The Grey Zone in Multiple Sleep Latency Test for Diagnosis of Narcolepsy: A Survey of Korean Neurologist

Objectives@#Clinicians often depend on the results of the the multiple sleep latency test (MSLT) for diagnosing narcolepsy, but the diagnosis can be confusing when there is a co-existence of obstructive sleep apnea (OSA). This study is aimed to address the diagnostic tendency and the strategies of treatment for narcolepsy and other hypersomnia in the grey zone. @*Methods@#We performed a web-based survey of Korean neurologists who were interested in narcolepsy and had experience with sleep studies. @*Results@#The results of this survey present their concerns according to the severity of comorbid OSA in analyzing the results of the MSLT. @*Conclusions@#This study also might help by providing the opinions of experienced Korean neurologists for the assessment and management of excessive daytime sleepiness.

Sleep Disorders and Risk of Motor Vehicle Accident

Driving is a complicated process that demands coordination between a range of neurocognitive functions, including attention, visuo-perception, and appropriate judgment, as well as sensory and motor responses. Therefore, several factors may reduce the driving performance of an individual, such as sleepiness, distraction, overspeeding, alcohol consumption, and sedative drugs, all of which increase the hazard of motor vehicle accidents. Among them, drowsy driving is a major cause of traffic accidents, leading to more serious injuries as compared to other causes of major traffic accidents. Although sleep disorders have been highly associated among drowsy drivers, they are often untreated and unrecognized as a disease. In particular, obstructive sleep apnea and narcolepsy are some sleep disorders that are highly related to traffic accidents. Insomnia, which can cause inadequate sleep duration and promote sedative effects from sleeping pills, may also cause traffic accidents. These conditions are especially applicable to commercial bus or truck drivers, nocturnal workers, and shift workers, who are highly vulnerable to drowsy driving. Therefore, assertive screening and management of sleep disorders are necessary in general private drivers and relevant occupational drivers.

Sleep Disorders and Risk of Motor Vehicle Accident

Driving is a complicated process that demands coordination between a range of neurocognitive functions, including attention, visuo-perception, and appropriate judgment, as well as sensory and motor responses. Therefore, several factors may reduce the driving performance of an individual, such as sleepiness, distraction, overspeeding, alcohol consumption, and sedative drugs, all of which increase the hazard of motor vehicle accidents. Among them, drowsy driving is a major cause of traffic accidents, leading to more serious injuries as compared to other causes of major traffic accidents. Although sleep disorders have been highly associated among drowsy drivers, they are often untreated and unrecognized as a disease. In particular, obstructive sleep apnea and narcolepsy are some sleep disorders that are highly related to traffic accidents. Insomnia, which can cause inadequate sleep duration and promote sedative effects from sleeping pills, may also cause traffic accidents. These conditions are especially applicable to commercial bus or truck drivers, nocturnal workers, and shift workers, who are highly vulnerable to drowsy driving. Therefore, assertive screening and management of sleep disorders are necessary in general private drivers and relevant occupational drivers.

Proposal for Preventing Motor Vehicle Accident Related to Drowsy Driving in Patients With Narcolepsy

Narcolepsy is a chronic sleep disorder characterized by irresistible sleep attacks, hypersomnolence, cataplexy (sudden loss of muscle tone provoked by emotion), and sleep paralysis. Individuals with narcolepsy are at a high risk of experiencing sleepiness while driving leading to road traffic accidents. To prevent such accidents, some countries have regulations for commercial and noncommercial drivers with narcolepsy. Evaluating sleepiness is essential. Therefore, several subjective reports and objective tests were used to predict the possibility of car crashes or near-misses. Brain stimulants are effective in treating narcolepsy and can reduce daytime sleepiness in these patients. However, no guideline has been established for the driving safety of patients with narcolepsy in Korea. The Korean Sleep Research Society has prepared this proposal for preventing motor vehicle accidents caused by drowsy driving in patients with narcolepsy.

