Satoshi Sakakibara

Gender difference of slow wave sleep in middle aged and elderly subjects

Sleep EEG of eight healthy males and eight females aged 54–72 years were recorded at their homes. The electroencephalograms were visually scored and analyzed by spectral analysis using the FFT method. There were no significant differences in sleep parameters except for a higher percentage of stage 3 + 4 in females. The spectral power of the delta band EEG was classified into two frequencies: 0.5–2 Hz and 2–4 Hz. The total amount of the delta band spectral power through the night was significantly larger in females. Periodic fluctuation of delta band power was observed in females along with non‐rapid eye movement–rapid eye movement cycles.

Effects of bright light at lunchtime on sleep of patients in a geriatric hospital I

The effects of lunchtime bright light exposure in patients of a geriatric hospital were investigated. Ten inpatients (six women and four men; mean age ± SD: 81.2 ± 8.8 years) with sleep disturbances were studied for 9 weeks. Nurses performed daily ratings for sleep–wakefulness disturbances. Approximately 8000 lx bright light exposure was performed for 3 weeks in the light therapy room. Before and after exposure, ocular function was evaluated. Clinical ratings of sleep‐wakefulness improved in eight patients. The score of difficulty in falling asleep and drowsiness in the morning declined during the light exposure. The score of drowsiness in the afternoon decreased during the post‐light exposure. Post‐exposure ocular disturbances were not found.

Effects of moderately bright light on subjective evaluations in healthy elderly women

Eight healthy elderly women aged 56–72 years (mean age: 67.4 years) participated in this study. They were exposed to moderately bright light (1000 lux) for 1 h in the morning every 6 days in their homes. Moderately bright light improved self evaluations for alertness, mood, motivation, happiness, refreshment, concentration and appetite after the second exposure to the light. Sleep maintenance, anxiety and integrated sleep feeling also improved after the fourth exposure to the light. The phase of rectal temperature rhythm did not change in a moderately bright light condition. These results suggest that bright light influences sleep quality and self evaluations without changing the biological rhythm phase.

Effects of morning bright light on sleep in healthy elderly women

Subjective sleep feeling and polysomnography were measured in 10 elderly women to investigate the effects of 8000 lux morning bright light (BL) exposure. The profile of sleep feeling in the BL condition was better than in the control condition. The proportion of awakening time in the first one‐third of night sleep decreased, and the amount of awakening time in the last one‐third increased in BL condition. Daytime napping reduced in BL condition. These findings suggested the effectiveness of exposure to bright light on the improvement of sleep quality and daytime vigilance of healthy elderly women.

Gender differences in the sleep of middle-aged individuals.

Abstract The study was designed to investigate gender differences in the sleep‐wake patterns of healthy middle‐aged individuals in their home environment. Polysomnography showed that daytime napping was more common in men than in women. Men had lower sleep efficiency index and experienced more stage 1 sleep. Males had significantly less stages 3 + 4 sleep, less stage REM sleep, and more transitions to wake from REM sleep. Men could not maintain stage REM as well as women. This study indicates that the gender differences in the sleep‐wake patterns have appeared in a group of middle‐aged individuals.

Motor activity rhythm in dementia with delirium

Abstract Using an actigraph, the activity patterns in 13 demented patients with delirium were examined. We analyzed the data of the eight patients, wearing the actigraphs for more than 10 days. They were classified into four types:type A, nocturnal delirium type; type B, wandering type; type C, hypobulia type; and type D, lying down type. The day to day activity variation was most prominent in type A and seemingly the least in type B. The dominant period of activity rhythm was nearly 24 h in all cases. Additional 12‐h period was observed in type C. Actigraphs might become useful in making therapeutic decisions regarding demented patients with delirium.

Effects of short duration morning bright light in healthy elderly. II:Sleep and motor activity

Abstract Subjective sleep feelings and motor activity were measured in seven healthy elderly subjects for 6 days. The subjects were exposed to bright light (6000 lux) for 30 min in the morning or instructed to sit in front of a desktop lighting device without light. The average level of motor activity during the night was significantly decreased in the bright light condition, compared with the controlled condition. However, daytime motor activity did not show significant differences between the two conditions. From these findings, even a short duration of morning bright light is effective in maintaining sleep without changing daytime activity.

Effects of short duration morning bright light in healthy elderly subjects. I:Subjective feeling and ophthalmological examinations

Abstract Seven aged subjects aged 61–78 years were exposed to 6000 lx bright light for 30 min during morning hours at their homes for 1 week. Visual analog scale was recorded before bedtime and after rising to assess subjective feelings. Ophthalmological examinations were made before and after light exposure, to exclude pre‐existing ocular disorders and to detect ocular damage. Furthermore, ocular fatigue was self‐evaluated immediately before and after exposure. Visual analog scale results indicated that alertness reduced significantly before bedtime. Ophthalmological abnormalities were not found after exposure. These findings suggest that short duration morning bright light exposure reduces night‐time vigilance.

Gender differences in self‐evaluated sleep quality and activity of middle‐aged and aged subjects

Abstract In order to investigate the gender difference of sleep and activity in middle‐aged and aged individuals, home‐based sleep was self‐evaluated for sleep quality and activity for 5 nights in 20 healthy adults (50–76 years old; 11 women, nine men). There was no significant gender difference for subjective sleep quality. However, the activity level and movement index at night were significantly higher in men than in women, and the activity level during the day was significantly lower in men than in women. The objective sleep quality of men was significantly worse than that of women, however, subjective sleep quality does not differ.

Effects of morning bright light in healthy elderly women: effects on wrist activity.

To investigate the effects of 8000 lux morning bright light in the elderly, home‐based motor activity on sleep was monitored for 5 days in 10 healthy women (mean age: 59.7 years old, range: 50–69 years old). The activity level and movement index on night 4 were significantly lower in bright light conditions, compared with the controlled condition. The activity level during the day was not significantly different between the two conditions. These results indicate that 8000 lux morning bright light improves sleep quality in healthy elderly women.