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Obstructive sleep apnea (OSA), a common condition observed in clinical practice, is a significant public health concern; however, several patients with OSA remain underdiagnosed and untreated. OSA is not merely anatomically driven but is a heterogeneous disorder attributable to complex pathophysiology. Therefore, anatomically driven therapy such as continuous positive airway pressure (CPAP), dental device use, or upper airway surgery offers limited benefit because these approaches do not consider the various clinical and other pathophysiological contributors to OSA. Poor long-term adherence is a limitation of CPAP, the most effective modality recommended as first-line therapy in patients with OSA. Recent advances in our understanding of the pathophysiology and heterogeneity of OSA have led to the identification of three OSA phenotypes based on pathophysiological traits, polysomnographic traits, and clinical/symptombased characteristics. In this review, we summarize recent progress and research trends in the phenotypic approach to OSA.

The pathogenesis of isolated rapid eye movement sleep behavior disorders (iRBD) is poorly understood. The severity of RBD may reflect its pathogenesis.We compared motor function and non-motor symptoms (NMSs) between iRBD patients and healthy volunteers. We correlated motor function, NMSs, and striatal dopaminergic activity with RBD severity using video-polysomnography.Twenty-one iRBD patients and 17 controls participated. The Unified Parkinson's Disease Rating Scale part III scores were higher in patients compared to controls (iRBD is a multisystem neurodegenerative disorder, and gait abnormalities may be a disease characteristic, possibly related to the akinetic-rigid phenotype of Parkinson's disease. The correlation between pain/visuospatial dysfunction and RBD severity may be related to its pathogenesis.

The Korean name of epilepsy was renamed in 2011 to reflect the modern scientific evidence and to avoid misconceptions of epilepsy. However, the degree of dissemination of the new name of epilepsy had not been studied in Korea. To determine the degree of dissemination of the new name, we retrieved the relative Internet search volume of the new name and the old name using Naver, a dominant Internet search engine in Korea.The relative search volume is referred to as the Naver Trend Index (NTI). Naver DataLab provides the information on queries only from January 2016, and we downloaded a total of 846 daily NTI for the new name and old name for Korean epilepsy from January 1, 2016 to April 25, 2018. The proportions of NTI for the new name over the old name were computed. A primary hypothesis was that the ratio of Internet search volume of the new name exceeds that of the old name in 2018. A secondary hypothesis was that the new name had been continuously replacing the old name.The old name was more frequently used for Internet search. We found that about one-fourth (26%) of the Internet searches for Korean epilepsy were carried out with the new name in Naver DataLab between January 2016 and April 2018. The mean log ratio (NTI new/NTI old) in 2018 was -0.87, which indicates that the new name was used in 29.6% of the total search volume. In all ages, robust regression revealed log (NTI new, day/NTI old, day) = -8.79 + 0.00037 ∗ day, P 0.001. The annual means of log (NTI new/NTI old) were the lowest in the 20s but increased with age and were higher in females than in males except for the age groups under 19 and over 60 years.The ratio of Internet search volume of the new name over the old name was 1:2.4 (29.6% of the total search volume) in 2018. The new name was used in 26% of the total Internet searches in the search period. The degree of dissemination of the new name seems to increase with age and with females being more likely to use the new name in Internet searches versus males. The implementation and utilization of the new name by the public is a slow process.

Background and Objective To investigate the trends of public interest in the sleep disorders by searching terms in Korea and English-language. Google and Naver offer the tools assessing Internet searching volumes that may represent public interest on search terms. Methods Search terms were limited to Korean in Naver Trends and English in Google Trends. We use the keywords insomnia, sleep apnea, snoring, restless legs syndrome (RLS). A reference trend of dementia was compared. Results The median Naver Trends score of insomnia [21.3, interquartile ranges (IQR), 17.9– 26.5] was consistently higher than that of dementia (11.7, IQR, 10.0–13.5), RLS (7.5, IQR, 5.9–9.3), snoring (7.3, IQR, 5.9–10.5) and sleep apnea (1.6, IQR, 1.2–2.0) January 2016–October 2017. The Naver Trends score of sleep disorders decreased over time. The median Google Trends score of dementia (49, IQR, 45–55) was higher than that of sleep apnea (42, IQR, 40–45), insomnia (36, IQR 34–38), snoring (24, IQR 21–28), and RLS (23, IQR, 22–27) January 2004–October 2017. The Google Trends score of snoring and insomnia increased over time, but RLS and sleep apnea decreased over time. However, when we matched the search period with Naver Trends, the trends scores of insomnia, sleep apnea, RLS, and dementia increased over time. Conclusions The Naver Trends score of insomnia was higher than that of dementia, but those of sleep apnea, RLS was relatively low. To the contrary, the Google Trends score of dementia and sleep apnea was higher than that of insomnia.

