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Introduction: Suboptimal sleep duration and poor sleep quality have been proposed to increase stroke risk. However, their significance in young ischemic stroke is unclear. We aimed to investigate the importance of sleep duration and quality on young ischemic stroke patients. Methods: A multicenter matched case-control study was performed to evaluate under-recognized risk factors in young (<45 years) ischemic stroke patients in 8 tertiary hospitals in Korea. A total of 225 patients and 225 age- and sex-matched controls were enrolled in the same period. Detailed information about patients' demographics, socioeconomic state, and traditional and nontraditional risk factors including sleep-related factors were obtained using structured questionnaires. Risk of ischemic stroke was estimated using conditional logistic regression analysis. Results: Although average sleep duration was similar in patients and controls, patients were more likely to have long (≥9 h) or extremely short (<5 h) sleep durations. In addition, the proportion of subjects with dissatisfaction with sleep quality was higher in patients than controls (66.2 vs. 49.3%, p < 0.001). In multivariable conditional logistic regression analysis, long sleep duration (OR: 11.076, 95% CI: 1.819–67.446, p = 0.009) and dissatisfaction with sleep quality (OR: 2.116, 95% CI: 1.168–3.833, p = 0.013) were independently associated with risk of ischemic stroke. Conclusions: Long sleep duration and dissatisfaction with sleep quality may be associated with increased risk of ischemic stroke in young adults. Improving sleep habit or quality could be important for reducing the risk of ischemic stroke. [ABSTRACT FROM AUTHOR]

Background: Hyperuricemia in patients with gout is associated with a low risk of neurodegenerative diseases, including dementia. However, the prevalence of dementia in patients with gout has not yet been reported. Objective: To analyze the prevalence of dementia among patients diagnosed with gout by utilizing the Health Insurance and Review Assessment database, a nationwide registry of the South Korean population. Methods: Data from the Health Insurance and Review Assessment database of patients diagnosed with gout between 2011 and 2018 were extracted. The annual prevalence of dementia according to age and sex was analyzed. We investigated whether there was an association between comorbidities and gout medication in patients with both gout and dementia and in patients with only gout. Results: Between 2011 and 2018, the age-adjusted prevalence of dementia per 100,000 persons ranged from 54.0 (95% confidence interval: 47.7–60.2) to 69.9 (95% confidence interval: 65.3–74.5). Compared to previous studies, the prevalence of dementia was lower in patients with gout than in the general population. Patients with both gout and dementia were more likely to be women, have a wide range of comorbidities, and be prescribed gout-related drugs, including allopurinol, febuxostat, nonsteroidal anti-inflammatory drugs, and steroids than patients with gout without dementia. Conclusions: This study demonstrated a relatively low prevalence of dementia in patients with gout. Gout, characterized by hyperuricemia, might be associated with a reduced risk of dementia. [ABSTRACT FROM AUTHOR]

BACKGROUND: A combination of plasma phospho‐tau (p‐tau), amyloid beta (Aβ)‐positron emission tomography (PET), brain magnetic resonance imaging, cognitive function tests, and other biomarkers might predict future cognitive decline. This study aimed to investigate the efficacy of combining these biomarkers in predicting future cognitive stage transitions within 3 years. METHODS: Among the participants in the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease (KBASE‐V) study, 49 mild cognitive impairment (MCI) and 113 cognitively unimpaired (CU) participants with Aβ‐PET and brain imaging data were analyzed. RESULTS: Older age, increased plasma p‐tau181, Aβ‐PET positivity, and decreased semantic fluency were independently associated with cognitive stage transitions. Combining age, p‐tau181, the Centiloid scale, semantic fluency, and hippocampal volume produced high predictive value in predicting future cognitive stage transition (area under the curve = 0.879). CONCLUSIONS: Plasma p‐tau181 and Centiloid scale alone or in combination with other biomarkers, might predict future cognitive stage transition in non‐dementia patients. Highlights: ‐Plasma p‐tau181 and Centiloid scale might predict future cognitive stage transition.‐Combining them or adding other biomarkers increased the predictive value.‐Factors that independently associated with cognitive stage transition were demonstrated. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to determine the efficacy of combining plasma phosphorylated tau (p‐tau)181, amyloid beta (Aβ)42/Aβ40, neurofilament light (NfL), and apolipoprotein E (APOE) genotypes for detecting positive amyloid positron emission tomography (PET), which is little known in the Asian population, in two independent cohorts. Methods: Biomarkers were measured using a single‐molecule array (Simoa) in a cohort study (Asan). All participants underwent amyloid PET. Significant changes in the area under the curve (AUC) and Akaike Information Criterion values were considered to determine the best model. The generalizability of this model was tested using another cohort (KBASE‐V). Results: In the Asan cohort, after adjusting for age and sex, p‐tau181 (AUC = 0.854) or APOE ε4 status (AUC = 0.769) distinguished Aβ status with high accuracy. Combining them or adding NfL and Aβ42/40 improved model fitness. The best‐fit model included the plasma p‐tau181, APOE ε4, NfL and Aβ42/40. The models established from the Asan cohort were tested in the KBASE‐V cohort. Additionally, in the KBASE‐V cohort, these three biomarker models had similar AUC in cognitively unimpaired (AUC = 0.768) and mild cognitive impairment (MCI) (AUC = 0.997) participants. Conclusions: Plasma p‐tau181 showed a high performance in determining Aβ‐PET positivity. Adding plasma NfL and APOE ε4 status improved the model fit without significant improvement in AUC. [ABSTRACT FROM AUTHOR]

