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PubMed2005

An 18-month follow-up study on vibrotactile sense, muscle strength and symptoms in computer users with and without symptoms.

OBJECTIVES: The aim was to explore whether symptoms, sensory perception and muscle strength among computer users with and without symptoms in forearm or hand had changed after 18 months. METHODS: Twenty-six out of 30 females, experienced computer users, from a baseline study participated in the follow-up. In addition, five control subjects participated. The subjects completed a questionnaire regarding exposure to computer work, prevalence and severity of symptoms, health status and physical activity. Perceived thresholds for vibration were measured twice with 3 h in between on the right hand on four different sites innervated by the radial, median or ulnar nerve. Furthermore, sensory perception was measured on the left hand on two sites innervated by the median and ulnar nerve, respectively. Skin temperature was measured at each site prior to sensory perception measurements. Maximal handgrip strength and maximal pinch-grip strength were measured for both hands. RESULTS: Eighty-three percent of the subjects who had symptoms at baseline still had symptoms and 21% of the subjects who did not have symptoms at baseline experienced symptoms at follow-up. The first and the second sensory perception measurement were highly correlated. Vibrotactile sensory threshold representing the radial nerve was increased since baseline among the subjects who originally had symptoms. At follow-up, the vibrotactile sense for the computer users who reported symptoms in forearm or hand at baseline was deteriorated for the sites representing the median, ulnar and radial nerves compared to the control group. Among the original symptom free subjects with intensive computer work increases in vibrotactile perception thresholds were found for the sites representing the median and ulnar nerves. Handgrip muscle strength remained unchanged for all groups. CONCLUSIONS: The study indicates that sensory dysfunctions as well as symptoms in forearm and hand among computer users to a high degree are persistent. Muscle strength seems to be well maintained.

Adult↗
PubMed2005

Computational modeling of vascular anastomoses.

Recent development of computational technology allows a level of knowledge of biomechanical factors in the healthy or pathological cardiovascular system that was unthinkable a few years ago. In particular, computational fluid dynamics (CFD) and computational structural (CS) analyses have been used to evaluate specific quantities, such as fluid and wall stresses and strains, which are very difficult to measure in vivo. Indeed, CFD and CS offer much more variability and resolution than in vitro and in vivo methods, yet computations must be validated by careful comparison with experimental and clinical data. The enormous parallel development of clinical imaging such as magnetic resonance or computed tomography opens a new way toward a detailed patient-specific description of the actual hemodynamics and structural behavior of living tissues. Coupling of CFD/CS and clinical images is becoming a standard evaluation that is expected to become part of the clinical practice in the diagnosis and in the surgical planning in advanced medical centers. This review focuses on computational studies of fluid and structural dynamics of a number of vascular anastomoses: the coronary bypass graft anastomoses, the arterial peripheral anastomoses, the arterio-venous graft anastomoses and the vascular anastomoses performed in the correction of congenital heart diseases.

Anastomosis, Surgical↗
PubMed1983

How accurate are computed tomographic scans in assessment of changes in tumor size?

The computed tomographic scan plays an integral part in the diagnosis and management of tumors; however, its potential has not yet been fully exploited. With a computer-assisted volume determination method, the reproducibility of derived volume calculations was assessed, and radiologists' standard interpretations of interval change on serial scans were compared with the investigators' calculations of tumor volume change. Interobserver reproducibility of tumor volume calculations of the mean of two repeated volume determinations was satisfactory (mean of 3 percent, median of 1 percent). There were 29 comparisons (47 scans of 19 patients with liver tumors) of computed tumor changes with the radiologists' computed tomographic reports of consecutive scans. In only 41 percent (12 of 29) of the cases did the radiologists' interpretations and the computer-assisted volume determinations agree. It is concluded that objective computer-assisted volume determination provides a potentially more sensitive assessment of tumor change and that such precise, specific, reproducible determination of tumor volume should further clinical research and improve patient care.

Adult↗
PubMed1986

Randomized trial of computer-assisted insulin delivery in patients with type I diabetes beginning pump therapy.

