Design issues for socially intelligent user interfaces. A discourse analysis of a data-to-text system for summarizing clinical data.

OBJECTIVES: This study aims to demonstrate the usability of discourse analyses as a means of evaluating medical informatics systems by examining one particular computer-based data-to-text system for delivering neonatal health care information. METHODS: Six textual summaries of clinical information, three produced by human clinicians and three by the data-to-text system, were subjected to fine-grain discourse analysis. Analysis was performed 'blind' on all six textual summaries. Analysis focused on the identification of lexical items and on the potential effects of these items on users of these clinical information summaries. RESULTS: Results showed that there were clear differences between human- and system-generated clinical summaries, with human clinicians providing better narrative flow and textual detail. The data-to-text system successfully produced textual summaries although it fell short of human abilities. CONCLUSIONS: These results indicate potential future improvements to the system. Discourse analysis as used here may offer significant advantages in evaluating and developing similar medical informatics systems.

The Tbilisi paper and pencil dual-task.

One function of the central executive component of the working memory model is the coordination of two simultaneous tasks (the dual-task method). The concept of a coordination function has proved effective in identifying brain damaged patients with severe behavioural problems and in discriminating the performance of patients with mild Alzheimer's disease from that of healthy elderly. A computerised version of the dual-task method was successfully used in previous laboratory studies but it is not suited to use in a practical, clinical setting. Thus a paper and pencil version of the dual-task method was devised. The present study was aimed at refining the paper and pencil dual-task method; investigating whether or not age per se affects performance; assessing its test-retest reliability and providing norms for the Georgian population. The new paper and pencil version of the dual-task was administered to 64 young and 64 middle-age and elderly participants. A new, modified, simpler version of the paper and pencil dual-task, the "Tbilisi paper and pencil motor task" was developed. This task has high test-retest reliability and correlates with the established computerised version of the task. No age or education effects were detected.

Neuropsychological evidence for separating components of visuo-spatial working memory.

There is increasing evidence to support the idea that visuo-spatial working memory can be segregated into separate cognitive subsystems. However, the nature of these systems remains unclear. In this paper we report data from two brain injured patients suggesting that information about visual appearance is retained in a different subsystem from information about spatial location, and that this differential processing can be observed when the style of presentation (sequential or simultaneous) is controlled.

Dissociating mental transformations and visuo-spatial storage in working memory: evidence from representational neglect.

A study is reported of visuo-spatial working memory in two individuals suffering from a cognitive deficit known as unilateral spatial neglect, and seven healthy control participants. Both patients have difficulties reporting details on the left side of imaged representations, and one has an additional difficulty with perceptual input to the left of his body midline. All participants were asked to report the location and identity of objects presented in novel 2 x 2 arrays that were either present throughout or were described orally by the experimenter, with no visual input. On half of the trials, the report was to be made from the opposite perspective, requiring 180 degree mental rotation of the mentally represented array. The patients show an impaired ability to report details from the presented or the imagined left, but had no difficulty with mental rotation. Results point to a clear separation between the processes of perception and those of visuo-spatial working memory. Results also suggest that the patients might be suffering from damage to the system used for holding visuo-spatial representations rather than a difficulty with attending to elements of that representation.

Dual task effects of walking when talking in Alzheimer's disease.

Previous studies with Alzheimer Disease (AD) patients have suggested that speed and accuracy in walking can be dramatically affected by a simultaneous secondary cognitive task, such as holding a conversation. Two experiments examined the impact on AD patients and age matched elderly controls of cognitive demands while walking. In Experiment 1 walking for AD patients was more affected than it was for the normal elderly by a concurrent cognitive demand. Experiment 2 demonstrated that both groups were equally impaired under dual task conditions when the demands of the cognitive tasks were adjusted for individual levels of ability. We conclude that walking may draw on general executive resources, that walking relies more heavily on these executive resources in the elderly, and on a damaged executive system for AD patients.

