Attentional bias in German Armed Forces veterans with and without posttraumatic stress symptoms - An eye-tracking investigation and group comparison
Abstract: Background and objectives: Most eye tracking based paradigms evidence patterns of sustained attention on threat coupled with low evidence for vigilance to or avoidance of threat in posttraumatic stress symptoms (PTSS). Still, eye tracking data on attention bias is particularly limited for military population. This eye tracking study investigated attentional bias in PTSS in a sample of German Armed Forces veterans. Methods: Veterans with deployment-related PTSS (N = 24), veterans with deployment-related traumatization without PTSS (N = 28), and never-deployed healthy veterans (N = 18) were presented with pairs of combat and neutral pictures, pairs of general threat and neutral pictures, and pairs of emotional and neutral faces. Their eye gazes were tracked during a free viewing task. 3 x 3 x 2 mixed general linear model analyses were conducted. Internal consistency of attention bias indicators was calculated for the entire sample and within groups. Results: Veterans with PTSS dwelled longer on general threat AOIs in contrast to non-exposed controls and shorter on general threat and combat associated neutral AOIs in contrast to both control groups. Veterans with PTSS entered faster to general threat AOIs than non-exposed controls. Veterans with PTSS showed circumscribed higher attention fluctuation in contrast to controls. Internal consistency varied across attention bias indicators. Limitations: Statistical power was reduced due to recruitment difficulties. Conclusions: Evidence is provided for the maintenance hypothesis in PTSS. No robust evidence is provided for hypervigilant behavior in PTSS. Findings on attention bias variability remain unclear, calling for more investigations in this field.
Abstract: Changes in physiological markers and physical performance in relation to paratroopers' initial body composition were investigated during a 20-day winter military field training (MFT) and the subsequent 10-day recovery period. Body composition, serum hormone concentrations and enzymatic biomarkers, and physical performance of 58 soldiers were measured before, during, and after MFT. Comparisons were done according to soldiers' body fat percentage before MFT between low-fat (12% body fat) groups. Correlations between body fat percentage preceding MFT and changes in muscle mass, physical performance, and serum hormone concentrations and enzymatic biomarkers were investigated. It was hypothesized that soldiers with a higher fat percentage would have smaller decrements in muscle mass, physical performance, and serum testosterone concentration. The change in muscle and fat mass was different between groups (p < 0.001) as the low-fat group lost 0.8 kg of muscle mass and 2.0 kg of fat mass, while there was no change in muscle mass and a loss of 3.7 kg of fat mass in the high-fat group during MFT. Fat percentage before MFT correlated with the changes in muscle mass (R2 = 0.26, p < 0.001), serum testosterone concentration (R-2 = 0.22, p < 0.001), and evacuation test time (R-2 = 0.10, p < 0.05) during MFT. The change in muscle mass was correlated with the changes in evacuation test time (R-2 = 0.11, p < 0.05) and countermovement jump test results (R-2 = 0.13, p < 0.01) during MFT. Soldiers with a higher initial fat percentage lost less muscle mass, and had smaller decrements in some aspects of physical performance, as well as in serum testosterone concentration during MFT.