Human cognitive performance in spaceflight and analogue environments.

Maintaining intact cognitive performance is a high priority for space exploration. This review seeks to summarize the cumulative results of existing studies of cognitive performance in spaceflight and analogue environments. We focused on long-duration (>21 d) studies for which no review has previously been conducted. There were 11 published studies identified for long-duration spaceflight (N = 42 subjects) as well as 21 shorter spaceflight studies (N = 70 subjects). Overall, spaceflight cognitive studies ranged from 6-438 d in duration. Some 55 spaceflight analogue studies were also identified, ranging from 6 to 520 d. The diverse nature of experimental procedures and protocols precluded formal meta-analysis. In general, the available evidence fails to strongly support or refute the existence of specific cognitive deficits in low Earth orbit during long-duration spaceflight, which may be due in large part to small numbers of subjects. The studies consistently suggest that novel environments (spaceflight or other) induce variable alterations in cognitive performance across individuals, consistent with known astronaut experiences. This highlights the need to better quantify the magnitude and scope of this interindividual variability, and understand its underlying factors, when predicting in-flight cognitive functioning for extended periods.

Learning to live on a Mars day: fatigue countermeasures during the Phoenix Mars Lander mission.

STUDY OBJECTIVES: To interact with the robotic Phoenix Mars Lander (PML) spacecraft, mission personnel were required to work on a Mars day (24.65 h) for 78 days. This alien schedule presents a challenge to Earth-bound circadian physiology and a potential risk to workplace performance and safety. We evaluated the acceptability, feasibility, and effectiveness of a fatigue management program to facilitate synchronization with the Mars day and alleviate circadian misalignment, sleep loss, and fatigue. DESIGN: Operational field study. SETTING: PML Science Operations Center. PARTICIPANTS: Scientific and technical personnel supporting PML mission. INTERVENTIONS: Sleep and fatigue education was offered to all support personnel. A subset (n = 19) were offered a short-wavelength (blue) light panel to aid alertness and mitigate/reduce circadian desynchrony. They were assessed using a daily sleep/work diary, continuous wrist actigraphy, and regular performance tests. Subjects also completed 48-h urine collections biweekly for assessment of the circadian 6-sulphatoxymelatonin rhythm. MEASUREMENTS AND RESULTS: Most participants (87%) exhibited a circadian period consistent with adaptation to a Mars day. When synchronized, main sleep duration was 5.98 ± 0.94 h, but fell to 4.91 ± 1.22 h when misaligned (P < 0.001). Self-reported levels of fatigue and sleepiness also significantly increased when work was scheduled at an inappropriate circadian phase (P < 0.001). Prolonged wakefulness (≥ 21 h) was associated with a decline in performance and alertness (P < 0.03 and P < 0.0001, respectively). CONCLUSIONS: The ability of the participants to adapt successfully to the Mars day suggests that future missions should utilize a similar circadian rhythm and fatigue management program to reduce the risk of sleepiness-related errors that jeopardize personnel safety and health during critical missions.

Behavioral and psychological issues in long-duration head-down bed rest.

INTRODUCTION: This report is one of a series on the Flight Analogs Project, which is designed to lay the groundwork for a standard bed rest protocol. Behavioral health services, similar to those offered to the U.S. astronauts who undertake 6-mo missions onboard the International Space Station, were provided to 13 long-duration head-down bed rest participants. Long-duration missions pose unique challenges and stressors, including separation from primary support group, monotonous environment, and loss of privacy and autonomy. METHODS: The psychological services team, consisting of a psychiatrist, a psychologist, and a master's level psychological support scientist, provided behavioral health services throughout all phases of the Flight Analogs Project (FAP) long-duration head-down bed rest study. During the initial screening phase, potential candidates completed 4 h of psychological testing and a 1.5-h clinical interview with a psychologist to assess their psychological fitness and ability to complete the study successfully. Additionally, the psychological services team provided pre-admission trainings on time management, stress management, and communication skills and conflict resolution. Throughout their stay on the research unit, study participants received regular individual and group visits from the psychological services team. Training was also provided to study personnel to address personality and behavioral management challenges. RESULTS: Psychological support and training provided to both subjects and study personnel have successfully improved the well being of study participants. DISCUSSION: Behavioral health services are indispensable to long-duration head-down bed rest studies.

Cognitive functioning in long-duration head-down bed rest.

