Reliability and validity of a twelve-minute walking test for coronary heart disease patients

This study examined the reliability and validity of a 12-min. walking test for coronary heart disease patients. CHD patients (28 men, 18 women) were recruited out of 86 CHD patients of the Martini Hospital Groningen, The Netherlands. 46 CHD patients (age M=66.0 yr., SD=6.8) participated in the reliability study and 24 (age M=62.0 yr., SD=9.2) in the validity study. A test-retest analysis showed a satisfactory Bland-Altman plot and an intraclass coefficient of .98. The Pearson correlation between the score on the test and the VO2 peak was .77. This test gives a reliable and valid assessment of cardiorespiratory fitness of CHD patients.     

Focal lung pathology detection in radiology: Is there an effect of experience on visual search behavior?

In radiology, 60% to 80% of diagnostic errors are perceptual. The use of more efficient visual search behaviors is expected to reduce these errors. We collected eye-tracking data from participants with different levels of experience when interpreting chest X-rays during the completion of a pathology-detection task. Eye-tracking measures were assessed in the context of three existing visual search theories from the literature to understand the association between visual search behavior and underlying processes: the long-term working memory theory, the information-reduction hypothesis, and the holistic model of image perception. The most experienced participants (radiology residents) showed the highest level of performance, albeit their visual search behaviors did not differ from the intermediate group. This suggests that radiology residents better processed the represented information on the X-ray, using a visual search strategy similar to the intermediate group. Since similar visual search resulted in more information extraction in the radiology residents compared with the intermediates, we suggest that this result might support the long-term working memory theory. Furthermore, compared with novices, intermediates and radiology residents fixated longer on areas that were more important to avoid missing any pathology, which possibly confirms the information-reduction hypothesis. Finally, the larger distances between fixations observed in more experienced participants could support the holistic model of image perception. In addition, measures of generic skills were related to a lower time cost for switching between global and local information processing. Our findings suggest that the three theories may be complementary in chest X-ray interpretation. Therefore, a unified theory explaining perceptual-cognitive superiority in radiology is considered.