Medical education videos as a tool for rehearsal: efficiency and the cases of background music and difficulty.

This study reports a field experiment investigating how instructional videos with and without background music contribute to the learning of examination techniques within a formal curriculum of medical teaching. Following a classroom teaching unit on the techniques for examining the knee and the shoulder joint, our participants (N = 175) rehearsed the studied techniques for either the knee or the shoulder joint with an instructional video with or without background music. As dependent measures, we collected a general questionnaire, a prediction of test performance, as well as performance on an exam-like knowledge test covering both joints. For both videos, the participants who had watched the particular video during rehearsal were more accurate in answering the corresponding questions than the participants who had seen the other video, signaling that instructional videos provide a useful tool for rehearsal (i.e., both groups reciprocally served as control groups). For the knee video (less difficult), we observed a detrimental effect of the background music, whereas we observed no such effect for the shoulder video (more difficult). Further explorations revealed that background music might be detrimental for learning, as it reduces the perceived demand characteristics. Because the impact of the demand characteristics might be more pronounced in less difficult instructional videos, we discuss video difficulty as a potential moderating factor. Overall, our study provides evidence that instructional videos could be usefully implemented in formal teaching curricula and that such instructional videos probably should be designed without background music.

Semiautomated Renal Cortex Volumetry in Spectral Computed Tomography: Effect of Monoenergetic Reconstructions on Measurement Precision and Interobserver Variability.

OBJECTIVE: The aim of this study was to determine the influence of virtual monoenergetic images (vMEIs) on renal cortex volumetry (RCV) and estimation of split-renal function. METHODS: Twenty-five patients (mean ± SD, 64.7 ± 9.9 years) underwent a contrast-enhanced dual-layer spectral detector computed tomography. Images were reconstructed with a reference standard (iterative model reconstruction, IMRRef), a newly spectral detector computed tomography algorithm (SPcon) and vMEI at 40, 60, 80, 100, and 120 keV. Two blinded independent readers performed RCV on all data sets with a semiautomated tool. RESULTS: Total kidney volume was up to 15% higher in vMEI at 40/60 keV compared with IMRRef (P < 0.001). Total kidney volume with vMEI at 80/100 keV was similar to IMRRef (P < 0.001). Split-renal function was similar in all reconstructions at approximately 50% ± 3%. Bland-Altman analysis showed no significant differences (P > 0.05), except for 40 keV versus SPcon (P < 0.05). The time required to perform RCV was reasonable, approximately 4 minutes, and showed no significant differences among reconstructions. Interreader agreement was greatest with vMEI at 80 keV (r = 0.68; 95% confidence interval, 0.39-0.85; P < 0.0002) followed by IMRRef images (r = 0.67; 95% confidence interval, 0.37-0.84; P < 0.0003). IMRRef showed the highest mean Hounsfield unit for cortex/medulla of 223.4 ± 73.7/62.5 ± 19.7 and a ratio of 3.7. CONCLUSIONS: Semiautomated RCV performed with vMEI and IMRRef/SPcon is feasible and showed no clinically relevant differences with regard to split-renal function. Low-kiloelectron volt vMEI showed greater tissue contrast and total kidney volume but no benefit for RCV. Moderate-kiloelectron volt vMEI (80 keV) results were similar to IMRRef with a faster postprocessing time.

Semiautomated Renal Cortex Volumetry in Multislice Computed Tomography: Effect of Slice Thickness and Iterative Reconstruction Algorithms.

