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ABSTRACT: This study was designed to assess the effects of road traffic noise and frogs' croaking on the objective and subjective quality of sleep in a laboratory. The subjects were seven male students aged 19–21 years. They were exposed to recorded road traffic noise and frogs' croaking, with 49·6 and 49·5 dB(A)LAeq , and 71·2 and 56·1 dB(A) LAmax, respectively. The background noise in the experimental room was 31·0 dB(A) LAeq. The sleep EEG was recorded according to standard methods. The sleep polygraphic parameters examined were the percentage of sleep stage relative to the total sleep time (%S1, %S2, %S(3+4), %SREM, %MT), total sleep time, sleep onset latency, and awakening during sleep in minutes and sleep efficiency. A structured sleep rating questionnaire (OSA), was administered to the subjects after they awakened. The %S2 increased and the %SREM decreased during exposure to road traffic noise. However, no significant effect of exposure to frogs' croaking was observed on any of the polygraphic sleep parameters. The subjective quality of sleep was degraded more by exposure to road traffic noise than that to frogs' croaking.
Journal of Sound and Vibration.
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ABSTRACT: The habituation of human sleep to a noisy environment was investigated by polysomnography (PSG), a wrist activity device (Actiwatch®), subjective evaluation and a performance test on the following morning. Eleven young male students slept for 17 nights in a sleep laboratory. PSG on the first, fourth, fifth, ninth, 14th, and 17th nights was judged visually. Four of the subjects were continuously monitored by the wrist activity device. From the fifth to 14th nights, there was exposure to road traffic noise all-night long, and consecutive experiments were conducted from the fifth to 17th nights. Agreement of sleep/wake assessment for Actiwatch®and PSG was 88·4%, on average, based on the data for 24 nights. Pearson's correlation coefficient of TST for Actiwatch®and sleep PSG was 0·848. Habituation to noise by wrist movement, sleep latency by PSG, and activity of mental muscles was not recognized. The association between wrist activity and mental muscle activity was significant for three subjects out of four (r=0·56, 0·81, 0·71, respectively). Percentages of positive wrist movement in each sleep stage, such as the 3+4 stages, REM stage and stage MT, were compared with those in other stages. Wrist activity in Stage REM was significantly more frequent than that in other stages for the three subjects. Wrist movement in Stage MT was significantly more frequent than in other stages for the three subjects. REM latency, REM cycle, and five factors of subjective sleep, from the Oguri–Shirakawa–Azumi questionnaire (SQ), showed significant differences by analysis of variance for repeated measurements. When change from the 4th night was checked, sleepiness, worry, integrated sleep feeling and sleep initiation by SQ showed habituation of sleep to noise. Namely, sleep quality recovered to the level on a silent night by the fifth noisy night during the experiment. There is thus a habituation of sleep to noise when a subjective evaluation of sleep, such as the SQ, is used.
Journal of Sound and Vibration.
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ABSTRACT: Habituation of sleep to a ship's noise was assessed by actigraphy and a sleep questionnaire. Four male students aged 21–24 years were studied for 15 consecutive nights in an experimental bedroom. During the first four nights, the subjects slept in a quiet environment. For the next eight consecutive nights, the subjects were exposed to the noise of a ship's engine with a sound level of 60dB(A) (the International Maritime Organization Standard) previously tape-recorded in a room of a diesel engine ship. On the last three experimental nights, the subjects again slept in a quiet environment. The subjects went to bed in the experimental room at about 0:00 and were woken at 8:00 a.m. the next morning by an alarm clock. Sleep was monitored by a wrist-worn actigraphy. On the morning following each experimental night, the subjects were instructed to answer the OSA questionnaire, a structured self-rating sleep scale developed in Japan. Habituation of sleep to the noise of a ship with a sound level of 60dB(A) was observed to some extent in the subjective sleep parameters but not in the sleep parameters measured by actigraphy.
Journal of Sound and Vibration 250(1):107-113. · 1.59 Impact Factor
