Showing papers by "Mathias Basner published in 2009"

Dubious bargain: trading sleep for Leno and Letterman.

Abstract: CURRENT ESTIMATES INDICATE THAT 20%1 TO 40%2 OF THE ADULT US POPULATION SLEEP LESS ON WEEKDAY NIGHTS THAN THE 7 TO 8 HOURS THOUGHT TO be needed by the majority of people to maintain behavioral alertness and avoid sleepiness-related risks of errors and accidents.3,4 The percentage of short sleepers may be even higher than self-report surveys suggest, because physiological sleep duration has been found to be as much as an hour or more below habitual sleep duration as reported in population studies.5,6 The issue of how much sleep people are obtaining nightly and what factors influence the habitual duration of sleep are important because reduced sleep duration has frequently been associated with a higher prevalence of obesity,7 morbidity, and mortality,8,9 although it is unclear whether these relationships are causal. This report focuses on lifestyle factors associated with shorter sleep times, in an effort to identify waking activities under discretionary control that may be a source for increasing sleep time in those who need to do so. Reduced sleep time in industrialized societies is primarily related to lifestyle. In a recent analysis of time use in the US, we found that work time was the primary activity that had a reciprocal relationship to sleep time.10 It suggests that Americans perceive sleep as a flexible commodity that can be exchanged for waking activities considered more essential or of greater value. If this is the case, reducing work time and its economic benefits in order to increase sleep time may not be feasible for most of the population. This prompted us to ask whether waking activities under discretionary control and adjacent to the sleep period may be a better source for increasing sleep time.

Determining physiological reaction probabilities to noise events during sleep

Abstract: Some of the activations that occur during sleep, e.g. awakening reactions, can be considered adverse effects of noise events (e.g., airplane overflights or train passings) during the night. The occurrence of such reactions is an important indicator of the sleep disturbing potential of the particular noise stimulus and it is often desired to exactly quantify that potential in terms of a probability. Awakenings are considered the strongest form of reaction to noise stimuli during sleep and are one of the most often adopted criteria in night time noise protection concepts. However, the correct determination of noise induced awakening probability has given rise to debate in the scientific community in recent years. Because during every night’s sleep, spontaneous awakenings can occur at any time, it remains unknown in principle, whether a particular awakening observed during the presence of a noise stimulus was induced by that stimulus or emerged spontaneously. Nevertheless, correctly determining the awakening probability in question is key when it comes to forecasting noise effects during the night. This article introduces two definitions of reaction probability, discusses their advantages and disadvantages, and develops a model of the influence of the time window duration in which reactions of sleepers are screened on the calculated reaction probability.

Pilot workload during approaches: comparison of simulated standard and noise-abatement profiles.

Abstract: Introduction: A new noise-reduced landing approach was tested – a Segmented Continuous Descent Approach (SCDA) - with regard to the resulting workload on pilots. Methods: Workload of 40 pilots was measured using physiological (heart rate, blood pressure, blink frequency, saliva cortisol concentration) and psychological (fatigue, sleepiness, tension and task load) parameters. Approaches were conducted in A320 and A330 full-flight simulators during night shift. SCDA was compared to the standard Low Drag Low Power (LDLP) procedure as reference. Results: Mean heart rate and blood pressure during the SCDA were not elevated, partly even significantly reduced (on average by 5 bpm and 4 mmHg regarding the flying Captain). Cortisol levels did not change significantly with mean values of 0.9 to 1.2 ng/ml. Landing was the most demanding segment of both approaches as indicated by significant increases in heart rate and decreases in blink frequency. Subjective task load was low. Discussion: Both approach procedures caused a similar workload level. Interpreting the results, methodological limitations have to be considered, e.g. the artificial and controlled airspace situation in the flight simulator. Nevertheless, it can be concluded that under these ideal conditions, the SCDA is operable without a higher workload for pilots compared to the common LDLP.

Validity of aircraft noise induced awakening predictions

Abstract: Aircraft noise disturbs sleep and impairs recuperation. Integrative noise measures like LDN or Lnight are commonly used to implicitly describe and limit nocturnal aircraft noise effects. However, noise exposures may differ in their sleep disturbing potential but nevertheless calculate to the same LDN or Lnight. Therefore, it has recently become more popular to use exposure-response relationships for single noise events to explicitly predict the degree of sleep fragmentation for a whole night with multiple noise events. These models have been criticized for not accounting for dependence between consecutive noise events, for disregarding the placement of noise events within the night, for disregarding other important acoustic parameters beside maximum sound pressure level (SPL) or single event level (SEL), and for not considering inter-individual differences in noise sensitivity. In this analysis, a Basic Model containing maximum SPL as the only explanatory variable and an Extended Model containing elapsed sleep time, time between maxima, and noise duration as additional variables are compared according to bias and precision in predicting the number of noise induced awakenings in single nights. Random subject effect logistic regression based on field study data, where the reaction to 16279 aircraft noise events was monitored in 64 subjects and 479 subject nights, was used for both models. The results indicate that a variable should only be included in the prediction model if (a) the variable has a relevant impact on sleep, (b) information on the distribution of the variable in the target population is available, and (c) the distribution of the variable in the target population differs relevantly from the distribution in the population that was used to generate the prediction model.

FFI and FNI - two effect based aircraft noise indices at Frankfurt Airport

Abstract: Within the planning process concerning the future expansion of Frankfurt Airport (construction of a new runway) in September 2007 the Regional Dialogue Forum Frankfurt Airport (RDF) proposed an Anti-Noise-Pact (ANP). ANP includes suggestions of upper limits and quantitative reduction goals for noise effects after the airport expansion and recommends the implementation of active noise control measures. Moreover, two regional aircraft noise indices for the description and control of the noise development in the vicinity of Frankfurt Airport are proposed. These are the 'Frankfurt Aircraft Noise Index' (FFI), and 'Frankfurt Night Index' (FNI). FFI is the primary index. Based on the 24 hours of the day, it describes the number of subjects highly annoyed by aircraft noise in areas within Ldn -contour 55 dB. FNI solely serves to assess nocturnal air traffic by displaying the number of awakenings additionally induced by aircraft noise emitted between 10pm and 6am, including regions where at least 0.5 additionally aircraft noise induced awakenings are expected. The proposed indices were subjected to a scientific evaluation by the authors of this contribution. In this contribution FFI and FNI and the involved requirements and objectives are described. It is concluded that effect based noise indices like FFI and FNI are in principle suitable to assess aircraft noise development around the airport as far as the underlying noise calculation method is able to reproduce the acoustical effects of changes in air traffic. However, several recommendations are given in order to improve the indices initially proposed by RDF.