1,720,982 research outputs found
Fabrication and characterization of thermally diffused expanded core fibers
No full text학위논문(석사) - 한국과학기술원 : 물리학과, 1995.2, [ iii, 52 p. ]한국과학기술원 : 물리학과
Effect of Long-Term Benzodiazepines for Chronic Insomnia on Cognitive Function and Waking Electroencephalography: A Case-Control Study
No full textOBJECTIVE: The relationship between benzodiazepine use and cognitive decline in insomnia patients has been reported, but still conflicting. Thus, we tried to determine whether long-term exposure of benzodiazepine might be associated with changes of cognition and electroencephalography (EEG) findings in patients with chronic insomnia. METHODS: Insomniacs using benzodiazepines (n=29), drug-free insomniacs (n=27), and age- and sex-matched controls (n=28) were recruited. Neurocognitive function tested with Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease Assessment Packet Neuropsychological Assessment Battery, quantitative EEG in awake state, and information of benzodiazepine usage were obtained. RESULTS: Drug-free insomniacs reported more severe symptoms than insomniacs using benzodiazepine (p<0.001). Insomniacs using benzodiazepine showed a decrease of executive function in Trail Making Test A than drug-free insomniacs and controls (0.73±0.66 vs. 1.27±0.38 vs. 1.09±0.47, p<0.001) and in categorical fluency than drug-free insomniacs (-0.01±0.99 vs. 1.26±0.97, p=0.002). However, such decrease of executive function was not proportional to daily dose or cumulative dose of benzodiazepine. The EEG was not significantly different between insomniacs using benzodiazepine and drug-free insomniacs, while EEG of insomniacs showed low relative theta power in frontal and parietal regions but high relative beta power in frontal region than that of controls. CONCLUSION: Benzodiazepine users with chronic insomnia showed an impairment of executive function compared to drug-free insomniacs and controls although they showed relatively decreased severity of insomnia symptoms. Chronic insomniacs showed a hyper-arousal manifestation in front-parietal region of brain regardless of benzodiazepine exposure
Clinical manifestation of patients with isolated rapid eye movement sleep behavior disorder after modest-to-long disease duration
No full text© The Author(s) 2022. Published by Oxford University Press on behalf of Sleep Research Society. All rights reserved. For permissions, please e-mail: [email protected] OBJECTIVES: Patients with isolated rapid eye movement (REM) sleep behavior disorder (iRBD) are known to be at risk of neurodegenerative diseases but the time process of neurodegeneration remains unclear and its ethnic difference is rarely discussed. The objective of this study was to investigate the clinical manifestation of iRBD according to disease duration in a Korean cohort. METHODS: Patients who had been diagnosed with iRBD for at least 5 years were tracked and those currently remaining as iRBD were invited for motor, autonomic, olfactory, color discrimination, and cognitive tests. Cross-sectional comparison between patients with iRBD with modest disease duration (5-9.9 years) and long disease duration (≥10 years) was conducted. RESULTS: There were total of 198 patients with iRBD (135 males, 68.2%) tracked, whose average age at diagnosis was 65.9 years. Thirty-three had developed parkinsonism and 17 had developed dementia, resulting in a phenoconversion risk of 35.7% at 10 years. Hazard rate showed a gradually increasing trend over time, beginning from 2.1 conversions per year to 8.5 at 10 years. Patients with iRBD with a long disease duration (n = 19) had slightly higher motor scores than those with a modest duration (n = 82). However, they showed no difference in the frequency of motor abnormality or other clinical markers. CONCLUSIONS: There is a possible racial or geographical difference of phenoconversion risk. The progression of neurodegeneration might be very subtle in that patients with iRBD with longer disease duration do not necessarily show higher frequency of neurodegeneration markers.N
Age-Limited Effects of Low-Frequency Transcutaneous Electric Nerve Stimulation on Insomnia: A 4-Week Multi-Center, Randomized Controlled Study
No full textOBJECTIVE: Insomnia disorder is a common condition with considerable harmful effects on health. We investigated the therapeutic efficacy and safety of low-frequency transcutaneous electric nerve stimulation (LF-TENS) as an alternative treatment option for insomnia disorder. METHODS: A 4-week, multi-center, randomized controlled study was conducted. A total of 160 individuals aged 40 to 80 years with insomnia disorder were included and randomized to the experimental group receiving active device (n=81) or control group receiving sham device (n=79). Both groups used the device for four weeks, more than five days a week. The participants also completed pre- and post-intervention assessment with questionnaires, sleep diaries, wrist actigraphy, and blood tests. RESULTS: There was no significant between-group difference in the changes of mood and sleep parameters and blood test results among the two study groups. Meanwhile, in the exploratory sub-group analysis of patients aged over 60 years, the experimental group showed better improvement after intervention in the change of Pittsburgh Sleep Quality Index (PSQI) score (-2.63±3.25 vs. -1.20±2.28, p=0.039; Cohen’s d=0.99 vs. 0.45) and blood cortisol level (-1.65±3.37 μg/dL vs. -0.16±3.49 μg/dL, p=0.007; Cohen’s d=0.56 vs. 0.05). In addition, no serious adverse reaction occurred during the study period in both groups. CONCLUSION: The effect of LF-TENS was limited to older patients aged over 60 years, which might be related to the modulation of hypothalamic-pituitary-adrenal axis activity
Comparison between tongue base and soft palate obstruction in obstructive sleep apnea
