Sleep Disruption Medical Intervention Forecasting (SDMIF) Module for the Integrated Medical Model

The NASA Integrated Medical Model (IMM) assesses the risk, including likelihood and impact of occurrence, of all credible in-flight medical conditions. Fatigue due to sleep disruption is a condition that could lead to operational errors, potentially resulting in loss of mission or crew. Pharmacological consumables are mitigation strategies used to manage the risks associated with sleep deficits. The likelihood of medical intervention due to sleep disruption was estimated with a well validated sleep model and a Monte Carlo computer simulation in an effort to optimize the quantity of consumables. METHODS: The key components of the model are the mission parameter program, the calculation of sleep intensity and the diagnosis and decision module. The mission parameter program was used to create simulated daily sleep/wake schedules for an ISS increment. The hypothetical schedules included critical events such as dockings and extravehicular activities and included actual sleep time and sleep quality. The schedules were used as inputs to the Sleep, Activity, Fatigue and Task Effectiveness (SAFTE) Model (IBR Inc., Baltimore MD), which calculated sleep intensity. Sleep data from an ISS study was used to relate calculated sleep intensity to the probability of sleep medication use, using a generalized linear model for binomial regression. A human yes/no decision process using a binomial random number was also factored into sleep medication use probability. RESULTS: These probability calculations were repeated 5000 times resulting in an estimate of the most likely amount of sleep aids used during an ISS mission and a 95% confidence interval. CONCLUSIONS: These results were transferred to the parent IMM for further weighting and integration with other medical conditions, to help inform operational decisions. This model is a potential planning tool for ensuring adequate sleep during sleep disrupted periods of a mission

Sleep problems reported by patients entering opioid agonist treatment

Treatment-seeking opioid-dependent individuals frequently report sleep-related problems. This study provides a detailed assessment of sleep duration and quality in this population, including their effect on daily functioning and relationship to psychiatric severity and drug use. Samples of newly admitted patients to opioid agonist maintenance treatment (n = 113) completed a series of questionnaires to assess sleep functioning, psychiatric severity, and drug use due to sleep problems over the past 30 days. The results showed that study participants reported considerable sleep-related difficulties that had little effect on their appraisals of daily functioning. Nevertheless, sleep problems were associated with psychiatric distress, and those reporting substance use specifically to increase or decrease sleepiness endorsed more sleep problems and lower levels of daily functioning. Overall, these results replicate and extend previous work showing poor sleep functioning in this population and show that sleep problems are associated with variables that often have an adverse impact on substance abuse treatment outcome. (C) 2008 Elsevier Inc. All rights reserved