INTRODUCTION: This report is one of a series on the Flight Analog Project, which is designed to lay the groundwork for a standard bed rest protocol. The Spaceflight Cognitive Assessment Tool for Windows (WinSCAT) is a self-administered battery of tests used on the International Space Station for evaluating cognitive functioning. Here, WinSCAT was used to assess cognitive functioning during extended head-down bed rest. METHODS: There were 13 subjects who participated in 60 or 90 d of head-down bed rest and took WinSCAT during the pre-bed rest phase, the in-bed rest phase, and the post-bed rest (reconditioning) phase of study participation. RESULTS: After adjusting for individual baseline performance, 12 off-nominal scores were observed out of 351 total observations during bed rest and 7 of 180 during reconditioning. No evidence was found for systematic changes in off-nominal incidence as time in bed rest progressed, or during the reconditioning period. DISCUSSION: Cognitive functioning does not appear to be adversely affected by long-duration head-down bed rest. Individual differences in underlying cognitive ability and motivation level are likely explanations for the current findings.

Human health and performance for long-duration spaceflight.

Future long-duration spaceflights are now being planned to the Moon and Mars as a part of the "Vision for Space Exploration" program initiated by NASA in 2004. This report describes the design reference missions for the International Space Station, Lunar Base, and eventually a Mars Expedition. There is a need to develop more stringent preflight medical screening for crewmembers to minimize risk factors for diseases which cannot be effectively treated in flight. Since funding for space life sciences research and development has been eliminated to fund program development, these missions will be enabled by countermeasures much like those currently in use aboard the International Space Station. Artificial gravity using centrifugation in a rotating spacecraft has been suggested repeatedly as a "universal countermeasure" against deconditioning in microgravity and could be an option if other countermeasures are found to be ineffective. However, the greatest medical unknown in interplanetary flight may be the effects of radiation exposure. In addition, a Mars expedition would lead to a far greater level of isolation and psychological stress than any space mission attempted previously; because of this, psychiatric decompensation remains a risk. Historically, mortality and morbidity related to illness and injury have accounted for more failures and delays in new exploration than have defective transportation systems. The medical care system on a future Mars expedition will need to be autonomous and self-sufficient due to the extremely long separation from definitive medical care. This capability could be expanded by the presence of a physician in the crew and including simple, low-technology surgical capability.

Artificial gravity as a multi-system countermeasure: effects on cognitive function.

The Space Flight Cognitive Assessment Tool for Windows (WinSCAT) is used on the International Space Station to evaluate cognitive functioning after physical insult or trauma. The current study uses WinSCAT to assess cognitive functioning in a space flight analog (bed rest) environment where intermittent artificial gravity (AG) is being tested as a countermeasure. Fifteen male subjects (8 treatment, 7 control), who participated in 21 days of 6 degree head-down tilt bed rest, were assessed during the acclimatization phase, bed rest phase, and recovery phase. Individual differences were found within both the treatment and control groups. The treatment group accounted for more off-nominal WinSCAT scores than the control group. The length of time spent in bed rest was not associated with a change in cognitive function. Individual differences in underlying cognitive ability and motivation level are other possible explanations for the current findings.

Operational behavioral health and performance resources for international space station crews and families.

The Behavioral Health and Performance Section (BHP) at NASA Johnson Space Center provides direct and indirect psychological services to the International Space Station (ISS) astronauts and their families. Beginning with the NASA-Mir Program, services available to the crews and families have gradually expanded as experience is gained in long-duration flight. Enhancements to the overall BHP program have been shaped by crewmembers' personal preferences, family requests, specific events during the missions, programmatic requirements, and other lessons learned. The BHP program focuses its work on four areas: operational psychology, behavioral medicine, human-to-system interface, and sleep and circadian. Within these areas of focus are psychological and psychiatric screening for astronaut selection as well as many resources that are available to the crewmembers, families, and other groups such as crew surgeon and various levels of management within NASA. Services include: preflight, in flight, and postflight preparation; training and support; resources from a Family Support Office; in-flight monitoring; clinical care for astronauts and their families; and expertise in the workload and work/rest scheduling of crews on the ISS. Each of the four operational areas is summarized, as are future directions for the BHP program.

Development and validation of the spaceflight cognitive assessment tool for windows (WinSCAT).

The Spaceflight Cognitive Assessment Tool for Windows (WinSCAT) was developed by an integrated product team as a tool to support medical operations at NASA Johnson Space Center and as way to monitor the neurocognitive status of space crews. It is based on 20 yr of experience in performance and cognitive testing within the U.S. Department of Defense. As a result, WinSCAT development has benefited from diverse efforts supporting its technical reliability and validation. The rationale, background, and development of WinSCAT are described, research supporting its use is summarized, and recommendations are made for its continued development.