Processing and storage in working memory span.

Two experiments are reported that address theoretical assumptions as to the nature of working memory involved in working memory span tasks (Daneman & Carpenter, 1980). Experiment 1 used a version of the sentence span task, and Experiment 2 combined arithmetic verification with recall of presented words. In each experiment, working memory processing span was assessed independently of temporary storage span prior to their combination. Combined task performance under high demand for each component resulted in substantial residual performance for both task elements, particularly in Experiment 2. The results do not challenge the utility of the sentence span task as a measure of on-line cognition, but they raise concerns as to how resource might be allocated to processing and storage elements of the task within a single flexible resource pool, or between different resources of a multiple component working memory system. Although both models lack predictive power regarding resource allocation in these tasks, the multiple resource model appears to offer the better account.

Prospective and retrospective memory in normal ageing and dementia: a questionnaire study.

Frequency of prospective memory and retrospective memory failures was rated on a 16-item questionnaire by 862 volunteers, from five groups: patients with Alzheimer Disease (rated by carers), carers of Alzheimer Disease patients, elderly, young, and a group of married couples. Reported memory failures were highest for Alzheimer Disease patients, and lowest for carers, with elderly and young controls in between. More prospective memory than retrospective memory failures were reported in all groups, although the difference was small for Alzheimer Disease patients who were rated near ceiling for both. Prospective memory failures of Alzheimer Disease patients were reported as more frustrating for carers than retrospective memory failures; prospective memory and retrospective memory failures frustrated Alzheimer Disease patients equally. Data from the couples indicated that there were no biases resulting from rating on behalf of someone else. These results suggest that: (1) normal ageing has no greater effect on self-reported retrospective memory than prospective memory failures, (2) the relatively small number of memory failures reported by carers may result from comparing themselves with the Alzheimer Disease patients in their care, and (3) prospective memory failures have a greater impact on the lives of the carers and are therefore more likely to be reported as early indicants of the disease.

Visual similarity effects in immediate verbal serial recall.

The role of visual working memory in temporary serial retention of verbal information was examined in four experiments on immediate serial recall of words that varied in visual similarity and letters that varied in the visual consistency between upper and lower case. Experiments 1 and 2 involved words that were either visually similar (e.g. fly, cry, dry; hew, new, few) or were visually distinct (e.g. guy, sigh, lie; who, blue, ewe). Experiments 3 and 4 involved serial recall of both letter and case from sequences of letters chosen such that the upper- and lower-case versions were visually similar, for example Kk, Cc, Zz, Ww, or were visually dissimilar, for example Dd, Hh, Rr, Qq. Hence in the latter set, case information was encoded in terms of both the shape and the size of the letters. With both words and letters, the visually similar items resulted in poorer recall both with and without concurrent articulatory suppression. This visual similarity effect was robust and was replicated across the four experiments. The effect was not restricted to any particular serial position and was particularly salient in the recall of letter case. These data suggest the presence of a visual code for retention of visually presented verbal sequences in addition to a phonological code, and they are consistent with the use of a visual temporary memory, or visual "cache", in verbal serial recall tasks.

Computerisation and decision making in neonatal intensive care: a cognitive engineering investigation.

This paper reports results from a cognitive engineering study that looked at the role of computerised monitoring in neonatal intensive care. A range of methodologies was used: interviews with neonatal staff, ward observations, and experimental techniques. The purpose was to investigate the sources of information used by clinicians when making decisions in the neonatal ICU. It was found that, although it was welcomed by staff, computerised monitoring played a secondary role in the clinicians' decision making (especially for junior and nursing staff) and that staff used the computer less often than indicated by self-reports. Factors that seemed to affect staff use of the computer were the lack (or shortage) of training on the system, the specific clinical conditions involved, and the availability of alternative sources of information. These findings have relevant repercussions for the design of computerised decision support in intensive care and suggest ways in which computerised monitoring can be enhanced, namely: by systematic staff training, by making available online certain types of clinical information, by adapting the user interface, and by developing intelligent algorithms.

