Mutation of the Human Circadian Clock Gene CRY1 in Familial Delayed Sleep Phase Disorder.

Patterns of daily human activity are controlled by an intrinsic circadian clock that promotes ∼24 hr rhythms in many behavioral and physiological processes. This system is altered in delayed sleep phase disorder (DSPD), a common form of insomnia in which sleep episodes are shifted to later times misaligned with the societal norm. Here, we report a hereditary form of DSPD associated with a dominant coding variation in the core circadian clock gene CRY1, which creates a transcriptional inhibitor with enhanced affinity for circadian activator proteins Clock and Bmal1.

Effects of a month-long napping regimen in older individuals.

Objectives: To examine the effects of a month-long nap regimen using one of two durations (45 minutes or 2 hours) on nighttime sleep and waking function in a group of healthy older participants and to assess the degree to which healthy older individuals are willing and able to adhere to such napping regimens.

Design: Three laboratory sessions, with 2-week at-home recording interspersed, using a between-participants approach.

Setting: Laboratory of Human Chronobiology at Weill Cornell Medical College and participants' homes.

Sex hormones, sleep, and core body temperature in older postmenopausal women.

Study Objectives: Assessment of relationships between polysomnographic sleep, sex hormones, and core body temperature in postmenopausal women.

Design And Participants: Ten women aged 57 to 71 years, at least 5 years past menopause.

Setting: Laboratory of Human Chronobiology at Weill Cornell Medical College.

Delayed sleep phase disorder in temporal isolation.

Study Objectives: This study sought to characterize sleep and the circadian rhythm of body core temperature of an individual with delayed sleep phase disorder (DSPD) in the absence of temporal cues and social entrainment and to compare those measures to age-matched normal control subjects studied under identical conditions.

Design: Polysomnography and body temperature were recorded continuously for 4 days in entrained conditions, followed immediately by 17 days in a "free-running" environment.

Setting: Temporal isolation facility in the Laboratory of Human Chronobiology, Weill Cornell Medical College.

The nature of spontaneous sleep across adulthood.

The decline in sleep quality that often accompanies aging is thought to be the consequence of alterations in both circadian and homeostatic processes widely assumed to be responsible for sleep/wake regulation. A number of experimental approaches have been used to examine various aspects of age-related sleep changes, but none has examined spontaneous sleep across the entire 24-h day. Using the 'disentrainment' protocol, we studied such sleep in young, middle-aged and older adults.

Effects of a nap on nighttime sleep and waking function in older subjects.

Objectives: To examine, in older subjects, the effect on waking function of increasing 24-hour sleep amounts by providing a nap opportunity; to assess what effects an afternoon nap may have on subsequent nighttime sleep quality and composition.

Design: Two-session, within-subject laboratory design.

Setting: The study was conducted in the Laboratory of Human Chronobiology at Weill Cornell Medical College.

Effects of an afternoon nap on nighttime alertness and performance in long-haul drivers.

The effects of an afternoon nap on alertness and psychomotor performance were assessed during a simulated night shift. After a night of partial sleep restriction, eight professional long-haul drivers either slept (nap condition) or engaged in sedentary activities (no-nap condition) from 14:00 to 17:00 h. Alertness and performance testing sessions were conducted at 12:00 (pre-nap baseline), 24:00, 02:30, 05:00 and 07:30 h, and followed 2-h runs in a driving simulator.

Failure of timed bright light exposure to alleviate age-related sleep maintenance insomnia.

Objectives: To determine whether a twice-weekly maintenance schedule of evening bright light exposure is effective in alleviating sleep maintenance insomnia on a long-term basis, after the establishment of a more favorable phase relationship between the core body temperature (CBT) rhythm and sleep.

Design: Subjects underwent light treatment while living at home. Eleven to 13 consecutive days of acute light treatment (active) were followed by a 3-month maintenance light treatment period (active or control).