Prospective Cohort Study

25. Multiple Imputation for Nonresponse in Surveys. By D. B. Rubin. ISBN 0 471 08705 X. Wiley, Chichester, 1987. 258 pp. £30.25.

Multiple Imputation for Nonresponse in Surveys

Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

Of Theory and Practice

Definition: To what extent does the study allow us to draw conclusions about a causal effect between two or more constructs? Issues: Selection, maturation, history, mortality, testing, regression towrd the mean, selection by maturation, treatment by mortality, treatment by testing, measured treatment variables Increase: Eliminate the threats, above all do experimental manipulations, random assignment, and counterbalancing.

Reliability and validity

저작근 근전도에 관한 정상교합자와 ii급 부정교합자의 비교 연구

We would like to thank Drs. Glozier and Grunstein for carefully reading and commenting on our article [1]. In hindsight, the article title would have better referred to “signs of progress” in the fight against sleep deficiency, which is still widespread in the US population [2]. As pointed out by the authors (and discussed in the introduction of our article), other studies have shown increases in sleep duration assessed with time use surveys in the United States over the past few decades (e.g. Bin et al. [3] and Luckhaupt et al. [4]). We are providing an update based on what is now a massive database of US time use data across 2003–2016. Our analyses show that the trend of increasing sleep duration has continued and probably even accelerated since the last review of the data in 2007. We believe that the strength of our article is not based on being the first to show this or not, but on the thorough investigation of concurrent trends in waking activities, and how they may explain some of the observed trends in sleep duration. Finally, we also agree with the authors (and repeatedly point out in the abstract and body of our article) that the nature and impact of the observed increase in the prevalence of long sleep duration deserve more attention from the research community. We would also like to thank Drs. Hertenstein, Riemann, and Nissen for their helpful comments. We agree that p-values have limited value when operating with large datasets that provide statistical power to find differences significant that are not necessarily also relevant [5]. We understand that an annual increase in sleep duration of 1.4 min per 24 hr on weekdays and 0.8 min per 24 hr on weekends sounds irrelevant. However, over the 14 year observation period it translates to 17.3 min more sleep each night, or 4.4 full days each year, at the end of the observation period compared with the beginning. Considering the cumulative nature of sleep and chronic sleep loss [6] and the fact that alertness increases in a monotonic fashion with prior sleep [7], we believe that this increase in sleep duration to be beneficial for some (especially short sleepers), and thus relevant. The sleep research community should be able to assess the relevance of the size of this increase in sleep duration, and we therefore refrained from providing additional effect size measures. In the multiple regression context, adjusted R2 is a standard effect size metric. Adding survey year to our fully adjusted model increased this metric by 2.1 per cent, and the model explained 9.9 per cent of the total variance in sleep time (ADJRSQ statement in SAS Proc Surveyreg, SAS Institute, Version 9.4, Cary, NC). The authors state that “mean sleep duration was slightly longer than 8 hours on weekdays and SLEEPJ, 2018, 1–2

Response to Letters to the Editor by Dr. Glozier and Grunstein and by Drs. Hertenstein, Riemann, and Nissen in response to our article "Sleep duration in the United States 2003-2016: first signs of success in the fight against sleep deficiency?"

Nachtfluglärmwirkungen - Band 5: Leistung

Sleep loss robustly disrupts mood and emotion regulation in healthy individuals but can have a transient antidepressant effect in a subset of patients with depression. The neural mechanisms underlying this paradoxical effect remain unclear. Previous studies suggest that the amygdala and dorsal nexus (DN) play key roles in depressive mood regulation. Here, we used functional MRI to examine associations between amygdala- and DN-related resting-state connectivity alterations and mood changes after one night of total sleep deprivation (TSD) in both healthy adults and patients with major depressive disorder using strictly controlled in-laboratory studies. Behavioral data showed that TSD increased negative mood in healthy participants but reduced depressive symptoms in 43% of patients. Imaging data showed that TSD enhanced both amygdala- and DN-related connectivity in healthy participants. Moreover, enhanced amygdala connectivity to the anterior cingulate cortex (ACC) after TSD associated with better mood in healthy participants and antidepressant effects in depressed patients. These findings support the key role of the amygdala-cingulate circuit in mood regulation in both healthy and depressed populations and suggest that rapid antidepressant treatment may target the enhancement of amygdala-ACC connectivity.

Mathias Basner

Papers

Response to Letters to the Editor by Dr. Glozier and Grunstein and by Drs. Hertenstein, Riemann, and Nissen in response to our article "Sleep duration in the United States 2003-2016: first signs of success in the fight against sleep deficiency?"

Nachtfluglärmwirkungen - Band 5: Leistung

Enhanced amygdala-cingulate connectivity associates with better mood in both healthy and depressive individuals after sleep deprivation.

Sleep disturbances - What are adequate descriptions?

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