Riko Kobayashi

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.

Clinical factors associated with post-ictal headache in patients with epilepsy

Objectives– To determine the incidence of post‐ictal headaches (PIH) and clinical risk factors associated with the occurrence of PIH in patients with localization‐related epilepsy. Materials and methods– The subjects were 77 patients with temporal lobe epilepsy (TLE), 34 patients with occipital lobe epilepsy (OLE), and 50 patients with frontal lobe epilepsy (FLE). The subjects were directly asked whether headaches occurred just after seizures. Medical charts were reviewed to ascertain the clinical characteristics of epilepsy in these patients. Results– The incidence of PIH was 23% for TLE, 62% for OLE, and 42% for FLE. The risk of PIH was significantly higher for OLE than for TLE or FLE, and for patients with generalized tonic–clonic seizures. Younger age at onset of epilepsy was also a risk factor for PIH. Conclusion– The occurrence of PIH may be related to the region of epileptic focus and the region of spread of epileptic discharges.

Diffusion-weighted MR findings in a reversible case of acute Wernicke encephalopathy

We report a case of acute Wernicke encephalopathy (WE) in which apparent diffusion coefficient maps showed areas of increased diffusion in the bilateral medial thalami that corresponded to the hyperintense lesions on T2‐weighted imaging. The hyperintense lesions on T2‐weighted imaging disappeared with full recovery from symptoms. These findings suggest that the hyperintense lesions of the acute changes of WE include reversible vasogenic edema and are not caused by acute ischemia.

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.