Sixteen patients with type I diabetes were randomly assigned to two groups to evaluate the utility of computer-assisted insulin dosage decision-making. All patients used the same solid-phase reagent strip system for glucose measurement and the same pump. The standard group (n = 9) used standard algorithms for insulin adjustment, whereas the computer group (n = 7) relied on interactive instruction from a small, inexpensive (less than $100) computer. At the beginning of the study, there were no significant differences between groups in C-peptide level, hemoglobin A1c level, age, or duration of diabetes. Mean blood glucose level during the study for the computer group was 121 mg/dl (6.7 mM), which was significantly lower (p less than 0.01) than glucose levels charted by the standard group: 148 mg/dl (8.2 mM). Mean number of blood glucose values charted by the computer group (58 per week) was significantly (p less than 0.01) greater than the number charted by the standard group (51 per week). Hemoglobin A1c values at six weeks correlated with the mean number of blood glucose values charted per week of the study. There was no difference between groups in symptomatic hypoglycemic episodes. Computer-assisted insulin dose decision-making is feasible, safe, and effective in enabling persons with type I diabetes mellitus to achieve lower mean blood glucose values over a six-week period while initiating pump therapy.

Adult↗
PubMed1991

Prenatal behavioral risk screening by computer in a health maintenance organization-based prenatal care clinic.

Cigarette smoking, alcohol and drug abuse, and stressful life events are significant contributors to prematurity and low birth weight in the United States. Identification and treatment of pregnant women with these risk factors require obtaining complete and accurate psychosocial histories. The purpose of this study was to determine whether a computer interview developed by our staff is appropriate for assessing behavioral risk factors for adverse pregnancy outcomes and for educating pregnant women about healthy behaviors during pregnancy. This computer interview asks about pregnant patients' perceived life stressors, diet, use of cigarettes and alcohol, and abuse of drugs. The study population consisted of 201 medically insured Hispanic and non-Hispanic white women attending a health maintenance organization--based prenatal clinic. Almost all subjects rated the computer interview favorably. Medical record reviews were conducted to compare participants' reports of cigarette, alcohol, and drug use obtained from paper-and-pencil interviews with behaviors reported during the computer interview. Although self-reported rates of smoking did not differ between the two interview techniques, a much higher percentage of women reported alcohol and drug use during the computer interview. Study participants scored significantly higher on a test measuring knowledge of the effects of stress, diet, and substances of abuse on pregnancy than did a control group. Results demonstrated the potential value of computer-interactive software programs for assessing high-risk behaviors among pregnant women in this population and educating them about healthy behaviors during pregnancy.

Adolescent↗
PubMed1982

Computed tomography in lung cancer.

Computed-assisted tomography produces a cross-sectional image of the body using x-ray absorption measurements. Density differences are much more apparent than on conventional radiographs, although spatial resolution is not so fine. Lung cancer, can be evaluated accurately with regard to size, location, and whether regional or mediastinal lymph nodes are enlarged. Although enlarged granulomatous nodes generally tend to be dense, histologic specificity is not available. Computed tomography is recommended as a screening technique in lung cancer staging for patients whose routine radiographs are normal but whose primary lesions fulfill criteria for mediastinoscopy. If findings on computed tomography are normal, thoracotomy should then be performed; if enlarged nodes are detected, then a biopsy is needed to exclude operability. This strategy presumes that computed tomography has high sensitivity, although it remains to be proven by further experience whether the false-negative rate of computed tomography is an acceptable 10 to 15 percent. Computed tomography has been shown to be of considerable value in optimizing radiation therapy of lung cancer, and in diagnosing pleural complications of the cancer or its treatment.

Humans↗
PubMed1977

A computer analysis of cardiac electrograms.

