Task Assessing the Impact of Chronic Sleep Restriction on Sleep and Performance-Associated Regional Brain Activation Using Near-Infrared Spectroscopy (Postdoctoral Fellowship) (Completed)
Last Published:  07/31/19 10:05:33 AM (Central)
Short Title: NIRS Sleep
Responsible HRP Element: Behavioral Health and Performance
Collaborating Org(s):
National Space Biomedical Research Institute (NSBRI)
Funding Status: Completed - Task completed and produced a deliverable
Procurement Mechanism(s):
NASA astronauts and ground crew need to maintain high levels of physical and cognitive performance to ensure successful completion of space missions and the safety of astronauts. Astronauts and ground crew are exposed to sleep loss arising from shifting and extended work schedules commonly associated with their missions. As a result, many astronauts and ground crew are at risk for fatigue-related accidents that can endanger the success of space missions and personal safety. A major challenge in combating fatigue is accurate diagnosis. Subjective sleepiness is reported significantly less often than observed objective performance decrements, indicating that self-diagnosis is inaccurate. Recent evidence suggests that sleep deprivation reduces activation in the prefrontal cortex (PFC), a brain region known to be important for executive function and cognitive performance. A recently-developed technology, developed substantially by Dr. Gary Strangman with NSBRI support, allows for the quantification of hemodynamic changes in oxygenated and deoxygenated blood within the brain using Near-Infrared Spectroscopy (NIRS). NIRS detects regional brain activity alterations associated with these hemodynamic changes. Current methodology for assessing hemodynamic changes requires large, expensive functional magnetic resonance imaging or positron emission tomography techniques that are impractical for use in space or most work environments. In contrast, ambulatory NIRS monitoring is relatively portable, relatively inexpensive, simple to apply and can record over 24 hours of data in a single session. Therefore, this non-invasive method for assessing regional brain activity overcomes the prohibitive restrictions of other neuroimaging systems and has the additional advantages of multi-hour recordings and ambulatory monitoring.

This study is using NIRS technology to examine PFC activity in experimental volunteers participating in chronic sleep restriction (CSR) and acute sleep deprivation (ASD) protocols. NIRS monitoring during these protocols will allow the investigators to address their specific aims:
1) To test the hypothesis that hemodynamic responses in the PFC to the psychomotor vigilance task (PVT) will exhibit a circadian rhythm.
2) To test the hypothesis that hemodynamic responses in the PFC to the PVT will be reduced during CSR.
3) To test the hypothesis that hemodynamic fluctuations in the PFC associated with delta wave sleep activity will increase in frequency following a 30-hour ASD.
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