Biomedical subjects

A Hasman

Publications and source records attributed to A Hasman.

At least 73 records · Page 4Linked to original sources

PubMed1999

Agreement and correctness in adjusting antiepileptic drug treatment: a need for rational drug treatment?

PURPOSE: To study interobserver variation in treatment decisions in a first follow-up contact after initiation of antiepileptic drug (AED) treatment. The results should aid us in the assessment of whether decision support can be of value in this situation. METHODS: Data from patient records were used to construct 270 different test cases containing information about the course of the disease after initiation of drug treatment. The cases were presented to five neurologists from different general hospitals who previously agreed about the diagnosis and the initial treatment for these cases. They were asked to write a prescription for each test case. RESULTS: All five neurologists agreed on a treatment decision in 21.9% of the 265 cases available for analysis. Each neurologist made a decision different from the decisions taken by all other neurologists in 14.0-19.6% of the cases. Kappa values for agreement among individual neurologists as well as for agreement between an individual and the group of his peers were low. In 82.6% of the cases, a majority of the neurologists agreed on a treatment decision. Comparing the decisions of individual neurologists with the majority decision reference (219 cases) showed a significant difference in correctness (range, 67.1-82.6%) among the neurologists. CONCLUSIONS: The fact that a majority decision could be reached in a considerable number of cases, as well as the variability in adjustment of an initiated drug treatment, leads us to the conclusion that decision support can contribute to a rational adjustment of drug treatment.

Ambulatory Care↗

PubMed1999

Maximum likelihood estimation in calibrating a stereo camera setup.

Motion and deformation of the cardiac wall may be measured by following the positions of implanted radiopaque markers in three dimensions, using two x-ray cameras simultaneously. Regularly, calibration of the position measurement system is obtained by registration of the images of a calibration object, containing 10-20 radiopaque markers at known positions. Unfortunately, an accidental change of the position of a camera after calibration requires complete recalibration. Alternatively, redundant information in the measured image positions of stereo pairs can be used for calibration. Thus, a separate calibration procedure can be avoided. In the current study a model is developed that describes the geometry of the camera setup by five dimensionless parameters. Maximum Likelihood (ML) estimates of these parameters were obtained in an error analysis. It is shown that the ML estimates can be found by application of a nonlinear least squares procedure. Compared to the standard unweighted least squares procedure, the ML method resulted in more accurate estimates without noticeable bias. The accuracy of the ML method was investigated in relation to the object aperture. The reconstruction problem appeared well conditioned as long as the object aperture is larger than 0.1 rad. The angle between the two viewing directions appeared to be the parameter that was most likely to cause major inaccuracies in the reconstruction of the 3-D positions of the markers. Hence, attempts to improve the robustness of the method should primarily focus on reduction of the error in this parameter.

Biomechanical Phenomena↗

PubMed1999

A rational request behavior: the development of prediction instruments regarding thyroid function tests in primary care.

A prospective study was performed to encourage a rational thyroid-stimulating hormone (TSH) test request behavior of physicians, using prediction instruments. The latter give direct feedback about request adequacy on the basis of pretest probabilities of hyperthyroidism using patients' signs and symptoms. For instrument design, stepwise logistic regression was used on diagnostic data acquired through questionnaires, answered by 80 physicians and 668 patients for whom physicians requested a TSH test. Instruments were designed for clinical and subclinical hyperthyroidism and for clinical hyperthyroidism alone. Use of the instrument for clinical or subclinical hyperthyroidism on the selected group, at a 5% probability threshold, can result in a 37% reduction of unnecessary TSH test requests. With the instrument for clinical hyperthyroidism at a 5% probability threshold, the number of unnecessary test requests can be reduced by 57%. Therefore, it can be concluded that the instruments can determine TSH test request adequacy and encourage a rational TSH test request behavior of physicians at low pretest probability thresholds.

Adolescent↗

PubMed1999

Development of a reminder system for general practitioners.

In this contribution we describe a prototype reminder system that has been developed to influence General Practitioners' (GP) test request behaviour. It is intended to substitute conventional written feedback by human experts. The system generates critical comments about the rationality of the test request at the moment the GP requests a test that is not in line with national or regional guidelines.

Artificial Intelligence↗

PubMed1999

An experimental electronic patient record for stroke patients.

