PubMed Health⌕ Search

Biomedical subjects

D S Lloyd

Publications and source records attributed to D S Lloyd.

18 recordsLinked to original sources
PubMed1995

A portable communicative architecture for electronic healthcare records: the Good European Healthcare Record project (Aim project A2014).

The European Union is supporting research into medical informatics via its Advanced Informatics in Medicine (AIM) program. One of the current AIM projects is the Good European Healthcare Record (GEHR) project. Its objective is to devise an architecture for electronic healthcare records that will enable them to be comprehensive, communicative, and portable to different systems. The work was funded from January 1992 to December 1994. The project team consisted of over 50 personnel representing clinicians, computer scientists, and computer programmers in eight European countries. The partner organizations are Health Data Management Partners (Belgium), Croix Rouge Francaise (France), France Telecom, Association des Medecins et Medicins Dentistes (Luxembourg), Instituto Clinica Geral Zona Norte (Portugal), Medical College of St Bartholomew's Hospital (UK), and SmithKline Beecham (UK). The work of the project has been carried out by three subgroups covering clinical, architecture, and systems aspects. One of the strengths of the project has been that most of the work has been done as collaborations between members of different groups. This has meant that there has been very close contact between clinicians and computer experts. The GEHR project is providing important input into the standardization process in Europe via, for example, PT011 of Working Group 1 of CEN TC/251 (the developing standards for the architecture of healthcare records).

Computer Communication Networks↗
PubMed1990

A comparison of different methods for calculating overall risk scores from risk factors ascertained in a computerized obstetric information system.

Current obstetric risk-scoring systems depend upon simple addition of weighted or unweighted risk factors. In this study a population of 994 pregnant women (470 primiparae; 524 multiparae) has been examined in order to compare the use of weighted and unweighted risk scores, together with Bayes theorem, in estimating an overall risk score from the presence of individual risk factors. The findings have been related to fetal outcome in these pregnancies and expressed as receiver-operating characteristic (ROC) curves for different cutoff levels between normal and abnormal. In primiparae, the use of weighted risk factors, with or without Bayes theorem, was clearly superior to the use of unweighted factors. In multiparae there was only a marginal difference between the three approaches. The increasing use of computerised information system in antenatal care should make calculation of risk scores for every pregnant woman a practical option.

Adolescent↗
PubMed1982

Determination of smooth pursuit eye movement velocity in humans by computer.

Smooth pursuit eye movements are the output of a system closely related to visual suppression of the vestibulo-ocular reflex, and impairment of these functions when performing day-to-day activities may be important. Smooth pursuit velocity has been assessed using a computerized electro-oculographic technique based on the amount of saccadic activity detected throughout a range of visual target velocities spanning the capability of the smooth pursuit system. Each test session lasts 2 min. With this technique the effects on smooth pursuit of various centrally acting compounds have been demonstrated in healthy subjects. Healthy females had lower smooth pursuit velocities when compared to age-matched males. A linear correlation was shown between smooth pursuit velocity determined by the computer technique and by a previously reported visual method. Such measures have wide application in neurological diagnosis and in the assessment of the central effects of drugs in man.

Computers↗
PubMed1981

An efficient technique for determining characteristics of saccadic eye movements using a mini computer.

A new technique has been developed to quantify objectively certain characteristics of saccadic eye movements which can be used as indices of the effect of centrally-acting compounds. During a three minute test session subjects sit with their heads in a fixed position and are asked to follow horizontal step displacements of a spot on a CRT screen, driven by signals previously recorded on FM analogue tape. Displacements of the spot are produced at random intervals which result in saccadic eye movements having amplitudes 10 degrees to 40 degrees. The corneo-retinal potentials are d.c. amplified and stored on the same on the same tape, later sampled at 256 Hz, filtered, differentiated and compared to the spot-displacement signal. Reaction time, duration, peak velocity, post saccadic interval and saccadic accuracy are then determined. Efficient use of computer resources has been achieved with improvements in control of experimental conditions, in reliability and in accuracy of measurements. Automatic unbiased rejection of erroneous data has been achieved. The efficiency of the technique has made extensive clinical trials possible in an environment where computer power is not devoted to eye movement-measurements. In confirmation of previous work the peak velocity characteristic has been identified as a sensitive measure of the effect of several benzodiazepines.

