What can an echocardiographer see in briefly presented stimuli? : perceptual expertise in dynamic search

Background: Experts in medical image perception are able to detect abnormalities rapidly from medical images. This ability is likely due to enhanced pattern recognition on a global scale. However, the bulk of research in this domain has focused on static rather than dynamic images, so it remains unclear what level of information that can be extracted from these displays. This study was designed to examine the visual capabilities of echocardiographers—practitioners who provide information regarding cardiac integrity and functionality. In three experiments, echocardiographers and naïve participants completed an abnormality detection task that comprised movies presented on a range of durations, where half were abnormal. This was followed by an abnormality categorization task. Results: Across all durations, the results showed that performance was high for detection, but less so for categorization, indicating that categorization was a more challenging task. Not surprisingly, echocardiographers outperformed naïve participants. Conclusions: Together, this suggests that echocardiographers have a finely tuned capability for cardiac dysfunction, and a great deal of visual information can be extracted during a global assessment, within a brief glance. No relationship was evident between experience and performance which suggests that other factors such as individual differences need to be considered for future studies

Cross-Species Transmission of a Novel Adenovirus Associated with a Fulminant Pneumonia Outbreak in a New World Monkey Colony

Adenoviruses are DNA viruses that naturally infect many vertebrates, including humans and monkeys, and cause a wide range of clinical illnesses in humans. Infection from individual strains has conventionally been thought to be species-specific. Here we applied the Virochip, a pan-viral microarray, to identify a novel adenovirus (TMAdV, titi monkey adenovirus) as the cause of a deadly outbreak in a closed colony of New World monkeys (titi monkeys; Callicebus cupreus) at the California National Primate Research Center (CNPRC). Among 65 titi monkeys housed in a building, 23 (34%) developed upper respiratory symptoms that progressed to fulminant pneumonia and hepatitis, and 19 of 23 monkeys, or 83% of those infected, died or were humanely euthanized. Whole-genome sequencing of TMAdV revealed that this adenovirus is a new species and highly divergent, sharing <57% pairwise nucleotide identity with other adenoviruses. Cultivation of TMAdV was successful in a human A549 lung adenocarcinoma cell line, but not in primary or established monkey kidney cells. At the onset of the outbreak, the researcher in closest contact with the monkeys developed an acute respiratory illness, with symptoms persisting for 4 weeks, and had a convalescent serum sample seropositive for TMAdV. A clinically ill family member, despite having no contact with the CNPRC, also tested positive, and screening of a set of 81 random adult blood donors from the Western United States detected TMAdV-specific neutralizing antibodies in 2 individuals (2/81, or 2.5%). These findings raise the possibility of zoonotic infection by TMAdV and human-to-human transmission of the virus in the population. Given the unusually high case fatality rate from the outbreak (83%), it is unlikely that titi monkeys are the native host species for TMAdV, and the natural reservoir of the virus is still unknown. The discovery of TMAdV, a novel adenovirus with the capacity to infect both monkeys and humans, suggests that adenoviruses should be monitored closely as potential causes of cross-species outbreaks

Expertise in visual search of medical and non-medical images

Theoretical thesis.Bibliography: pages 202-206Chapter 1: General introduction -- Chapter 2: The time course of rapid target detection and localisation -- Chapter 3: Finding cancer in mammograms: if you know it's there, do you know where? -- Chapter 4: The influence of prior expectation and expertise on attentional cueing in medical images -- Chapter 5: General discussion.This thesis aims to understand the crucial cognitive mechanisms that underpin visual search in medical images and the influence of expertise. Research suggests that experienced radiologists use information from an initial glance at an image to set the basis of their diagnosis. This research explores the information that can be extracted from images regarding the presence and location of a target. I use two stimulus types: real medical images on which I test both novices and expert radiologists, and natural scenes as a model for radiologist search. In Chapter 1, I present an overview of the literature relevant to these aims. Chapter 2 presents two experiments where I showed that a target could be both detected and located in a natural scene after a brief presentation (33 ms), but that visual clutter interferes with performance in a predictable way. In Chapter 3, I showed radiologists were able to detect and localise an abnormality in a mammogram presented for 250 ms at levels better than guessing.Crucially I demonstrated that a normal patient variant, high levels of breast density,affects performance. I conducted an in-depth analysis which emphasises the importance of considering factors such as stimulus variability, response imprecision, and participant guessing. In Chapter 4, I investigated the extent to which expertise guides attention based on prior experience with the prevalence of cancer, using a novel cueing paradigm where a chest radiograph (with or without a suspicious nodule) formed a prime. For naïve observers, an artificially boosted nodule in the prime radiograph guided attention, validating the task. Radiologists viewing true, more subtle nodules did not show the same effect, nor did they show any attentional guidance from cancer prevalence. However, more experienced radiologists seemed to be more sensitive to the subtle nodules than less experienced radiologists, suggesting that viexpertise might boost nodule salience. Finally, in Chapter 5, the implications of these findings are discussed in a broader context along with suggestions for areas of future research. Overall, my research shows that there is a large amount of information available after observers first look at a scene or medical image; more than previously thought. Further, the visual complexity of the display affects performance. Together, the experiments presented in this thesis advance the scientific understanding of the type of information available in the first glance and has clear implications for radiologist teaching and clinical benefits.1 online resource (255 pages

The mere presence of a mobile phone : Does it influence driving performance?