OBJECTIVE: The aim of the study was to evaluate the effect of slice thickness, iterative reconstruction (IR) algorithm, and kernel selection on measurement accuracy and interobserver variability for semiautomated renal cortex volumetry (RCV) with multislice computed tomography (CT). METHODS: Ten patients (62.4 ± 17.2 years) undergoing abdominal biphasic multislice computed tomography were enrolled in this retrospective study. Computed tomography data sets were reconstructed at 1-, 2-, and 5-mm slice thickness with 2 different IR algorithms (iDose, IMRST) and 2 different kernels (IMRS and IMRR) (Philips, the Netherlands). Two readers independently performed semiautomated RCV for each reconstructed data set to calculate left kidney volume (LKV) and split renal function (SRF). Statistics were calculated using analysis of variance with Geisser-Greenhouse correction, followed by Tukey multiple comparisons post hoc test. Statistical significance was defined as P ≤ 0.05. RESULTS: Semiautomated RCV of 120 data sets (240 kidneys) was successfully performed by both readers. Semiautomated RCV provides comparable results for LKV and SRF with 3 different slice thicknesses, 2 different IR algorithms, and 2 different kernels. Only the 1-mm slice thickness showed significant differences for LKV between IMRR and IMRS (P = 0.02, mean difference = 4.28 bb) and IMRST versus IMRS (P = 0.02, mean difference = 4.68 cm) for reader 2. Interobserver variability was low between both readers irrespective of slice thickness and reconstruction algorithm (0.82 ≥ P ≥ 0.99). CONCLUSIONS: Semiautomated RCV measurements of LKV and SRF are independent of slice thickness, IR algorithm, and kernel selection. These findings suggest that comparisons between studies using different slice thicknesses and reconstruction algorithms for RCV are valid.

Cross-codal integration of bridging-event information in narrative understanding.

Visual narratives communicate event sequences by using different code systems such as pictures and texts. Thus, comprehenders must integrate information from different codalities. This study addressed such cross-codal integration processes by investigating how the codality of bridging-event information (i.e., pictures, text) affects the understanding of visual narrative events. In Experiment 1, bridging-event information was either present (as picture or text) or absent (i.e., not shown). The viewing times for the subsequent picture depicting the end state of the action were comparable within the absent and the text conditions. Further, the viewing times for the end-state picture were significantly longer in the text condition as compared to the pictorial condition. In Experiment 2, we tested whether replacing bridging-event information with a blank panel increases viewing times in a way similar to the text condition. Bridging event information was either present (as picture) or absent (not shown vs. blank panel). The results replicated Experiment 1. Additionally, the viewing times for the end-state pictures were longest in the blank condition. In Experiment 3, we investigated the costs related to integrating information from different codalities by directly comparing the text and picture conditions with the blank condition. The results showed that the distortion caused by the blank panel is larger than the distortion caused by cross-codal integration processes. Summarizing, we conclude that cross-codal information processing during narrative comprehension is possible but associated with additional mental effort. We discuss the results with regard to theories of narrative understanding.

Construction or updating? Event model processes during visual narrative comprehension.

The plot of a narrative is represented in the form of event models in working memory. Because only parts of the plot are actually presented and information is continually changing, comprehenders have to infer a good portion of a narrative and keep their mental representation updated. Research has identified two related processes (e.g., Gernsbacher, 1997): During model construction (shifting, laying a foundation) at large coherence breaks an event model is completely built anew. During model updating (mapping) at smaller omissions, however, the current event model is preserved, and only changed parts are updated through inference processes. Thus far, reliably distinguishing those two processes in visual narratives like comics was difficult. We report a study (N = 80) that aimed to map the differences between constructing and updating event models in visual narratives by combining measures from narrative comprehension and event cognition research and manipulating event structure. Participants watched short visual narratives designed to (not) contain event boundaries at larger coherence breaks and elicit inferences through small omissions, while we collected viewing time measures as well as event segmentation and comprehensibility data. Viewing time, segmentation, and comprehensibility data were in line with the assumption of two distinct comprehension processes. We thus found converging evidence across multiple measures for distinct model construction and updating processes in visual narratives.

Do a pedagogical agent's clothing and an animated video's setting affect learning?

Pedagogical agents are often used to enhance social cues in learning materials. The inclusion of pedagogical agents raises several design questions, for example on what kind of clothing the agent should wear. Further, it is not yet clear how the setting of an animated learning video (i.e., the digitally created background) affects learning. In an online experiment (N = 200), we investigated whether creating thematically appropriate clothing and setting has some added value in that it improves learning outcomes in comparison to more neutral assets. Whereas all participants acquired knowledge from the animated video, there were no main effects of clothing and setting for any of the dependent variables, but an interaction for learning outcomes (ηp2=0.02), indicating that the appropriately dressed agent worked better combined with the inappropriate setting than with the appropriate setting. Overall, given those non-significant main effects and the small effect size of the interaction, there seem to be some degrees of freedom for designers of pedagogical agents in animated learning videos. However, these degrees of freedom may be limited to at least moderate (i.e., neutral) levels of appropriateness.

