Showing papers by "Shosuke Suzuki published in 1989"

[Effects of noise on sleep. Part 1. Development of an automatic analysing system for all-night sleep polygraphy by microcomputer].

Abstract: In order to assess the effects of noise on sleep, the authors have developed a microcomputer system which determines the sleep stage based on an all-night EEG (electroencephalogram), rapid eye movement and an EMG (electromyogram). All the polygraphic parameters for each epoch (including spindle, rapid eye movement, alpha and delta waves, and amount of muscle tension), which are necessary to determine the sleep stage, were determined by a microcomputer using a digital data processing program. Recognition of EEG waves is based on Fujimori's method with some modifications. The rules of Rechtschaffen et al. were adopted for judging sleep stage with a slight modification. Data were obtained from six healthy students of a university. Each student was polygraphed for five to six nights under various conditions of noise exposure. Judgements of the sleep stage were made by two medical doctors. Using randomly selected 10 nights' data, the agreement between judgements by the microcomputer system and by the doctor was 77%. The percentage of agreement increased to 84% for the epochs in which the two doctors agreed. It takes about one hour to determine all-night sleep stages by this system.

Effects of noise on sleep. Part 2. A case report of the effects of three levels of stationary sound on sleep parameters

Abstract: The effect of steady noise on sleep was examined experimentally for 24 nights by sleep polygraphy of a twenty-eight-year-old man. The parameters used for sleep polygraphy were sleep stage, sleep latency, frequency of sleep stage shift per hour, average sleep depth, the gradient and intercept of a regression line of sleep depth against time, and subjective sleep. The sleep stage was judged and estimated based on the criteria of Rechtschaffen & Kales by the authors' original system using a microcomputer. For the calculation of sleep depth at a given time, stages W (waking), 1, REM, 2, 3 and 4 were weighted to be 0, 1, 1.5, 2, 3 and 4, respectively. Sleep parameters were compared between the data of non-noise and noise-exposed nights. The noise exposure was overnight stationary pink noise of 40, 50 and 60 dB (A). General findings were a decreased REM stage, an increased stage 2, and deepened average sleep depth of the 60 dB (A)-night sleep compared with the control and 40 dB(A) exposure nights. When the control nights were excluded and parameters were compared between the three levels of stationary noise exposure, stage 2, the intercept of the regression line, and average sleep depth were increased almost in proportion to the increased noise exposure. In contrast, sleep latency, frequencies of sleep stage shift, stages W, 1, 3, MT, and REM, as well as the gradient of the regression line were decreased with increased noise exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

[Baseline study of sleep electroencephalography--daily variation and individual variation].

Abstract: The aims of the present study were to observe the daily habituation to night sleep in a laboratory environment and to make clear the daily and individual sleep variations by using polygraph parameters, including electroencephalography (EEG). Sleep EEG records were obtained from a subject who slept ten successive nights, and from six subjects who each slept one night in the laboratory. The parameters used were as follows: sleep stage %, sleep latency (SL), REM latency (RL), number of stage shifts, subjective sleep, integral EMG, and slope (a) and intersect (b) of a regression equation used to estimate the sleep depth against sleep time.Stage WAKE and SL, slope (a), intersect (b) and the mean depth of sleep were found to become stable from the fifth night. Stage MT, the number of stage shifts, and integral EMG increased significantly from the fifth night and later, showing p<0.01, p<0.01, and p<0.05, respectively. Judging from these findings, the sleep habituation of the subject in the laboratory was completed within the first four nights.Coefficients of variation of sleep stage 2 and stage REM of the ten-nights' EEG were the lowest among all the sleep parameters examined. Almost all the parameters of day-to-day sleep of the subject who slept for ten successive nights in the laboratory showed smaller variations than those of the other six subjects. It may be concluded that the mist effect on sleep could be assessed more precisely by using an individual repeatedly than by using a group of subjects.