Background and Objective The snoring, tiredness, observed apnea, and high blood pressure– body mass index, age, neck circumference, and gender (STOP-Bang) questionnaire is known as a simple but useful tool for the diagnosis of high-risk obstructive sleep apnea (OSA). However, the utility of STOP-Bang questionnaire in rapid eye movement (REM) sleep behavior disorder (RBD) populations is not validated. This study aimed to determine the diagnostic value of the STOP-Bang questionnaire in patients with RBD at high risk for OSA. Methods We collected data from 65 consecutive patients who were diagnosed with RBD in a tertiary sleep center (20 women; mean age, 64.3 ± 12.5 years). All the patients visited sleep center with complaints of abnormal behavior during sleep, and underwent testing with STOP-Bang questionnaire and polysomnography. The diagnosis of RBD was based on the International Classification of Sleep Disorders, second edition. We diagnosed OSA when apnea-hypopnea index (AHI) was at least 5/h. The receiver operating characteristic (ROC) curves were plotted. Results The mean AHI was 18.2 ± 16.5/h, and 75.4% (n = 49) had an AHI ≥ 5. The STOP-Bang (threshold ≥ 3) identified 70.7% of patients as high risk for OSA, and sensitivity, specificity, positive and negative predictive values were 81.6, 62.5, 87, and 52.6%, respectively. The area under the ROC curve (AUC) was 0.79 (p < 0.001). The STOP (threshold ≥ 2) identified 70.7% of patients at high risk for OSA, and sensitivity, specificity, positive and negative predictive values were 75.5, 87.5, 94.9, and 53.8%, respectively. The AUC was 0.86 (p < 0.001). A pairwise comparison of ROC curve between STOP-Bang and STOP was insignificant (p = 0.145). Conclusions In RBD population, the STOP-Bang or STOP questionnaire is a useful screening tool to identify patients at high risk for OSA.

Perry syndrome is a rare, adult-onset, autosomal dominant, progressive neurodegenerative disorder that is characterized by parkinsonism, weight loss, psychiatric symptoms, and central hypoventilation. We report the case of a 51-year-old man, whose condition was genetically identified as Perry syndrome. Here we focus the polysomnographic (PSG) findings and discuss the correlations between PSG and neuropathological findings.

Extrapyramidal signs are neurological dysfunction commonly associated with Wilson's disease (WD). In addition, cognitive dysfunction has been reported in the early stages of WD. In this report, we describe a 49-year-old woman presenting with memory impairments and without Parkinsonian or extrapyramidal signs. She was diagnosed with WD based on the presence of Kayser-Fleischer rings around the irises of her eyes and two ATP7B gene mutations, R778L at exon 8 and A874V at exdyon 11. Serial magnetic resonance imaging analysis and neuropsychological tests showed improvements following treatment with trientine.

This study aimed to identify factors predicting the response to antiepileptic drugs in patients with newly diagnosed epilepsy. We prospectively studied 176 patients with newly diagnosed epilepsy. Patients were included if they had a history of two or more clinically definite unprovoked seizures, or had a definite epileptic focus on MRI or epileptiform discharges on electroencephalography if they had suffered only one seizure. The primary endpoint was seizure freedom during the initial 6 months of antiepileptic drug treatment. The secondary endpoint was the time to the first seizure during the maintenance period of antiepileptic drug treatment. A total of 100 patients were included, and seizure freedom for 6 months was achieved in 73 patients. The response to antiepileptic drugs was significantly lower in patients with early age at seizure onset (⩽ 16 versus >16 years old, odds ratio=4; 95% confidence interval [CI] 1.5-12.9; relative risk=1.4; 95% CI 1.1-1.8). In addition, the time to the first seizure during the maintenance period was significantly earlier in patients with age at seizure onset ⩽ 16 years compared with those with age at seizure onset >16 years on the Kaplan-Meier survival analysis (p=0.011). Early age at seizure onset is an important factor influencing the response to antiepileptic drugs in patients with newly diagnosed epilepsy.