Digital images are hard to resist: Teaching viewers about the effects of camera angle does not reduce the camera angle's impact on power judgments.

Digital images on the internet are often designed to manipulate viewers' interpretations. Therefore, it is important to educate viewers regarding potential effects of such techniques. We investigated whether two interventions addressing potential effects of camera angle affect the technique's effect on participants' power-related judgments of depicted persons. In two experiments, participants were assigned to one of two conditions with introductory information that either included information about the effect of camera angle or did not include such information. In Experiment 2, we additionally varied whether participants engaged in a task practicing the detection of camera angles or not. None of the interventions affected how participants rated digital pictures of persons that were shot from different camera angles. However, both experiments demonstrated that the interventions were successful in making viewers aware of the potential effects of camera angles - as evident in the participants' responses to open-ended questions. Potential reasons for the lack of effects on the participants' power-related judgments of the depicted persons are discussed.

Buffering - Please Be Patient! Does the Attribution of Pauses to Technical Issues Hamper Learning?

In educational contexts, system-determined pauses are often used to interrupt the transient flow of information and thus avoid cognitive overload in dynamic learning materials. However, next to these didactically motivated interruptions, video-based learning materials may also be interrupted due to technical issues with regard to constrained bandwidth or outdated technology. Against this background, the current experiment investigated whether the interruption of dynamic representations due to technical issues negatively affects learning. For this purpose, 64 participants watched an Arabic language tutorial. They were either informed that the video included breaks in order to support learning or that there may be breaks due to technical issues. Contrary to our pre-registered hypotheses, the attribution of the pauses to technical issues did not hamper learning and did not affect participants' ratings regarding the usefulness and the disturbance caused by the pauses. However, exploratory analyses revealed a negative correlation between the perceived usefulness and the disturbance caused by the pauses. Limitations and implications of these findings are discussed.

Actual and Perceived Knowledge About COVID-19: The Role of Information Behavior in Media.

The COVID-19 pandemic poses a health threat that has dominated media coverage. However, not much is known about individual media use to acquire knowledge about COVID-19. To address this open research question, this study investigated how the perceived threat is linked to media use and how media use is associated with perceived and actual knowledge about COVID-19. In a German online survey conducted between April 16 and April 27, 2020, N = 952 participants provided information on their perceived threat and media use to inform themselves about COVID-19. In this process, they indicated how well they were informed about COVID-19 (perceived knowledge) and subsequently completed a COVID-19 knowledge test (actual knowledge). Results indicated that individuals who felt more threatened by COVID-19 used media more often to inform themselves (b = 0.20, p < 0.001) but focused on fewer different media channels (b = 0.01, p < 0.001). Further, frequent media use was associated with higher perceived knowledge (b = 0.47, p < 0.001), but not with higher actual knowledge about COVID-19 (b = -0.01, p = 0.938), reflecting an illusion of knowledge. Additionally, using fewer media channels was linked to higher perceived (b = 2.21, p < 0.001) and actual knowledge (b = 2.08, p = 0.008). Finally, explorative analyses on the use of different media channels revealed that an illusion of knowledge emerged for using social media, public television, and newspapers. Potential explanations for the findings and implications for future research are discussed.

Phantomless assessment of volumetric bone mineral density using virtual non-contrast images from spectral detector computed tomography.

OBJECTIVE: To evaluate phantomless assessment of volumetric bone mineral density (vBMD) based on virtual non-contrast images of arterial (VNCa) and venous phase (VNCv) derived from spectral detector CT in comparison to true non-contrast (TNC) images and adjusted venous phase conventional images (CIV(adjusted)). METHODS: 104 consecutive patients who underwent triphasic spectral detector CT between January 2018 and April 2019 were retrospectively included. TNC, VNCa, VNCv and venous phase images (CIV) were reconstructed. vBMD was obtained by two radiologists using an FDA/CE-cleared software. Average vBMD of the first three lumbar vertebrae was determined in each reconstruction; vBMD of CIV was adjusted for contrast enhancement as suggested earlier. RESULTS: vBMD values obtained from CIV(adjusted) are comparable to vBMD values derived from TNC images (91.79 ± 36.52 vs 90.16 ± 41.71 mg/cm3, p = 1.00); however, vBMD values derived from VNCa and VNCv (42.20 ± 22.50 and 41.98 ± 23.3 mg/cm3 respectively) were significantly lower as compared to vBMD values from TNC and CIV(adjusted) (all p ≤ 0.01). CONCLUSION: Spectral detector CT-derived virtual non-contrast images systematically underestimate vBMD and therefore should not be used without appropriate adjustments. Adjusted venous phase images provide reliable results and may be utilized for an opportunistic BMD screening in CT examinations. ADVANCES IN KNOWLEDGE: Adjustments of venous phase images facilitate opportunistic assessment of vBMD, while spectral detector CT-derived VNC images systematically underestimate vBMD.

