency band (delta, theta, alpha and beta) were measured and analyzed. Results: Compared with normal controls, narcoleptic patients showed decrease in monopolar interhemispheric coherence of alpha frequency bands in occipital ($O_1/O_2$), parietal ($P_3/P_4$), and temporal ($T_5/T_6$) areas and beta frequency band in the occipital ($O_1/O_2$) area. Monopolar intrahemispheric coherences of alpha frequency bands in left hemispheric areas ($T_3/T_5$, $C_3/P_3$ & $F_3/O_1$) decreased. Decrease of monopolar interhemispheric asymmetry of delta frequency band in the occipital ($O_1/O_2$) area was also noted. The monopolar absolute powers of beta frequency bands decreased in occipital ($O_2,\;O_z$) areas. Conclusion: Decreases in coherences of narcoleptic patients compared with normal controls may indicate fewer posterior neocortical interhemispheric neuronal connections, and fewer left intrahemispheric neuronal connections than normal controls in a wakeful state. Therefore, we suggest that abnormal neurophysiological sites of narcolepsy may involve complex areas such as neocortex and subcortex as well as the brainstem.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.44-48
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• 2019

Objectives: Insomnia is one of the most prevalent sleep disorders. Recent studies suggest that cognitive and physical arousal play an important role in the generation of primary insomnia. Studies have also shown that information processing disorders due to cortical hyperactivity might interfere with normal sleep onset and sleep continuity. Therefore, focusing on central nervous system arousal and normalizing the information process have become current topics of interest. It has been well known that neurofeedback can reduce the brain hyperarousal by modulating patients' brain waves during a sequence of behavior therapy. The purpose of this study was to investigate effects of neurofeedback therapy on electroencephalography (EEG) characteristics in patients with primary insomnia. Methods: Thirteen subjects who met the criteria for an insomnia diagnosis and 14 control subjects who were matched on sex and age were included. Neurofeedback and sham treatments were performed in a random order for 30 minutes, respectively. EEG spectral power analyses were performed to quantify effects of the neurofeedback therapy on brain wave forms. Results: In patients with primary insomnia, relative spectral theta and sigma power during a therapeutic neurofeedback session were significantly lower than during a sham session ($13.9{\pm}2.6$ vs. $12.2{\pm}3.8$ and $3.6{\pm}0.9$ vs. $3.2{\pm}1.0$ in %, respectively; p < 0.05). There were no statistically significant changes in other EEG spectral bands. Conclusion: For the first time in Korea, EEG spectral power in the theta band was found to increase when a neurofeedback session was applied to patients with insomnia. This outcome might provide some insight into new interventions for improving sleep onset. However, the treatment response of insomniacs was not precisely evaluated due to limitations of the current pilot study, which requires follow-up studies with larger samples in the future.

• Sleep Medicine and Psychophysiology
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• v.14 no.2
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• pp.86-91
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• 2007

Background: Actigraphy is a reliable and valid method for assessing sleep in normal, healthy populations, but it may be less reliable and valid for detecting disturbed sleep in patients. In this study, we attempted to assess the utility of actigraphy in the estimation of sleep quality in patients with obstructive sleep apnea syndrome (OSAS), a major sleep disorder. Method: We analyzed the data of patients who underwent polysomnography (PSG) and actigraphy simultaneously for one night at the Center for Sleep and Chronobiology, Seoul National University Hospital from November 2004 to March 2006. Eighty-nine subjects with OSAS alone and 21 subjects with OSAS and periodic limb movement disorder (PLMD) were included for final data analyses between groups. Polysomnographic and actigraphic data were also compared. Results: In subjects with mild OSAS (RDI<15), modretae ($15{\leq}RDI$<30), and OSAS with PLMD, PSG and actigraphy did not show significant difference in total sleep time and sleep efficiency. However in severe ($30{\leq}RDI$) OSAS subjects, PSG and actigraphy showed significant difference in total sleep time and sleep efficiency. In all patients, no correlations were found between sleep parameters from PSG and from those using actigraphy. Conclusions: We suggest that in severe OSAS patients, PSG is the diagnostic tool. In mild and moderate cases, actigraphy might be used as a screening tool.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.407-421
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• 2016

This paper reports a meta-analysis of sixteen studies that evaluated the efficacy of cognitive behavioral therapy (CBT) for persistent primary insomnia. PubMed, Cochrane Library, EMBASE, CINAHL and several Korean databases were searched between January 2015 and June 2015. The main search strategy involved the terms that indicate CBT-I (Cognitive Behavioral Therapy-Insomnia) and presence of insomnia. Methodological quality was assessed using Cochrane's Risk of Bias. Data were analyzed by the RevMan 5.3 program of Cochrane Library. Sixteen clinical trials met the inclusion criteria, resulting in a total of 1503 participants. Stimulus control, sleep restriction, sleep hygiene education, and cognitive restructuring were the main treatment components. CBT-I was conducted for a mean of 5.4 weeks, 5.5 sessions, and an average of 90 minutes per session. The effects of CBT-i on total sleep time (d=-0.31), sleep onset latency (d=-0.29), awakening time after sleep onset (d=-0.55), sleep efficiency (d=-0.70), insomnia severity (d=-0.77) and sleep belief (d=-0.64) were significant. Overall, we found a range from small to moderate effect size. CBT-I also was effective for anxiety (d=-0.30) and depression (d=-0.35). The findings demonstrate that CBT-I interventions will lead to the improvement of both sleep quality and quantity in patients with insomnia.