Proposal for Prevention of Drowsy Driving-Related Motor Vehicle Accidents in Patients With Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is known to be associated with various health concerns, including sleepiness, fatigue, cognitive dysfunction, diminished quality of life, hypertension, cardiovascular diseases, and stroke. OSA-induced sleepiness at the wheel reduces vigilance and driving performance, which significantly increase the risk of motor vehicle accidents. Sleepiness-induced motor vehicle accidents are characterized by high morbidity and mortality. OSA is a well-established significant risk factor for drowsy driving-related motor vehicle accidents, which can be prevented through appropriate treatment. However, currently no clinical guidelines or regulations are available for evaluation or management of the risk of motor vehicle accidents in patients with OSA in Korea. In this review, we discuss the risk of motor vehicle accidents in patients with OSA, the effects of positive airway pressure therapy as a preventive measure to reduce this risk, and the published recommendations for OSA in other countries with regard to fitness to drive. We propose recommendations for screening, evaluation, and treatment of OSA with regard to the risk of motor vehicle accidents, which would serve as useful practical guidelines for sleep specialists in clinical practice. Further research is warranted to establish optimal strategies for effective improvements in OSA-related traffic safety.

The Relationship between Obstructive Sleep Apnea and Functional Dyspepsia

Objectives@#Functional dyspepsia is one of the most common functional gastrointestinal disorders. We aimed to investigate the relationship between obstructive sleep apnea (OSA) and functional dyspepsia in patients with the complaint of sleep-disordered breathing. @*Methods@#We prospectively recruited patients who visited the institute for the evaluation of sleep-disordered breathing. All patients underwent overnight polysomnography and submitted their responses to sleep questionnaires. A validated Korean version of the Rome III criteria was used to estimate functional dyspepsia. Functional dyspepsia was classified into two subtypes of epigastric pain syndrome and postprandial distress syndrome. @*Results@#Out of 130 subjects with sleep disturbances, a total of 79 patients (60 men, 19 women) were enrolled. The mean (±standard deviation) age was 46.9±13.4 years. Functional dyspepsia was diagnosed in 8 (10%) patients. Patients with functional dyspepsia showed significantly higher values of Stanford Sleepiness Scale, the proportion of N1 sleep, arousal index, and apnea-hypopnea index compared to patients without functional dyspepsia (p=0.018, p=0.021, p=0.041, and p=0.039, respectively). With respect to OSA severity, 12% of patients with moderate OSA and 22% patients with severe OSA had functional dyspepsia. Severe OSA was significantly associated with a higher proportion of postprandial distress syndrome (p=0.030). @*Conclusions@#Our patients with snoring or OSA revealed that functional dyspepsia is associated with more severe daytime sleepiness and apnea-hypopnea index compared to those without functional dyspepsia. In addition, postprandial distress syndrome was a prevalent subtype of functional dyspepsia in patients with severe OSA.

Clinical Usefulness of Intraoperative Motor-Evoked Potential Monitoring during Temporal Lobe Epilepsy Surgery

BACKGROUND AND PURPOSE: We aimed to determine the effectiveness of intraoperative neurophysiological monitoring focused on the transcranial motor-evoked potential (MEP) in patients with medically refractory temporal lobe epilepsy (TLE). METHODS: We compared postoperative neurological deficits in patients who underwent TLE surgery with or without transcranial MEPs combined with somatosensory evoked potential (SSEP) monitoring between January 1995 and June 2018. Transcranial motor stimulation was performed using subdermal electrodes, and MEP responses were recorded in the four extremity muscles. A decrease of more than 50% in the MEP or the SSEP amplitudes compared with baseline was used as a warning criterion. RESULTS: In the TLE surgery group without MEP monitoring, postoperative permanent motor deficits newly developed in 7 of 613 patients. In contrast, no permanent motor deficit occurred in 279 patients who received transcranial MEP and SSEP monitoring. Ten patients who exhibited decreases of more than 50% in the MEP amplitude recovered completely, although two cases showed transient motor deficits that recovered within 3 months postoperatively. CONCLUSIONS: Intraoperative transcranial MEP monitoring during TLE surgery allowed the prompt detection and appropriate correction of injuries to the motor nervous system or ischemic stroke. Intraoperative transcranial MEP monitoring is a reliable modality for minimizing motor deficits in TLE surgery.

Continuous Positive Airway Pressure Therapy in a Patient with Pantothenate-Kinase-Associated Neurodegeneration

No abstract available.

Unusual Presentation of Propriospinal Myoclonus Occurring during Stable Sleep

No abstract available.

Giant Cell Arteritis Associated Arteritic Anterior Ischemic Optic Neuropathy: Sudden Vision Loss on the Contralateral Side of Headache

No abstract available.

