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 Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases.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

Aircraft noise effects on sleep - Results of 2240 polysomnographically recorded subject nights in laboratory and field studies

Noise is defined as unwanted sound, and as such has both an objective (physical) and subjective (psychological) component. Its effects are multifarious. Sound pressure levels that are too high for too long or extreme even for a short time lead to hearing loss, which can be increasingly observed in non-occupational settings (e.g., due to music that is too loud). However, even at lower levels sound can affect an organism. These “nonauditory” effects of noise include annoyance reactions, communication interference, delayed speech development in children, and sleep disturbances (1). According to the World Health Organization (WHO), the nonauditory effects of noise are responsible for the loss of at least 1 million DALYs (disability-adjusted life years) every year in Western Europe (2).

Much Ado About Noise.

The temporal trajectories and neural mechanisms of recovery of cognitive function after a major perturbation of consciousness is of both clinical and neuroscientific interest. The purpose of the present study was to investigate network-level changes in functional brain connectivity associated with the recovery and return of six cognitive functions after general anesthesia. High-density electroencephalograms (EEG) were recorded from healthy volunteers undergoing a clinically relevant anesthesia protocol (propofol induction and isoflurane maintenance), and age-matched healthy controls. A battery of cognitive tests (motor praxis, visual object learning test, fractal-2-back, abstract matching, psychomotor vigilance test, digital symbol substitution test) was administered at baseline, upon recovery of consciousness (ROC), and at half-hour intervals up to 3 h following ROC. EEG networks were derived using the strength of functional connectivity measured through the weighted phase lag index (wPLI). A partial least squares (PLS) analysis was conducted to assess changes in these networks: (1) between anesthesia and control groups; (2) during the 3-h recovery from anesthesia; and (3) for each cognitive test during recovery from anesthesia. Networks were maximally perturbed upon ROC but returned to baseline 30-60 min following ROC, despite deficits in cognitive performance that persisted up to 3 h following ROC. Additionally, during recovery from anesthesia, cognitive tests conducted at the same time-point activated distinct and dissociable functional connectivity networks across all frequency bands. The results highlight that the return of cognitive function after anesthetic-induced unconsciousness is task-specific, with unique behavioral and brain network trajectories of recovery.

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Distinct and Dissociable EEG Networks Are Associated With Recovery of Cognitive Function Following Anesthesia-Induced Unconsciousness.

Background Adding noise to a system to improve a weak signal’s throughput is known as stochastic resonance (SR). SR has been shown to improve sensory perception. Some limited research shows noise can also improve higher order processing, such as working memory, but it is unknown whether SR can broadly improve cognition. Objective We investigated cognitive performance while applying auditory white noise (AWN) and/or noisy galvanic vestibular stimulation (nGVS). Methods We measured cognitive performance (n = 13 subjects) while completing seven tasks in the cognition test battery (CTB). Cognition was assessed with and without the influence of AWN, nGVS, and both simultaneously. Performance in speed, accuracy, and efficiency was observed. A subjective questionnaire regarding preference for working in noisy environments was collected. Results We did not find broad cognitive performance improvement under the influence of noise (p > 0.1). However, a significant interaction was found between subject and noise condition for accuracy (p = 0.023), indicating that some subjects exhibited cognitive changes with the addition of noise. Across all metrics, noisy environment preference may trend to be a potential indicator of whether subjects will exhibit SR cognitive benefits with a significant predictor in efficiency (p = 0.048). Conclusion This study investigated using additive sensory noise to induce SR in overall cognition. Our results suggest that using noise to improve cognition is not applicable for a broad population; however, the effect of noise differs across individuals. Further, subjective questionnaires may be a means to identify which individuals are sensitive to SR cognitive benefits, but further investigation is needed.

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Effects of additive sensory noise on cognition

Introduction: Surveys suggest that - at the same noise level - railway noise is less annoying than aircraft or road traffic noise. Thus, railway noise is less strongly regulated in some European countries. However, in a laboratory study performed at the DLR-Institute of Aerospace Medicine railway noise lead to higher degrees of sleep fragmentation than aircraft noise. Our objective was to compare reactions to aircraft and railway noise in the field.
Methods: In a field study on railway noise, 33 healthy participants (mean age 36.2 years ± 10.3 (SD); 22 females) were examined during nine consecutive nights. Polysomnography and noise events were recorded during every night. In total, 8866 railway noise events were used for analysis of noise-induced awakenings. In a field study on aircraft noise, data from 64 subjects and 10658 noise events were recorded. The datasets from rail and aircraft noise were pooled to facilitate a direct comparison.
Results: In agreement with former studies, macrostructure of sleep was only slightly altered by noise. Awakening probability (sleep stage changes to wake/S1) due to railway noise increased significantly from 6.5% at 35 dB(A) to 20.5% at 80 dB(A) maximum sound pressure level (p<0.0001). In the comparison of traffic noise sources, awakening probability decreased in the order freight train noise, aircraft noise, and passenger train noise. Different reaction probabilities were explained amongst others by the sound pressure rise time of the noise event.
Conclusions:
In contrast to the results of annoyance surveys, nocturnal freight train noise lead to significantly increased awakening probabilities that exceeded those observed for aircraft noise at the same maximum sound pressure level. In line with our laboratory findings these awakening probabilities were higher than for aircraft noise. Freight wagons that are technically outdated or more developed may result in different physiological reaction probabilities.

Mathias Basner

Papers

Aircraft noise effects on sleep - Results of 2240 polysomnographically recorded subject nights in laboratory and field studies

Much Ado About Noise.

Distinct and Dissociable EEG Networks Are Associated With Recovery of Cognitive Function Following Anesthesia-Induced Unconsciousness.

Effects of additive sensory noise on cognition

Impact of nocturnal railway and aircraft noise on awakening probability in the field