Action Potentials↗
PubMed1979

Visual and computer-assisted assessment of the EEG in epilepsy of late onset.

A study was made of 275 patients presenting with suspected epilepsy after the age of 20 years. In 122 it was concluded that the attacks were non-epileptic. In 60 others cerebral pathology was found. If the EEG was visibly abnormal the risk of cerebral pathology was 8 times greater than when the record was normal. The EEGs were also assessed by an automatic pattern recognition technique, which classified them as abnormal by reference to a control population of 300 volunteers. 90% of EEGs from patients with pathology were classified as abnormal and, conversely, 86% of patients with abnormal records (as assessed by the automatic analysis) had pathology.

Adult↗
PubMed1978

Computer-assisted interpretation of clinical EEGs.

A multivariate pattern recognition technique has been developed, to distinguish the EEGs of patients with cerebral pathology from those of normal controls and to localize any abnormalities detected. Two methods of feature extraction have been used, power spectral density and slope descriptor analysis, together with various types of feature compression. These techniques have been evaluated on EEGs from 63 patients with proven pathology. Spectral analysis proved more reliable than slope descriptor analysis and predicted the site of cerebral pathology more accurately than did visual assessment of the EEGs. This apparent improvement over the diagnostic reliability of visual analysis in considered to justify further development and evaluation of this technique.

Adult↗
PubMed1976

The contingent negative variation and psychological findings in chronic hepatic encephalopathy.

Early diagnosis of chronic hepatic encephalopathy (CHE) in the latent stage before the appearance of clinical signs, should reduce both morbidity and mortality as deterioration is often preventable by treatment. Since existing diagnostic procedures are inadequate, we have investigated a test in which morphine is used as a provocative agent and any resulting change in cerebral function assessed by measurement of the CNV in conjuction with a psychological trail test. Twenty six patients were studied, 6 of whom had clinically overt CHE. A significant correlation (P less than 0.05) between the change in CNV amplitude with morphine and the initial CNV amplitude, consistent with the theoretical model of Tecce (1972), was found. However, the CNV and trail test results taken as a whole did not allow even those patients with overt CHE to be distinguished and we conclude that it is unlikely that differing degrees of latent CHE could be detected.

Chronic Disease↗
PubMed1970

Electroencephalographic prediction of fatal anoxic brain damage after resuscitation from cardiac arrest.

Ninety-three electroencephalograms (E.E.G.s) were recorded within a week of cardiac resuscitation from 41 patients in whom the subsequent outcome was known to be either recovery of cerebral function or death with associated pathological evidence of gross anoxic brain damage. A statistical analysis of observations on these E.E.G.s yielded a discriminant function for predicting death or survival. Predictions based on each of the 93 individual E.E.G.s would have been correct in 92 and at a confidence level better than 99%. The same discriminant function was found to be applicable to a further 19 patients who died but did not undergo neuropathological studies and to 33 others in whom the clinical picture was complicated by such factors as uraemia or head injury. Thus it seems that the presence or absence of fatal brain damage after cardiac arrest can be reliably predicted from E.E.G.s taken within a week of resuscitation. An estimate of the probability of survival is now routinely included in the clinical report on each E.E.G. taken after cardiac arrest.

Adolescent↗
PubMedDate not supplied

Evaluation of a fetal risk-scoring system.

A population of 2029 pregnant women (929 primiparas; 1100 multiparas) has been used to examine aspects of the calculation of obstetric risk scores from the presence of individual risk factors. The findings have been related to fetal outcome in these pregnancies and the following conclusions were reached: (1) the use of Bayes theorem for the calculation of a risk score is superior to the simple addition of weighted risk factors; (2) the diagnostic efficiency of a risk score is somewhat reduced when the data base used for calculation of the score is derived from a population different from that of the current pregnancy; (3) there is almost total overlap of risk scores in women with satisfactory and unsatisfactory fetal outcome. It is concluded that risk scores can be used to identify a small group of women at particularly high risk; in the remainder of the population scores are unhelpful except perhaps to indicate the women who do not require an intensive program of antenatal care.

Bayes Theorem↗