A Twenty-Minute Nap Boosts the Planning Domain of Executive Function in Sleep Deprived Late Adolescents

OBJECTIVES: The positive effects of nap on cognitive function and memory have been researched intensively among children and adults. However, the relationship between afternoon nap and executive function among sleep deprived late adolescents has not been studied as much. METHODS: Ten sleep deprived, otherwise healthy Korean high school students were recruited, and asked to fill out Pittsburgh Sleep Quality Index questionnaire. They were put to nap for 5 min on three days during the first week, then for 10, 20, and 30 min in the same protocol during the consecutive weeks. After a 1-h class, both the students themselves and their corresponding teachers evaluated the participation level of the participants. They were then divided into two groups, and were instructed to play iPad game ‘Free Flow’. One group took a nap while the other group was prohibited from taking a nap. Both groups were instructed to play the game again. This was repeated once every afternoon for three days. RESULTS: The experiment showed that 20-min nap was superior in subjective evaluations to the other nap duration, and the mean game score differences before and after were significantly higher in the nap taking group after the 20-min nap when analyzed using non-parametric statistical method (p-value 0.04). CONCLUSIONS: Therefore, 20-min nap is likely to boost planning domain of executive function on sleep deprived late adolescents.

Repetitive Questioning and Writing in a Patient with Transient Global Amnesia

No abstract available.

Prevalence of Self-Perceived Snoring and Apnea and Their Association with Daytime Sleepiness in Korean High School Students

BACKGROUND AND PURPOSE: There has been no nationwide population-based study of the prevalence of self-perceived snoring/apnea in Korean adolescents. The purpose of this study was to estimate prevalence of self-perceived snoring/apnea in Korean high-school students and to evaluate their association with daytime sleepiness. METHODS: An online survey was used to investigate 12,672 students at 75 high schools across the 15 nationwide districts of South Korea. The variables were obtained using a self-reported questionnaire. The students answered questions about self-perceived snoring/apnea during the past 30 days. Daytime sleepiness was measured using a validated Korean version of the Epworth Sleepiness Scale, which was modified for adolescents. Covariates were the sex, school grade, frequency of self-perceived snoring/apnea, body mass index, sleep duration during a school day, and subjective perception of sleep duration. RESULTS: The prevalence of self-perceived snoring/apnea was 22.8% (26.4% for males vs. 18.8% for females, p<0.001) and 9.2% (10.5% for males vs. 7.7% for females, p<0.001). Obesity was significantly associated with self-perceived snoring [odds ratio (OR)=2.18, 95% confidence interval (CI)=1.94–2.46] and apnea (OR=1.57, 95% CI=1.33–1.86). Multivariate analysis showed that any frequency of self-perceived snoring/apnea was significantly associated with excessive daytime sleepiness (EDS). The OR of EDS increased significantly with the frequency of snoring and apnea. Female, sleep duration of <5 hours during a school day, and subjective perceptions of insufficient and considerable sleep durations were also significantly associated with EDS. CONCLUSIONS: The prevalence of self-perceived snoring/apnea was significantly higher in students who were male and obese. Students with self-perceived snoring/apnea exhibited more significant EDS and an increased risk of EDS as the frequency of snoring and apnea increased.

Erratum to: Asymmetric Gray Matter Volume Changes Associated with Epilepsy Duration and Seizure Frequency in Temporal-Lobe-Epilepsy Patients with Favorable Surgical Outcome

Jeong Sik Kim(a,b*), Dae Lim Koo(c*), Mi-Ri Kang(a), Min Jae Seong(a), Won Gu Lee(a), Eun Yeon Joo(a,b), Sung Tae Kim(d), Dae Won Seo(a,b), Seung Bong Hong(a,b)

Asymmetric Gray Matter Volume Changes Associated with Epilepsy Duration and Seizure Frequency in Temporal-Lobe-Epilepsy Patients with Favorable Surgical Outcome

