This study, conducted on a sample of 403 adult subjects, set out to explore the relationships between measures of digit span (forward and reversed), motor and spatial span, and their dependence on a broad range of measures of cognitive function. The results revealed that measures of digit span are closely related, as are measures of motor and spatial span, but these pairs of memory span measures are relatively independent of each other. Furthermore, reverse digit span, motor span, and spatial span appear to rely on what might be regarded as intellectual or executive cognitive functions. As such, the results provide little support for accounts of serial recall, which suggest that order and/or item information are more adequately modelled in a modality-independent form.

We are developing a statistical decision support system for use in screening mammography, and here we report on the rationale underlying its design, and on some preliminary tests of the system. A single expert radiologist described 200 mammograms, with known outcome, in terms of 38 critical features. We then compared discriminant function analysis (DFA), logistic regression (LR) and a backpropagation neural network (BNN) on their performance in classifying the 200 mammograms as normal or abnormal. All three approaches achieved greater than 90% correct classification, but DFA had low sensitivity and LR had a 9% miss rate, whereas the BNN detected all the cancers. External evaluation of LR and BNN on a new set of 167 mammograms showed that specificity was still high (greater than 96%) but sensitivity was less than 85%. We propose developing a system combining LR and BNN.

The Schwab‐Gilleard Depression Scale is a short self‐report index for assessing depression in elderly people. The aim of this study is to investigate the psychometric properties of this device with particular reference to its reliability, criterion validity and ability to discriminate depression from dementia. The total sample comprised 166 elderly people living in Part III residential homes in south‐west London. For 111 of these, the Schwab‐Gilleard Depression Scale (SGDS), the Geriatric Depression Scale (GDS), the Short‐Comprehensive Assessment and Referral Evaluation (CARE), and the Clifton Assessment Procedures for the Elderly (CAPE) were completed. The GDS and CAPE only were completed with the remaining 55 participants. Psychiatric diagnoses were available from the medical notes on each resident. In addition, a subsample of 49 had been assessed using the SGDS and CARE 14 months previously. These data were available for test‐retest analyses. The self‐rating SGDS was found to be a reliable and valid measure of depression and is recommended for use as a screening tool for depression in elderly people in residential homes.

After a brief formal training period screening mammographers are expected to further improve their skill as a result of learning from experience. However, it has been found that little improvement in screening performance occurs after initial training. One possible reason for this lack of improvement is because mammographers often receive no individual feedback on their performance during routine screening practice. While exposure to stimuli without feedback is sufficient to induce some types of learning, in other cases learning as a result of simple experience may not occur. In this paper we report two studies designed to investigate the importance of feedback for the learning of two visual detection tasks. Experiment one investigated whether the provision of feedback improved observers' ability to detect target features in x rays. Results indicated that in the absence of feedback no improvement in detection accuracy occurred, but that when feedback was provided performance improved. Experiment two examined the effects of feedback on the learning of a probabilistic target detection task using computer generated images. Observers' detection performance improved with practice. This improvement was not contingent upon observers receiving feedback although there was a trend for observers who received trial by trial feedback to exhibit better overall performance.

We report two studies on the design of training schedules for medical-image readers. Experiment 1 required subjects to learn to classify ultrasound images of six different phantoms; one group of subjects trained on images that varied on just two of the four possible dimensions of variation on each day, while the other group trained on images that varied on all four dimensions of variation each day. Performance improved on each day, and learning transferred to novel stimuli shown on successive days. Initially performance was worse for the high-variation group, but by the final session they had reached the same level as the restricted variation group. Within-category similarity increased after training and inter-category similarity decreased. In the second experiment, the stimuli were x-rays of perspex blocks with holes drilled in one of five possible locations. The subject's task was to search for the image- feature produced by the hole (a dark spot). One group of subjects judged 'easy' images for the first four days, and then switched to judgments of 'difficult' holes on the final day, while a second group underwent the reverse order. Although both groups improved, the group that had trained on the easy stimuli showed positive transfer to the more difficult stimuli, but the group that trained on the difficult stimuli showed no transfer to the easy stimuli.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.