Despite recent studies suggesting a declining incidence and prevalence of dementia on a global scale, epidemiologic results with respect to Alzheimer's disease (AD) are lacking due to the methodological limitations inherent to conducting large-scale cohort investigations of this topic. The aim of the current study was to investigate the incidence and prevalence of AD in Korea. We conducted a secondary analysis within the National Health Insurance System (NHIS) database, a unique resource that reports medical information for the entire Korean population. AD diagnoses as well as evaluations of vascular risks were defined based on International Statistical Classification of Diseases (ICD-10) codes along with prescription records. The cut-off age for diagnosing AD was defined as the age of the patient's highest Youden index. In this study, the incidence and prevalence of AD in the Korean population aged 40 years or older showed an overall increase between 2006 and 2015. Although both older and younger age groups showed an increase in the incidence and prevalence of AD, the highest increase was observed in older age groups. Based on the highest Youden's index value (sensitivity + specificity – 1), the cut-off value for the diagnosis of AD was 69 years with an area under the curve (AUC) of 0.92. We found that the incidence of AD was higher in individuals with underlying vascular risks. However, in recent years, the prevalence of AD was conversely found to be lower in individuals with hypertension or dyslipidemia. Despite efforts toward reducing the number of AD cases through educational, policy, and various public health and preventive medicine interventions, the incidence and prevalence of AD continues to grow in Korea. Efforts aimed at early diagnosis and the modification of underlying risks may be critical to reducing the socioeconomic burden of AD. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the risk and prognosis of Alzheimer's disease (AD) and vascular dementia (VaD) in patients with insomnia using the National Health Insurance Service database covering the entire population of the Republic of Korea from 2007 to 2014. In total, 2,796,871 patients aged 40 years or older with insomnia were enrolled, and 5,593,742 controls were matched using a Greedy digit match algorithm. Mortality and the rate of admission to a long-term care facility were estimated using multivariable Cox analysis. Of all patients with insomnia, 138,270 (4.94%) and 26,706 (0.96%) were newly diagnosed with AD and VaD, respectively. The incidence rate ratios for AD and VaD were 1.73 and 2.10, respectively, in patients with insomnia compared with those without. Higher mortality rates and long-term care facility admission rates were also observed in patients with dementia in the insomnia group. Known cardiovascular risk factors showed interactions with the effects of insomnia on the risk of AD and VaD. However, the effects of insomnia on the incidence of AD and VaD were consistent between the groups with and without cardiovascular risk factors. Insomnia is a medically modifiable and policy-accessible risk factor and prognostic marker of AD and VaD. [ABSTRACT FROM AUTHOR]