BACKGROUND AND PURPOSE: This study aimed to estimate the changes in gray matter volume (GMV) and their hemispheric difference in patients with mesial temporal lobe epilepsy (MTLE) using a voxel-based morphometry (VBM) methodology, and to determine whether GMV changes are correlated with clinical features. METHODS: VBM analysis of brain MRI using statistical parametric mapping 8 (SPM8) was performed for 30 left MTLE (LMTLE) and 30 right MTLE (RMTLE) patients and 30 age- and sex-matched healthy controls. We also analyzed the correlations between GMV changes and clinical features of MTLE patients. RESULTS: In SPM8-based analyses, MTLE patients showed significant GMV reductions in the hippocampus ipsilateral to the epileptic focus, bilateral thalamus, and contralateral putamen in LMTLE patients. The GMV reductions were more extensive in the ipsilateral hippocampus, thalamus, caudate, putamen, uncus, insula, inferior temporal gyrus, middle occipital gyrus, cerebellum, and paracentral lobule in RMTLE patients. These patients also exhibited notable reductions of GMV in the contralateral hippocampus, thalamus, caudate, putamen, and inferior frontal gyrus. We observed that GMV reduction was positively correlated with several clinical features (epilepsy duration and seizure frequency in RMTLE, and history of febrile seizure in LMTLE) and negatively correlated with seizure onset age in both the RMTLE and LMTLE groups. CONCLUSIONS: Our study revealed GMV decreases in the hippocampus and extrahippocampal regions. Furthermore, the GMV reduction was more extensive in the RMTLE group than in the LMTLE group, since it included the contralateral hemisphere in the former. This difference in the GMV reduction patterns between LMTLE and RMTLE may be related to a longer epilepsy duration and higher seizure frequency in the latter.

Clinical Considerations of Obstructive Sleep Apnea with Little REM Sleep

BACKGROUND AND PURPOSE: Obstructive sleep apnea (OSA) is more severe during rapid eye movement (REM) sleep than during non-REM sleep. We aimed to determine the features of patients with OSA who experience little REM sleep. METHODS: Patients with a chief complaint of sleep-disordered breathing were enrolled. All subjects underwent overnight polysomnography (PSG) and completed questionnaires on sleep quality. Patients were divided into the following three groups according to the proportion of REM sleep detected in overnight PSG: little REM sleep [REM sleep 25% of TST). Multiple logistic regression analyses were applied to the data. The success rate of continuous positive airway pressure (CPAP) titration was estimated in these groups. RESULTS: The age and body mass index of the patients were 47.9±15.9 years (mean±SD) and 25.2±4.1 kg/m², respectively. The 902 patients comprised 684 (76%) men and 218 (24%) women. The apnea-hypopnea index (AHI) in the little-REM-sleep group was 22.1±24.4 events/hour, which was significantly higher than those in the other two groups (p<0.05). Multiple logistic regression showed that a higher AHI (p<0.001; odds ratio, 1.512; 95% confidence interval, 1.020–1.812) was independently predictive of little REM sleep. The titration success rate was lower in the little-REM-sleep group than in the normal-REM-sleep group (p=0.038). CONCLUSIONS: The AHI is higher and the success rate of CPAP titration is lower in OSA patients with little REM sleep than those with normal REM sleep.

Sleep Perception in Obstructive Sleep Apnea: A Study Using Polysomnography and the Multiple Sleep Latency Test

BACKGROUND AND PURPOSE: Discrepancies between objectively measured sleep and subjective sleep perception in patients with insomnia have been reported. However, few studies have investigated sleep-state misperception in patients with obstructive sleep apnea (OSA). We designed this study to 1) delineate the factors that could affect this discrepancy and 2) infer an underlying mechanism in patients with OSA. METHODS: We recruited patients who visited our sleep clinic for the evaluation of their snoring and/or observed OSA. Participants completed a structured questionnaire and underwent overnight polysomnography. On the following day, five sessions of the multiple sleep latency test (MSLT) were applied. We divided the patients into two groups: normal sleep perception and abnormal perception. The abnormal-perception group included patients whose perceived total sleep time was less than 80% of that measured in polysomnography. RESULTS: Fifty OSA patients were enrolled from a university hospital sleep clinic. Excessive daytime sleepiness, periodic limb movement index (PLMI), and the presence of dreaming were positively associated with poor sleep perception. REM sleep near the sleep termination exerted important effects. Respiratory disturbance parameters were not related to sleep perception. There was a prolongation in the sleep latency in the first session of the MSLT and we suspected that a delayed sleep phase occurred in poor-sleep perceivers. CONCLUSIONS: As an objectively good sleep does not match the subjective good-sleep perception in OSA, physicians should keep in mind that OSA patients who perceive that they have slept well does not mean that their OSA is less severe.

The Physiology of Normal Sleep / 한양의대학술지

Sleep is a highly organized and complicated state that is fundamental to life. We have an absolute need to sleep during about one-third of our lives. There are two types of sleep, non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM sleep is divided into stages 1, 2, and 3 which is representing a degree of relative depth in sleep. Each sleep stage shows unique features including some variations in electroencephalographic waves, eye movements, and muscle tone. Although sleep pattern changes are associated with aging, how sleep physiology and sleep patterns change over an individual's life span is not well-defined. Circadian rhythms, which are the daily rhythms in physiology and behavior, regulate the sleep-wake cycle. Comprehensive understanding of normal sleep physiology should be very important to better understand not only the effects of sleep related diseases but also the impacts of pathological sleep on various diseases of other systemic organs. This review aims to enhance knowledge focused on normal sleep physiology and its regulation.

