Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
16 Sleep Disturbance Data Analysis Plan The primary outcome of this study is an exposure-response relationship between acoustical properties of single aircraft noise events (e.g., SEL, LAS,max) and physiological reactions during the sleep period (here: EEG awakenings determined by either polysomnography [protocol #1] or by actigraphy and the ECG [protocol #2]). Aircraft noise events will be identified by human scorers, if possible with the help of flight schedule data provided by the airport. The beginning and end of each aircraft noise event will be marked and several acoustical descriptors will be calculated (e.g., LAS,max, SEL, rise time, spectral composition). Equivalent noise levels LA,eq will be calculated for the sleep period time (exposure and control group) and for aircraft noise events only (exposure group only) for each study night. EEG awakenings (defined as EEG arousals ⥠15 s to avoid the low temporal resolution of 30-s sleep stage epochs) will be either determined by trained scorers and blinded to the acoustical data according to the criteria of Rechtschaffen et al.5 based on polysomnographic data (protocol #1) or by an automatic algorithm based on actigraphy and the ECG (protocol #2). For each aircraft noise event, the physiological data will be screened for an EEG awakening for the duration of the noise event. The outcome is binary (awakening yes/no). A random intercept logistic regression model with LAS,max as the only explanatory variable will be used to derive the exposure- response relationship and 95% confidence intervals. This constitutes the primary endpoint of the study. Secondary analyses will include models that incorporate individual (age, gender), situational (elapsed sleep time), and acoustical (SPL rise time, spectral composition) moderators. Sleep fragmentation (defined as awakenings per h sleep period time) will be calculated for and compared between the exposure and the control group. It will also be investigated whether sleep fragmentation varies as a function of Lnight calculated for each investigated study night. Spontaneous awakening probability will be both derived from noise-free intervals within the exposure group and from the control group. 49
