• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.2
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• pp.246-254
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• 2018

Psychological stress and physical fatigue, such as anxiety, fear, sleep disturbance, etc., caused by exposure to the war, can lead to post-traumatic stress syndrome(PTSD) or war syndrome. The military has also prepared for drug use to minimize war syndrome and preserve combat strength. However, efforts to prevent war syndrome are still lacking. This study was conducted to identify biomarkers that can track psychophysiological changes. Psychophysiological changes associated with PTSD can be divided into four main categories. The four categories are behavioral changes, changes in brain cognition, neuroimmunological changes, and changes in innate immunity. This study suggest that biomarker profile can be made by the distance moved and the anxiety-like behavior in the open field for behavior category, brain BDNF levels in the brain cognition category, serum corticosterone in the neuroimmunology category, and inflammatory cytokine levels in the innate immunity category.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.30 no.1
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• pp.42-44
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• 2019

Hashimoto's encephalopathy (HE) is a rare and underdiagnosed neuropsychiatric illness. We present the case of a 17-year-old girl who was admitted to a tertiary-care psychiatric center with acute onset psychosis and fever. Her psychotic symptoms were characterized by persecutory and referential delusions, as well as tactile and visual hallucinations. Her acute behavioral disturbance warranted admission and treatment in a psychiatric setting (risperidone tablets, 3 mg/day). She had experienced an episode of fever with a unilateral visual acuity defect approximately 3 years before admission, which was resolved with treatment. Focused clinical examination revealed an enlarged thyroid, and baseline blood investigations, including thyroid function test results were normal. Abnormal laboratory investigations revealed elevated anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) levels (anti-TPO of 480 IU/mL; anti-TG of 287 IU/mL). Results of other investigations for infection, including cerebrospinal fluid examination, electroencephalography, and brain magnetic resonance imaging were normal. She was diagnosed with HE and was treated with intravenous corticosteroids (methylprednisolone up to 1 g/day; tapered and discontinued after a month). The patient achieved complete remission of psychotic symptoms and normalization of the anti-thyroid antibody titers. Currently, at the seventh month of follow-up, the patient is doing well. This case highlights the fact that in the absence of well-defined clinical diagnostic criteria, a high index of suspicion is required for early diagnosis of HE. Psychiatrists need to explore for organic etiologies when dealing with acute psychiatric symptoms in a younger age group.

• 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.

• Sleep Medicine and Psychophysiology
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• v.14 no.2
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• pp.92-98
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• 2007

Objectives: Obstructive sleep apnea syndrome (OSAS) is the most common form of sleep-disordered breathing and often presents with comorbid depressive symptoms. In this study, we evaluated the relationship between depressive symptoms and sleep parameters as measured by nocturnal polysomnography (NPSG) and simultaneous wrist actigraphy. Methods: Two hundred sixty-four subjects with clinically suspected cases of OSAS underwent one-night polysomnography, while simultaneously wearing a wrist actigraphy device. They also completed two questionnaires；the Epworth Sleepiness Scale-Korean version (ESS-K) and the Beck Depression Inventory (BDI). Of the cases studied, 105 subjects were proven by NSPG to have OSAS without other sleep disorders. NPSG and wrist actigraphy data from the subjects were analyzed. Pearson correlation and paired t-test were used in order to evaluate the relationship between depressive symptoms and sleep-parameters. Results: Mean age of the subjects was $46.1{\pm}13.1$ years. Means of the ESS-K score and BDI scores were $10.9{\pm}4.7$ and $12.8{\pm}8.1$, respectively. NPSG sleep parameters significantly differed from those of wrist actigraphy. There was no correlation found between subjects' respiratory disturbance index (RDI) and BDI scores. When directly comparing sleep parameters between subjects who were more depressed versus subjects who were less depressed, both total sleep time and sleep efficiency were decreased in the more depressed. A correlation between RDI and ESS-K scores was also found in the more depressed group. Conclusions: Although our findings suggest that there is no relationship between RDI and depressive symptoms, there are other significant differences in the sleep parameters between subjects who are more depressed versus those without depression. We recommend that patients with depression should also be evaluated for clinical symptoms of OSAS.

• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.68-71
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• 2005

We report a case of obstructive sleep apnea syndrome, which occurred primarily during the REM sleep stage. A 55-year-old female patient who complained of chronic insomnia on the initial visit turned out to have obstructive sleep apnea syndrome of a mild degree (respiratory disturbance index (RDI) of 13.8/hour, %time spent below 90% of SaO2=5.0%) on nocturnal polysomnography. Interestingly, apnea episodes and desaturations mainly occurred during REM sleep stage. And RDI and destaturations during REM sleep stage were found to be severe enough to classify as a severe degree of obstructive sleep apnea syndrome. These findings suggest that severe obstructive sleep apnea syndrome might be masked under the symptom of chronic insomnia and that apneas can be predominantly localized within REM sleep epochs. In terms of treatment, "REM sleep-dependent" apneas may call for different methods of treatment, especially REM sleep-specific pharmacological intervention.

• Sleep Medicine and Psychophysiology
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• v.11 no.1
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• pp.50-54
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• 2004

The obstructive sleep apnea syndrome can occur due to various etiologies in children. In otherwise healthy children, adenotonsillar hypertrophy is the leading cause of childhood obstuctive sleep apnea. Obstructive sleep apnea caused by adenotonsillar hypertrophy can lead to a variety of symptoms and sequelae such as behavioral disturbance, enuresis, failure to thrive, developmental delay, cor pulmonale, and hypertension. So if obstructive sleep apnea is clinically suspected, proper treatment should be administered to the patient after diagnostic examinations. More than 80% improvement is seen in symptoms of obstructive sleep apnea caused by adenotonsillar hypertrophy in children after tonsillectomy and adenoidectomy. However, when it is impossible to treat the patient using surgical methods or residual symptoms remained after tonsillectomy and adenoidectomy, additional treatments such as weight control, sleep position change, and continuous positive airway pressure (CPAP), should be considered. This paper reports a case using weight control and Auto-PAP to control mild sleep apnea and snoring, which in long-term follow-up were not resolved after tonsillectomy and adenoidectomy for severe obstructive sleep apnea.

• Convergence Security Journal
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• v.18 no.1
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• pp.117-128
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• 2018

The purpose of this paper is to analyze the behavior of North Korea's cyber attack against South Korea since 2009 based on major international security theories and suggest South Korea's policy option. For this purpose, this paper applied the behavioral domain and characteristics of 'cyber power' and 'coercion dynamics' model, which are attracting attention in international security studies. The types of cyber attacks from North Korea are classified into the following categories: power-based incarceration, leadership attacks and intrusions, military operations interference, and social anxiety and confusion. In terms of types and means of cyber power, North Korean GPS disturbance, the Ministry of Defense server hacking and EMP are hard power with high retaliation and threat and cyber money cashing and ransomware are analyzed by force in the act of persuasion and incentive in the point of robbing or asking for a large amount of money with software pawns. North Korea 's cyber attack has the character of escape from realistic sanctions based on the second nuclear test. It is important for South Korea to clearly recognize that the aggressive cyberpower of North Korea is changing in its methods and capabilities, and to ensure that North Korea's actions result in far greater losses than can be achieved. To do this, it is necessary to strengthen the cyber security and competence to simultaneously attack and defend through institutional supplement and new establishment such as cyber psychological warfare, EMP attack preparation, and enhancement of security expertise against hacking.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.1-15
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• 2020

This study was conducted to determine whether invasive muskrats settle in the natural ecosystem of Korea. The study also aimed to provide information on the selection of target areas, basic behavioral characteristics, and habitat use-related data, all of which are essential for effective management strategy establishment and site management. To this end, a trend in international muskrat management was identified to examine the management direction according to the settlement stage. We also secured the location of 72 domestic farmers and classified five regions in Gyeonggi-do, Chungcheongnam-do, Gyeongsangbuk-do, and Sejong Special Self-governing City into regions with high potential for natural leakage to raise the need for a quick survey. We determined that muskrats successfully settled in the natural ecosystem of Korea, based on the fact that we consistently identified a muskrat habitat at the same point for three years, from 2016 to 2018, the age of the captured population was estimated to be 1.2 years, and there had been no additional make-up factors near the habitat since 2012. The muskrats that settled in Korea showed a small home range of 0.0027 ㎢ (MCP 95%) and were estimated to show regular mobility before Spring and Autumn. Also, the areas where the muskrat habitat was observed had a high level of habitat environment disturbance and their ecological and food intake characteristics reflected that disturbance. Muskrat traces were high in hydrophyte vegetation, which can be used as a hideout in open waters and where the growth of both floating leaved plants and floating plants are prevalent. Since international invasive muskrats have already settled in the domestic ecosystem and there is concern about their proliferation in the future, the government must consider a preemptive response and scientific management.

• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.58-63
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• 2005

Objectives: REM sleep behavior disorder (RBD), characterized by excessive motor activity during REM sleep, is associated with loss of muscle atonia. In recent years, it has been reported that RBD has high co-morbidity with CNS disorders (especially, Parkinson's disease, dementia, multiple system atrophy, etc.). We aimed to assess differences in clinical and polysomnographic findings among RBD patients, depending on the presence or absence of central nervous system (CNS) disorders. Methods: The medical records and polysomnographic data of 81 patients who had been diagnosed as having RBD were reviewed. The patients were classified into two groups: associated RBD (aRBD, i.e., with a clinical history and/or brain MRI evidence of CNS disorder) and idiopathic RBD (iRBD, i.e., without a clinical history and/or brain MRI evidence of CNS disorder) groups. Twenty-one patients (25.9%) belonged to the aRBD group and 60 patients (74.1%) belonged to the iRBD group. The clinical characteristics and polysomnographic findings of the two groups were compared. Results: Periodic limb movement disorder (PLMD), i.e., PLMI (periodic limb movement index)>5, was observed more frequently in the aRBD group than in the iRBD group (p<0.001, Fisher's exact test). Also, obstructive sleep apnea syndrome (OSAS), i.e., RDI (respiratory disturbance index)>5, was found more frequently in the aRBD group (p=0.0042, Fisher's exact test). The percentages for slow wave sleep and sleep efficiency were significantly lower in the aRBD group than in the iRBD group. Conclusion: We found that 1 out of 4 RBD patients had associated CNS disorders, warranting more careful neurological evaluation and follow-up in this category of RBD. In this category of RBD patients, we also found more frequent PLMD and OSAS. These patients were also found to have lower slow wave sleep and sleep efficiency. In summary, RBD patients with associated CNS disorders suffer from more disturbed sleep than those without them.

• Sleep Medicine and Psychophysiology
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• v.11 no.1
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• pp.22-28
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• 2004

Objective: The purpose of this study is to investigate the prevalence rate of OSA in subjects whose main sleep complaint is insomnia and to find differential factors of OSA in these insomniac subjects. Method: We reviewed the medical records and polysomnographic findings of patients referred to the Sleep Laboratory at Seoul National University Hospital from January 1996 to December 2002. Four-hundred and seventy subjects complained of insomnia as their main sleep problem (235 males and 235 females, mean age $53.6{\pm}12.4\;years$). First, we investigated the prevalence rate of OSA in these insomniac patients. Second, we compared the clinical and demographic characteristics of the OSA-associated group with those of the non-associated group. Third, we examined whether the degree or presence of differential factors within the OSA group correlate with severity of OSA, as determined by the respiratory disturbance index (RDI). Results: Among 470 insomniac subjects, 125 subjects (26.6%) were diagnosed as OSA by nocturnal polysomnography. OSA-associated subjects were significantly older ($58.4{\pm}12.3\;years$ vs. $51.8{\pm}11.2\;years$, p<0.01), and had significantly higher body mass index (BMI) ($23.4{\pm}3.3\;kg/m^2$ vs. $22.5{\pm}3.1\;kg/m^2$, p=0.44) than non-associated subjects. The OSA-associated group had more subjects with male gender (64.0% vs. 44.9%, p<0.01), hypertension (20.0% vs. 9.3%, p<0.01) or snoring (96.0% vs. 63.5%, p<0.01). Within the OSA-associated group, age had a significant positive correlation with RDI (p=0.01). Conclusion: We found that a considerable portion of patients complaining of insomnia as their main sleep problem were diagnosed as OSA. Snoring, old age, male gender, obesity, and comorbid hypertension were found to be differential factors of OSA in insomniac patients. We suggest that diagnostic efforts including nocturnal polysomnography are needed for insomniac patients with any of the above risk factors of OSA.