Background Perry syndrome (PS) caused by DCTN1 gene mutation is clinically characterized by autosomal dominant parkinsonism, depression, severe weight loss, and hypoventilation. Previous pathological studies have reported relative sparing of the cerebral cortex in this syndrome. Here, we characterize novel clinical and neuroimaging features in 3 patients with PS. Methods 18 F-fluorinated N -3-fluoropropyl-2-s-carboxymethoxy-3-β-(4-iodophenyl) nortropane ([ 18 F]FP-CIT) PET, [ 18 F]fluorodeoxyglucose PET, or volumetric MRI was performed in probands, and imaging data were analyzed and compared with those of control subjects. Results We identified 2 novel mutations of DCTN1 . Oculogyric crisis that presented before levodopa treatment was observed in 1 case. One patient had supranuclear gaze palsy. In 2 cases, [ 18 F]FP-CIT showed marked loss of dopamine transporter binding with only mild parkinsonism. Areas of hypometabolism or cortical thickness change were observed in dorsolateral frontal, anterior cingulate, lateral temporal, and inferior parietal cortices. Conclusion Oculomotor manifestations are not uncommon in PS. Neuroimaging studies suggest involvement of the frontotemporoparietal cortex, which may be the clinical correlate of apathy and depression, as well as pathological changes in subcortical structures.

Received November 10, 2015 Revised December 10, 2015 Accepted December 14, 2015 Address for correspondence Ki-Hwan Ji, MD Department of Neurology, Busan Paik Hospital, Inje University College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan 47392, Korea Tel: +82-51-890-8769 Fax: +82-51-890-6130 E-mail: kihwanji@gmail.com A condition of underestimation of sleep is classified as paradoxical insomnia or sleep state misperception. However, overestimation of sleep, so called positive sleep state misperception has not been clearly described. Here we report a middle-aged woman with positive sleep state misperception who presented excessive sleepiness mimicking hypersomnia. J Sleep Med 2015;12(2):64-66

Address for correspondence Seung Bong Hong, MD, PhD Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea Tel: +82-2-3410-3592 Fax: +82-2-3410-0052 E-mail: sbhong@skku.edu Objectives: We investigated the demographic, clinical and polysomnographic features in rapid eye movement (REM) sleep behavior disorder (RBD). Methods: We enrolled the consecutive 53 patients with untreated RBD confirmed by ICSD-2 criteria. All patients showed typical sleep related injurious or disruptive behavior on history and REM sleep without atonia was revealed in polysomnography (PSG). Results: Male (n=38) to female (n=15) ratio was 2.53 : 1. Mean age of RBD onset and age of diagnosis was 58.9 yrs and 62.9 yrs, respectively. The age of diagnosis was not different but the age of onset was younger in female. Twenty two (41.5%) showed sleep-related injury to self or bed partner in history. Twenty seven (50.9%) showed dream acting out using proximal muscle in PSG. Among them, 12 (44.4%) could recall their dream. Two patients with RBD met the diagnostic criteria of Parkinson’s disease. Nine patients who underwent the University of Pennsylvania Smell Identification test in any reason showed anosomia (n=1) or hyposomia (n=8). PSG showed increased N1, normal N2, decreased N3 and preserved REM sleep. Twentytwo (41.5%) patients could be diagnosed with obstructive sleep apnea (OSA). Conclusions: We identified 53 patients with RBD confirmed with both clinical history and polysomnography. This study shows a higher proportion of female cases, and less association with neurodegenerative disease than earlier reports. OSA prevalence in RBD seems to be higher in this study compared with general population. J Korean Sleep Res Soc 2012;9:41-45

Received November 28, 2012 Revised December 18, 2012 Accepted December 18, 2012 Address for correspondence Seung Bong Hong, MD, PhD Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea Tel: +82-2-3410-3592 Fax: +82-2-3410-0052 E-mail: sbhong@skku.edu Many patients with headaches complain of various sleep symptoms and have obstructive sleep apnea. Usually, treatment of sleep apnea with nasal continuous positive airway pressure (CPAP) may improve or resolve headache in a subset of patients. We report a case of new-onset headache after nasal CPAP therapy in an obstructive sleep apnea syndrome patient. J Korean Sleep Res Soc 2012;9:57-60

