Engineering topics
Publications and source records attributed to Levere, T. E..
The dynamic nature of sleep is reviewed. Research is then presented concerning two fundamental issues: (1) does an individual react differently to auditory sounds when asleep as compared to when the individual is awake and (2) does sleep disruption necessarily involve behavioral awakening?
The present research was concerned with whether or not a 15 dB(A) reduction in overall noise level would lessen the sleep disturbing properties of jet aircraft flyover noise and, if less disturbing, whether this would be subjectively appreciated by the sleeping individual. The results indicate that a reduction of 15 dB (A) does result in less sleep disruption but only during sleep characterized by fast-wave electroencephalographic activity. During sleep characterized by slow-wave electroencephalographic activity, such a reduction in the sleep-disturbing properties of jet aircraft noise has little effect. Moreover, even when effective during fast-wave sleep, the decreased arousal produced by the lower noise levels is not subjectively appreciated by the individual in terms of his estimate of the quality of his night's sleep. Thus, reducing the overall noise level of jet aircraft flyovers by some 15 dB(A), is, at best, minimally beneficial to sleep.
The research describes the sleep disturbing effects of jet aircraft flyover noise as it occurs at different times during the night. The results indicate that individuals respond statistically more, in terms of greater cortical desynchronization, during the first and last thirds of the night. During the middle third, while there is still a significant amount of cortical desynchronization in response to the jet aircraft noise, this is always less than that which occurs earlier or later in the night. The implications of this data are that it might be possible to reduce the disruptive effects of at least certain extrinsic sonic stimulation by appropriate scheduling.
The present research presents data relative to the objective evaluation of the effects of a specific complex auditory stimulus presented during sleep. The auditory stimulus was a jet aircraft flyover of approximately 20-sec duration and a peak intensity level of approximately 80 dB (A). Our specific interests were in terms of how this stimulus would interact with the frequency pattern of the sleeping EEG and whether there would be any carry-over effects of the nocturnally presented stimuli to the waking state. The results indicated that the physiological effects (changes in electroencephalographic activity) produced by the jet aircraft stimuli outlasted the physical presence of the auditory stimuli by a considerable degree. Further, it was possible to note both behavioral and electroencephalographic changes during waking performances subsequent to nights disturbed by the jet aircraft flyovers which were not apparent during performances subsequent to undisturbed nights.
Circadian rhythm of isolated free-running nemestrina monkey
Circadian rhythm of activity during isolation in nemestrine monkey
EEG data computer assessment as measure of fatigue in humans and monkeys induced by simulated space flight, determining performance decrease