Myasthenia in Acquired Neuromyotonia

변정익,문혜진,홍윤호 대한신경과학회 2014 Journal of Clinical Neurology Vol.10 No.1

Background Acquired neuromyotonia (NMT) forms part of the spectrum of acquired peripheral nerve hyperexcitability syndrome, and is thought to be caused by antibodies to voltage-gated potassium channels (VGKC). Exertional weakness is unusual unless autoimmune myastheniagravis (MG) is superimposed. Case Report A case of acquired NMT accompanied by exertional weakness without coexistence of seropositive MG is reported herein. Conclusions Clinical and electrophysiological observations suggest that the cholinergic overactivity in NMT can compromise the safety factor sufficiently to cause a defect in neuromuscular junction transmission.

Association of Nucleus Basalis of Meynert Functional Connectivity and Cognition in Idiopathic Rapid-Eye-Movement Sleep Behavior Disorde

변정익,차광수,김민아,이우진,이한상,신정원,김태준,전진선,김한준,Carlos H. Schenck,이상건,정기영 대한신경과학회 2022 Journal of Clinical Neurology Vol.18 No.5

Background and Purpose Cognitive impairments are common in isolated rapid-eye-movement sleep behavior disorder (iRBD), in which the cholinergic system may play an important role. This study aimed to characterize the cortical cholinergic activity using resting-state functional connectivity (FC) of the nucleus basalis of Meynert (NBM) according to the cognitive status of iRBD patients. Methods In this cross-sectional study, 33 patients with polysomnography-confirmed iRBD and 20 controls underwent neuropsychological evaluations and resting-state functional magnetic resonance imaging. Thirteen of the iRBD patients had mild cognitive impairment (iRBDMCI), and the others were age-matched patients with normal cognition (iRBD-NC). The seed-to-voxel NBM–cortical FC was compared among the patients with iRBD-MCI, patients with iRBD-NC, and controls. Correlations between average values of significant clusters and cognitive function scores were calculated in the patients with iRBD. Results There were group differences in the FC of the NBM with the left lateral occipital cortex and lingual gyrus (adjusted for age, sex, and education level). The strength of FC was lower in the iRBD-MCI group than in the iRBD-NC and control groups (each post-hoc p<0.001). The average NBM–lateral occipital cortex FC was positively correlated with the memory-domain score in iRBD patients. Conclusions The results obtained in this study support that cortical cholinergic activity is impaired in iRBD patients with MCI. FC between NBM and posterior regions may play a central role in the cognitive function of these patients.

신경성기립저혈압의 치료

변정익,김상범 대한평형의학회 2017 Research in Vestibular Science Vol.16 No.3

Orthostatic hypotension (OH) is a common feature of sympathetic autonomic dysfunction and can lead to lightheadedness, weakness, dizziness, and syncope. It is defined as decrease in systolic blood pressure of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg within 3 minutes of standing. OH is associated with an increased incidence of cerebrovascular disease, myocardial infarction, and mortality. Non-pharmacological treatments may alleviate OH-re-lated symptoms; however, are not sufficient when used alone. Pharmacological treatment is essential in managing OH. In this review, we aimed to discuss non-pharmacological and pharmacological treatment options for OH.

Usefulness of Using Alternative Body-Mass Index and Neck Circumference Criteria for STOP-Bang Questionnaire in Screening South Korean Obstructive Sleep Apnea Patients