Computer programs were constructed for the temporal analysis of 8 electrograms obtained from various regions of isolated dog hearts. The electrograms were recorded on photosensitive paper. A computer program written in the Fortran II language allowed an x-y digitizing table to be used to input the coordinates of each electrogram into a computer. Each electrode recording within a given cardiac cycle was digitized in this manner, and the temporal intervals between the 28 combinations of electrode pairs were calculated. The program also computed the heart rate and cardiac cycle length. Subroutine options permitted the grouping of data into experiment, record, and event numbers. All data were stored on a magnetic disk. A separate computer program written in the Fortran IV language performed basic statistical operations on each of the data files. The computer system described in the present report accurately and reliably processed over 10,000 cardiac cycles. Such a system can be used to analyze large amounts of data from sources other than electrograms. Temporal analysis of the standard electrocardiogram is offered as an example of the versatility of the programs.

Animals↗
PubMed1976

Evoked potential analysis: on-line signal optimization using a mini-computer.

An automated computer-based system is described for the analysis of evoked potentials. All procedures are carried out in real-time A small computer performs the following functions; timing of random stimulus presentation, rejection of artifact contaminated responses, collection of digital data, computation of averaged evoked responses, computation of the Wiener filter, storage of the filtered and unfiltered averages and display of the resultant averages. The Wiener filter as described by Walter (1969) and Doyle (1975) is used to improve the estimate of the evoked potential by discriminating against frequencies likely to be contaminated with noise. The defining equation for the Wiener filter states that information at any frequency is to be weighted by the ratio of the power known to be in the signal (response) at that frequency over the corresponding power known to be in both the signal (response) and the noise (background EEG) at the same frequency. The technique requires the computation of the Fourier transform for each response in order to produce the power spectra necessary for the Wiener filter. Earlier reports dealing with this technique have usee large computers to analyze the evoked potential data off-line. The system described here allows for greater routine utilization of this powerful technique and the concomitant automated rejection of artifact contaminated responses. Highly improved estimates of the evoked potential are resultant using a minimal number of stimuli.

Computers↗
PubMed1986

Visual versus computer evaluation of thiopental-induced EEG changes in temporal lobe epilepsy.

Thiopental-induced EEG beta activity was analyzed both visually and by computer in 33 patients with complex partial epilepsy. Studies were done in 16 patients with depth electrodes in limbic structures and 17 patients with scalp and sphenoidal electrodes. The percentage of drug-induced change in beta activity was quantified by computer using spectral analysis. The statistical significance of asymmetries between homologous sites in the amount of change was determined. The spatial distribution of significant asymmetries was used for localization and compared with the results of independent visual analysis of the thiopental EEG. Concordance between computer and visual evaluation occurred in 10 of 17 scalp/sphenoidal and 10 of 16 depth electrode tests. The accuracy of visual and computer localization was determined by comparing them with locus of itcal EEG onset, interictal spikes, and positron emission tomography. In scalp/sphenoidal studies, computer analysis indicating asymmetry appeared more likely to correlate with independent clinical criteria than visual analysis. In depth studies the reverse appeared to be true. Scalp/sphenoidal tests yielded positive results in 25-30% of patients whereas depth electrode tests were positive in 50-70% of patients. The results indicate that computer analysis of surface thiopental tests is an accurate and useful supplement to visual evaluation of these tests.

Brain↗
PubMed1984

Malignant pleural mesothelioma: the role of computed tomography.

Computed tomography is believed to have a definite role in the evaluation of malignant pleural mesothelioma based on a review of computed tomography findings in 23 of our patients and previous reports. Twelve patients had a single computed tomography examination, and 11 had two or more studies. Computed tomography permits better appreciation of the extent of the tumor. This permits appropriate selection of therapy and may demonstrate that surgery or radiotherapy is not indicated. computed tomography often permits more accurate evaluation following chemotherapy and may be the only means by which to follow a patient after radical surgery. Computed tomography also has a role in differential diagnosis. It facilitates distinction of malignant pleural mesothelioma from rounded atelectasis, pleural changes of asbestosis, and pleural involvement with lymphoma and thymoma. It aids, but may not be diagnostic, in separating malignant pleural mesothelioma from metastases to the pleura.

Adult↗
PubMed1985

Differential diagnosis of low-attenuation splenic lesions on computed tomography.

