Cognition during sustained operations: comparison of a laboratory simulation to field studies.
BACKGROUND
Military operations, especially combat, expose individuals to multiple stressors, including sleep loss, food deprivation, and sustained physical activity. Civilians, such as woodland firefighters, disaster victims, and relief workers, are also exposed to such environments. Our laboratory developed a brief, intense, laboratory-based simulation of a multistressor environment which included sleep loss, continuous physical activity, and food deprivation.


METHODS
During this sustained operations (SUSOPS) scenario, and a control period, cognitive performance and mood were measured in 13 volunteers. The scenario included road marches, battle drills, and land navigation. Physical activity and sleep were assessed with actigraphs.


RESULTS
Significant decrements in visual vigilance, choice reaction time, and matching-to-sample, a test of short-term memory, were observed. Marksmanship was stable and physical activity significantly increased. Mood states assessed by the Profile of Mood States (POMS: Tension, Depression, Anger, Vigor, Fatigue and Confusion) also significantly deteriorated.


CONCLUSIONS
Cognitive function declined more extensively and rapidly than physical performance. Decrements in cognitive performance were comparable to those in a field study conducted for an equivalent period of time in uncontrolled conditions. This demonstrates that decrements in cognitive function and increased physical activity, similar to those in highly stressful field environments, can be duplicated under controlled conditions. The simulated SUSOPS scenario is an appropriate paradigm for assessment of adverse effects of military and civilian multistressor environments on human performance, physiology, and interventions designed to mitigate them.
Lieberman
Harris R
HR
U.S. Army Research Institute of Environmental Medicine, Natick 01760-5007, USA. harris.lieberman@us.army.mil
Niro
Philip
P
Tharion
William J
WJ
Nindl
Bradley C
BC
Castellani
John W
JW
Montain
Scott J
SJ
D000328:Adult; D000339:Affect / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D004190:Disasters; D005508:Food Deprivation / Q000502:physiology*; D006801:Humans; D008297:Male; D008889:Military Personnel; D009483:Neuropsychological Tests; D005082:Physical Exertion / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012066:Relief Work; D012892:Sleep Deprivation / Q000503:physiopathology*; D011795:Surveys and Questionnaires