This contribution describes an electronic patient record for stroke patients at the neurology ward of the Maastricht University Hospital. Daily practice at the ward will be supported with the developed electronic patient record that integrates both the medical and the nursing record, that will provide decision support and it will be connected to the hospital information system. In an evaluation project we will study the effects of the usage of the electronic patient record and additional effects of providing decision support.

Data Collection↗

PubMed1999

The effect of item observability, clarity and wording on patient/nurse ratings when using the ASA scale.

Many studies show discrepancies between patients' and professionals' ratings on the same questionnaire regarding the patient's health. A relevant question is whether the differences in ratings reflect real differences between patients and professionals or whether they are caused by characteristics of the instrument. In this study, we address the latter option by examining the effects of 3 item characteristics (item wording, observability and clarity) on the degree of patient/nurse discrepancies in ratings of the items of the Appraisal of Self-care Agency (ASA) scale. Secondary analysis on 252 patient/nurse ratings showed that item wording (positively and negatively formulated items), and the observability of the items have a significant effect on the mean absolute difference score. No effect was found for clarity. These results were generally confirmed by subgroup analyses.

Humans↗

PubMed1998

Computer-based assistance in family medicine.

In this paper, the fully integrated General Practitioner (GP) Information and Research System HIOS and Decision Support System HIOS+ are described. Both systems were developed with the Phased Development Methodology (PDM), which is also presented. HIOS consists of an administrative module, medical modules, and a research module to support GPs in daily practice activities and research. It was implemented at a general practice and a health centre, and was evaluated positively. HIOS+ was developed by extending HIOS with modules which offer several types of decision support to assist GPs in (diagnostic) decision making. The modules offer passive and active decision support. HIOS+ can present textbook information, generate advice and warnings, support the creation of models, generate reports, and can be used in education. Some HIOS+ modules were evaluated by GPs in evaluation studies, all with positive results.

Computer Systems↗

PubMed1998

Education and training in health informatics: the IT-EDUCTRA project.

In this contribution both the EDUCTRA project of the European Advanced Informatics in Medicine Programme and the IT-EDUCTRA project of the Telematics Applications Programme (Health Sector) are described. EDUCTRA had as aim to investigate which gaps in knowledge health professionals have with respect to health informatics and to suggest ways to remedy this. It was assumed that health professionals had a basic understanding of health informatics and that additional educational material only had to cover the knowledge necessary for appreciating the new products coming from the AIM programme. A state-of-the-art survey revealed that the knowledge of health professionals with respect to health informatics was deplorable. Guidelines for curricula were therefore proposed to enable potential teachers to design courses. IT-EDUCTRA is a continuation of the EDUCTRA project. It has as aim to create learning materials covering a broad area of health informatics.

Curriculum↗

PubMed1998

Combining a scientific approach and prototyping in the design of EHCR systems.

In this paper, it is emphasized that electronic medical record systems cannot totally be developed in the traditional way. The underlying process of how physicians or nurses are searching for information is not fully understood. Therefore, a method that combines a scientific approach and prototyping is advocated. With the help of this advocated approach, these questions could be answered in a way that was also scientifically sound. In this contribution, two examples of the use of this method are presented. One concerns the determination of the optimum granularity of the narrative parts of the electronic healthcare record (EHCR) and the other concerns the use and impact of stand-alone protocol systems.

Clinical Protocols↗

PubMed1998

Electronic patient records.

In this contribution several aspects of electronic medical records are discussed. Attention is paid to data entry and data presentation. An example is given of a study, investigating the influence of the granularity with which information is presented on the time it takes to retrieve this information. Finally some implementation problems are discussed.

Humans↗

PubMed1998

Decision support for health professionals.

In this contribution two decision support tools are discussed. One is used for reducing the number of inadequately requested tests by GPs and the other to support neurologists in prescribing medications for epilepsy patients. The experiences with both programs will be discussed.

Decision Support Systems, Clinical↗

PubMed1998

Education of health professionals.

In this contribution the problem-based educational system is explained. As an example the system, current in the Faculty of Medicine, is discussed. The appreciation of students of the system is very high, as is apparent from investigations performed by two independent organizations.

Health Personnel↗

PubMed1998

Presenting treatment protocols with Web technology.