The aim of this study is to investigate regional cerebral blood flow (rCBF) in patients with syncope. We compared brain single photon emission computed tomography (SPECT) images of neurally mediated syncope patients with those of age/sex matched healthy volunteers. (99m)Tc-ethylcysteinate dimer (ECD) brain SPECT was performed in 35 patients (M/F = 17/18, mean 36.6 years) with syncope during the asymptomatic period, and in 35 healthy volunteers. For statistical parametric mapping (SPM) analysis, all SPECT images were spatially normalized to the standard SPECT template and then smoothed using a 14-mm full width at half maximum Gaussian kernel. The mean duration of syncope history was 4.9 years and the mean number of syncope episodes was 6.3. In all patients, syncope or presyncope episodes occurred during head-up tilt tests, and all were the vasodepressive type. SPM analysis of brain SPECT images showed significantly decreased rCBF in the right anterior insular cortex, left parahippocampal gyrus, bilateral fusiform gyri, bilateral middle and inferior temporal gyri, left lingual gyrus, bilateral precuneus and bilateral posterior lobes of the cerebellum in syncope patients at a false discovery rate corrected p < 0.05. There were no brain regions that showed increased rCBF in syncope patients. Furthermore, we found a negative correlation between the total number of syncopal episodes and the rCBF of the right prefrontal cortex, and between the duration of syncope history and the rCBF of the right cingulate gyrus at uncorrected p < 0.001. Decreases of rCBF in multiple brain regions may be responsible for autonomic dysregulation and improper processing of emotional stress in neurally mediated syncope patients, and frequent syncope episodes may lead to frontal dysfunction.

Objectives: Obstructive sleep apnea (OSA) is known to increase the risk of cardiovascular diseases through endothelial damage or functional impairment. Endothelial progenitor cells (EPCs) are blood markers for endothelial functional reservoirs, and a reduction in the number of EPCs is associated with a greater cardiovascular risk. We investigated the EPC in patients with OSA. Methods: We prospectively enrolled consecutive subjects referred to our institution for the evaluation of habitual snoring or apnea. The subjects were diagnosed as OSA based on the results of overnight polysomnography. The number of colony-forming units (CFUs) on cell cultures for seven days was adopted as an EPC index. Results: CFU tends to show higher value in severe OSA than mild-to-moderate OSA (54.4±29.1 vs. 33.8±26.8; t-test, p=0.16). Other vascular risks have no effect on CFU level Conclusions: Severe OSA may induce the release of EPC from bone-marrow to peripheral blood to compensate on-going vascular injury. Further study is required to validate the relationship between OSA and EPC.

Fatigability after exercise and restoration of strength by rest are clinical hallmarks of myasthenia gravis (MG). These unique features are originated from a reduced safety factor, which is related to a defect of acetylcholine receptor, and post-exercise exhaustion of neuromuscular junction transmission. Therefore, most patients with MG feel recharged muscle strength and show normal muscle power after nocturnal sleep. As such, worsening of MG symptoms during nighttime is usual. However, in very rare cases, some patients with MG complain fatigability and weakness in the morning, so called "paradoxical weakness (PW)." We report two MG patients with typical PW, diagnosed with OSA by polysomnography. CPAP therapy successfully improved their morning symptoms and quality of life. So far, the detailed mechanism of PW in MG is unknown; however, our report highlights the possible role of sleep disorders in developing a PW in MG and the therapeutic target for life quality of MG.

Purpose To analyze the characteristics of neuropsychological profiles and gray matter volume in de novo, drug-naive Parkinson's disease with mild cognitive impairment (PD-MCI). Methods Fifty-two newly diagnosed PD patients were assessed with neuropsychological testing, and PD-MCI was defined in patients with at least one or more abnormal cognitive test domains. PD with normal cognition (PD-NC) did not meet the criteria for PD-MCI or PD with dementia. Brain MRI scans was acquired from the patients and healthy controls (HC). The imaging processing and analysis of the gray matter (GM) volume were performed platform to determine the difference between PD-MCI and PD-NC. Results There were no differences of motor subscores between PD-MCI and PD-NC. The clinical dementia rating, global deterioration scale, and verbal memory were significantly worse in PD-MCI than in PD-NC. GM volume loss was observed in the right hippocampus, right cuneus, and right precuneus in PD-NC compared to in the HC. PD-MCI had significantly decreased GM volume in the bilateral temporal and frontal areas compared with that of the HC. The GM volume was significantly decreased in the right temporal pole, left precuneus, medial frontal and posterior cingulated gyrus in PD-MCI compared with PD-NC. Conclusions Clinical dementia ratings and global deterioration scales could differentiate PD-MCI from PD-NC. Verbal memory impairment is characterized as a cognitive deficit of de novo PD-MCI and is associated with the posterior cortical area.

