How many days are enough? Sleep-wake timing regularity and fragmentation scores change with the number of days included.

The duration of sleep data collection from actigraphy is often influenced by practical factors (e.g. workdays versus non-workdays), but the impact of the variation of duration on outcome measures of interest has not been well explored. This study investigates the effect of the duration of actigraphy measurement on non-parametric measures of 24-hr sleep-wake rhythms. We examined regularity inter-daily stability and fragmentation intra-daily variation over 14 days or the first 7 days in participants (n = 41) undergoing evaluation for sleep disorders. Bland-Altman plots assessed the impact of fewer than 14 or 7 days, respectively, on inter-daily stability and intra-daily variation scores. Intra-daily variation values were also calculated for each day and compared with the 14-day intra-daily variation. Compared with the entire 14-day period, using shorter durations (< 7 days) led to a higher estimated bias and increased variance in the limits of agreement for inter-daily stability. Intra-daily variation values showed increased variation in the limits of agreement with fewer days. Similar trends were observed when comparing shorter actigraphy periods 3 or 5 days-7 days. Daily intra-daily variation calculations indicate that individuals with higher daily fragmentation experienced more pronounced day-to-day fragmentation and greater variability in the degree of fragmentation, in a linear association between daily intra-daily variation standard deviation and 14-day intra-daily variation values. Our data indicate that a minimum of 7 full days of actigraphy is recommended to reduce measurement errors, and intra-daily variation and inter-daily stability derived from less than 7 days cannot be compared with those from more than 7 days without significant error.

A Multiple Mediator Model of Depression, Dysfunctional Beliefs about Sleep, and Sleep Effort in the Relationship between Psychological Inflexibility and Insomnia in Shift Working Nurses.

The aims of this study were to explore the influence of shift working nursing professionals' psychological inflexibility on their level of insomnia. Additionally, we investigated the mediation effect of depression and sleep-related cognitions on this association. An online survey was conducted among 202 nursing professionals at Asan Medical Center from July to August, 2023. Participants responded to questionnaires including the Insomnia Severity Index (ISI), Acceptance and Action Questionnaire-II (AAQ-II), Dysfunctional Beliefs and Attitudes about Sleep - 16 (DBAS-16), Glasgow Sleep Effort Scale (GSES), Patient Health Questionnaire-9 items (PHQ-9), and the Discrepancy between desired time in bed and desired total sleep time index (DBST index). Pearson's correlation and linear regression were performed to explore the factors predicting ISI scores. Mediation analysis was implemented. Linear regression revealed that insomnia severity was predicted by DBAS-16 (ß = 0.15, p = 0.008), GSES (ß = 0.48, p < 0.001), and PHQ-9 (ß = 0.26, p < 0.001). Mediation analysis showed that the relationship between the psychological inflexibility of shift-working nursing professionals' and insomnia severity was fully mediated by depression, dysfunctional beliefs about sleep, and sleep effort. Psychological inflexibility does not directly influence insomnia severity, but depression, dysfunctional beliefs about sleep, and sleep effort fully mediate the relationship.

Validation of the Parental Understanding and Misperceptions about BAby's Sleep Questionnaire using auto-videosomnography.

BACKGROUND: Previous studies have suggested that parental cognitions about child's sleep may be an important factor underlying pediatric sleep problems. The current study aimed to (a) develop an assessment tool measuring parental understanding and misperceptions about baby's sleep (PUMBA-Q); (b) validate the questionnaire using self-report and objective sleep measures. METHODS: There were 1,420 English-speaking caregivers (68.0% mothers, 46.8% of children being females, mean age 12.3 months), who has completed online self-reported questionnaires. The PUMBA-Q, which was developed for this study, Dysfunctional Beliefs and Attitudes about Sleep (DBAS) and Maternal Cognitions about Infant Sleep Questionnaire (MCISQ) were included to evaluate participant's thoughts on their own or child's sleep. Insomnia Severity Index (ISI) was collected to access participant's subjective insomnia severity. Brief Infant Sleep Questionnaire-Revised (BISQ-R) was used to assess parental-reported child sleep. Auto-videosomnography was used to record child's sleep. RESULTS: Exploratory factor analysis indicated the best fit with a 4-factor model using 23 items (RMSEA = .039). The four subscales were labeled: (a) Misperceptions about parental intervention; (b) Misperceptions about feeding; (c) Misperceptions about child's sleep; and (d) General anxiety of parents. Internal consistency was adequate (Cronbach's alpha = .86). PUMBA-Q scores were significantly associated with MCISQ (r = .64, p < .01), DBAS (r = .36, p < .01), ISI (r = .29, p < .01), BISQ-R (r = .-49, p < .01), objective child's total sleep time (r = -.24, p < .01) and objective number of parental nighttime visits (r = .26, p < .01). CONCLUSIONS: The results demonstrated that PUMBA-Q 23 is a valid assessment tool for parental cognitions of child sleep. The link between parental cognitions and child sleep highlights the importance of managing parental cognitions about child sleep when treating pediatric sleep problems.