Working memory and vigilance: evidence from normal aging and Alzheimer's disease.

Both single unit recording and neuroradiological studies suggest that frontal and executive processes are necessary for visual maintenance rehearsal. This observation is linked to the classic vigilance literature by the proposal that vigilance decrement is found when the subject is required to maintain a representation over a brief delay. Vigilance performance was therefore studied in a sample of elderly subjects who were tested over a 40-min period involving perceptual or memory-based tasks which were matched for initial level of performance. There was a significant interaction between task and delay, with only the memory-based task showing decrement. A second study used the same two tasks to investigate vigilance performance in patients suffering from probable Alzheimer's Disease. Over a 15-min delay period, an equivalent interaction effect occurred, again indicating substantially greater decrement for the memory-based task. The results are interpreted as consistent with a role for the executive processes of working memory in both visual rehearsal and vigilance performance.

Storage and processing in visuo-spatial working memory.

Visuo-spatial working memory has been used to account for performance in a wide range of visuo-spatial tasks, including perceptuo-motor tracking and immediate recall of visually presented patterns. However a developing body of evidence points to a fractionation of the concept into visuo-spatial processing that calls on general purpose executive resources, and a visual 'cache' memory for temporary storage in on-line cognition. Two related experiments are described which address whether processing and temporary memory draw on overlapping or on distinct resources in working memory. Experiment 1 demonstrates that participants can accurately respond to a series of targets appearing in random locations whether or not they have the additional load of retaining and subsequently recalling the appearance of each target. Memory for target appearance likewise is largely unaffected by the additional load of requiring a response to each target. Experiment 2 demonstrates similar findings when verbal labeling of the patterns is inhibited through the use of articulatory suppression. Results are interpreted as consistent with a multiple component working memory system.

The role of memory in the Tower of London task.

The Tower of London (TOL) task is widely used as a neuropsychological test of planning. Relatively little is known of the cognitive components of the task, and in particular the role of memory in performance. The current studies on normal adults looked at the role of verbal and spatial working memory in the TOL. The effects of verbal and visuospatial dual-task manipulations on TOL performance were examined in an experiment with 36 participants. Both verbal and visuospatial executive secondary tasks caused poorer performance on the TOL; however, concurrent articulatory suppression enhanced performance. The results suggest that executive and spatial components are important in the task, and raise questions about the role of preplanning in the TOL.

Dissociation between recency and span: neuropsychological and experimental evidence.

This article reports dissociations between verbal span and the recency portion of the serial position curve in immediate free recall, in 2 neuropsychological case studies and in 3 experiments with normal participants. Patient A. N. presented with an impaired serial verbal span while showing an intact recency effect. The opposite pattern was observed in patient G. C., who despite a poor recency showed normal span in verbal serial recall tasks. Experiments 1 and 2 showed a recency effect with visually and auditory presented lists and written recall was resistant to the effects of articulatory suppression and of irrelevant speech, but was disrupted by the suffix effect. Experiment 3 showed that in contrast with recency, memory span was affected by articulatory suppression and irrelevant speech during presentation but not by a suffix. These findings are not consistent with the idea that span and recency measure aspects of the same memory system. Moreover, in clinical practice, they should not be used as equivalent alternatives.

What the eyes perceive, the brain ignores: a case of pure unilateral representational neglect.

Bisiach and Luzzatti (1978) provided evidence that unilateral spatial neglect is not only a disorder of visual perception, but also can affect mental representations such that patients fail to report the left side of scenes or objects in mental imagery. However in case reports of representational neglect generally it is accompanied by perceptual neglect. We report a rare occurrence of a patient (NL) who presents a persistent unilateral neglect which appears to be limited to visual imagery. The deficit appeared in tasks which require the formation and manipulation of new visuo-spatial representations as well as those which require access to information about familiar scenes. The patient, who had a lesion in the right parietal lobe, showed no evidence of perceptual or personal neglect, although there was some evidence of visual extinction. We argue that the concept of visuo-spatial working memory can provide a framework within which to interpret aspects of the representational form of neglect, whether or not it is accompanied by perceptual neglect.

