Self-reported strategy generation and implementation in the multiple errands test: A qualitative description.

The Multiple Errands Test (MET) is a naturalistic assessment of executive function. Strategy use during the MET can provide useful information for the development of a cognitive profile and intervention plan in patients with brain injury. However, while observed external strategy use in the MET is well-documented, information about internal strategy use and reference data with healthy controls is limited. Contextual influences on strategy selection in this real-world assessment are also not well understood. This qualitative descriptive study explored the internal and external strategies used during MET performance by cognitively intact adults. Strategies were categorized as planning, checking, and problem solving. When planning, participants simplified and familiarized themselves with MET requirements before developing an action plan. They checked their performance by asking for help and using cues in the physical environment. When problems arose, these were solved through self-talk, comparing alternatives, applying context and modifying their plan. Results highlighted that individuals employ both visible and hidden strategies during the MET. This suggests that reflective discussions with patients following cognitive task engagement may be important, to uncover and understand strategy use, both to inform analysis of performance and guide strategy training.

Numerical modelling of blood rheology and platelet activation through a stenosed left coronary artery bifurcation.

Coronary bifurcations are prone to atherosclerotic plaque growth, experiencing regions of reduced wall shear stress (WSS) and increased platelet adhesion. This study compares effects across different rheological approaches on hemodynamics, combined with a shear stress exposure history model of platelets within a stenosed porcine bifurcation. Simulations used both single/multiphase blood models to determine which approach best predicts phenomena associated with atherosclerosis and atherothrombosis. A novel Lagrangian platelet tracking model was used to evaluate residence time and shear history of platelets indicating likely regions of thrombus formation. Results show a decrease in area of regions with pathologically low time-averaged WSS with the use of multiphase models, particularly in a stenotic bifurcation. Significant non-Newtonian effects were observed due to low-shear and varying hematocrit levels found on the outer walls of the bifurcation and distal to the stenosis. Platelet residence time increased 11% in the stenosed artery, with exposure times to low-shear sufficient for red blood cell aggregation (>1.5 s). increasing the risk of thrombosis. This shows stenotic artery hemodynamics are inherently non-Newtonian and multiphase, with variations in hematocrit (0.163-0.617) and elevated vorticity distal to stenosis (+15%) impairing the function of the endothelium via reduced time-averaged WSS regions, rheological properties and platelet activation/adhesion.