Predictors of dropout in university students participating in an 8-week e-mail-based cognitive-behavioral therapy for insomnia intervention.

PURPOSE: We conducted an exploratory study to identify risk factors of dropout in an 8-week e-mail-based cognitive-behavioral therapy for insomnia (REFRESH) to improve sleep among university students with insomnia symptoms. METHODS: University and graduate students in Hong Kong and Korea who scored higher than 10 on the Insomnia Severity Index participated in REFRESH. RESULTS: Of 158 participants from Hong Kong (n = 43) and Korea (n = 115), 90 (57%) did not complete all 7 sessions, while 52 of 90 (57.8%) dropped out prior to the fourth session. ROC analysis was conducted on the entire sample of 158 participants with intervention completion vs. dropout (non-completion) as the outcome variable. Predictors of dropout were wake time after sleep onset (WASO) < 7.1 min on the weekly sleep diary and expectations for sleep (a subscale of dysfunctional beliefs and attitudes about sleep; DBAS) < 18 at baseline. CONCLUSIONS: These findings indicate that shorter WASO and less expectations for sleep at baseline were associated with risk of dropout from e-mail delivered self-help CBT-I-based intervention. Our results highlight the importance of identifying and tailoring treatment formats to students based on their presenting sleep characteristics.

Differences in Treatment Effects of Cognitive-behavioral Therapy for Insomnia Based on Sleep Reactivity: A Preliminary Study.

INTRODUCTION: Sleep reactivity is the trait-like degree to which stress disrupts sleep, resulting in difficulty falling and staying asleep. Although previous studies have suggested that individuals who have high sleep reactivity may be resistant to cognitive-behavioral therapy for insomnia (CBT-I) effects, there have been no studies that have investigated this empirically. This study explored differential treatment responses in CBT-I based on sleep reactivity levels. MATERIAL AND METHOD: Participants for this study were nineteen insomnia patients who met DSM-5 criteria for insomnia disorder. All participants received four weekly sessions of structured cognitive-behavioral therapy for insomnia (CBT-I). Individuals completed the Insomnia Severity Index (ISI), Korean version of Center for Epidemiologic Studies Depression Scale-Revised (K-CESD-R), Ford Insomnia Response to Stress Test (FIRST), Dysfunctional Beliefs and Attitudes about Sleep Scale-16 (DBAS-16), the Daily Inventory of Stressful Events (DISE) and a sleep diary. Participants were classified into two groups based on sleep reactivity level (high and low sleep reactivity). RESULT: Following treatment, significant changes were found for ISI, K-CESD-R, DBAS-16 and FIRST scores, sleep onset latency, wake after sleep onset, sleep efficiency, number of awakenings, sleep quality and feeling refreshed upon awakening in both groups. Improvements in sleep efficiency was lower in the high sleep reactivity group compared to the low sleep reactivity group. No differences in ISI, K-CESD-R, DBAS-16 scores, and stress event frequency during the treatment duration were found between groups. CONCLUSION: These findings suggest that sleep reactivity level may be an important factor that affects treatment outcome of CBT-I. Furthermore, the results may suggest that individual response to stress events are more important than the stressor itself.

Relationship between screen time among children and lower economic status during elementary school closures due to the coronavirus disease 2019 pandemic.

