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Biomedical subjects

J L Talmon

Publications and source records attributed to J L Talmon.

9 recordsLinked to original sources

The effect of noise and biases on the performance of machine learning algorithms.

This paper describes the results of experiments with a machine learning algorithm for the induction of classification trees. We mainly address the impact of noise on the resulting classification tree and on the classification results obtained with the derived tree. We use the domain of the biochemical assessment of thyroid diseases as an example. Some suggestions for quality assessment are outlined that should be available in tools that assist users in deriving classification trees in noisy domains.

Algorithms

Evaluation of computerised questionnaires designed for patients referred for gastrointestinal endoscopy.

The aim of this prospective study was to assess the applicability of a computerised medical history system at the open-access endoscopy unit of a University Hospital during routine clinical practice. We studied feasibility, acceptability and reproducibility of computerised questionnaires designed for patients referred for endoscopy of either the upper or lower gastrointestinal (GI) tract, partly in comparison with almost identical paper questionnaires. In the first period of the study 1134 patients were referred of whom 73% answered the paper questionnaire, and during the second period 537 patients were referred of whom 64% answered the computerised questionnaire (P less than 0.001). There was no sex dependency regarding the ability to answer both types of questionnaires. A significant age dependency regarding the ability to answer the paper questionnaires was observed for patients referred for upper and lower GI endoscopy (P less than 0.0001 and P less than 0.0001). Corresponding with this observation, the ability to answer the computerised questionnaires significantly decreased with increasing age for both groups of patients (P less than 0.0001 and P less than 0.0001). The average completion times of both computerised questionnaires, designed for the upper and lower GI tract, were 11 min. The completion times did not depend on sex, but there was a slight positive correlation with age (P less than 0.0001 with multiple R = 0.27 and P = 0.0593 with multiple R = 0.12). Answering our computerised questionnaires was consistently reported to be interesting and easy, and did not last too long according to the respondents. After patients had answered the computerised history system, the insight into their complaints had increased in 40%, and 45% could put their complaints into words more easily. Only 25% of the patients were unable to express all their complaints. A reproducibility of medical history data of 85% was observed between paper and computerised questionnaires. Our computerised questionnaires can provide us with a detailed and uniformly acquired medical history of most patients referred for GI endoscopy. They are well accepted by the patients and can be completed during the normal waiting period. The medical history data obtained with these questionnaires are quite reproducible.

Adult

Electrocardiogram waveform in fetal sheep: a system for ECG analysis.

Computerised ECG analysis is helpful for the analysis of fetal ECGs, recorded during animal experiments. It provides a tool for rapid measurement of characteristics of ECG signals. Such an ECG analysis system is described. The different steps of the signal analysis are discussed and preliminary results are presented. The current version of the program is implemented in Turbo-Pascal and runs on an IBM-compatible PC with an 8087 processor and an EGA colour display.

Animals

A computer program for ECG classification according to the Minnesota code.

A program for the automated generation of Minnesota-codes from the standard 12-lead electrocardiogram (ECG) recorded at rest has been developed. The program has been written as a part of the Modular TNO ECG/VCG Processing System. Results of the program on two sets of ECG'S (279 predominantly normal recordings and 286 consecutive recordings from a Cardiological Department) are presented. These electrocardiograms were also coded by hand by different ECG technicians. An agreement of 83% between hand and computer coding was obtained. One-third of the disagreements (6% of the cases) is caused by small differences (less than 5%) in the measurements between technicians and computer.

Diagnosis, Computer-Assisted