Group aggregates and individual reliability: the case of verbal short-term memory.

Two experiments examined the generalizability of the effects of word length and phonological similarity with visual and auditory presentation in immediate verbal serial ordered recall. In Experiment 1, data were collected from 251 adult volunteers drawn from a broad cross-section of the normal population. Word length and phonological similarity in both presentation modes significantly influenced the group means. However, 43% of the subjects failed to show at least one of the effects, and the likelihood that effects appeared was highly correlated with verbal memory span. In Experiment 2, 40 subjects of the original sample were retested, 20 of whom had failed to show one or more effects in Experiment 1. Whether or not an effect had appeared for individual subjects on the first test session was a poor predictor of whether the effect would appear on retest. Finally, an analysis of subject reports demonstrated that the patterns of experimental data could be accounted for in part by the strategies that subjects reported using, and the effect of strategy was independent of the effect of span. The implications of these findings for theories of verbal short-term memory are discussed.

The bailiwick of visuo-spatial working memory: evidence from unilateral spatial neglect.

An accurate representation of the visual environment is crucial for successful interaction with objects in that environment. The means by which that representation is formed in working memory is a major focus of the issues and research discussed in this paper. The discussion draws on experimental studies of healthy adults and of patients with impairments of visual perceptual processing or of visuo-spatial mental representation. These disorders are most commonly linked with the disorder referred to clinically as unilateral spatial neglect. We discuss the observed dissociation between perceptual neglect and representational neglect, and the phenomenon of implicit processing of information in the neglected hemifield. In so doing we explore the implications of the findings from this literature for the development of theories of visuo-spatial working memory.

Aberdeen polygons: computer displays of physiological profiles for intensive care.

The clinician in an intensive therapy unit is presented regularly with a range of information about the current physiological state of the patients under care. This information typically comes from a variety of sources and in a variety of formats. A more integrated form of display incorporating several physiological parameters may be helpful therefore. Three experiments are reported that explored the potential use of analogue, polygon diagrams to display physiological data from patients undergoing intensive therapy. Experiment 1 demonstrated that information can be extracted readily from such diagrams comprising 8- or 10-sided polygons, but with an advantage for simpler polygons and for information displayed at the top of the diagram. Experiment 2 showed that colour coding removed these biases for simpler polygons and the top of the diagram, together with speeding the processing time. Experiment 3 used polygons displaying patterns of physiological data that were consistent with typical conditions observed in the intensive care unit. It was found that physicians can readily learn to recognize these patterns and to diagnose both the nature and severity of the patient's physiological state. These polygon diagrams appear to have some considerable potential for use in providing on-line summary information of a patient's physiological state.

Visuospatial working memory, movement control and executive demands.

Developments in the concept of a specialist visuospatial resource in working memory owe much to a pair of tasks originally developed by Brooks (1967), involving respectively the generation and retention of a mental image of a matrix pattern and the retention of a verbal sequence. Previous literature has demonstrated that the matrix task calls on cognitive resources which are involved in both the processing of visual input and the generation of movement sequences. Using dual task methodology, the study reported here demonstrates that the matrix and verbal versions of the task do indeed rely on separate, specialized cognitive resources, one of which is also involved in generation of action. However, when the secondary task (random generation of numbers) was very demanding of general purpose cognitive resources both the matrix and verbal tasks were performed poorly, suggesting that each of these tasks draw heavily on a common, general purpose resource as well as on their respective specialist resources. It is argued that random generation offers a means to assess general purpose cognitive resources and that the cognitive processes involved in the Brooks tasks may be more complex than has been previously assumed.