BACKGROUND: This study aimed to examine whether the extended use of a variety of digital screen devices was associated with lower economic status and other environmental factors among Korean elementary school children and their caregivers during school closures precipitated by the coronavirus disease 2019 (COVID-19) pandemic. METHODS: A total of 217 caregivers of children 7-12 years of age from Suwon, Korea, were recruited and asked to respond to a self-administered questionnaire in June 2020. The questionnaire addressed demographic information and children's use of digital media, in addition to their caregivers. The t-test was used for continuous variables, and the Kruskal-Wallis test was used for variables measured on an interval scale. A multiple regression analyses were performed to examine the effects of significant correlative factors on screen time in children as predictors. RESULTS: Children with lower household incomes demonstrated a higher frequency and longer duration of smartphone and tablet personal computer use compared to those from higher income households. Children of households in which incomes decreased after COVID-19 used smartphones and tablet PCs more often and for longer durations. Children from households that experienced decreased income(s) after COVID-19 used personal computers more often and for a longer duration, and children from low-income families engaged in longer screen time on smartphones. A change in primary caregiver(s) may have increased children's screen time on smartphones. CONCLUSION: Lower household income was associated with longer screen time among children, and poor mental health among caregivers during school closures precipitated the COVID-19 pandemic.

Developing a Psychological Intervention for Decreasing Bedtime Procrastination: The BED-PRO Study.

INTRODUCTION: Bedtime Procrastination (BP) is defined as the behavior of going to bed later than intended, without having external reasons for doing so. Previous studies have shown that BP has a negative effect on sleep and health, emphasizing the need to develop interventions to decrease BP. This intervention development study is a proof-of-concept study for a psychological intervention designed for decreasing bedtime procrastination, namely BED-PRO. MATERIAL AND METHOD: The intervention was developed based on behavioral modification principles and motivational interviewing techniques. The final intervention was a weekly three-session intervention, with one additional booster call. Twenty individuals with high BP participated in the study, and data was collected for pre- and post-intervention, and one-month follow-up. Individuals completed the Bedtime Procrastination Scale, Epworth Sleepiness Scale, Fatigue Severity Scale, Morningness-Eveningness Questionnaire, Insomnia Severity Index, and a sleep diary. RESULT: Significant changes were found for BPS scores, bedtime procrastination duration (Δ51 mins, 63.8% reduction compared to baseline), wake after sleep onset, sleep efficiency and feeling refreshed upon awakening measured by sleep diaries following the intervention. In addition, changes in BPS, ISI, and ESS scores, wake after sleep onset, sleep efficiency and feeling refreshed upon awakening were maintained or continued to improve at 1-month follow-up. CONCLUSION: This study verified the feasibility and acceptability of the BED-PRO intervention and the potential for being the first intervention to target bedtime procrastination. Considering the research about negative implications of BP, we expect that this intervention could be a step forward in considering BP as a serious health behavior.

A Randomized Controlled Trial Comparing Neurofeedback and Cognitive-Behavioral Therapy for Insomnia Patients: Pilot Study.

Insomnia is a common disease that negatively affects patients both mentally and physically. While insomnia disorder is mainly characterized by hyperarousal, a few studies that have directly intervened with cortical arousal. This study was conducted to investigate the effect of a neurofeedback protocol for reducing cortical arousal on insomnia compared to cognitive-behavioral treatment for insomnia (CBT-I). Seventeen adults with insomnia, free of other psychiatric illnesses, were randomly assigned to neurofeedback or CBT-I. All participants completed questionnaires on insomnia [Insomnia Severity Index (ISI)], sleep quality [Pittsburgh Sleep Quality Index (PSQI)], and dysfunctional cognition [Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS-16)]. The neurofeedback group showed decreases in beta waves and increases in theta and alpha waves in various areas of the electroencephalogram (EEG), indicating lowered cortical arousal. The ISI and PSQI scores were significantly decreased, and sleep efficiency and sleep satisfaction were increased compared to the pre-treatment scores in both groups. DBAS scores decreased only in the CBT-I group (NF p = 0.173; CBT-I p = 0.012). This study confirmed that neurofeedback training could alleviate the symptoms of insomnia by reducing cortical hyperarousal in patients, despite the limited effect in reducing cognitive dysfunction compared to CBT-I.