The ubiquity of mobile phones has led to a rapid increase in its presence and use in vehicles, especially among young adults (up to 25 years), who are generally the least experienced group of drivers. The potential for phones to draw attention away from the main driving task has significant consequences for road safety. Previous studies have found that the mere presence of a mobile phone can be distracting by impairing attention in experimental non-driving contexts. However, the effect of phone presence, independent to usage, has not yet been examined in the context of driving. As such, the present study examined whether the mere presence of a mobile phone, its proximity to the driver, and power status (on/off) influenced the driving performance of young drivers. Additionally, this study assessed whether the effects of phone presence and proximity were moderated by an individual’s level of dependence on, or emotional attachment to, their phone. A sample of 127 undergraduate psychology students (M = 19.76, SD = 1.63) were randomly assigned to one of four conditions: (1) phone absent (control), (2) phone on, in holder, (3) phone off, in holder, and (4) phone on, in pocket. They all completed the same simulated drive, and were measured for degree of phone dependence and phone emotional attachment. Overall, drivers in all the phone present conditions made significantly more driving errors (speeding and collision) compared to those in the phone absent (control) condition, irrespective of proximity to the phone and whether it was on or off. Phone dependence, but not phone emotional attachment, moderated the effect of phone presence on speeding behaviour. These findings suggest that the mere presence of a phone is distracting for drivers, especially so for those who are highly dependent on their phone, which may place them at a greater risk of a distraction induced crash

Finding cancer in mammograms: if you know it’s there, do you know where?

Abstract Humans can extract considerable information from scenes, even when these are presented extremely quickly. The ability of an experienced radiologist to rapidly detect an abnormality on a mammogram may build upon this general capacity. Although radiologists have been shown to be able to detect an abnormality ‘above chance’ at short durations, the extent to which abnormalities can be localised at brief presentations is less clear. Extending previous work, we presented radiologists with unilateral mammograms, 50% containing a mass, for 250 or 1000 ms. As the female breast varies with respect to the level of normal fibroglandular tissue, the images were categorised into high and low density (50% of each), resulting in difficult and easy searches, respectively. Participants were asked to decide whether there was an abnormality (detection) and then to locate the mass on a blank outline of the mammogram (localisation). We found both detection and localisation information for all conditions. Although there may be a dissociation between detection and localisation on a small proportion of trials, we find a number of factors that lead to the underestimation of localisation including stimulus variability, response imprecision and participant guesses. We emphasise the importance of taking these factors into account when interpreting results. The effect of density on detection and localisation highlights the importance of considering breast density in medical screening

A 'snapshot' of the visual search behaviours of medical sonographers

Introduction: Visual search is a task that humans perform in everyday life. Whether it involves looking for a pen on a desk or a mass in a mammogram, the cognitive and perceptual processes that underpin these tasks are identical. Radiologists are experts in visual search of medical images and studies on their visual search behaviours have revealed some interesting findings with regard to diagnostic errors. In Australia, within the modality of ultrasound, sonographers perform the diagnostic scan, select images and present to the radiologist for reporting. Therefore the visual task and potential for errors is similar to a radiologist. Our aim was to explore and understand the detection, localisation and eye-gaze behaviours of a group of qualified sonographers. Method: We measured clinical performance and analysed diagnostic errors by presenting fifty sonographic breast images that varied on cancer present and degree of difficulty to a group of sonographers in their clinical workplace. For a sub-set of sonographers we obtained eye-tracking metrics such as time-to-first fixation, total visit duration and cumulative dwell time heat maps. Results: The results indicate that the sonographers' clinical performance was high and the eye-tracking metrics showed diagnostic error types similar to those found in studies on radiologist visual search. Conclusion: This study informs us about sonographer visual search patterns and highlights possible ways to improve diagnostic performance via targeted education.8 page(s

Static versus dynamic medical images : the role of cue utilization in diagnostic performance

Echocardiographers can detect abnormalities accurately and rapidly from dynamic images. This is likely due to the application of cue-based associations resident in memory, a process known as cue utilization. This study investigated whether cue utilization is associated with the ability to apply within-domain capabilities (dynamic) to more degraded images (static). Fifty-eight echocardiographers completed the echocardiography edition of the Expert Intensive Skills Evaluation 2.0 (EXPERTise 2.0) to establish behavioral indicators of within-domain cue utilization. They also completed an abnormality detection and categorization task that comprised briefly presented static and moving images (50% abnormal). Behaviors consistent with higher cue utilization were associated with greater accuracy in detecting both static and dynamic images but not for categorization. This study provides important information about how experts who have the capacity to utilize cue-based strategies can rapidly and accurately detect abnormalities from domain-specific stimuli and generalize their skills to more challenging stimuli

'My wife ordered me to come!' A discursive analysis of doctors' and nurses' accounts of men's use of General Practitioners

This study used a discursive approach to analysing doctors’ and nurses’ accounts of men’s health in the context of general practice. The analysis worked intensively with interview material from a small sample of general practitioners and their nursing colleagues. We examine the contradictory discursive framework through which this sample made sense of their male patients. The ‘interpretative repertoires’ through which doctors and nurses constructed their representations of male patients and the ‘subject positions’ these afforded men are outlined in detail. We describe how hegemonic masculinity is both critiqued for its detrimental consequences for health and paradoxically also indulged and protected. These constructions reflect a series of ideological dilemmas for men and health professionals between the maintenance of hegemonic masculine identities and negotiating adequate health care. Men who step outside ‘typical’ gender constructions tended to be marked as deviant or rendered invisible as a consequence