Funding Status:
Active - Currently funded and in progress
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Procurement Mechanism(s):
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Aims:
The
overall goal of this project is to study how a programmable solid state
lighting system would be used operationally to improve sleep, enhance alertness
and performance, maintain optimal circadian entrainment, and readapt circadian
phase if the circadian misalignment occurs, in a high fidelity simulation of
the International Space Station (ISS) lighting environment, such as the Human
Exploration Research Analog (HERA). The
HERA has been fitted with programmable LED lighting that is representative of
the new solid state light assemblies (SSLAs) to be installed on the ISS. The new SSLAs
incorporate three pre-determined settings to address different operational
needs: 1) white light for general vision; 2) blue-enriched high intensity white
light to enhance alertness and circadian adaptation; 3) blue-depleted low
intensity white light to minimize alertness prior to sleep. A Dynamic Lighting
Schedule (DLS) has been developed to determine when each of these three settings will be used
to optimize lighting to improve alertness and performance, reset circadian
rhythms and enhance sleep, while maintaining vision. This project will apply the DLS in the HERA as
the next step in examining the feasibility and efficacy of the SSLA system, and
to provide the testing necessary to finalize the operational procedures for
in-flight testing of the new lights aboard ISS.
The specific aims of this study are:
In a
series of 30-day 2016 HERA Campaign missions, conduct randomized crossover
within-subject clinical trials to test the hypotheses that deployment of the DLS,
as compared to deployment of a standard, static lighting schedule, and while
also maintaining acceptable visual performance and color discrimination for
operational tasks, will:
i)
significantly improve polysomnographic and subjective measures of sleep
latency, sleep quality and sleep efficiency;
ii)
significantly improve cognitive performance, subjective alertness and mood, and
objective EEG correlates of alertness (suppression of EEG-derived delta-theta
activity [0.5-5.5 Hz]) and enhancement of EEG-derived high-alpha activity
[10.5-12 Hz]);
iii)
significantly increase the rate of circadian adaptation, as measured using the
circadian rhythm of melatonin and its metabolites before and after the shift.
The results of this investigation will yield knowledge needed for implementing a light countermeasure in the operational environment (specifically, ISS) as well as laying the ground work for testing the effectiveness, feasibility and acceptability of alternative protocols (e.g., pulsing) for Exploration vehicles.
A supplemental aim was added to examine Shuttle-period actigraphy data to determine if a relationship exists between reduced sleep quantity and CO2 levels between 3 mmHg and 2 mmHg CO2.