Effects of Depression and Resilience of Public Workers on Work-related Stress and Anxiety in Response to the COVID-19 Pandemic.

BACKGROUND: This study explored the clinical variables related to public workers' stress and anxiety regarding the viral epidemic, and the mediating effect of resilience on the relationship between their depression and anxiety in response to coronavirus disease 2019 (COVID-19) pandemic. METHODS: A total of 938 public workers answered anonymous questionnaires in May 2020. The survey included rating scales such as the Stress and Anxiety to Viral Epidemics-9 (SAVE-9), Patients Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Connor-Davidson Resilience Scale 2 items (CD-RISC 2), and subjects also answered whether they were employed in COVID-19 related fields. RESULTS: Married, female, junior, public workers reported a higher level of stress and anxiety in response to the viral epidemic. Furthermore, high levels of stress and anxiety toward the epidemic are defined by high PHQ-9, high GAD-7, and low CD-RISC 2 scores. It could also be seen that resilience mediated the effect of depression in public workers and their stress and anxiety levels toward the epidemic. CONCLUSION: It is important to reduce the psychological burden of public workers and manage their mental health to help them cope with the epidemic wisely and efficiently. Among many mental health factors, psychological resilience represents an essential target for psychological intervention among public workers.

Development of the Stress and Anxiety to Viral Epidemics-9 (SAVE-9) Scale for Assessing Work-related Stress and Anxiety in Healthcare Workers in Response to Viral Epidemics.

BACKGROUND: The coronavirus disease 2019, or COVID-19, has had a major psychological impact on healthcare workers. However, very few scales are available to specifically assess work-related stress and anxiety in healthcare workers responding to a viral epidemic. This study developed a new assessment tool, the Stress and Anxiety to Viral Epidemics-9 (SAVE-9) and aimed to validate it among healthcare workers directly affected by COVID-19 in Korea. METHODS: A total of 1,019 healthcare workers responded through anonymous questionnaires during April 20-30, 2020. Exploratory factor analysis (EFA) was conducted to explore the construct validity, and the reliability was assessed using internal consistency measures of Cronbach's alpha coefficients. Receiver operating characteristic analysis was conducted to define the most appropriate cut-off point of SAVE-9 using the Generalized Anxiety Disorder-7 scale (GAD-7; ≥ 5). Second, Spearman's rank correlation coefficient was used to establish convergent validity for the SAVE-9 questionnaire with GAD-7 and the Patient Health Questionnaire-9. RESULTS: The nine-item scale had satisfactory internal consistency (Cronbach's α = 0.795). It adopted a two-factor structure: 1) anxiety regarding viral epidemics and 2) work-related stress associated with viral epidemics. A cut-off score of 22 for the SAVE-9 ascertained levels of stress and anxiety in response to a viral epidemic in healthcare workers that warranted clinical attention. Correlations between the SAVE-9 and the other scales were statistically significant (P < 0.05). CONCLUSION: The results suggest that the SAVE-9 is a useful, reliable, and valid tool to evaluate stress and anxiety responses in healthcare workers during viral epidemics.

Factorial Validity of the Arabic Version of the Stress and Anxiety to Viral Epidemics-6 Items (SAVE-6) Scale among the General Population in Lebanon.

This study explored the psychometric properties of the Arabic version of the Stress and Anxiety to Viral Epidemics-6 items (SAVE-6) scale for assessing people's anxiety in response to the viral epidemic in Lebanon. The 406 participants responded voluntarily to the online survey that included the SAVE-6, Generalized Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire-9 (PHQ-9) tools. The single-structure SAVE-6 model showed good internal consistency (Cronbach's α = 0.773). The SAVE-6 scale also showed good convergent validity with the GAD-7 (Spearman's ρ = 0.42, P < 0.001) and PHQ-9 (ρ = 0.38, P < 0.001). Receiver operating characteristic (ROC) analysis revealed an Arabic SAVE-6 cut-off score of 12 points (area under the curve [AUC] = 0.753; sensitivity = 62.74%; specificity = 78.26%) for an at least mild degree of anxiety (GAD-7 score ≥ 5). The Arabic version of the SAVE-6 was a reliable, valid, and solely usable scale for measuring the anxiety response of the general population to the viral epidemic.

