紀要論文

間欠的な高照度光照射による昼間の眠気や反復性睡眠潜時テストやP300 の効果

The effects of intermittent bright light exposure during daytime on daytime sleepiness, the multiple sleep latency test and P300

jpn

04412486

https://doi.org/10.15002/00006751

法政大学文学部

60

113

119

2010-03-10

Version of Record

While phase shifting effects of bright light (BL) by the circadian system have been well investigated, relatively less attention has been paid to its direct effects on psychological function. The aim of this study was to understand whether daytime sleepiness and selective attention could be improved by BL exposure. We analyzed the diurnal changes of sleepiness, P300 (an auditory event-related potential that reflects cognitive function), and performance test during the daytime. Ten healthy young volunteers (six males and four females, mean age 21.11years: range 18-24 years) participated in the experiment after informed consent. For the 7 days before the experiments, their regular sleepwake patterns were confirmed by Actiwatch (Respitronics, USA). On the experimental day, subjects wore a goggle from their home to the lab to avoid exposure to sunlight. Each of the subjects participated in two experiments: exposure to ordinary room light (RL, <300 lx) and exposure to BL of more than 3,000 lx from 9:00 to 18:00 except during the MSLT and the P300 evaluation. We examined MSLT and P300 every 2 hours using EEG equipments (Nihonkoden, Japan). P300 was computed with a software developed by Miyukigiken, Japan. The subjects estimated their subjective symptoms on visual analog scale and Stanford Sleepiness Scale. Compared to RL condition, objective and subjective sleepiness measured by the MSLT and Sleepiness Scales significantly decreased under BL condition (F=6.70, p<0.05; F=21.19, p<0.005, respectively). The average latency of P300 shortened significantly (F=33.58, p<0.001), and the amplitude of P300 increased significantly (F=6.47，p<0.05) under BL condition. Reaction time in oddball paradigm shortened significantly (F=13.18, p<0.01). Time effect was seen in MSLT and reaction time (F=7.31, p<0.001; F=3.66, p<0.05, respectively). Sleep latency and reaction time at 10:00 were significantly shorter and longer, respectively, than those at 18:00. Intermittent exposure to BL during daytime counteracts sleepiness. The reduction of sleepiness by BL exposure may improve selective attention and prevent mistakes. Time dependent effect of BL exposure may exist, but the training effect of the performance test may also need to be considered.

Article

AN00226157