Alastair G. Gale

Labeling of Medicines and Patient Safety: Evaluating Methods of Reducing Drug Name Confusion:

Objective: We report three experiments evaluating the proposal that highlighting sections of drug names using uppercase (“tall man”) lettering and/or color may reduce the confusability of similar drug names. Background: Medication errors commonly involve drug names that look or sound alike. One potential method of reducing these errors is to highlight sections of names on labels in order to emphasize the differences between similar products. Method: In Experiments 1 and 2, participants were timed as they decided whether similar name pairs were the same name or two different names. Experiment 3 was a recognition memory task. Results: Results from Experiments 1 and 2 showed that highlighting sections of words using tall man lettering can make similar names easier to distinguish if participants are aware that this is the purpose of the intervention. Results from Experiment 3 suggested that tall man lettering and/or color does not make names less confusable in memory but that tall man letters may increase attention. Conclusion: These findings offer some support for the use of tall man letters in order to reduce errors caused by confusion between drug products with look-alike names. Application: The use of tall man letters could be applied in a variety of visual presentations of drug names - for example, by manufacturers on packaging, labeling, and computer software, and in pharmacies on shelf labels. Additionally, this paper demonstrates two meaningful behavioral measures that can be used during product design to objectively assess confusability of packaging and labeling.

Inspection times and the selection task: What do eye-movements reveal about relevance effects?

Abstract Three experiments are reported that used eye-movement tracking to investigate the inspection-time effect predicted by Evans’ (1996) heuristic-analytic account of the Wason selection task. Evans’ account proposes that card selections are based on the operation of relevance-determining heuristics, whilst analytic processing only rationalizes selections. As such, longer inspection times should be associated with selected cards (which are subjected to rationalization) than with rejected cards. Evidence for this effect has been provided by Evans (1996) using computer- presented selection tasks and instructions for participants to indicate (with a mouse pointer) cards under consideration. Roberts (1998b) has argued that mouse pointing gives rise to artefactual support for Evans’ predictions because of biases associated with the task format and the use of mouse pointing. We eradicated all sources of artefact by combining careful task constructions with eye-movement tracking to measure directly on-line attentional processing. All three experiments produced good evidence for the robustness of the inspection-time effect, supporting the predictions of the heuristic-analytic account.

Human Response to Visual Stimuli

The human response to a visual stimulus depends upon many factors, not the least of which is the particular task set the observer. At the simplest level we may be interested in the detection (is it present?) or identification (what is it?) of a stimulus which may be just a small spot of light. Alternatively we may be interested in a more complex problem such as the detection of a target in a large visual field containing many possible targets. An example of the latter is the detection of a particular type of military vehicle from satellite imagery.

Eye movements of large populations: I. Implementation and performance of an autonomous public eye tracker.

This paper details the design and construction of an autonomous public eye tracker exhibit, which was installed at the National Gallery, London, in 2000/2001. For over 3 months, it functioned both as an informative exhibit and as a controlled eye movement experiment, gathering data from over 5,000 participants. The issues associated with automatic unattended recording of the eye movements of members of the public are discussed. The performance of the exhibit is examined, and its successes and problem areas are highlighted with regard to potential applications and future exhibits. The success of the project proves the viability of autonomous public eye trackers as both data-gatherers and public exhibits.

Computer aids to mammographic diagnosis

The improvement of mammographic specificity was investigated by means of identifying specific radiological features. Data are presented on the first 500 patients studied who had previously undergone mammography followed by biopsy. The presence of specific mammographic features on each radiograph, first determined by retrospective examination, was entered into a computer database. Subsequent discriminant function analysis demonstrated the importance of a small number of features whose presence could be used in an algorithm to predict diagnostic outcome. Using this algorithm, this feature-identification approach correctly identified 87.6% of benign and 79% of malignant cases. Specificity was improved to 88% as compared with the original radiological diagnosis of 49%. It is argued that this approach is very promising and a computer-assisted diagnosis based on these findings is described.

Tracking Eye Gaze during Interpretation of Endoluminal Three-dimensional CT Colonography: Visual Perception of Experienced and Inexperienced Readers