Development of Dysfunctional Beliefs and Attitude about Sleep Scale for Cancer Patients.

Study objectives: This study aimed to develop a scale utilizing the original Dysfunctional Beliefs and Attitudes about Sleep (DBAS) scale that measured maladaptive cognitions associated with sleep that is especially sensitive to cancer patients. In addition to the original scale, we added two additional items that reflected cancer-specific dysfunctional beliefs about sleep. Methods: Participants consisted of 337 cancer patients (mean age 54.0 ± 11.8 years, 32.0% men). All participants completed the DBAS-16, two cancer specific items, and the Insomnia Severity Index. Item-to-total-score correlations, internal consistency, item selection, and factor structure were examined. Results: The DBAS-16 was found to be reliable, and internal consistency was also adequate when adding two cancer-specific questions (Cronbach's alpha = 0.89). A total of 14 items were selected, and a four-factor model was selected using exploratory factor analysis (Tucker-Lewis index = 0.86, root mean square error of approximation = 0.08). The four factors were (a) sleep expectations, (b) worry about insomnia, (c) perceived consequences of insomnia and medication, and (d) two cancer-related items. The modified 14 items of the Cancer-related DBAS (C-DBAS-14) well differentiated cancer patients with and without insomnia. Conclusions: The C-DBAS-14 is a promising measure that has adequate internal consistency. It is also sensitive to sleep-related cognitions in cancer patients and can discriminate patients with cancer who are experiencing insomnia from those who are good sleepers. The enhanced utility of the shortened 14-item scale tailored specifically to cancer patients may be useful in both clinical practice and research settings.Abbreviations: CBT: cognitive behavioral therapy; C-DBAS-14: Cancer-Related Dysfunctional Beliefs and Attitude about Sleep; C-DBS: Cancer-Related Dysfunctional Beliefs about Sleep; DBAS-16: Dysfunctional Beliefs and Attitudes about Sleep; ISI: Insomnia Severity Index.

Social Support as a Mediator Between Insomnia and Depression in Female Undergraduate Students.

Objectives/Background: Despite findings that insomnia and depression have a bidirectional relationship, the exact psychological mechanisms that link these disorders are largely unknown. The goal of this study was to identify whether social support mediates the relationship between insomnia and depression. Methods: The study sample (N = 115) consisted of females only, and all participants (mean age 21.77 ± 1.80) completed self-report measures of insomnia severity, depression, and social support. Results: Insomnia severity was significantly associated with low levels of social support (B = -1.04, SE = .27, p < .001) and high levels of depression (B = .18, SE = 0.05, p < .001). Social support mediated the effects of insomnia on depression (95% CI [.03, .15]). However, social support did not mediate the effects of depression on insomnia (95% CI [-.01, .32]). Conclusions: These findings suggest that interpersonal factors such as social support may be an important factor to consider in female insomnia patients in the context of preventing depression in this population.

Trends in Digital Media Use in Korean Preschool Children.

BACKGROUND: Children today are exposed to various media devices, and their usage of these is increasing. Prior studies have outlined forms of harm this can potentially cause. However, there has been little empirical research on the use of media devices among preschool children in Asia. The aim of this study was to examine and analyze longitudinal trends in media device use among Korean preschool children, focusing on the frequency of engagement, time spent with, and ownership of media devices, delineated by sex. METHODS: Four hundred parents of children aged 2-5 years were invited to enroll. The baseline assessment, Wave 1, was conducted between December 2015 and June 2016, and follow-up assessments, Wave 2 and Wave 3, were conducted annually for the following 2 years. Time of media use, frequency of media use, and ownership of media devices (TV, tablet PCs, and smartphones) were investigated. RESULTS: Ownership of tablet PCs increased significantly between Wave 1 and Wave 3 for boys and girls (corrected P < 0.001). Frequency of media use increased significantly between Wave 1 and Wave 3 only in boys' use of tablet PCs (mean difference 0.8 day/wk). Time of media use increased significantly between Wave 1 and Wave 3 for both sexes in all devices, measured by mean difference on weekdays and weekends (TV by 0.6 and 0.7 hr/day, tablet PCs by 0.6 and 0.8 hr/day, and smartphones by 0.4 and 0.4 hr/day). Children spent more time using media devices during weekends than on weekdays. CONCLUSION: This study observed an increase in the tendency of media device use among preschool children in Korea. The patterns of use indicate that paying attention to the types of devices children use is needed, as well as vigilance on weekends.

