Providing the Tools for Warfighters to Maintain Their Cognition Under Extreme Cold Weather Environments

For U.S. warfighters working in extreme operational environments, the cold-shock response doesn’t just take your breath away, it can disrupt the ability to think. In these high-stress emergencies, the ability to recall survival training is critical to saving the lives of the individual and, potentially, the unit.

Scientists from Naval Health Research Center’s (NHRC) Expeditionary Cognitive Science Group and Environmental & Thermal Physiology research team spent 5 days at Joint Base Elmendorf-Richardson in Anchorage, Alaska, during the final weeks of March conducting a field-data collection event, focused on memory encoding under cold stress. Working up to 14 hours a day in temperatures under 25 degrees Fahrenheit, the research team had one goal in mind; preparing the U.S. warfighter to understand and face the risks of harsh climatic regions.

NHRC researchers worked in collaboration with Maj. Titus Rund, flight surgeon for the 20th Aviation Troop Command. This cold-water-training event, sponsored by the Office of Naval Research (ONR) Physiology for Operational Performance Program, and held at Joint Base Elmendorf-Richardson, gives NHRC’s researchers the perfect opportunity to conduct the Memory Encoding under Cold Stress event, gathering data on over 50 volunteer participants from the Army Guard & Air Force over a 2-day period.

While the physiological effects of cold shock response are well studied, the specific cognitive processes that cold-water exposure effects are less understood. How well individuals can encode details plays a critical role in the recall of information in more complex cognition and decision making further down the line.

“We are trying to disentangle which specific cognitive processes are affected during the different stages of cold-water immersion,” explained Tim Dunn, principal investigator of NHRC’s Expeditionary Cognitive Science Group. “Specifically, we are looking at how encoding information [the process of taking in and committing information to memory] is affected during the initial cold shock versus the period after, when the body experiences the prolonged effects of cold.”

On day one, researchers gathered bodily metrics and basic BMI readings from study, followed by a memory encoding task. This task required participants to view a series of randomly generated images of shapes and colors, called “kaleidoscope images,” and identify the color that was most prominent to them.

The kaleidoscope images strip away any context that could otherwise influence memory encoding-based on key characteristics. For example, images of animals are not shown because of the natural tendency to better remember animate versus inanimate objects.

After the test, participants have a 12-minute delay before picking out the specific kaleidoscope image they saw from three other randomly generated images they previously have not seen. Upon completion of this step, participants rated their confidence in the answers; this confidence rating allows the researchers to measure participants metacognition (their own evaluation of their cognitive processes).

On the second day, the Expeditionary Cognitive Science Group randomly divides participants into two groups, and outfits each participant with a waterproof keyboard, a series of data-collection devices such as heart rate straps, core and skin temperature monitors and a spirometer. Researchers then immerse participants in 45° water; the first group completes the tasks immediately once they enter the cold water, while the second group takes the exam a short time after entering the water.

“The importance of this research is to lead a focused effort in the development of a toolbox of mitigation strategies that the warfighter can use,” Dunn explained. “While we can't get rid of the stress and pain entirely, having these tools can help them perform better and mitigate some of the negative effects.”

NHRC researchers are still compiling the preliminary findings of the study. Initial findings suggest that individuals have equal difficulty encoding information whether they enter the cold water immediately or after the cold shock response subsides. Additionally, individuals’ certainty in their responses appears to decrease, even when they make correct responses, suggesting that the cold can affect confidence in one’s decision.

The discoveries made by Expeditionary Cognitive Science team have the potential to lead to new, better-informed training techniques for service members which can help them make better decisions that not only get themselves and others to safety faster but also help maintain performance even after they are out of the water.