• Sleep Medicine and Psychophysiology
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• v.24 no.1
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• pp.24-31
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• 2017

Objectives: Periodic limb movement disorder (PLMD) has been debated with regard to its clinical significance and diagnostic criteria. The current diagnostic criterion for PLMD in adults has been changed from periodic limb movement index (PLMI) > 5/hour to PLMI > 15/hour by the International Classification of Sleep Disorders (ICSD). In this study, we aimed to investigate the changes in polysomnographic sleep variables according to PLMI and to determine the relevance of the diagnostic criterion for PLMD. Methods: Out of 4195 subjects who underwent standard polysomnography, we selected 666 subjects (370 males and 296 females, aged $47.1{\pm}14.8$) who were older than 17 years and were not diagnosed with primary insomnia, sleep apnea, narcolepsy, or REM sleep behavior disorder. Subjects were divided into three groups according to PLMI severity: group 1 ($PLMI{\leq}5$), group 2 (5 < $PLMI{\leq}15$), and group 3 (PLMI > 15). Demographic and polysomnographic sleep variables and Epworth sleepiness scale (ESS) were compared among the three groups. Results: There were significant differences among the three groups in age and gender. Sleep efficiency (SE) and stage 3 sleep percentage in group 1 were significantly higher than those in groups 2 and 3. The wake after sleep onset (WASO) score in group 1 was significantly lower than those in groups 2 and 3. However, there were no significant differences in SE, stage 3 sleep percentage, or WASO between groups 2 and 3. Sleep latency (SL) in group 1 was significantly lower than that in group 3, but there was no difference in SL between group 2 and group 3. ESS score in group 1 was significantly higher than that in group 3, but there was no difference between group 2 and group 3. Partial correlation analysis adjusted by age showed that PLMI was significantly related to SE and WASO. Conclusion: This study suggests that PLMI influences polysomnographic sleep variables. In addition, we found the individuals who did not have PLMD but had PLMI > 5 were not different in polysomnographic sleep variables from the individuals who had PLMD according to the current criterion. These results raise questions about the relevance of the current diagnostic criterion of PLMD.

• Journal of Korean Biological Nursing Science
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• v.11 no.1
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• pp.23-31
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• 2009

Purpose: The purpose of the present study was to investigate the prevalence and related factors of sleep-wake disturbance (SWD) in Korean post-stroke patients. This study was the first to address post-stroke SWD in Korea using a structured questionnaire. Method: We investigated the prevalence of SWD and related factors including lesion location, stroke severity, presence of depression and fatigue. We assessed sleep-wake pattern including quality of sleep, sleep latency, wake episodes, wake time after sleep onset, daytime sleep episode and sleep time at daytime. Ninety stroke patients admitted to a university affiliated hospital in Seoul between the period September 2008 and January 2009 were included in the study. Result: Thirty five patients (38.9%) complained insomnia and 32 (35.6%) complained excessive daytime sleepiness (EDS). Quality of sleep (p=.000), sleep latency (p=.000) and total sleep time (p=.001) were significantly poorer in 16 patients with both insomnia and EDS than in the others. The related factors to insomnia were level of education (p=.030), depression (p=.007) and fatigue (p=.034), though related factors to EDS were stroke onset time (p=.049), stroke severity (p=.005), motor dysfunction (p=.035), dysphasia (p=.018), fatigue (p=.001) and lesion location (p=.019). Conclusion: Sleep-wake disturbance is a common problem in Korean stroke patients. Strategies to improve quality of sleep are urgently needed in the post-stroke patients.

• Journal of Biomedical Engineering Research
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• v.37 no.4
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• pp.127-133
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• 2016

This study proposes the feasibility for automatic classification of sleep/wakefulness using nasal pressure in patients with sleep-disordered breathing (SDB). First, SDB events were detected using the methods developed in our previous studies. In epochs for normal breathing, we extracted the features for classifying sleep/wakefulness based on time-domain, frequency-domain and non-linear analysis. And then, we conducted the independent two-sample t-test and calculated Mahalanobis distance (MD) between the two categories. As a results, $SD_{LEN}$ (MD = 0.84, p < 0.01), $P_{HF}$ (MD = 0.81, p < 0.01), $SD_{AMP}$ (MD = 0.76, p = 0.031) and $MEAN_{AMP}$ (MD = 0.75, p = 0.027) were selected as optimal feature. We classified sleep/wakefulness based on support vector machine (SVM). The classification results showed mean of sensitivity (Sen.), specificity (Spc.) and accuracy (Acc.) of 60.5%, 89.0% and 84.8% respectively. This method showed the possibilities to automatically classify sleep/wakefulness only using nasal pressure.

