RESEARCH ARTICLE
Development and Validation of the Cognition Test
Battery for Spaceflight
Mathias Basner; Adam Savitt; Tyler M. Moore; Allison M. Port; Sarah McGuire; Adrian J. Ecker;
Jad Nasrini; Daniel J. Mollicone; Christopher M. Mott; Thom McCann; David F. Dinges; Ruben C. Gur
BACKGROUND: Sustained high-level cognitive performance is of paramount importance for the success of space missions, which
involveDelivered by Publishing
environmental, physiological,Technology to: University
and psychological ofmay
stressors that Pennsylvania Library Despite subjective
affect brain functions.
symptom reports ofIP: 165.123.243.167
cognitive fluctuations in On: Wed,
spacefl 18 nature
ight, the Nov 2015 15:22:07 functioning in space has not
of neurobehavioral
been clarified. Copyright: Aerospace Medical Association
METHODS: We developed a computerized cognitive test battery (Cognition) that has sensitivity to multiple cognitive domains and
was specifically designed for the high-performing astronaut population. Cognition consists of 15 unique forms of 10
neuropsychological tests that cover a range of cognitive domains, including emotion processing, spatial orientation, and
risk decision making. Cognition is based on tests known to engage specific brain regions as evidenced by functional
neuroimaging. Here we describe the first normative and acute total sleep deprivation data on the Cognition test battery
as well as several efforts underway to establish the validity, sensitivity, feasibility, and acceptability of Cognition.
RESULTS: Practice effects and test-retest variability differed substantially between the 10 Cognition tests, illustrating the impor-
tance of normative data that both reflect practice effects and differences in stimulus set difficulty in the population of
interest. After one night without sleep, medium to large effect sizes were observed for 3 of the 10 tests addressing
vigilant attention (Cohen’s d 5 1.00), cognitive throughput (d 5 0.68), and abstract reasoning (d 5 0.65).
CONCLUSIONS: In addition to providing neuroimaging-based novel information on the effects of spaceflight on a range of cognitive
functions, Cognition will facilitate comparing the effects of ground-based analogues to spaceflight, increase consistency
across projects, and thus enable meta-analyses.
KEYWORDS: neuropsychological test, cognitive test, cognition, space, spaceflight, performance, astronaut, microgravity, stress,
confinement, isolation, sleep deprivation.
Basner M, Savitt A, Moore TM, Port AM, McGuire S, Ecker AJ, Nasrini J, Mollicone DJ, Mott CM, McCann T, Dinges DF, Gur RC. Development and validation of the
Cognition test battery for spaceflight. Aerosp Med Hum Perform. 2015; 86(11):942–952.
S
uccessful human space exploration depends on the integ- high levels of daytime performance, yet astronauts on Space
rity of a range of cognitive abilities for unprecedented Shuttle and International Space Station (ISS) missions have
durations. Errors and accidents may have debilitating or averaged less than 6.1 h sleep per 24 h.2 This amount of sleep is
fatal consequences, lead to the loss of expensive equipment, and comparable to that of chronic sleep restriction, which has been
compromise mission success. In addition to the physiological
From the Division of Sleep and Chronobiology, Department of Psychiatry, and the
effects of microgravity, the spacecraft setting can involve expo- Behavior Laboratory, Department of Psychiatry, Perelman School of Medicine at the
sure to a number of environmental toxicants and operational University of Pennsylvania, Philadelphia, PA; Pulsar Informatics, Inc., Philadelphia, PA;
and Joggle Research, Seattle, WA.
stressors that have the potential to degrade astronaut cognitive
This manuscript was received for review in April 2015. It was accepted for publication in
performance. Among these factors are radiation, noise, hyper- August 2015.
capnia, hypoxia, decompression, dietary restrictions, fluid Address correspondence to: Mathias Basner, M.D., Ph.D., M.Sc., Associate Professor of
shifts, increased intracranial pressure, side effects of certain Sleep and Chronobiology in Psychiatry, Perelman School of Medicine at the University of
Pennsylvania, 1019 Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104-6021;
medications, and psychological factors related to isolation, con- basner@upenn.edu.
finement, and operational and interpersonal distress. Sleep of Reprint & Copyright © by the Aerospace Medical Association, Alexandria, VA.
sufficient length and quality is of paramount importance for DOI: 10.3357/AMHP.4343.2015
942 AEROSPACE MEDICINE AND HUMAN PERFORMANCE Vol. 86, No. 11 November 2015
, COGNITION TEST & SPACEFLIGHT—Basner et al.
shown to induce cognitive and neurobehavioral deficits and predominantly probes working memory, but fails to assess cogni-
negative health outcomes.1 Although the reasons for reduced tive domains like spatial orientation, abstract reasoning, emo-
sleep durations in spaceflight are unknown, factors that con- tion processing, stability of sustained attention, and risk decision
tribute to sleep disturbance in spaceflight include non-24 h making that are also important for space mission success.