Aim: Association between reversible cerebral vasoconstriction syndrome (RCVS) and the reactivation of varicella-zoster virus (VZV) was analyzed. Materials & methods: VZV-specific IgG and IgA responses on day 1 and 28 in plasma was compared and VZV DNA with real-time PCR in saliva was measured in case-patients (diagnosed with RCVS), control-patients (ischemic stroke with intracranial artery stenosis) and healthy volunteers. Results: The case-patients (n = 11) revealed significantly higher VZV-specific IgG levels on day 28 than on day 1 (p = 0.004), while the age-matched control-patients and healthy volunteers exhibited no significant changes. Positive VZV DNA PCR result in saliva was revealed in one case-patient. Conclusion: RCVS might be associated with VZV. This result warrants a full-scale study to evaluate the association between them. [ABSTRACT FROM AUTHOR]

Introduction: To devise appropriate preventive strategies after stroke, knowledge of the association between post-stroke cognitive impairment (PSCI) and prognosis of stroke patients is important. We investigated the association between PSCI and the vascular outcomes in patients with ischemic stroke with best medical care considering their risk factors and adherence to medications. Methods: Of the 1534 ischemic stroke patients who randomly assigned to aspirin or cilostazol treatment with best medical therapy by the PICASSO (PreventIon of CArdiovascular events in iSchemic Stroke patients with high risk of cerebral hemOrrhage) trial, 1240 with baseline mini-mental state examination (MMSE) scores were analysed retrospectively. The patients were classified into three groups based on MMSE scores. Recurrence of ischemic stroke, stroke of any type and composite of major vascular events were compared among them. Results: Of the 1240 patients, 376 had MMSE scores of 28–30 (highest tertile), 419 had scores of 24–27 (middle tertile) and 445 had scores of 0–23 (lowest tertile). The average time from stroke onset to MMSE examination was 31.8 days. By trend analysis, lower tertile of MMSE score was significantly associated with recurrent ischemic stroke (p = 0.0017), stroke of any type (p = 0.0053) and composite vascular outcome (p = 0.0122). After adjustment for covariates, PSCI was independently associated with risk of recurrent ischemic stroke (HR 2.40, 95% confidence interval 1.12–5.14). Conclusions: Cognitive impairment was associated with recurrence of ischemic stroke in high risk patients during adequate medical therapy including antiplatelet therapy. However, the other vascular events were not. [ABSTRACT FROM AUTHOR]

The demand for surface‐mounted permanent‐magnet (SPM) motors with high torque and power densities has increased as these motors are becoming more widely used in applications requiring high performance in limited spaces, such as electric vehicles and robot arms. Some studies have increased the torque and power densities, such as hybrid flux permanent‐magnet motors utilising radial and axial magnetic fluxes, dual‐rotor and dual‐stator permanent‐magnet motors. Although these motors offer high performance, there are some problems such as low productivity and poor applicability to small motors have arisen due to their complicated structures. An overhang structure can be a simple and effective means of solving the aforementioned problems. However, the overhang effects do not increase linearly but tend to converge as the length of the overhang increases. Therefore, a novel flux‐absorbing structure (FAS) that effectively enhances the overhang effects of SPM motors even in cases with considerable overhang was proposed. The magnetic flux path from the overhang to the stator can be efficiently improved via the proposed FAS. Thereby, the performances of a SPM motor can be effectively enhanced when the FAS is adopted. The effectiveness of the proposed FAS was verified via a 3D finite‐element analysis and in experiments. [ABSTRACT FROM AUTHOR]

Background: A combination of plasma phospho‐tau (p‐tau), amyloid beta (Aβ)‐PET, brain magnetic resonance imaging, cognitive function tests, and other biomarkers might predict future cognitive decline. This study aimed to investigate the efficacy of combining these biomarkers in predicting future cognitive stage transitions within 3 years. Method: All participants were from the validation cohort of the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease (KBASE‐V) study. Among the participants in the KBASE‐V study, 49 mild cognitive impairment (MCI) and 113 cognitively unimpaired (CU) participants with Aβ‐PET and brain imaging data were analyzed. Main outcome was cognitive stage transitions within 3 years. The best combination model that predicts cognitive stage transition was considered by significant change of area under the curve (AUC) and Akaike information criterion value. Result: Within 3 years, 19.1% of the participants showed a cognitive stage transition. Older age, increased plasma p‐tau, Aβ‐PET positivity, and decreased semantic fluency were independently associated with cognitive stage transitions. Plasma p‐tau181 (AUC = 0.673) and the Centiloid scale (AUC = 0.769) alone predicted cognitive stage transition well and correlated with each other significantly. Combining age, p‐tau181, the Centiloid scale, semantic fluency, and hippocampal volume produced better accuracy (AUC = 0.879). In MCI participants, the model combining age, p‐tau181, and the Centiloid scale demonstrated the highest predictive value (AUC = 0.963). Conclusion: Plasma p‐tau181 and Centiloid scale, in combination with other biomarkers, might have high predictive value in predicting future cognitive stage transition in non‐dementia patients. [ABSTRACT FROM AUTHOR]