No full textConclusions. In obstructive sleep apnea syndrome (OSAS), respiratory disturbances are more serious in tongue base-associated obstructions (TBOs) than in soft palate-associated obstructions (SPOs), and the proportion of TBO was predicted by average duration of apnea and hypopnea, and inversely by percentage time of snoring. Objective. To compare the polysomnographic characteristics of two main obstruction sites of OSAS, the soft palate and tongue base, and to identify those variables correlated with tongue base obstructions in patients with OSAS. Patients and methods. Thirty-one patients (28 men and 3 women) with OSAS were enrolled in this study. To identify airway obstruction levels upper airway pressure manometry was applied during polysomnography. Airway obstructions were categorized as SPO and TBO by observing pressure patterns. All analyses of events were performed in the supine position. Results. Average duration of apnea and hypopnea, percentage of apnea among apnea-hypopneas, average O(2) desaturation, and percentage of event-related arousals were significantly higher in TBOs compared with SPOs (all p<0.05). The percentage of TBO among total obstructions (TBO%) was independently associated with average duration of apnea and hypopnea (beta = 0.38, p<0.05) and percentage time of snoring (beta = 0.44, p<0.01) (adjusted R(2) = 30%, p<0.01).N
Lower Serum Calcium Levels Associated with Disrupted Sleep and Rest–Activity Rhythm in Shift Workers
Get PDFVitamin D deficiency is prevalent in many developed countries, and several studies suggest that vitamin D plays an essential role in brain function. A recent study showed that vitamin D deficiency was closely associated with daytime sleepiness and shorter sleep time. The relationshipbetween vitamin D levels and calcium levels is well established, and calcium level regulates slow-wave sleep generation. It is conceivable that the sleep disturbance in vitamin D deficiency may be due to an altered calcium level. Nonetheless, calcium levels, sleep disturbances, and activity rhythms have not been investigated directly. Therefore, we hypothesized that calcium and vitamin D levels might be important in regulating sleep and activity rhythm, and we analyzed the correlation with calcium levels by actigraphy analysis. Interestingly, a negative correlation was found between calcium level and sleep latency, total sleep time, use of sleep medicine, and daytime dysfunction among shift workers. In contrast, non-shift workers showed a negative correlation between the calcium level and the circadian phase. These findings suggest that low serum calcium levels may disrupt sleep–wake control and rest–activity rhythm, even if they are within the normal range
A Longitudinal Study on Attenuated Structural Covariance in Patients With Somatic Symptom Disorder
Get PDFOBJECTIVE: This study was performed to investigate altered regional gray matter volume (rGMV) and structural covariance related to somatic symptom disorder (SSD) and longitudinal changes after treatment. Additionally, this study examined the relationships of structural alteration with its phenotypic subtypes. METHODS: Forty-three unmedicated patients with SSD and thirty normal controls completed psychological questionnaires and neurocognitive tests, as well as brain magnetic resonance imaging. Voxel-based morphometry and structural covariances were compared between groups and between subgroups within the SSD group. After 6 months of treatment, SSD patients were followed up for assessments. RESULTS: Patients with SSD exhibited attenuated structural covariances in the pallidal-cerebellar circuit (FDR < 0.05–0.1), as well as regions in the default mode and sensorimotor network (FDR < 0.2), compared to normal controls. The cerebellar rGMVs were negatively correlated with the severity of somatic symptoms. In subgroup analyses, patients with somatic pain showed denser structural covariances between the bilateral superior temporal pole and left angular gyrus, the left middle temporal pole and left angular gyrus, and the left amygdala and right inferior orbitofrontal gyrus, while patients with headache and dizziness had greater structural covariance between the right inferior temporal gyrus and right cerebellum (FDR < 0.1–0.2). After 6 months of treatment, patients showed improved symptoms, however there was no significant structural alteration. CONCLUSION: The findings suggest that attenuated structural covariance may link to dysfunctional brain network and vulnerability to SSD; they also suggested that specific brain regions and networks may contribute to different subtypes of SSD
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Comparison between mono-bloc and bi-bloc mandibular advancement devices for obstructive sleep apnea
No full textAlthough mandibular advancement device (MAD) is widely used, there are a few papers comparing the efficacy and compliance at the same time according to the type of MAD. The aim of this study is to compare the efficacy and compliance between mono-bloc and bi-bloc MAD in the treatment of obstructive sleep apnea (OSA). Ninety-three patients who treated with mono-bloc MAD and 60 patients with bi-bloc MAD from January 2007 through September 2011 were retrospectively enrolled. All the patients underwent full-night polysomnography(PSG) before and 3 months after MAD was applied. The response rate was significantly higher in the patients using mono-bloc than those using bi-bloc MAD (77.4 vs. 58.3 %; P = 0.012). In contrast, the compliance rate of MAD use was significantly higher in the patients using bi-bloc than those using mono-bloc MAD (68.8 vs. 83.3 %; P = 0.044) at 1 year. According to the severity of OSA, the response rate was significantly higher in severe OSA than in mild to moderate OSA (P = 0.033 for mono-bloc MAD and P = 0.048 for bi-bloc MAD). However, there was no difference in the compliance between mild to moderate OSA and severe OSA. Our study showed that mono-bloc MAD was superior to bi-bloc MAD in efficacy while bi-bloc MAD is superior to mono-bloc MAD in compliance. We propose that both the efficacy and compliance should be considered in using MAD for treatment of OSA.N
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