• Sleep Medicine and Psychophysiology
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• v.12 no.2
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• pp.133-138
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• 2005

Objectives: Narcolepsy is characterized by excessive sleepiness, cataplexy, sleep paralysis and hypnagogic hallucination. As there have been few researches on narcolepsy symptomatology in adolescents, we examined gender differences and prevalence of narcolepsy tetrad among students attending high school. Methods: Total 20,407 subjects, ages 14-19 years filled out Ullanlinna Narcolepsy Scale (UNS). Subjects whose UNS scores were equal to or more than 14 were interviewed by telephone using semi-structured questionnaire. Variables included questions to evaluate tetrad of narcolepsy. Results: UNS scores were higher in female than male ($11.1{\pm}5.2$ vs. $9.6{\pm}4.5$, p<0.001). Subjects scoring the UNS equal to or more than 14 were 4,535 (22.2% of all the participants), more frequently observed in female than in male (p<0.001). Excessive daytime sleepiness, cataplexy-like symptoms, sleep paralysis and hypnagogic hallucination in subjects of UNS ${\geq}14$ were significantly higher in female subjects than male ones. However, no significant gender difference was observed in the frequencies of severe sleep attack and cataplexy-like symptoms. Sleep paralysis was most frequently reported during sleep. There was significant correlation between sleep paralysis and hypnagogic hallucination (r=0.235, p<0.01). Conclusions: Our findings were that female adolescents complained more frequently narcolepsy symptoms than male subjects. Female adolescents might be more sensitive than male ones to physical complaints such as sleepiness or muscle weakness.

• Sleep Medicine and Psychophysiology
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• v.12 no.1
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• pp.45-49
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• 2005

Objectives: To compare the biogenetic temperament and character patterns of subjects with narcolepsy and those of healthy control subjects. Methods: Twenty-two subjects with narcolepsy, diagnosed with the International Classification of Sleep Disorder (ICSD) criteria, and 22 healthy control subjects were recruited. The Korean version of the Temperament and Character Inventory was administered to all subjects. Results: Compared to healthy control subjects, subjects with narcolepsy showed significantly higher Novelty-Seeking (ANCOVA, F=5.42, p=0.025), lower Persistence (F=8.41, p=0.006) and lower Self-Directedness scores (F=4.70, p=0.036). Conclusion: Narcoleptic patients have a distinct pattern of biogenetic temperament and character. Our findings suggest that narcoleptic patients are exploratory in response to novelty but give up easily. In addition, our findings show that narcoleptic patients consider themselves ineffective, purposeless, and fragile.

• Sleep Medicine and Psychophysiology
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• v.12 no.2
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• pp.122-132
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• 2005

Objectives: The objective of this study is to assess cognitive functions and their relationship with sleep symptoms in young narcoleptic patients. Methods: Eighteen young narcolepsy patients and 18 normal controls (age: 17-35 years old) were recruited. All narcolepsy patients had HLA $DQB_1$ *0602 allele and cataplexy. Several important areas of cognition were assessed by a battery of neuropsychological tests consisting of 13 tests: executive functions (e.g. cognitive set shifting, inhibition, and selective attention) through Wisconsin card sorting test, Trail Making A/B, Stroop test, Ruff test, Digit Symbol, Controlled Oral Word Association and Boston Naming Test; alertness and sustained attention through paced auditory serial addition test; verbal/nonverbal short-term memory and working memory through Digit Span and Spatial Span; visuospatial memory through Rey-Osterrieth complex figure test; verbal learning and memory through California verbal learning test; and fine motor activity through grooved pegboard test. Sleep symptoms in narcolepsy patients were assessed with Epworth sleepiness scale, Ullanlinna narcolepsy scale, multiple sleep latency test, and nocturnal polysomnography. Relationship between cognitive functions and sleep symptoms in narcolepsy patients was also explored. Results: Compared with normal controls, narcolepsy patients showed poor performance in paced auditory serial addition (2.0 s and 2.4 s), digit symbol tests, and spatial span (forward)(t=3.86, p<0.01; t=-2.47, p=0.02; t=-3.95, p<0.01; t=-2.22, p=0.03, respectively). There were no significant between-group differences in other neuropsychological tests. In addition, results of neuropsychological test in narcolepsy patients were not correlated with Epworth sleepiness scale score, Ullanlinna narcolepsy scale score and sleep variables in multiple sleep latency test or nocturnal polysomnography. Conclusion: The current findings suggest that young narcolepsy patients have impaired attention. In addition, impairment of attention in narcolepsy might not be solely due to sleep symptoms such as excessive daytime sleepiness.

• Journal of agricultural medicine and community health
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• v.38 no.2
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• pp.97-107
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• 2013