Therapeutic Drug Monitoring of Topiramate in Status Epilepticus

PURPOSE: Status epilepticus (SE) is a pathologic state where pharmacokinetic alterations can be more pronounced and more rapid than during the other epileptic states. The consequences of such changes can exert negative influences on the timely adequate treatments for stopping uncontrolled seizures during SE. Topiramte (TPM) is one of new antiepileptic drugs with high efficacy in epilepsy, which can also be effectively used in SE. The aim of this study was to evaluate the pharmacokinetic changes during the SE by an analysis of the therapeutic drug monitoring (TDM) of TPM in patients with SE.METHODS: We retrospectively analyzed 49 serum measurements of TPM from 22 subjects with SE. The serum concentrations of TPM were measured by HPLC-tandem mass spectrometry. TDM data were categorized into malignant status epilepticus (MSE), refractory status epilepticus (RSE), and non-status epilepticus (NSE) groups. We compared concentration-to-dose ratio (CDR) among those groups.RESULTS: Among 49 cases, 11 were in MSE, 19 in RSE, and 19 in NSE. The daily dose of TPM was higher in MSE (median, interquartile range: 600, 600-800 mg) than in RSE (300, 250-600 mg) and NSE (200, 150-400 mg). The daily dose adjusted for body weight was also higher in MSE (12.2, 10.4-13.9 mg/kg) than in RSE (4.5, 3.8-12.2 mg/kg) and NSE (4.1, 2.3-7.1 mg/kg) (p<0.01). Serum concentrations of TPM were less in MSE (5.8, 4.2-7.3 mg/L) and RSE (4.9, 2.9-6.0 mg/L) than in NSE (5.5, 3.3-9.0 mg/L), which were not significantly different among the groups (p>0.1). However, the concentration-to-dose ratio (CDR) was significantly lower in MSE (0.41, 0.35-0.59 kg/L) and RSE (0.85, 0.39-1.23 kg/L) than in NSE (1.72, 0.96-2.24 kg/L) (post hoc analysis, p<0.005, 0.05).CONCLUSIONS: The serum concentrations of TPM can be influenced by SE, particularly in MSE. The higher range of dose of TPM could be needed for an adequate treatment of SE.

Therapeutic Drug Monitoring of Topiramate in Status Epilepticus / 대한간질학회지

PURPOSE: Status epilepticus (SE) is a pathologic state where pharmacokinetic alterations can be more pronounced and more rapid than during the other epileptic states. The consequences of such changes can exert negative influences on the timely adequate treatments for stopping uncontrolled seizures during SE. Topiramte (TPM) is one of new antiepileptic drugs with high efficacy in epilepsy, which can also be effectively used in SE. The aim of this study was to evaluate the pharmacokinetic changes during the SE by an analysis of the therapeutic drug monitoring (TDM) of TPM in patients with SE. METHODS: We retrospectively analyzed 49 serum measurements of TPM from 22 subjects with SE. The serum concentrations of TPM were measured by HPLC-tandem mass spectrometry. TDM data were categorized into malignant status epilepticus (MSE), refractory status epilepticus (RSE), and non-status epilepticus (NSE) groups. We compared concentration-to-dose ratio (CDR) among those groups. RESULTS: Among 49 cases, 11 were in MSE, 19 in RSE, and 19 in NSE. The daily dose of TPM was higher in MSE (median, interquartile range: 600, 600-800 mg) than in RSE (300, 250-600 mg) and NSE (200, 150-400 mg). The daily dose adjusted for body weight was also higher in MSE (12.2, 10.4-13.9 mg/kg) than in RSE (4.5, 3.8-12.2 mg/kg) and NSE (4.1, 2.3-7.1 mg/kg) (p0.1). However, the concentration-to-dose ratio (CDR) was significantly lower in MSE (0.41, 0.35-0.59 kg/L) and RSE (0.85, 0.39-1.23 kg/L) than in NSE (1.72, 0.96-2.24 kg/L) (post hoc analysis, p<0.005, 0.05). CONCLUSIONS: The serum concentrations of TPM can be influenced by SE, particularly in MSE. The higher range of dose of TPM could be needed for an adequate treatment of SE.