A retrospective computed tomography evaluation of proved low-attenuation splenic lesions in nontraumatic cases was done. Computed tomography was able to distinguish cystic from solid lesions. Although computed tomography examination is sensitive in the detection of low-attenuation lesions, the computed tomography findings alone are not helpful in differentiation of different low-attenuation lesions. Associated computed tomography findings in other organs and clinical findings are more helpful than the size, shape, and computed tomography attenuation of the lesions. Splenic lesions may be the only metastatic manifestation in some cancer patients. A thin needle aspiration may be done to document the nature of the pathologic lesion in problematic cases.

Abscess↗
PubMed1985

Computed tomography in the pretreatment assessment of carcinoma of the cervix.

Fifty-nine patients with primary or recurrent carcinoma of the cervix were evaluated by computed tomography as part of their presurgical evaluation. The computed tomography staging results were compared with the surgical staging. Computed tomography staging was accurate in 71% (42 of 59), whereas clinical staging was accurate in 66% (39 of 59). In assessing paraaortic nodes by CT, there were 10 true-positive, 20 true-negative, 1 false-positive, and 2 false-negative results (sensitivity, 83%; specificity, 95%), for an overall accuracy of 91%. For pelvic nodes, there were 10 true-positive, 11 true-negative, 3 false-positive, and 6 false-negative results (sensitivity, 62.5% specificity, 78%), for an overall accuracy of 70%. Excretory urograms and barium enemas provided no information not obtained by computed tomography and are probably unnecessary if computed tomography is used as a routine staging examination. At present, computed tomography should not replace clinical assessment of extent of the disease. Its chief advantage over clinical staging is its ability to detect metastases beyond the true pelvis.

Adenocarcinoma↗
PubMed1986

Computed tomography in interstitial lung disease.

The number and scope of published articles dealing with computed tomography of interstitial lung disease are limited. We present seven cases in which computed tomography detected the presence or extent of interstitial lung disease better than conventional radiography: two patients with histiocytosis X, one with bronchopulmonary dysplasia, one with bleomycin lung toxicity, and three with radiation-induced lung injury. The computed tomography appearance of histiocytosis X and bronchopulmonary dysplasia have not been previously described. Transverse computed tomography images provide information regarding stage of activity and nature of interstitial lung processes not available with standard imaging techniques. We advocate the use of computed tomography in the initial investigation and follow-up of patients with histiocytosis X. Post-radiation pneumonitis and fibrosis can be detected earlier with computed tomography as well.

Adolescent↗
PubMedDate not supplied

Computer-aided system for diabetes care in Berlin, G.D.R.

In the Centre of Diabetes and Metabolic Disorders of Berlin, G.D.R., a computer-aided care system has been used since 1974, aiming at relieving physicians and medical staff from routine tasks and rendering possible epidemiological research on an unselected diabetes population of a defined area. The basis of the system is the data bank on diabetics (DB), where at present data from approximately 55,000 patients are stored. DB is used as a diabetes register of Berlin. On the basis of standardised criteria of diagnosis and therapy of diabetes mellitus in our dispensary care system, DB facilitates representative epidemiological analyses of the diabetic population, e.g. prevalence, incidence, duration of diabetes, and modes of treatment. The availability of general data on the population or the selection of specified groups of patients serves the management of the care system. Also, it supports the computer-aided recall of type II diabetics, treated either with diet alone or with diet and oral drugs. In this way, the standardised evaluation of treatment strategies in large populations of diabetics is possible on the basis of uniform metabolic criteria (blood glucose plus urinary glucose). The system consists of a main computer in the data processing unit and of personal computers in the diabetes centre which can be used either individually or as terminals to the main computer. During 14 years of experience, the computer-aided out-patient care of type II diabetics has proved efficient in a big-city area with a large population.

Ambulatory Care↗
PubMed1994

Computation of multifactorial receiver operator and predictive accuracy characteristics.