PURPOSE To identify and compare key stages of the visual process in experienced and inexperienced readers and to examine how these processes are used to search a moving three-dimensional ( 3D three-dimensional ) image and their relationship to false-negative errors. MATERIALS AND METHODS Institutional review board research ethics approval was granted to use anonymized computed tomographic (CT) colonographic data from previous studies and to obtain eye-tracking data from volunteers. Sixty-five radiologists (27 experienced, 38 inexperienced) interpreted 23 endoluminal 3D three-dimensional CT colonographic videos. Eye movements were recorded by using eye tracking with a desk-mounted tracker. Readers indicated when they saw a polyp by clicking a computer mouse. Polyp location and boundary on each video frame were quantified and gaze data were related to the polyp boundary for each individual reader and case. Predefined metrics were quantified and used to describe and compare visual search patterns between experienced and inexperienced readers by using multilevel modeling. RESULTS Time to first pursuit was significantly shorter in experienced readers (hazard ratio, 1.22 [95% confidence interval: 1.04, 1.44]; P = .017) but other metrics were not significantly different. Regardless of expertise, metrics such as assessment, identification period, and pursuit times were extended in videos where polyps were visible on screen for longer periods of time. In 97% (760 of 787) of observations, readers correctly pursued polyps. CONCLUSION Experienced readers had shorter time to first eye pursuit, but many other characteristics of eye tracking were similar between experienced and inexperienced readers. Readers pursued polyps in 97% of observations, which indicated that errors during interpretation of 3D three-dimensional CT colonography in this study occurred in either the discovery or the recognition phase, but rarely in the scanning phase of radiologic image inspection.

Single stroke gaze gestures

This paper introduces and explains the concept of single stroke gaze gestures. Some preliminary results are presented which indicate the potential efficiency of this interaction method and we show how the method could be implemented for the benefit of disabled users and generally how it could be integrated with gaze dwell to create a new dimension in gaze controlled interfaces.

Method for Tracking Eye Gaze during Interpretation of Endoluminal 3D CT Colonography: Technical Description and Proposed Metrics for Analysis

PURPOSE To develop an eye-tracking method applicable to three-dimensional (3D) images, where the abnormality is both moving and changing in size. MATERIALS AND METHODS Research ethics committee approval was granted to record eye-tracking data from six inexperienced readers who inspected eight short (<30 seconds) endoluminal fly-through videos extracted from computed tomographic (CT) colonography examinations. Cases included true-positive and false-positive polyp detections from a previous study (polyp diameters, 5-25 mm). Eye tracking was performed with a desk-mounted tracker, and readers indicated when they saw a polyp with a mouse click. The polyp location on each video frame was quantified subsequently by using a circular mask. Gaze data related to each video frame were calculated relative to the visible polyp boundary and used to identify eye movements that pursue a polyp target as it changes size and position during fly-through. Gaze data were then related to positive polyp detections by readers. RESULTS Tracking eye gaze on moving 3D images was technically feasible. Gaze was successfully classified by using pursuit analysis, and pursuit-based gaze metrics were able to help discriminate different reader search behaviors and methods of allocating visual attention during polyp identification. Of a total of 16 perceptual errors, 15 were recognition errors. There was only one visual search error. The largest polyp (25 mm) was seen but not recognized by five of six readers. CONCLUSION Tracking a readers gaze during endoluminal interpretation of 3D data sets is technically feasible and can be described with pursuit-based metrics. Perceptual errors can be classified into visual search errors and recognition errors. Recognition errors are more frequent in inexperienced readers.

Breast cancer screening: comparison of radiologists' performance in a self-assessment scheme and in actual breast screening

The PERFORMS self-assessment scheme is used by the UK Breast Screening Programme as an educational tool. From this scheme a radiologist can gain insight into their own sensitivity, specificity, feature and cancer detection performance. Such data may, however, be questionable if they are not well related to the radiologists performance in actual breast screening. Consequently, data from the scheme were compared with those from actual breast screening performance. Some correlations were found in performance, this indicates that continued use of the scheme is important to identify any areas of individual difficulty.

The influence of ‘Tall Man’ lettering on errors of visual perception in the recognition of written drug names

Visual errors in the perception of written drug names can reflect orthographic similarity amongst certain names. Drug names are typically printed in lowercase text. ‘Tall Man’ lettering, the capitalisation of the portions that differ amongst orthographically similar drug names, is employed in the field of medication labelling and prescribing to reduce medication errors by highlighting the area most likely to prevent confusion. The influence of textual format on visual drug name perception was tested amongst healthcare professionals (n = 133) using the Reicher-Wheeler task. Relative to lowercase text, Tall Man lettering improved accuracy in drug name perception. However, an equivalent improvement in accuracy was obtained using entirely uppercase text. Thus, character size may be a key determinant of perceptual accuracy for Tall Man lettering. Specific considerations for the manner in which Tall Man lettering might be best formatted and implemented in practice to reduce medication errors are discussed. Statement of Relevance:Tall Man lettering aims to prevent medication errors by reducing visual confusions amongst orthographically similar drug names. It was found that, compared to lowercase text, Tall Man lettering improved accuracy in drug name perception. Character size appeared to be a key determinant of perceptual accuracy for Tall Man lettering.