This paper describes a Web-based version of a protocol information system (ProtoVIEW) with which a wide range of diagnostic or therapeutic protocols can be retrieved and viewed. The Web-based version contains all functionalities of the non web-based version plus several new functionalities. The web version contains an X-ray viewer and a great deal of interactivity such as validation of electronic patient data forms. The most important additional function is the context sensitive protocol support which may lead to improved protocol adherence. Finally, the web-based version can be accessed from any working place since patient data and protocols are stored centrally.

Clinical Protocols↗

PubMed1998

Automatic coding of diagnostic reports.

A method is presented for assigning classification codes to pathology reports by searching similar reports from an archive collection. The key for searching is textual similarity, which estimates the true, semantic similarity. This method does not require explicit modeling, and can be applied to any language or any application domain that uses natural language reporting. A number of simulation experiments was run to assess the accuracy of the method and to indicate the role of size of the archive and the transfer of document collections across laboratories. In at least 63% of the simulation trials, the most similar archive text offered a suitable classification on organ, origin and diagnosis. In 85 to 90% of the trials, the archive's best solution was found within the first five similar reports. The results indicate that the method is suitable for its purpose: suggesting potentially correct classifications to the reporting diagnostician.

Diagnosis, Computer-Assisted↗

PubMed1997

[What do people talk about in Danish hospital elevators?].

Hospital elevators make up a part of the public space of hospitals which is used by both employees, patients, and patients' relatives. We performed an observational study to ascertain the frequency of ethically problematic conversations between employees in the elevators of three Danish hospitals. We defined a conversation as problematic if it breached confidentiality or if it could raise doubts about the professional or ethical standard of the hospital or its employees. Based on this definition we found that problematic conversations occurred in 18 out of 201 elevator-trips where more than one member of the hospital staff was present in the elevator (9%, 95% confidence limits 5-14%). The most common types of problems were breaches of confidentiality (6 cases), complaints about stressful work (4 cases), and complaints about the organisation (3 cases).

Confidentiality↗

PubMed1997

Tracking markers with missing data by lower rank approximation.

Motion and deformation of an object may be quantified by following attached markers in video or cine frame sequences. When recording cardiac motion by video (256 x 256 pixels, 50 Hz), generally no more than approximately 20 markers can be followed due to difficulties in proper identification of marker images. In the present study we developed the lower rank (LR) tracking method which can automatically follow considerably more than 20 markers. The performance of the method was evaluated in computer simulations of naturally moving myocardial markers observed in a sequence of 60 video frames. White noise was added to the marker coordinates. Realistic loss of data due to detection failure was simulated by deleting a generated marker image when the distance to another marker image was below a given minimum value. In a test, realistic values were substituted for the noise level sigma (0.5 pixel) and the minimum marker distance dm (4 pixels). For numbers of markers ranging from 50 to 100, 95-90% of the detected marker images was correctly tracked. Less than 0.7% was part of a false track, i.e. a track containing images of different markers. Under less favourable conditions (sigma = 1 pixel; dm = 8 pixels) the method was robust: for 75 markers with 40% of the marker images missing, still 70% of the detected images was correctly tracked, while the fraction in false tracks did not increase. The LR tracking method appears reliable for automatic tracking of large amounts of moving markers in a sequence of video or cine frames.

Algorithms↗

PubMed1997

Graphical information retrieval by browsing meta-information.

This paper discusses an approach to alleviate the problem in information retrieval of finding the right information. This problem arises in traditional query-based systems when users do not have enough knowledge about the domain or if they do not have an articulate information need. We address this problem by combining information about the documents and about the domain of the documents. This meta-information can then be browsed by the users with a graphical browser. Several navigation aids help the user to find his way. The system contains a representation of the medical domain and records from the Medline literature database. The paper discusses the representation of the meta-information, the browser and the evaluation of the system.

Algorithms↗

PubMed1997

An experimental electronic medical-record system with multiple views on medical narratives.

In this article we describe a prototype electronic medical-record system that has been developed specifically to facilitate searching through medical narratives, as part of a preparatory study to the development of a medical workstation. This system contains a searching structure in which several views on the medical data are combined. We describe the structure of the database and the user-interface. A second design goal was to prepare the system for conducting research with respect to the use of the medical record. We address the kind of test designs the system can support and describe the research module that was implemented. We also describe a study we conducted with the system and report part of its results. We discuss the significance of this medical-record system compared to systems in the literature, some technical and functional problems encountered, and our future plans with the system.

Humans↗