The Effects of Thermal Strain on Cognition

Military operations in tropical environments have imposed a significant challenge to the Australian Defence Force (ADF). The hot and humid conditions are known to cause debilitating effects on soldiers deployed to northern regions of Australia, with the consequence that the effectiveness and efficiency of operations were severely compromised. while the adverse effects of thermal stress on soldiers' physiological capability are well established, this has not been confirmed for cognitive performance. Tbis impact of thermal strain on cognition has now been studied using psychometric testing and functional brain electrical activity imaging to investigate the impact of thermal stress on cognitive performance. The brain electrical activity of subjects was measured while undertaking a range of cognitive tasks. Steady State Probe Topography (SSPT), a novel brain imaging technology, was employed to monitor the changes in regional brain activity and neural processing speed of subjects under thermal stress. The psychometric test batteries, developed by the Brain Sciences Institute (BSI), were made up of the Rey auditory-verbal learning test, the inspection time, the digit span test the spatial working memory task and the AX-continuous performance task The functional brain imaging provides topographical information, which shows changes of electrical activity in response to thermal stress during cognitive task performance. The changes in brain electrical activity and%%neu%al speed in%uced by thermal stress will help to identify the type of cognitive functions --Original contains color plates: All DTIC reproductions will be in black and white.