Sex Differences in Insomnia: from Epidemiology and Etiology to Intervention.

PURPOSE OF REVIEW: Insomnia is approximately 1.5 times more common in women than in men. To date, research has advanced our knowledge about why women report significantly more sleep problems than men despite not being reflected in objective sleep measures. Precisely understanding the symptomatology and pathological mechanisms underlying sex differences is important for prevention and providing appropriate interventions. RECENT FINDINGS: Sex differences found in insomnia goes beyond simple explanations and have been proven to be a complicated interplay of biological, psychological, and social factors that play different roles throughout the life span. This paper will review sex differences in insomnia based on risk factors, mechanisms, and consequences, as well as treatment response. In addition, we will also discuss treatment recommendations when working with female populations at different stages in the life span that may be more vulnerable to insomnia. Future studies utilizing prospective, longitudinal designs are needed to understand the interactions of various factors that can explain existing sex differences in insomnia.

Validation of the Korean Munich Chronotype Questionnaire.

PURPOSE: The Munich Chronotype Questionnaire (MCTQ) assesses actual sleep-wake timing and has advantages compared to prior chronotype questionnaires in that it differentiates sleep-wake patterns between work days and free days and uses corrected mid-sleep time on free days after correcting for accumulated sleep debt over the week to categorize chronotype. The current study, we validated the Korean version of the MCTQ. METHODS: In this study, 310 participants (mean age = 27.09 ± 5.64; 78.1% females) completed the Korean version of the MCTQ. RESULTS: MCTQ parameters were significantly correlated with MEQ (Morningness-Eveningness Questionnaire) scores (│r│ ≥ 0.48), and test-retest reliability was ≥ 0.72. Cutoff scores of 2.5%, which correlated to 2.36 and 8.57 mid-sleep times in our sample, showed the best convergence with MEQ when categorizing chronotype. CONCLUSIONS: Our study suggests that the MCTQ is a useful questionnaire in assessing chronotype in young adults.

Chronotype Differences in Health Behaviors and Health-Related Quality of Life: A Population-Based Study Among Aged and Older Adults.

This study investigates health behaviors, health-related quality of life (HRQOL) and sleep among chronotypes in a community-based sample (n = 2,976). Analysis of covariance indicated evening types (E-types) had a significantly higher percentage of current smokers and more sleep-interfering behaviors compared to intermediate and morning types (M-type), and also lower physical activity and more sleep disturbance compared to M-types. E-types also had worse mental HRQOL compared to both chronotypes, and worse physical HRQOL compared to M-types. Exploratory analyses indicated E-types consumed more caffeinated beverages at night, smoked or ate heavy meals before bedtime, kept irregular sleep-wake schedules, and took more naps. Mediational analyses indicated that sleep-interfering behavior partially mediated the relationship between chronotype and sleep disturbance, and physical activity partially mediated the relationship between chronotype and mental HRQOL. E-types had more unhealthy behaviors, which may subsequently place them at higher risk for health problems.

Effects of long-term treatment on brain volume in patients with obstructive sleep apnea syndrome.

We assessed structural brain damage in obstructive sleep apnea syndrome (OSA) patients (21 males) and the effects of long-term continuous positive airway pressure (CPAP) treatment (18.2 ± 12.4 months; 8-44 months) on brain structures and investigated the relationship between severity of OSA and effects of treatment. Using deformation-based morphometry to measure local volume changes, we identified widespread neocortical and cerebellar atrophy in untreated patients compared to controls (59 males; Cohen's D = 0.6; FDR < 0.05). Analysis of longitudinally scanned magnetic resonance imaging (MRI) scans both before and after treatment showed increased brain volume following treatment (FDR < 0.05). Volume increase was correlated with longer treatment in the cortical areas that largely overlapped with the initial atrophy. The areas overlying the hippocampal dentate gyrus and the cerebellar dentate nucleus displayed a volume increase after treatment. Patients with very severe OSA (AHI > 64) presented with prefrontal atrophy and displayed an additional volume increase in this area following treatment. Higher impairment of working memory in patients prior to treatment correlated with prefrontal volume increase after treatment. The large overlap between the initial brain damage and the extent of recovery after treatment suggests partial recovery of nonpermanent structural damage. Volume increases in the dentate gyrus and the dentate nucleus possibly likely indicate compensatory neurogenesis in response to diminishing oxidative stress. Such changes in other brain structures may explain gliosis, dendritic volume increase, or inflammation. This study provides neuroimaging evidence that revealed the positive effects of long-term CPAP treatment in patients with OSA.