Size and volume of kidney stones in computed tomography: Influence of acquisition techniques and image reconstruction parameters.

PURPOSE: Computed tomography (CT) is routinely used to assess suspected urolithiasis. Information obtained from CT include presence, location and size of stones, with the latter frequently determining treatment strategy. While there is consensus regarding measurements procedures of kidney stones, influence of radiation dose and reconstruction techniques on stone measurements are unknown. The purpose of this study was to systematically evaluate the influence of these technical determinants on kidney stone size measurements. METHOD: 47 kidney stones of different composition were scanned using a 64-row-multi-detector CT in a 3D-printed, semi-anthropomorphic phantom. Reference stone sizes were measured manually with a digital caliper (Man-M). Stones were imaged with 2 and 10 mGy CTDI. Images were reconstructed using filtered-back-projection, hybrid-iterative and model-based-iterative reconstruction algorithms (FBP, HIR, MBIR) in combination with different kernels and denoising levels. All stones underwent semi-automatic, threshold-based segmentation for computation of maximum diameter and volume. Statistics were conducted using ANOVA ±â€¯correction for multiple comparisons. RESULTS: Overall stone size as compared to manual measurements was overestimated in CT (10.0 ±â€¯3.1 vs. 8.8 ±â€¯2.9 mm, p < 0.05) yet showing a good correlation (R2 = 0.66). Radiation dose and denoising levels did not significantly influence measurements (p > 0.05). MBIR and sharp kernels showed closest agreement with Man-M (9.3 ±â€¯3.1 vs. 8.8 ±â€¯2.9 mm, p < 0.05). Differences within single stones were as high as 40 % (e.g. Man-M: 5.9 mm, CT: 7.3-12.0 mm). CONCLUSIONS: CT-based measurements of kidney stone size appear unaffected by radiation dose and denoising technique, whereas reconstruction algorithms and kernels demonstrate a relevant impact on size measurements. Smallest differences were found using MBIR with a sharp kernel.

Can computed tomography volumetry of the renal cortex replace MAG3-scintigraphy in all patients for determining split renal function?

OBJECTIVES: The current gold standard for determination of split renal function (SRF) is Tc-99m-mercapto-acetyltriglycin (MAG3) scintigraphy. Initial studies comparing MAG3-scintigraphy and CT-based renal cortex volumetry (RCV) for calculation of SRF have shown similar results in highly selected patient collectives with normal renal function (i.e. living kidney donors). This study aims to compare MAG3-scintigraphy and CT-RCV within a large unselected patient collective including patients with impaired renal function. MATERIALS AND METHODS: For this assessment, 279 datasets (131 men, 148 women; mean age: 54.2 ±â€¯12.9 years, range: 24-84 years) of patients who underwent MAG3-scintigraphy and contrast-enhanced abdominal CT within two weeks were retrospectively analyzed. Two independent readers assessed the CT-RCV in all CT datasets using a semi-automated volumetry tool. The MAG3-scintigraphy and CT-RCV methods were compared, stratified for the eGFR. Statistical analysis included descriptive statistics as well as inter- observer agreement. RESULTS: The absolute mean difference between the percentage contribution of the left and the right kidneys in total MAG3-clearance was 8.6%. Independent of eGFR, an overall sufficient agreement between both methods was established in all patients. A relatively small, tolerable systemic error resulted in an underestimation (max. 2%) of the left renal contribution to overall RCV. CONCLUSION: The results demonstrate that CT-RCV is a potential clinical replacement for MAG3-scintigraphy for calculation of SRF: CT-RCV demonstrates clinically tolerable differences with MAG3-scintigraphy, independent of patient eGFR. The relative complexity of the RCV method utilized is a potential limitation and may have contributed to the acceptable but only fair to moderate level of intra-reader reliability.