Deteriorations in sleep are common in the elderly. These disturbances are associated with increased morbidity and mortality. Preliminary data suggest that some of these changes can be reversed with interventions designed to improve sleep. These reversals may be associated with improvements in health and well-being. The neurobiology of sleep and sleep interventions in the elderly however are unknown. This proposal will study regional cerebral glucose metabolism using [18F]-FDG PET during sleep before, and after interventions designed to improve sleep in 28 healthy elderly subjects. We propose that age-related declines in slow wave sleep will be associated with 1) age-related declines in prefrontal cortex metabolism, and 2) with age-related increases in metabolism in brain structures linked with behavioral arousal. These include the ascending reticular activating system and limbic and paralimbic structures known to modulate this system. We also propose that changes in REM sleep during aging result from: 1) increased metabolism in brain structures related to behavioral arousal (pontine reticular formation, basal forebrain, posterior hypothalamus, amygdala, thalamus and ventromedial prefrontal cortex), and 2) decreased metabolism in anterior paralimbic structures (anterior cingulate cortex and medial prefrontal cortex) and in prefrontal cortex. Eighteen months of mild sleep restriction and sleep education will result in less severe deterioration in age-related sleep neurobiology than will an attention-only control condition. In order to address these hypotheses we will perform neurobiological studies of sleep in 33 elderly subjects (greater than or equal to 75 yrs) at baseline and following either an 18-month sleep restriction + sleep education intervention (n=14) or an 18-month attention-only (n=14) control period. Comparisons between elderly pre-intervention measures with those of a sex-matched young adult control group (ages 25-45 yrs) will assess the effects of age. Group (intervention vs control) by time (pre- vs. post-intervention) interactions in a repeated measures ANOVA will assess the effects of the sleep intervention. Analysis of the main effect of time in this analysis will assess within-subject effects of aging.
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