light–dark cycles, acute operational shifts in sleep timing, high There are other reasons why cognitive deficits may go unde-
workload and physical stress. tected in spaceflight. Well-educated, highly trained, motivated
While astronauts have reported cognitive symptoms (often astronauts may be able to transiently compensate for deficits in
referred to as space fog or neurasthenia23), especially after ini- cognitive performance induced during spaceflight by team-
tial exposure to the spacecraft environment, the results of work and other strategies. Countermeasures used by astronauts
objective cognitive testing in spaceflight have been inconclusive may reverse or mask a cognitive deficit. Astronauts may not
and most often fail to show statistically significant changes in subjectively be aware of some cognitive deficits that could be
cognitive performance.42 Therefore, the extent, etiology, and detected by a sensitive test battery. For example, sleep depriva-
persistence of these symptoms are still unknown. Several fac- tion studies indicate that subjective and objective assessments
tors may contribute to the discrepancy between subjective of performance may differ substantially.45 Although perfor-
symptom reports and objective assessment of cognitive func- mance capability is mostly overestimated during periods of
tions in space. sleep restriction, especially during the biological night, it is pos-
Performance on most cognitive tests improves with repeated sible that the opposite can happen in spaceflight. This under-
administration. This practice effect may confound (or mask) scores the need for brief and valid objective assays of cognitive
any cognitive deficits induced by the spacecraft environment. performance in spaceflight.
Depending on the complexity of the cognitive tests and given Here, we describe the development of an improved neuro-
Delivered
pre-mission time constraints, by Publishing
it will often not beTechnology
possible to to: cognitive
University of Pennsylvania
assessment Library
tool, named Cognition, provide learning
IP: 165.123.243.167 On:
achieve asymptotic performance levels preflight. Additionally, Wed, 18 Nov 2015 15:22:07
curves for each of its 10 cognitive tests, and show that each test
Copyright: Aerospace Medical Association
existing studies often lack adequate ground-based control differs in its sensitivity to acute total sleep deprivation. Cogni-
groups, and ground-based normative data usually do not exist tion was specifically designed to assess cognitive functions in
for the astronaut population.42 astronauts and address some of the more than 25 knowledge
Spaceflight studies are often underpowered due to small gaps and health risks that mention cognition in NASA’s Human
sample sizes, and test batteries and cognitive domains they Research Roadmap.12 Cognition covers the main cognitive
assess typically differ among studies, complicating systematic domains – executive, episodic memory, complex cognition,
meta-analyses that could increase statistical power. Further- social cognition, and sensorimotor speed – and is based on tests
more, the tests used in the individual studies may simply lack known to engage specific brain systems during functional neu-
sensitivity because they were designed for clinical populations roimaging.19,41 The latter may provide information on the neu-
or populations with lower aptitudes. They may be sensitive rostructural origin of a cognitive deficit, which is important as
enough to detect symptoms associated with manifest distur- we currently have no neuroimaging capability in spaceflight.
bances such as severe brain trauma, but fail to detect subclinical Cognition is involved in several ongoing and soon-to-be com-
deficits that can degrade optimal performance in high func- menced validation studies. The goal is to advance knowledge
tioning individuals such as astronauts. Although subclinical on the cognitive effects of spaceflight by offering a brief and
deficits may not constitute an operational concern, they can be well-validated battery of tests that are acceptable to the astro-
valuable in the early detection of environmental or psychologi- naut population, feasible in spaceflight, and that provide crucial
cal stressors and thus in the prevention of manifest cognitive clinical feedback on neurobehavioral functions in space. This
deficits. research tool will hopefully increase consistency across projects
Another limitation of available test batteries is that they and facilitate meta-analyses.
often only probe a few cognitive domains (i.e., they are not
comprehensive), despite having multiple cognitive evaluations.
It is thus possible that deficits in domains not covered by these METHODS
batteries may have been overlooked. NASA currently uses the
WinSCAT test battery operationally.24 WinSCAT consists of Subjects
a 5-test subset of the larger Automated Neuropsychological A normative study in astronauts/astronaut candidates (N 5 8,
Assessment Metrics (ANAM) test system developed by the mean age 44.1 yr, range 34-53 yr, 38% female) and mission con-
Department of Defense:39 1. Mathematical Processing; 2. Run- trollers (N 5 11, mean age 28.0 yr, range 22-38 yr, 55% female)
ning Memory Continuous Performance; 3. Delayed Matching was completed in 2014 at Johnson Space Center, Houston, TX.
to Sample; 4. Code Substitution; and 5. Code Substitution This study was approved by NASA’s Institutional Review Board
Delayed Recognition. The cognitive domains assessed by these and subjects signed written informed consent prior to study
tests are: 1. basic computational skills and working memory; 2. participation. The Cognition battery was also performed by a
attention and working memory; 3. spatial processing and visuo- total of 44 different subjects (mean age 6 SD 34.1 6 8.7 yr, 50%
spatial working memory; 4. complex scanning, visual track- male) in two sleep restriction protocols that included acute total
ing, and attention; and 5. memory. Therefore, the WinSCAT sleep deprivation (i.e., one night without sleep). These studies
AEROSPACE MEDICINE AND HUMAN PERFORMANCE Vol. 86, No. 11 November 2015 943