• Journal of Sleep Medicine
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• v.15 no.2
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• pp.62-67
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• 2018

Objectives: Restless leg syndrome (RLS) is a common sensorimotor disorder and is frequently associated with periodic limb movement in sleep (PLMS). Also about one third of patient with RLS have periodic limb movement during wakefulness (PLMW). However there is little research on the correlation between PLMW and RLS. We aimed to evaluate difference in sleep characteristics between patients with RLS with PLMW and those without PLMW. Methods: Our study included twenty eight RLS patients. Subjects underwent suggested immobilization test (SIT) prior to one full-night polysomnography study. Patients were classified into two groups according to the presence of PLMW based on SIT-PLMW index. Polysomnographic findings, subjective sleep quality, and hematologic results were analyzed and compared between the two groups. Results: Mean age of patient with frequent PLMW (SIT-PLMW ${\geq}40/hr$) was significantly higher. RLS patients with frequent PLMW were also significantly related to insomnia severity. The PLMS index was higher in patients with PLMW and showed a significant correlation with the PLMW index. Conclusions: PLMW influence sleep quality such as insomnia and is correlated with movement during sleep.

• Korean Journal of Psychosomatic Medicine
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• v.11 no.2
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• pp.196-204
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• 2003

Objectives: It is known that sedative hypnotics would make cross tolerance with alcohol and deteriorate quality of sleep in alcoholics. Light therapy is effective non-pharmacological intervention for sleep disturbance in circadian phase disorders, jet-lag, shift-work and age-related sleep disorders. Authors would investigate the effects of morning light therapy on sleep of patients with alcohol dependence during recovery state without withdrawal symptoms. Methods: 13 patients with alcohol dependence who have not any alcohol withdrawal symptom were recruited. Light therapy during 1 hour in the morning had been administered by 2500 Lux light box through serial 3 days. Sleep state of subjects were assessed by sleep log and the subjective satisfaction at sleep was by 100 mm visual analogue scale. Sleepiness, depressive mood, anxiety were evaluated by 100mm visual analogue scale at 8 AM, 2 PM and 8 PM. For assessment of performance ability that would be associated with sleepiness and vigilance, trail making test A, B and digit symbol substitution test were performed by two times on base line and 4th day. Univariate repeated-measures ANOVAs were performed for each measures except performance tests which were analysed by paired t-test. Results: Sleep latency and sleep efficiency were significantly improved with light therapy and satisfaction at sleep was. There was no significant difference in sleepiness at 2 PM with light therapy but sleepiness at 8 AM significantly decreased and at 8 PM increased. The time to complete Trail making test and digit symbol substitution test were significantly shortened at 4th day compared with baseline. Fatigue at 8 AM were not significantly changed with light therapy but at 2 PM and 8 PM significantly decreased. Depressive mood and anxiety were not significantly changed with light therapy. Conclusion: Although this study had some limitations, it showed that light therapy would be effective modality on sleep disturbance of patients with alcohol dependence who have recovered from alcohol withdrawal symptoms. It is proposed that short term light therapy could be used clinically for alcoholics with insomnia. In the future, long term controlled studies using more objective tools for sleep are required to further investigate the effect of light therapy in alcoholics.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.166-175
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• 2017

Objectives: Shiftwork is known to be one of the common causes of sleep and health problems and finally causes the decreased quality of life. The purpose of this study was to investigate the sleep patterns of shift-working and daytime psychiatric nurses using actigraphy and compare it with subjective assessment for sleep. Methods : Twenty-three shift-working and 25 daytime nurses were enrolled. They rated their sleep quality using Pittsburgh Sleep Quality Index(PSQI) and other self-rating scales were measured for psychosocial aspects. Actigraphy was applied to the subjects for a total of 7 days to measure the sleep parameters. They also wrote sleep diaries during the period of wearing actigraphy. Sleep-related parameters of actigraphy, global score and components of PSQI, and the results of other self-rating scales were compared between shift-working and daytime nurses. Results : Although the global score of PSQI did not show significant difference, the PSQI components showed significant differences between two groups: the shift-working nurses showed lower sleep quality, more sleep disturbance and hypnotic medication use, and worsened daytime dysfunction than daytime nurses. The shift-working nurses showed significantly shorter total time in bed and total sleep time, lower sleep efficiency, and longer average awakening time than those of daytime nurses in actigraphy. Conclusions : The results showed that shift-working nurses experienced more sleep disturbances in both subjective and objective aspects of sleep than daytime nurses. This study also suggests that actigraphy may be useful to measure the objective aspects of sleep that are difficult to assess with subjective questionnaires alone.