Phase-shifting effects of bright morning light as treatment for delayed sleep phase syndrome
ABSTRACT Bright light has recently been shown to have phase-shifting effects on human circadian rhythms. In this study we applied this effect to 20 patients with delayed sleep phase syndrome (DSPS) who were unable to fall asleep at conventional clock times and had a problem staying alert in the morning. In a controlled treatment study, we found that 2 h of bright light exposure in the morning together with light restriction in the evening successfully phase advanced circadian rhythms of core body temperature and multiple sleep latencies in these patients. This finding corroborates the importance of light for entraining human circadian rhythms.
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ABSTRACT: A growing body of research has identified significant sleep problems in children with autism. Disturbed sleep-wake patterns and abnormal hormone profiles in children with autism suggest an underlying impairment of the circadian timing system. Reviewing normal and dysfunctional relationships between sleep and circadian rhythms will enable comparisons to sleep problems in children with autism, prompt a reexamination of existing literature and offer suggestions for future inquiry. In addition, sleep and circadian rhythms continue to change over the course of development even in typical, healthy humans. Therefore, exploring the dynamic relationship between circadian rhythms and sleep throughout development provides valuable insight into those sleep problems associated with autism. Ultimately, a better understanding of sleep and circadian rhythms in children with autism may help guide appropriate treatment strategies and minimize the negative impact of these disturbances on both the children and their families.Neuroscience & Biobehavioral Reviews 12/2009; 34(5):755-68. DOI:10.1016/j.neubiorev.2009.11.017 · 10.28 Impact Factor
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ABSTRACT: Circadian rhythms have a strong effect on the ability to sleep across the 24-h period. Maximum sleepiness occurs at the phase of lower endogenous core body temperature. This period is bracketed by two periods of alertness: a "wake-maintenance zone" occurring 6-10h before the time of core temperature minimum, and a "wake-up zone" occurring 4-7h after the minimum. Therefore, if the circadian rhythm drifts earlier with respect to the attempted sleep period, the wake-up zone can impinge on the end of the normal sleep period resulting in premature awakening and the development of early morning awakening insomnia. Similarly, a delay of the circadian rhythm can impose the wake-maintenance zone on the attempted bedtime and lead to sleep onset insomnia. Therefore, these two types of insomnia should be treatable with chronobiologic effects such as bright light and, possibly, melatonin administration. Bright light stimulation at normal wake-up time and melatonin administration 4-8h before normal bedtime can phase advance circadian rhythms to an earlier time. While morning bright light has been efficacious for sleep onset insomnia, evening melatonin administration has yet to be tested. Early morning awakening insomnia has been treated with phase delays imposed by evening bright light but not yet with morning melatonin administration. There is now sufficient evidence to warrant the consideration of chronobiologic manipulations such as bright light therapy for the treatment of chronic sleep onset and early morning awakening insomnia that show evidence of circadian delay or advance, respectively.Sleep Medicine 10/2007; 8(6):637-44. DOI:10.1016/j.sleep.2006.10.003 · 3.10 Impact Factor
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ABSTRACT: Blood levels of the pineal hormone melatonin are high at night and low during the day. Its secretion is regulated by a rhythm-generating system located in the suprachiasmatic nucleus of the hypothalamus, which is in turn regulated by light. Melatonin is regulated not only by that circadian oscillator but acts as a darkness signal, providing feedback to the oscillator. Melatonin has both a soporific effect and an ability to entrain the sleep-wake rhythm. It also has a major role in regulating the body temperature rhythm. Melatonin rhythms are altered in a variety of circadian rhythm disorders. Melatonin treatment has been reported to be effective in treatment of disorders such as jet lag and delayed sleep phase syndrome.Journal of psychiatry & neuroscience: JPN 12/1994; 19(5):345-53. · 7.49 Impact Factor