Sleepiness and the Risk of Falling

Awakening from sleep is well documented to impair cognitive performance in young adults. This phenomenon, called sleep inertia, has been reported to impair performance just as much as one night of total sleep deprivation, suggesting that there are significant functional consequences to sleep inertia. However, whether walking stability is impaired by sleep inertia is unknown. If sleep inertia impairs walking stability, it could be an important but currently unrecognized risk factor for falls in older adults. Also, the impact of aging on sleep inertia-related impairments in cognitive performance is unknown. Sleeping medication use is higher in older than younger adults, and is a risk factor for falls. Current evidence suggests that sleeping medications impair walking stability and cognitive performance in young and older adults during wakefulness; however, no study has examined walking stability and cognitive performance of young and older adults upon awakening from sleep at night after taking a hypnotic (sleeping medication). Therefore, the purpose of this study is to determine whether sleep inertia and hypnotic use impairs walking stability and cognitive performance more in healthy older than in healthy younger adults. It is expected that findings from the proposed study will provide evidence for sleep inertia as a risk factor for falls in older adults. Twelve older (aged 60-85) and twelve younger (aged 18-35) healthy male and female volunteers will participate in the study. The investigational procedures will include medical screening (e.g., physical, blood and urine tests, and bone mineral density assessment), home monitoring of sleep schedules for three weeks, and three overnight visits in the laboratory spaced approximately one week apart. During the laboratory visits, participants will be awakened in the middle of the night to perform walking stability and cognitive function tests. Before going to bed, participants will take either a placebo pill or a sleeping medication. On one of the visits, participants will be asked to go to bed about 2 hours later than usual.