Optimization of an electric machine is a nonlinear multi-variable problem. For optimization of the nonlinear multi-variable problem, many function evaluations are required, which in turn requires much time. To address this problem, we propose a novel optimization algorithm of which the convergence speed, accuracy, and reliability are superior compared to those of widely used conventional algorithms. The performance of the proposed algorithm is verified through mathematical test functions and applied to a practical optimization scenario of cogging torque minimization for an interior permanent magnet synchronous machine. [ABSTRACT FROM AUTHOR]

Background: The relationship between sleep parameters and longitudinal shortening of telomere length is unclear. This study aimed to investigate the relationship between sleep parameters and the shortening of leukocyte telomere length (LTL) over two years. Method: Among the participants in the validation cohort of the Korea Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease, participants who measured both baseline and follow‐up (two years later) of LTL were analyzed. They were dichotomized according to the degree of LTL attrition. Clinical characteristics, including sleep duration, sleep latency, Pittsburgh Sleep Quality Index (PSQI), Stanford Sleepiness Scale, and Epworth Sleepiness Scale scores were compared between the two groups. Result: A total of 238 patients were analyzed in current study. Participants with faster LTL shortening had a shorter duration of sleep (P = 0.013) and longer sleep latency (P = 0.007). Among the components of the PSQI, subjective measures of sleep quality, sleep latency, sleep duration, and sleep efficiency were significantly worse in participants with faster LTL shortening. Multivariate logistic regression analysis showed that sleep latency (odds ratio [OR] = 1.015, confidence interval [CI] = 1.001–1.029, P = 0.029), global PSQI score (OR = 1.130, CI = 1.017–1.256, P = 0.023), shortest sleep duration (OR = 5.057, CI = 1.189–21.502; P = 0.028), and lowest sleep efficiency (OR = 8.598, CI = 1.584–46.672, P = 0.013) were independently associated with faster LTL shortening. Conclusion: Poor sleep quality, specifically long sleep latency, less than 5 hours of sleep, and low sleep efficiency were associated with faster longitudinal shortening of the LTL. [ABSTRACT FROM AUTHOR]

BACKGROUND White matter lesions (WMLs) are a common finding in stroke patients, and the most important risk factors are old age and hypertension. Although many studies have described the association between WMLs and ambulatory blood pressure monitoring (ABPM) parameters in healthy subjects and hypertensive patients, little is known about the association in hypertensive ischemic stroke patients. METHODS From July 2009 to June 2012, 169 consecutive hypertensive noncardioembolic ischemic stroke patients were recruited within 1 week of suffering a stroke, and ABPM was applied 1 or 2 weeks after stroke onset. The subjects were classified into 2 groups according to the presence of advanced WMLs, and their ABPM parameters were compared. Finally, multivariable logistic regression analyses were performed to investigate the independent relationships between WMLs and ABPM parameters. RESULTS Seventy (41%) patients had advanced WMLs. In univariable analysis, higher 24-hour, awake, and asleep systolic blood pressure (SBP)/diastolic blood pressure levels and 24-hour pulse pressure were associated with advanced WMLs. However, circadian blood pressure parameters such as 24-hour BP variability, morning surge, and nocturnal dipping pattern were not associated with advanced WMLs. After adjustments, old age (odds ratio (OR) = 1.063; 95% confidence interval (CI) = 1.024–1.104; P = 0.002), high 24-hour SBP levels (OR = 1.055; 95% CI = 1.028–1.082; P < 0.001), and high 24-hour heart rate (OR = 1.041; 95% CI = 1.006–1.078; P = 0.023) were independently associated with advanced WMLs. CONCLUSIONS In addition to old age and elevated 24-hour SBP, increased heart rate is associated with advanced WMLs in ischemic stroke patients. Heart rate deserves more attention in predicting advanced WMLs in those patients. [ABSTRACT FROM PUBLISHER]