Cindy H. Lio

Measuring Surgeons’ Mental Workload With a Time-Based Secondary Task

The use of secondary task performance to assess mental workload in a primary task is appealing because the method clearly reflects a central goal of workload assessment – to determine what other functions an operator can undertake while satisfactorily performing the ongoing (primary) technical challenges of a job. For example, does a surgeon performing a suturing task have the cognitive reserves to maintain situation awareness, deal with unanticipated events, or coordinate the efforts of other team members? Unfortunately, secondary task measures have a reputation for being intrusive, artificial, and difficult to use. In the current article, we describe procedures to minimize these concerns, specifically when using an interval production secondary task. Although our suggestions for implementing interval production are based on experience in surgical training environments, the method is grounded in workload assessment research from a variety of other contexts over the past two decades. The methodology appears to be highly adaptable.

Equivalent-Forms Reliability of Printed and Spoken Versions of the NASA-TLX

Sixty-four participants provided subjective workload assessments after each of 15 trials of selected laparoscopic training tasks, including cannulation, ring transfer, and rope inspection. Half of the participants responded to the NASA-TLX using the traditional printed format with manual (written) responses. The remainder listened to auditory scale cues and made vocal responses. A comparison of the two formats revealed strong (r > .80) correlations and equivalent sensitivity to task and training effects, indicating that the vocal format may be a suitable substitute for traditional administration methods in the evaluation of surgical technology.

Do Operators Take Advantage of A Secondary, Global-Perspective Display when Performing a Simulated Laparoscopic Search Task?

Multi-display surgical environments have the potential to increase performance and efficiency while decreasing errors and workload. However as more and more information is required for complex task execution and decision making, we must continually assess how the information is presented and whether we are helping or hindering surgeons by providing more content. Most laparoscopic surgeries are performed utilizing a single, two-dimensional (2-D) display. In the current experiment, we compared display usage, subjective workload, and workload measured via eye-tracking data to determine the effectiveness of an additional three-dimensional (3-D) display for a simulated surgical search task. We found that while participants did use the additional display in less demanding conditions (e.g., with fewer search targets), they did not use the supplemental display in conditions with greater demands, and they did not receive a substantial benefit from the presence of the supplemental display in either condition. Both increased saccades per target and increased perceived workload via the NASA-TLX provided support that more workload was experienced in conditions with more targets. And while participants did perceive decreased workload for more targets when the 3-D display was available, eye-tracking metrics were not consistent with participants’ subjective workload estimates. Since subjective workload ratings may be influenced by expectancies for benefits for the additional display, future research should attempt to understand this workload dissociation as well as breakdowns in the usage of supplemental displays as a function of task difficulty.

A Mental Workload Study on the 2d and 3d Viewing Conditions of the da Vinci Surgical Robot

Fifteen medical students performed a standard training task using the da Vinci Surgical robots 2d and 3d viewing conditions. Measures of mental workload associated with both viewing conditions were assessed using a secondary interval production task as well as the NASA Task Load Index (NASA-TLX) and the Multiple Resources Questionnaire (MRQ). The Results of the NASA-TLX indicated that the 3d viewing condition results in lower scores of mental workload when compared to the 2d condition. The MRQ data provided diagnostic information regarding which information processing pools were stressed in both the 2d and 3d viewing conditions.

How Knowledgeable are Salespeople About the Usability of Their Merchandise

Salespeople (selling dryers, cell phones, recliners, or jewelry) in 25 stores were asked to recommend products they believed to be easy to use. They were also asked which products or features were most likely to be helpful to customers with specific physical, cognitive, or sensory limitations. There was little consensus across salespeople selling the same product. There were surprising omissions and some examples of incorrect claims. Further, salespeople largely ignored (or were unaware of) design features that enhance sensory and cognitive usability. The majority of claims dealt with product features that purportedly reduce physical strain.

Potential Performance Costs Associated with Large-Format Tiled Displays for Surgical Visualization

Twenty-five participants performed a surgical training task on a large format display created from one projector or by tiling the images from a 4-, or 9-projector array. Utilizing a large-format display consisting of tiled projector images brings the potential benefits of increased display size with the potential threats to performance of inherent visual artifacts. The effect of these artifacts on performance and subjective workload was assessed. Results indicate that while display size did not affect performance on the surgical task, differences in mental workload were observed. Although a global measure of workload indicated that the tiled displays were the least demanding to use, participants reported deploying additional but highly specific cognitive resources when using these same displays. Their resource shifts seemed to involve adjustments to the perceived control gains created by enhanced size and also degraded ability to compare target sizes in the larger display, possibly due to the obscuring effect of tile edges.

Verbal Time Production as a Secondary Task: Which Metrics and Target Intervals are Most Sensitive to Workload for Fine Motor Laparoscopic Training Tasks?:

Although time production is frequently used as a secondary task, research has not thoroughly investigated whether the length of the to-be-produced interval or the metric used to summarize productions affects sensitivity to mental workload. Fourteen participants produced four target intervals (6, 11, 16, or 21 s) while performing a surgical training task that required putting small beads into a cup (easy) or onto a peg (difficult). Intervals were summarized into two metrics of central tendency and four metrics of dispersion previously used in the literature. Results indicate that metrics of central tendency and shorter target intervals are more sensitive to mental workload.

Immersive visualization in K-12 education

In this presentation we review prior research of immersive visualization technology for K-12 educational settings, discuss current research, affordable technology and effective strategies to support K-12 education with immersive displays. Open dialog is encouraged among participants to identify and discuss challenges, solutions, and explore future directions. Costs of immersive visualization displays, invasiveness of devices, interactivity, mobility and re-deploy ability of displays, selecting appropriate content applications, content development, and integration with teachers and curriculum are among topics addressed. Present work at the University of Kentuckys Center for Visualization and Virtual Environments is featured using commodity based collaboratively rendered environments suitable for educational settings and diverse populations.

Interval Production as a Secondary Task Workload Measure: Consideration of Primary Task Demands for Interval Selection

Twenty-eight participants performed a surgical training primary task along with a concurrent time estimation (interval production) secondary task. Fourteen participants were given a primary task that varied in motor demand; the other fourteen performed a primary task that varied in cognitive demand. Time estimation is an attractive option as a workload measure due to its low cost and ease of implementation. Currently it is unclear whether the structure of task demands influences the sensitivity of time estimation tasks that use different intervals. The sensitivity of both a short (3 second) and long (21 second) interval were observed in tasks that differed in level of workload. Results indicated that short intervals were more sensitive to changes in motor workload while long intervals displayed more sensitivity to changes in cognitive demand.

Talk is Cheap: On the Usability Advice Salespeople offer to Older Consumers:

When older consumers approach a salesperson with questions about product usability, what advice are they likely to receive? To find out, we interviewed salespeople selling four types of products – cell phones, dryers, recliners, and jewelry. Our 63 participants were more likely to recommend specific features rather than specific products, and they were more likely to focus on mobility rather than cognitive or sensory issues. However, when directly asked to make suggestions for a person who had sensory or cognitive concerns, the salespeople were generally able to do so. We found no evidence that the type of store, the salespersons gender, or the salespersons age predicted the amount of usability information they could provide. However, we did learn that the people who provided the most suggestions generally reported coming up with their advice through direct interaction with older adults rather than from reading product literature or from personal product use.