Simon A. Jackson

Extracorporeal Membrane Oxygenation for Very High-risk Transcatheter Aortic Valve Implantation

BACKGROUND Transcatheter aortic valve implantation (TAVI) can cause profound haemodynamic perturbation in the peri-operative period. Veno-arterial extracorporeal membrane oxygenation (ECMO) can be used to provide cardiorespiratory support during this time, either prophylactically or emergently. METHOD 100 TAVI procedures were performed between 2009 and 2013 in our institution. ECMO was used in 11 patients, including eight prophylactic and three rescue cases. Rescue ECMO was required for ventricular fibrillation after valvuloplasty, and aortic annulus rupture. The criteria for prophylactic ECMO included heart failure requiring stabilisation pre-TAVI, haemodynamic instability with balloon aortic valvuloplasty performed to improve heart function pre-TAVI, moderate or severe left and/or right ventricular failure, or borderline haemodynamics at procedure. Differences in preoperative characteristics and postoperative outcomes between ECMO and non-ECMO TAVI patients were compared, and significant results were further assessed controlling for EuroSCORE. RESULTS Compared to TAVI patients who did not require ECMO, ECMO patients had significantly higher mean EuroSCORE (51 vs. 30%, p<.05). Postoperative outcomes, however, were largely comparable between the two groups. All-cause mortality occurred in nil prophylactic ECMO patients, one rescue ECMO patient, and two non-ECMO patients. The difference in mortality between ECMO and non-ECMO patients was not significantly different (9 vs. 2%; p>.05). ECMO patients were more likely to develop acute renal failure than non-ECMO patients (36 vs. 8%, p<.05), which was most likely due to haemodynamic collapse and end-organ dysfunction in patients that required ECMO rescue. CONCLUSIONS Instituting prophylactic ECMO in selected very high-risk patients may help avoid consequences of intra-operative complications and the need for emergent rescue ECMO.

Measures of the trait of confidence

This chapter reviews the item content, intended use, and psychometric properties of two main kinds of assessments that have been employed in studies of individual differences in confidence: Self-report questionnaires assessing one’s own beliefs to accomplish different tasks; and online, on-task confidence judgments of performance accuracy. First, we review six self-report measures that assess either cognitive (academic and vocational tasks) or physical (sports) confidence. We then briefly describe the use of confidence measures in studies of self-efficacy, outlining their differences and similarities with broader on-task measures of confidence. Finally, we focus on the online, performance-based, assessment of confidence and consider different indices of confidence calibration with accuracy. To date, online on-task measures have demonstrated the sound psychometric properties. This includes demonstrations of the greatest predictive validity for a range of outcomes such as educational achievement and decision-making behavior. Currently, no evidence exists relating self-report and online measures of confidence. Directions for future studies are offered for both types of assessments.

Low cognitive load and reduced arousal impede practice effects on executive functioning, metacognitive confidence and decision making.

The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times – before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants’ performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving.

Cognitive Abilities, Monitoring Confidence, and Control Thresholds Explain Individual Differences in Heuristics and Biases

In this paper, we investigate whether individual differences in performance on heuristic and biases tasks can be explained by cognitive abilities, monitoring confidence, and control thresholds. Current theories explain individual differences in these tasks by the ability to detect errors and override automatic but biased judgments, and deliberative cognitive abilities that help to construct the correct response. Here we retain cognitive abilities but disentangle error detection, proposing that lower monitoring confidence and higher control thresholds promote error checking. Participants (N = 250) completed tasks assessing their fluid reasoning abilities, stable monitoring confidence levels, and the control threshold they impose on their decisions. They also completed seven typical heuristic and biases tasks such as the cognitive reflection test and Resistance to Framing. Using structural equation modeling, we found that individuals with higher reasoning abilities, lower monitoring confidence, and higher control threshold performed significantly and, at times, substantially better on the heuristic and biases tasks. Individuals with higher control thresholds also showed lower preferences for risky alternatives in a gambling task. Furthermore, residual correlations among the heuristic and biases tasks were reduced to null, indicating that cognitive abilities, monitoring confidence, and control thresholds accounted for their shared variance. Implications include the proposal that the capacity to detect errors does not differ between individuals. Rather, individuals might adopt varied strategies that promote error checking to different degrees, regardless of whether they have made a mistake or not. The results support growing evidence that decision-making involves cognitive abilities that construct actions and monitoring and control processes that manage their initiation.

Greater response cardinality indirectly reduces confidence

ABSTRACT Koriats Self-Consistency Model of subjective confidence proposes that the consistency and accessibility with which a response is retrieved are cues to confidence in the accuracy of that response. The Self-Consistency Model, however, has only been assessed using two-alternative forced-choice questions. Consideration of open-ended questions suggested that response cardinality—the number of unique response options that might come to mind—should directly reduce response consistency, and thus indirectly reduce confidence. Australian undergraduate students (N = 389) completed a 20-item open-ended general-knowledge test with confidence ratings attached to each answer. Replicating previous Self-Consistency Model findings, but in an open-ended format for the first time, consistency and accessibility were independent positive predictors of confidence, though the prediction of accessibility did not reach statistical significance. Extending the model, the number of unique responses given by participants, a measure of response cardinality, was found to be a strong negative predictor of consistency and indirect negative predictor of confidence. Implications of the results therefore include the use of simple strategies such as prompting or providing varying numbers of response options as potentially effective for manipulating cardinality and thus confidence.

It's the deceiver, not the receiver: No individual differences when detecting deception in a foreign and a native language.

Individual differences in lie detection remain poorly understood. Bond and DePaulo’s meta-analysis examined judges (receivers) who were ascertaining lies from truths and senders (deceiver) who told these lies and truths. Bond and DePaulo found that the accuracy of detecting deception depended more on the characteristics of senders rather than the judges’ ability to detect lies/truths. However, for many studies in this meta-analysis, judges could hear and understand senders. This made language comprehension a potential confound. This paper presents the results of two studies. Extending previous work, in Study 1, we removed language comprehension as a potential confound by having English-speakers (N = 126, mean age = 19.86) judge the veracity of German speakers (n = 12) in a lie detection task. The twelve lie-detection stimuli included emotional and non-emotional content, and were presented in three modalities–audio only, video only, and audio and video together. The intelligence (General, Auditory, Emotional) and personality (Dark Triads and Big 6) of participants was also assessed. In Study 2, a native German-speaking sample (N = 117, mean age = 29.10) were also tested on a similar lie detection task to provide a control condition. Despite significantly extending research design and the selection of constructs employed to capture individual differences, both studies replicated Bond and DePaulo’s findings. The results of Study1 indicated that removing language comprehension did not amplify individual differences in judge’s ability to ascertain lies from truths. Study 2 replicated these results confirming a lack of individual differences in judge’s ability to detect lies. The results of both studies suggest that Sender (deceiver) characteristics exerted a stronger influence on the outcomes of lie detection than the judge’s attributes.

Commentary--A United Front: Using the Range of Psychological Variance in Cutting-Edge Practice and Emerging Research.

Psychological and behavioral variance can be explained by differences in the environment, and between and within individuals. Almost 60 years ago, Cronbach (1957) called for converging investigations into all three sources as important for the development of accurate science and useful applications in the real world. Yet rifts among researchers tackling these various sources still exist. The articles in this issue, for example, differ greatly in terms of content, methodological approaches, and the sources of variance being addressed. On the basis of these articles, this commentary seeks to reignite Cronbachs call as an important step for psychological research to progress as a unified and useful science.