Keith A. Berry’s research while affiliated with Pennsylvania State University and other places

We assess whether emergency tourniquet use for transfused war casualties admitted to military hospitals is associated with survival. A retrospective review of trauma registry data was made of US casualties in Afghanistan and Iraq. Patients with major limb trauma, transfusion, and tourniquet use were compared with similar patients who did not receive tourniquet use. A propensity-matching analysis was performed by stratifying for injury type and severity by tourniquet-use status. Additionally, direct comparison without propensity matching was made between tourniquet use and no tourniquet use groups. There were 720 casualties in the tourniquet use and 693 in the no-tourniquet use groups. Of the 1,413 casualties, 66% (928) also had nonextremity injury. Casualties with tourniquet use had worse signs of hemorrhagic shock (admission base deficit, admission hemoglobin, admission pulse, and transfusion units required) than those without. Survival rates were similar between the 2 groups (1% difference; 95% confidence interval -2.5% to 4.2%), but casualties who received tourniquets had worse shock and received more blood products. In propensity-matched casualties, survival rates were not different (2% difference; 95% confidence interval -6.7% to 2.7%) between the 2 groups. Tourniquet use was associated with worse shock and more transfusion requirements among hospital-admitted casualties, yet those who received tourniquets had survival rates similar to those of comparable, transfused casualties who did not receive tourniquets. Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

Adding a physiological representation to a cognitive architecture offers an attractive approach to modeling the effects of stress on cognition. We introduce ACT-R/Φ, an extended version of the ACT-R cognitive architecture that includes an integrative model of physiology. The extension allows the representation of how physiology and cognition interact. This substrate was used to represent potential effects of a startle response and task-based stress during a mental arithmetic (subtraction) task. We compare predictions from two models loaded into the new hybrid architecture to models previously developed within ACT-R. General behavior differed between models in that the ACT-R/Φ models had dynamic declarative memory noise over the course of the task based on varying epinephrine levels. They attempted more subtractions but were less accurate; this more closely matched human performance than the previous ACT-R models. Using ACT-R/Φ allows a more tractable integration of current physiological and cognitive perspectives on stress. ACT-R/Φ also permits further exploration of the interaction between cognition and physiology, and the emergent effects on behavior caused by the interaction among physiological subsystems. This extension is useful for anyone exploring how the human mind can occur in and be influenced by the physical universe.

Connecting a physiological model to a cognitive architecture presents an attractive option to better simulate a wide range of human behavior. This connection should facilitate both the effects of physiology on cogni-tion (e.g. hunger and decision-making), and the effects of cognition on physiology (e.g. autonomic responses to memory featuring particularly aversive stimuli). To add physiology to a cognitive architecture, it should be represented as a separate module or substrate. We present ACT-RΦ (ACT-R Phi), a connection of the physiology simulation system HumMod (Hester et al., 2011) and the cognitive architecture ACT-R (Anderson, 2007) using an newly created ACT-R module. A model of the startle response and its consequent effects on cognition and physiolo-gy is presented to demonstrate an example use of the new substrate. This extended version of ACT-R allows a user to computationally realize theories involving cognition, physiology, and their interaction. This architecture has poten-tial applications to training simulations.