Received November 20, 2014 Revised December 26, 2014 Accepted December 26, 2014 Address for correspondence: Seong-il Oh, MD Department of Neurology, Busan Paik Hospital, Inje University College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan 614-735, Korea Tel: +82-51-890-6130 Fax: +82-51-892-8811 E-mail: seongil.oh@gmail.com 츠츠가무시병(tsutsugamushi disease, scrub typhus)은 Orientitia tsutsugamushi에 의해 감염된 털진드기유충에 물렸을 때, 혈액 과 림프액을 통해 전신혈관염이 발생하는 급성 발열질환으로, 물린 부위에 가피(eschar)를 만들고 발진, 전신림프절종대 등을 동반한다. 고열이 지속될 때 적절한 치료를 하지 않으면 중추 신경계합병증인 수막염과 뇌염이 발생하기도 한다. 이러한 이유로 인해 효과적인 독시사이클린(doxycycline)치료를 위하 여 가피의 발견과 혈청검사를 통한 빠른 진단이 중요하다. 츠

To investigate the effect of modafinil on cortical excitability in patients with narcolepsy using transcranial magnetic stimulation (TMS).Nineteen drug-naïve narcolepsy patients with cataplexy (10 males, 9 females, and mean age 28.5 years) and 25 age- and sex-matched healthy controls were recruited. In this double-blind, randomized, crossover study, patients and controls received a single dose of 400mg modafinil or placebo. Modafinil and placebo administrations were separated by a 2-week washout period. TMS parameters, such as resting motor thresholds (RMT), motor-evoked potential (MEP) amplitudes, cortical silent periods (CSP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF), were measured before and 3h after administering modafinil or placebo. The differences of TMS parameters were statistically tested between patients and controls and between before and after modafinil or placebo administration.Narcolepsy patients had significantly increased CSP durations compared to controls (independent t-test, P0.05), indicating decreased excitability of cortical networks in human narcolepsy. In patients after modafinil administration, MEP amplitudes, SICI, and ICF increased, and CSP duration shortened significantly, meaning enhanced motor excitability, whereas in controls modafinil did not change TMS parameters significantly. Placebo administration did not affect TMS parameters both in patients or controls.Narcolepsy patients with cataplexy showed decreased cortical excitability than normal healthy controls. Single dose modafinil significantly increased motor excitability in narcolepsy patients but had no effect in healthy controls.

We report a case of severe obstructive sleep apnea (OSA) in a patient with symptomatic daytime cardiac bradyarrhythmia. Continuous positive airway pressure therapy prevented atrioventricular blocks that emerged after cardiac pacing for sick sinus syndrome. OSA could be associated with daytime bradyarrhythmia.

An association between zolpidem administration and sleep-related eating disorder (SRED) has been suggested. The authors observed zolpidem-induced SRED in restless legs syndrome (RLS). With the review of previous reports, we identified a common occurrence of RLS in zolpidem-induced SRED.

A 17-year-old girl visited the sleep clinic because of excessive daytime sleepiness (EDS) for five years. She went to bed at 22:00 and woke up at 10:00. Recently sleepiness got worse. She had no cataplexy, sleep hallucination or sleep paralysis. She had been taking a nap about 3–4 hour, but she had not felt refreshed. She denied of snoring or witnessed apnea. Epworth Sleepiness Scale was 17. She reported that visual acuity in the left eye has decreased since six months ago. In medical history, she had an irregular menstrual cycle and complained of amenorrhea recently. Central hypersomnia due to medical disorder should be excluded considering decreased visual acuity and amenorrhea. For exclusion of central hypersomnia, brain MRI was taken (Fig. 1). Patients with sustained damage to the hypothalamic/pituitary regions develop EDS regardless of the etiology. Increased daytime somnolence or sleep disturbances may continue despite tumor removal. Physicians should give an attention to the sleep symptoms to prevent the delay in the diagnosis and effective intervention.

Copyright 2014 by The Korean Society of Clinical Neurophysiology This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Address for correspondence; Ki-Hwan Ji Department of Neurology, Busan Paik Hospital, Inje University College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan 614-735, Korea Tel: +82-51-890-8769 Fax: +82-51-895-6367 E-mail: kihwanji@gmail.com Brief Communication