변정익,Dong-Ha Kim,Jeong-Su Kim,신원철 대한수면학회 2020 sleep medicine research Vol.11 No.1

Background and Objective The conventional criteria for body-mass index (BMI > 35 kg/m2) and neck circumference (NC > 40 cm) in the snoring, tiredness, observed apnea, high blood pressure, BMI, age, NC, and gender (STOP-Bang) Questionnaire may be too high to screen Korean obstructive sleep apnea (OSA) patients properly. We hypothesized that using a modified STOP-Bang Questionnaire with lower BMI and NC criteria may be more appropriate when screening South Korean patients with OSA. We aimed to evaluate the utility of the modified STOP-Bang Questionnaires and to compare it with that of conventional STOP or STOP-Bang Questionnaire. Methods This was a cross-sectional single-center study done at Kyung Hee University Hospital at Gangdong. Consecutive patients who underwent polysomnography and had done the STOPBang Questionnaire between November 2010 and December 2017 were reviewed. We used alternative cut-off criteria for BMI as 30 kg/m2 and for NC as 36.3 cm. Results A total of 778 patients was evaluated; 73.1% of them had some OSA [apnea-hypopnea index (AHI) > 5/hr] and 54.5% had moderate to severe OSA (AHI > 15/hr). The area under the curve (AUC) of the modified STOP-Bang was slightly larger than for the conventional STOP-Bang or STOP for having any OSA (AUC 0.787, 0.781, and 0.765, respectively) or for moderate to severe OSA (AUC 0.749, 0.747, and 0.721). The conventional STOP-Bang Questionnaire with a cut-off score of 3 identified all OSA and moderate to severe OSA patients with a sensitivity of 94.7% and 96.9%, respectively. The modified STOP-Bang showed improved sensitivity for any or moderate to severe OSA of 95.6% and 98.1%, respectively, with a decrease in exchange for lower specificity. Conclusions Because of the high prevalence of undiagnosed OSA, the modified STOP-Bang might be more appropriate in screening South Korean patients with OSA.

Treatment of Propriospinal Myoclonus at Sleep Onset

변정익,이동환,이학영,신원철 대한신경과학회 2017 Journal of Clinical Neurology Vol.13 No.3

렘수면행동장애의 치료와 관리의 최신지견

변정익,신원철 대한신경과학회 2021 대한신경과학회지 Vol.39 No.2

Rapid eye movement sleep behavior disorder (RBD) is a parasomnia that is characterized by dream-enactment behavior, which can often result in sleep related injury. RBD is strongly associated with neurodegenerative disease especially with alpha-synucleinopathy. More than 70% of the patients convert to neurodegenerative disease including Parkinson’s disease or diffuse Lewy body dementia with a median period of 7.5 years. Treatment for RBD is currently focused on symptomatic treatment to prevent the injury. First step is establishing safe sleep environment to avoid injury. Clonazepam and melatonin are most commonly used medication for symptomatic treatment for RBD, however, well-designed randomized clinical trials are lacking. Prognostic counselling with longitudinal follow-up is also crucial in managing patients with RBD, which should be individualized for each patient with regular systematic follow-up evaluation.

Difference in Psychological Distress between Patients with Periodic Limb Movement Disorder and Restless Legs Syndrome

변정익,신원철,yu yong shin,kyoung jin hwang,Yu Jin Jung,김정수 대한수면학회 2019 sleep medicine research Vol.10 No.1

Background and ObjectiveaaWe used the Symptom Checklist 90-Revised (SCL-90-R) to com- pare the psychosomatic symptom profiles between periodic limb movement disorder (PLMD) and restless legs syndrome (RLS) patients. MethodsaaTwenty consecutive drug-naïve RLS patients, 20 age- and sex-matched patients with PLMD and healthy controls were enrolled. Questionnaires evaluating sleep (Pittsburgh Sleep Qual- ity Index, and Insomnia Severity Index), depression (Beck Depression Inventory II), and psychoso- matic symptoms (SCL-90-R) were administered. Polysomnography was performed in the patients with PLMD or RLS. ResultsaaThe mean age of the subjects was 57.5 ± 10.9 years, and half of the subjects were male. Compared with the patients with RLS, the patients with PLMD exhibited a reduced total sleep time (276.6 ± 41.3 vs. 322.4 ± 42.9, p = 0.04) and a decreased proportion of REM sleep (12.5 ± 6.6 vs. 17.8 ± 7.8, p = 0.009). The patients with RLS exhibited higher SCL-90-R T-scores on the somatiza- tion (post hoc p < 0.001), obsessive-compulsive (post hoc p < 0.001), interpersonal sensitivity (post hoc p = 0.003), anxiety (post hoc p = 0.005), and psychoticism (post hoc p = 0.004) domains than the controls. Compared to the controls, the patients with PLMD exhibited higher SCL-90-R scores only in hostility (post hoc p = 0.016). Somatization in the RLS patients was significantly worse than that in the PLMD patients (post hoc p = 0.003). ConclusionsaaThe results of our study demonstrate that psychosomatic distress is greater in RLS patients and lesser in PLMD patients. Somatization was a distinguishing symptom between RLS and PLMD.

