10 Nox T3s sleep‑monitoring systems with accessories and training services.

V. 08.23.22 Statement of Work Human Systems Integration Division System furniture for N262 building offices BACKGROUND Project Title: Revising the Exploration Atmosphere Hypoxia Limit to Mitigate Decompression Sickness During Surface EVA The Fatigue Countermeasures Laboratory (Human Systems Integration Division - Code TH) will purchase 10 Nox T3 home sleep test (HST)devices used to measure respiratory function during sleep as part of a project in collaboration with NASA JSC. There are a number of effects of hypoxia on sleep. Respiratory function is altered during sleep at altitude or in hypobaric chambers simulating sleep at altitude. Sleeping at elevations as low as 1630 m can modestly increase the apnea-hypopnea index (AHI) and disrupt sleep (Lashtang et al. 2013), while sleep at higher elevations induces periodic breathing with apneas (West et al. 1986; Salvaggio et al. 1998; Reite et al. 1975). Males appear to be much more susceptible to the negative respiratory effects experienced at altitude, with males experiencing an increase in the apnea-hypopnea index that is more than 10 times greater that of females at 3400 m (Lombardi et al. 2013). The respiratory disturbances that occur at altitude usually reduce after a few nights of exposure, although some studies suggest that it can take more than a week for symptoms to resolve in some individuals (Lombardi et al. 2013), with it taking more than a month for some at altitudes over 5000 m. Oxygen supplementation is an effective countermeasure for reducing periodic breathing with apneas (Reite et al. 1975; Luks et al. 1998). Hypoxia also appears to alter sleep architecture. Studies consistently demonstrate that slow-wave sleep is reduced during sleep at altitude (Salvaggio et al. 1998; Selvamurthy et al. 1986; Miller and Horvath 1977; Reite et al. 1975; Barash et al. 2001; Lashtang et al. 2013). This may because respiratory disturbances result in arousals that interfere with the maintenance of slow-wave sleep (Reite et al. 1975; Salvaggio et al., 1998). The impact of sleeping at altitude on other sleep stages is mixed, with most studies reporting no changes, although two studies reported more transitions to light sleep (Reite et al., 1975; Miller and Horvath 1977), with one study reporting a reduction in REM sleep at 4500 m (de Aquino Lemos et al., 2012). Few studies have examined changes in sleep architecture over time at altitude, but one study reported that the reduction in slow-wave sleep observed at 3500 m persisted for two weeks after the return to sea level (Selvamurthy et al. 1986). Interestingly, most studies have not found reductions in sleep duration, measured via polysomnography or actigraphy, during sleep at altitude compared to sleep at sea level (Salvaggio et al. 1998; Selvamurthy et al. 1986; Miller and Horvath 1977; Reite et al. 1975; Barash et al. 2001), although one study reported a modest reduction in sleep duration after one night in a hypobaric chamber simulation of 4500 m (de Aquino Lemos et al. 2012). -- 1 of 4 -- V. 08.23.22 While there are clear and measurable differences in respiratory function and sleep architecture during sleep at altitude, the effects of altitude-related sleep disruption on performance are less clear. Some studies have not observed changes in performance at elevations of 1630 m, 2590 m, and 3800 m (Luks et al. 1998; Lashtang et al. 2013), although it is possible that these null findings were due to the methodology used (e.g., frequency and timing of tests). A separate study found differences in several domains of performance, including attention, working memory, executive function, inhibitory control, and processing speed at 4500 m compared to sea level (de Aquino Lemos et al. 2012), while a different study suggests that sleep deprivation worsens performance to a greater extent at altitude compared to at sea level (Mertens and Collins, 1986). Collectively, these studies highlight the importance of measuring changes in respiratory variables during sleep, ideally also including measurement of sleep staging to assess changes in sleep architecture. These studies also suggest that it is important to evaluate cognition at intervals frequent enough to capture any potential impacts of sleep disturbance on performance. OBJECTIVE or REQUIREMENTS Sleep-related Aims 1. We aim to characterize the impact of hypoxia on respiratory outcomes during sleep. a. We further aim to characterize the time course of adaptation to hypoxia and to identify interindividual or sex differences. b. We aim to collect exploratory data on REM/NREM sleep architecture using a novel algorithm to discriminate these global stages. 2. We aim to compare actigraphy to respiratory measures to determine whether respiratory-related arousals can be detected through movement. Sleep-related Methods Respiratory outcomes. Participants will wear the Nox T3 (or a similar device) for the first three nights and then every other night to evaluate respiratory function during sleep. This will allow us to evaluate acute changes in respiratory function in response to hypoxia and it will also enable us to evaluate the time course of adaptation to the hypoxic environment. This device is frequently used by clinicians to conduct at-home sleep apnea tests, making it easy to use compared to a traditional laboratory polysomnography. The Nox T3 has been validated in clinical settings and is accurate and reliable for detecting apneas and hypopneas. The apnea-hypopnea index is calculated using a validated automated scoring algorithm. The Nox T3 does not include electroencephalography, which is the gold- standard for measuring sleep architecture, but it does include algorithms to estimate REM and non-REM sleep, providing some data to evaluate sleep architecture. -- 2 of 4 -- V. 08.23.22 Actigraphy. Participants will wear actigraphy continuously. This will enable us to compare nights when respiratory function is not measured to nights when it is measured to …