Objective: This study aimed to evaluate attention, memory and executive function in patients with narcolepsy. Methods: This study included 23 narcoleptic patients whose diagnosis were confirmed by the International Classification of Sleep Disorders(ICSD) at Chonnam National University Hospital Sleep Disorders Clinic or an other hospital in Korea, from 2005 to 2008, as well as 23 normal controls. All participants were given an IQ test for Korean-Wechsler Adult Intelligence Scale and several neuropsychological function tests (the d2 test for attention function, the Rey Complex Figure Test for nonverbal memory, the Korean-California Verbal Learning Test [K-CVLT] for verbal memory, and the Wisconsin Card Sorting Test for executive function). Clinical features of narcoleptic patients, including the frequency of excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic hallucination, were investigated by a structured clinical interview administered by a neuropsychiatist. Excessive daytime sleepiness was evaluated by the Epworth sleepiness scale. Results: Characteristic symptoms of narcolepsy observed in this study included excessive daytime sleepiness (n=23, 100.0%), cataplexy (n=19, 82.6%), hypnagogic hallucination (n=5, 21.7%) and sleep paralysis (n=12, 52.2%). In nocturnal polysomnographic findings, stage 2 sleep and REM latency were found to be significantly decreased in narcoleptic patients compared with the control group, and were accompanied by significant increases in stage 1 sleep. Narcoleptic patients had lower scores than the control group on total number, Total Number-Total Error, Concentration Performance and Fluctuation Rate on the d2 test, which measures attention. Also, there were significant differences between the performance of patient and control groups on the B list of the K-CVLT, which measures verbal memory. Conclusion: Narcoleptic patients showed decreased attention and verbal memory performance compared to the control group; however, in many areas, narcoleptic patients still demonstrated normal cognitive function.

• Sleep Medicine and Psychophysiology
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• v.15 no.1
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• pp.33-38
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• 2008

Introduction: It has been proposed that narcolepsy and REM sleep behavior disorder (RBD) have overlapped symptom profile and pathophysiology. This study was aimed at measuring and comparing changes in EEG frequency band of REM sleep in narcolepsy and RBD, applying EEG spectral analysis method. Methods: Nine patients diagnosed as narcolepsy and the same number of RBD patients were studied. Spectral analysis of the REM sleep EEG was performed in each patient on 9 epochs selected evenly from the first, second, and third REM periods. Then, we compared frequency band percentages of REM sleep EEG in narcolepsy and RBD. Results: Narcolepsy patients had significantly higher delta frequency ratio than RBD ones (p=0.00). In alpha and beta2 frequency bands, RBD patients showed higher percentage than narcolepsy ones. Slow wave sleep was more prevalent in narcolepsy patients. But, no difference of REM sleep percentage was found between the two groups (p=0.93). Conclusion: Higher delta frequency ratio in REM sleep of narcolepsy patients than RBD ones reflects that sleep-promoting mechanism is more dominant in narcolepsy than in RBD.

• Sleep Medicine and Psychophysiology
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• v.8 no.2
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• pp.107-112
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• 2001

Introduction: Narcolepsy, a sleep disorder characterized by excessive daytime sleepiness and cataplexy, is known to be closely associated with the human leukocyte antigen (HLA) DQB1*0602. Several studies have suggested that HLA-DQB1*0602 is strongly linked with narcolepsy-cataplexy. However, no studies have yet been made on whether HLA DQB1*0602 is associated with Korean patients with narcolepsy. This study was designed to investigate the frequency of HLA-DQB1*0602 of Korean patients with narcolepsy. Methods: Twenty patients were selected (mean age: $28.2{\pm}3.0$, 11 men and 9 women). The patients were confirmed to have narcolepsy by the overnight polysomnography and multiple sleep latency test (MSLT) in addition to their clinical history and symptoms at St. Vincent's Hospital and Korea University Hospital Sleep Disorders Clinic. Any subjects co-morbid with other hypersomnic sleep disorders such as sleep apnea or periodic limb movements during sleep were excluded. Clinical data was collected through a semi-structured interview for narcoleptic patients. All patients and 21 control did HLA typing for the presence of DQB1*0602. Results Obtained were as Follows: 1) Mean sleep latency was 2.4 (${\pm}2.0$ minutes) and mean frequency of sleep-onset REM period was 3.0 (${\pm}1.6$) by MSLT. 2) Characteristic symptoms of narcolepsy investigated were as follows: excessive daytime sleepiness (100%), cataplexy (100%), sleep paralysis (60%), hypnagogic hallucination (70%) and disrupted nocturnal sleep (75%). 3) Strong emotional expression such as laughing (80%) and joking (70%) triggered cataplexy which affects the knee and leg region (80%) and jaw region (30%). 4) HLA-DR2 was found in 90% of patients and 35% in controls. The frequency of HLA-DQB1*0602 in patients and controls was 90%, and 24%, respectively. Conclusions: These results, which exhibit high HLA-DQB1*0602 expression in Korean patients with narcolepsy, suggest that HLADQB1*0602 could be a strong genetic marker in narcolepsy.

• 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.13 no.2
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• pp.67-74
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• 2006

Introduction: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. Methods: Twelve narcoleptic patients (7 male, age: $22.9{\pm}2.6\;yrs$) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. Results: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. Discussion: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.

• The Safety technology
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• no.100
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• pp.32-33
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• 2006

• Sleep Medicine and Psychophysiology
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• v.18 no.1
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• pp.17-22
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• 2011

Childhood narcolepsy is one of the underdiagnosed diseases even the first symptoms often appear in childhood. Making diagnosis through history taking is not always easy because the symptoms of childhood narcolepsy are different from those of adulthood. Diagnostic laboratory tests such as sleep studies, tests for human leukocyte antigens, cerebrospinal fluid hypocretin measurement should be considered when the child has excessive daytime sleepiness without cataplexy. Treatment approach should be start as early as possible to avoid secondary academic, emotional difficulties. Both pharmacological and non-pharmacological management, and close cooperation between parents and school teachers should be maintained. In the near future, childhood narcolepsy can be a key to understand the pathogenesis of narcolepsy.