렘수면행동장애 진단을 위한 수면다원검사 지침에 대한 전문가 의견

변정익,지기환,Shin Hye-Rim,구대림,정유진,김태준,선우준상,양태원,전진선,신정원,정기영 대한수면연구학회 2023 Journal of sleep medicine Vol.20 No.2

Rapid eye movement (REM) sleep behavior disorder (RBD) is diagnosed based on a history of dream-enactment behavior and documentation of REM sleep without atonia (RWA) on polysomnography (PSG). RWA can be quantified using various methods. To establish comprehensive and clear PSG criteria for diagnosing RBD, the International RBD Study Group (IRBDSG) has recently published guidelines, which include the use of a video-PSG technical setup, REM sleep staging, RWA scoring, video and audio recording and analyses, and a video-PSG procedure for the diagnosis and identification of the prodromal stages of neurodegenerative diseases. Although the guidelines can identify patients with homogeneous RBD, their applicability in a real-world setting, particularly in Korea, presents challenges. Therefore, the aim of the present study was to evaluate and introduce IRBDSG guidelines and results of Korean sleep experts’ opinion survey for diagnosing RBD based on PSG findings.

비침습적 뇌 자극의 수면과 수면장애에 대한 효과

변정익,신원철,정기영 대한수면연구학회 2023 Journal of sleep medicine Vol.20 No.3

Non-invasive brain stimulation (NIBS), including transcranial magnetic and electrical stimulations, has recently been used to modulate sleep and treat sleep disorders. Herein, we reviewed studies that used NIBS to modulate sleep in healthy populations or patients with sleep disorders. Repetitive transcranial magnetic stimulation enhanced sleep slow oscillations and consistently improved subjective symptoms in patients with insomnia and restless legs syndrome. Transcranial electrical stimulation also increased slow-wave sleep in healthy populations and improved subjective sleep symptoms in patients with insomnia. Individualized NIBS and other NIBS techniques may be promising for treating sleep disorders, and future studies are warranted to determine optimal stimulation parameters and evaluate their long-term safety.

Efficacy of Oral Appliance Therapy as a First-Line Treatment for Moderate or Severe Obstructive Sleep Apnea: A Korean Prospective Multicenter Observational Study

변정익,김동하,안수진,양광익,조용원,Peter A. Cistulli,신원철 대한신경과학회 2020 Journal of Clinical Neurology Vol.16 No.2

Background and Purpose Responses to oral appliances (OAs) in obstructive sleep apnea (OSA) vary, and have not been fully evaluated in Korean patients. In this study we aimed to determine the efficacy of OAs for the first-line treatment of Korean patients with moderate or severe OSA. Methods This multicenter prospective observational study included 45 patients with moderate or severe OSA that had been newly diagnosed between March 2017 and May 2018 and who underwent OA treatment for 1 month. Questionnaires were completed and polysomnography (PSG) was performed before and after OA treatment. The primary outcome measures were improvement in the absolute apnea-hypopnea index (AHI) and the percentage reduction in the AHI. The secondary outcomes were improvements in the questionnaire scores related to sleep-associated symptoms and PSG parameters. Results The patients were aged 47.4±12.1 years (mean±SD), only two of them were female, and their AHI at baseline was 29.7±10.9/h. After OA treatment the AHI had reduced by 63.9± 25.8%, with the reduction was similar between the patients with moderate OSA and those with severe OSA. Overall 31.1% of the patients achieved a normal AHI (<5/h), and 64.4% had an AHI of ≤10/h after the treatment. The body mass index (BMI) was the most reliable factor for predicting the percentage reduction in the AHI. The OAs also improved the sleep architecture and subjective sleep-related symptoms. Conclusions The OAs were effective in patients with moderate or severe OSA. The OAs reduced the mean AHI to 63.9% of the baseline value, and this reduction was influenced by the BMI.