Technology and Health Care

It has been suggested that quantitative ultrasound (QUS) could be used as a selective population pre-screen, to maximise the cost effectiveness of referral for dual energy X-ray absorptiometry (DXA) assessment of bone mineral density (BMD). We set out to examine how such an approach might perform in the assessment of women who were referred by general practitioners for DXA via the open access service in Cardiff. In 115 women aged 40–80 (mean 69) years we used DXA to measure BMD at lumbar spine and hip, and QUS to measure broadband ultrasound attenuation (BUA) in the heel. A bottom-up approach was used to estimate the costs of DXA and QUS. We examined the cost effectiveness of using QUS as a pre-screen, only referring subjects for the more expensive DXA assessment if BUA were less than a pre-determined threshold. The unit costs of pencil-beam DXA and QUS were approximately £44 and £16 respectively. We identified a BUA threshold of 60 dB/MHz as the most cost effective, and calculated a sensitivity of 81% and specificity of 89% in identifying those subjects whom DXA assessment subsequently identified as having osteoporosis. At the BUA threshold of 60 dB/MHz, pre-screening saved £969 at the expense of missing ten women with osteoporosis as diagnosed by DXA. Therefore the cost per additional woman with osteoporosis identified using DXA alone was only £97. QUS assessment does not appear to have a significant cost effective benefit as a pre-screen for DXA in the studied population. A QUS pre-screen would be cost effective only if this investigation could be performed at a substantially lower cost.

Chronic diseases do not only manifest themselves as sets of pathophysiological factors. They bring about an equally important psychosocial impact. Unfortunately, it is difficult to account for this impact in the development of supportive technologies. This study describes and explores a method for elicitation of requirements on technologies supporting self-management including emotional aspects. The method takes advantage of a self-documentary media kit for collection of data from the everyday context of chronic disease. The resulting contextual data can contribute new insights to multi-disciplinary teams in the design of supporting technologies.

It is assumed that bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA) has its limitation in identifying bone strength, and therefore other methods should be developed. Non-invasive strength measurement, which is needed to diagnose and monitor metabolic bone diseases such as osteoporosis, can become an alternative to current methods. In this study, mechanical vibration analysis was compared to BMD measured by DXA in human female tibia. Seven mother (Ms) and daughter (Ds) pairs' (total n = 14) left and right tibiae were evaluated by DXA and mechanical vibration analysis. Mechanical vibration analysis was consistent in the same bone and also in both sides. Correlation between BMD measured by DXA and vibration analysis was found in the Ds and Ms groups; the former being stronger than the latter. Natural frequencies of the Ms group were higher than that of the Ds group, and the response velocity of the Ds group was shorter than that of the Ms group. It is concluded that mechanical vibration analysis is consistent in bones and a correlation between BMD measured by DXA and vibration analysis can be established in young females that may be used in field studies to predict peak bone strength.

Falling related injuries are associated with morbidity and mortality among older persons. An accurate and comparable assessment of postural sway may offer a method for detecting those at risk for falling. Our purpose was to assess the validity and repeatability of an inclinometric method in assessing postural sway during quiet standing. To assess repeatability, 51 elderly women (aged 72 to 74 years) were measured twice by the same tester. To assess validity, postural sway in 29 elderly subjects (aged 69 to 86 years) was assessed using simultaneously the inclinometric and a force platform method. The test-retest reliability correlation of the inclinometric method was high for sway path length (coefficient of determination r² = 0.683), and moderate for sway area (r² = 0.500) and the analysis revealed no sign of bias. The correlation was moderate between the values of the inclinometric sway path length and those of the force platform for antero-posterior (r² = 0.466), lateral (r² = 0.694) and combined lateral and antero-posterior (r² = 0.623) directional sway movements. The inclinometric method offers an accurate and repeatable method for assessing postural sway and may be a feasible method to be used in the risk stratification of falling.

The aim of this study is to determine more accurate prediction method between linear and non-linear methods for prediction of babies’ birth weight among maternal demographic characteristics. Three hundred pregnant women were included in the study. Blood glucose level before and after ingestion of glucose load, age, body mass index, % of change in weight during pregnancy, height, gestational age, parity, fetal sex, were collected as independent variables and baby birth weight as dependent variable. In linear regression, least squares estimation method was used to estimate parameters. Non-linear regression method was performed using neural network model with multilayer perceptrons, back propagation method was preferred as learning algorithm.

Coefficient of determination, R², of the linear regression equation was found 59.8% and the standard error of the estimate was calculated as 325.69 gr. In non-linear regression method R² value was also found 59.8% and standard error of estimate was calculated as 320.30 gr. According to the results of the present study, one method is not significantly better than the other. When ‘accuracy in prediction’ is aimed, it is better to use the two methods and compare the results, and then decide on the selection of the favourable method.