Validation of the Karolinska Sleepiness Scale in Korean.

BACKGROUND AND PURPOSE: The Karolinska Sleepiness Scale (KSS) is widely used for assessing current level of sleepiness, but it has not been validated in South Korea. This study aimed to validate the KSS using the Stanford Sleepiness Scale (SSS), polysomnography (PSG), and electroencephalography (EEG). METHODS: The sample consisted of 27 adult participants in this study aged 40.5±7.7 years (mean±standard deviation) and included 22 males. They completed questionnaires and underwent EEG recording and overnight PSG. The KSS was completed from 18:00 to 24:00 every 2 hours and following PSG (at 07:00). KSS scores changed over time and in particular increased with the time since waking, with the score peaking at 24:00. RESULTS: Convergent validity of the KSS was verified by performing a Spearman correlation analysis between the KSS and SSS (r=0.742, p<0.01). Concurrent validity of the KSS was verified by performing a Spearman correlation analysis between the KSS administered before sleep and the sleep onset latency measured using PSG (r=-0.456, p<0.05). Alpha waves were measured 5 minutes before administering the KSS, and the KSS scores were compared with these alpha waves. There were no significant correlations observed between the KSS scores and alpha waves measured in the left occipital area (O1), left frontal area (F3), or left central area (C3). In addition, Spearman correlation analyses of the difference between KSS scores and alpha waves measured at O1, F3, and C3 produced no significant results. CONCLUSIONS: This study verified the convergent validity and concurrent validity of the KSS, and confirmed the capabilities of this scale in assessing sleepiness changes over time.

Association of nightmares with cardio-cerebrovascular disease, hypertension and hyperlipidemia in older adults: A population-based cross-sectional study.

OBJECTIVE: This cross-sectional study investigated the relationship of nightmares with cardio-cerebrovascular disease (CVD), hypertension and hyperlipidemia which are major preceding diseases of CVD in older adults. METHODS: Participants (n = 2824; mean age 63.6 ± 6.6 years, females 49.3%) completed the Disturbing Dream and Nightmare Severity Index (DDNSI), which was used to divide the sample into either the Nightmare or Non-Nightmare group (cut-off score ≥ 10). Demographic information, history of CVD (cerebrovascular disease, myocardial infarction, congestive heart failure, coronary artery disease, and arrhythmia), hypertension, hyperlipidemia, and self-report questionnaires about stress (Perceived Stress Scale), depression (Beck Depression Inventory), sleep quality (Pittsburgh Sleep Quality Index), and insomnia symptoms were also collected. RESULTS: Among the sample, 379 participants (13.4%) reported experiencing nightmares more than once a year, and 73 participants (2.6%) were classified as having nightmare disorder based on DDNSI scores (≥10). 11.3% of participants (n = 319) reported having more than one CVD. Approximately half of the participants reported a history of hypertension (52.1%, n = 1471) and hyperlipidemia (47.7%, n = 1346). Logistic regression analysis indicated the Nightmare group was 2.04 times at higher risk for hyperlipidemia (OR = 2.04, 95% CI 1.22-3.40, p = .006) after controlling for covariates compared to the Non-Nightmare group. Although non-significant, there was a trend toward a higher risk of hypertension in the Nightmare group (OR = 1.67, 95% CI 0.99-2.84, p = .056). CONCLUSIONS: Results of this study indicate frequent nightmares in older adults may be associated with hyperlipidemia, which are risk factors for CVD. Further studies are needed to explore nightmares' directionality and health consequences in an aging population.