The computation of the so-called receiver operator characteristics (i.e. functions that assign the maximum specificity to each value of sensitivity) is simple when the characteristics are based on univariate data. On the contrary, multivariate characteristics are difficult to compute, as the complexity of their calculation increases exponentially with the dimension of the data. This paper describes an algorithm for computation of multivariate receiver operator characteristics and derived functions (namely positive and negative predictive characteristics). The algorithm is based on several concepts that increase its computational efficiency. The most important of them is a pre-sorting of the data in each dimension and the division of each dimension into groups in which the positive and negative cases are 100% stratified. The paper also presents a risk stratification study that utilised this algorithm. The study was aimed at identifying those survivors of acute myocardial infarction who are at risk of early death. A cohort of 539 patients was stratified based on time-domain (three variables) and spectral turbulence (six variables) indices of signal-averaged electrocardiogram. The computing times of the algorithm in this study are presented in the text, and the efficiency of the computation is discussed in detail.

Algorithms↗
PubMed1986

Physician utilization of computers in medical practice: policy implications based on a structural model.

The development of policies regarding computer-based medical technology is hampered by a lack of knowledge about the process by which such applications are adopted and utilized by physicians. This study was designed to test a model of the process by which physicians change their practice behavior by utilizing a computer-based hospital information system (HIS). A structural model was developed, estimated, and tested using data from 270 members of the medical staff of a 1160 bed, private teaching hospital. The overall model consists of a measurement model which assumes that the observed variables are generated by a smaller number of unobserved variables or factors; and a structural equation model that relates exogenous and endogenous variables. The model indicates that consultation with other physicians on a hospital service leads to greater exposure to potential computer applications resulting in less concern about the potential impact of computers on medical practice. Physicians who are more knowledgeable about computers are far more likely to tailor the system to their individual practice by developing their own personal order sets for use on the HIS. All of these factors result in increased use of the HIS by physicians. A number of policy implications related to the introduction of new computer-based technology into medical practice settings are discussed.

Attitude to Computers↗
PubMed1996

Collapsing a coevolutionary process into a computable function.

It is shown how the entire dynamics of a class of evolutionary systems can be used to perform a computation. The argument is constructive by presenting a Turing-machine-based set-up implemented in Enact, an artificial-life world embedded in a family of cellular automata; in this system, a population of agents move about in a two-dimensional space, interacting with their environment, reproducing and undergoing developmental and coevolutionary processes. As a byproduct, the paper also serves to characterise the main model of computation underlying Enact. This model is essentially parallel, and relies upon the machinery defined by the artificial-life processes. According to the model, a particular computation is considered to have been performed, if and only if, for some initial population and environmental configuration, at least one agent has developed into a state configuration that is insensitive to any further environmental interactions; in this situation, if the computation involved is a function, this individual has the result. If the population ever vanishes, or if the environment becomes short of the resources needed for development, the cellular space has to be re-initialized, and the process iterated. The presentation relies on the implementation of a function that recognises a particular context-free language. Implications of the model of computation are then discussed, in particular the model of coupled computations suggested by it.

Algorithms↗
PubMed1991

Computer-CT planning of the electron boost in definitive breast irradiation.

Treatment planning of the electron boost in breast irradiation at this institution is performed by using information from CT scanning and from surgical clips used to define the tumor bed. A refinement of this technique, taking into account the surgical axis of approach, using computer-CT planning is now implemented. The location of the scar and the clips are digitized using a computer to define the tumor bed dimensions. With 3-D computer software a line, simulating the surgical axis and the central ray of the electron beam, is drawn between the deepest clip and the surgical scar. This beam's eye view along the surgical axis is projected onto a screen as a starting point. Appropriate gantry angle, treatment table position, beam energy, and precise shaping of the electron field borders with a 2 cm margin around the clips and the scar are determined. Simulation films comparing clinically set-up fields and computer-CT planned fields were reviewed. In only 5 of 17 patients did the clinically set-up field have adequate inclusion of the tumor bed within the treatment volume. Computer-CT planned fields ensured adequate inclusion of the tumor bed in all, including the remaining 12. In 7 patients obvious increased sparing of normal breast tissue was seen with computer-CT planned fields. This technique enables accurate placement of a shaped electron field and further refinement of electron boost treatment planning. This is especially true in situations in which the tumor bed is located at a site distant from the lumpectomy scar rather than directly beneath it and in cases where the tumor bed lies deep within the breast.

Breast Neoplasms↗