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Wind Farms: Noise
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Air Quality and Energy Systems, 2020
Daniel Shepherd, Chris Hanning, Bob Thorne
Noise may also cause awakenings and arousals. Arousal is a brief lightening of sleep that is not recalled. Sleep becomes fragmented and, if enough arousals occur, induces the same consequences as reduction of total sleep time. Awakenings are arousals of sufficient degree for wakefulness to be reached and long enough (greater than 10 sec) to be recalled. Arousals are more likely than awakenings, and thus, relying on reported awakenings underestimates the magnitude of the noise effects. The likelihood of an arousal depends upon the volume, character, and duration of the noise as well as the sleep stage and individual propensity (i.e., noise sensitivity). In an investigation into hospital noise, dose–response curves were created for different noises in different sleep stages.[50] Noises with characteristics designed to alert (e.g., telephone, alarms) were more likely to arouse. These noises tend to be impulsive in character, as does wind turbine noise. Noises that were classified as continuous broadband noises (e.g., traffic noise) were less likely to arouse. Another study[51] has shown that subjects with fewer sleep spindles (electrophysiological markers characteristic of stage II sleep) are more easily aroused by noise (Figure 9). Sleep spindles are taken as a marker of sleep stability and may provide a physiological marker of sleep quality.
Automated Processing of Big Data in Sleep Medicine
Published in Ervin Sejdić, Tiago H. Falk, Signal Processing and Machine Learning for Biomedical Big Data, 2018
Sara Mariani, Shaun M. Purcell, Susan Redline
Sleep spindles are discrete events observed in the scalp EEG signal that are generated as a result of interactions between several regions of the brain including thalamic and corticothalamic networks [46]. They appear as brief, powerful bursts of synchronous neuronal firing in thalamocortical networks and are a defining feature of stage N2 sleep. Sleep spindles are involved in new learning and are considered an index of brain plasticity and function, including intellectual abilities and memory consolidation during sleep [47].
Chaos or Randomness? Effect of Vagus Nerve Stimulation During Sleep on Heart-Rate Variability
Published in IETE Journal of Research, 2022
Karthi Balasubramanian, Nithin Nagaraj, Sandipan Pati
Multiple epochs of ECG data (each lasting 10–15 min) were collected from both the CASE and the CONTROL patients. For the VNS implanted case, four epochs were selected each during stage II sleep with VNS turned ON and OFF. Stage II sleep was identified based on detection of sleep spindles, K-complex and vertex sharp waves. Similarly, eight epochs of ECG data were collected from the patients who were not implanted with the VNS device. This forms the control data. Among the eight epochs of the controls, six were from positive controls (data from patients suffering from epilepsy) and two were from negative controls (data from patients not suffering from epilepsy).