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Results for “Error minimization”

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At least 397 records · Page 22Linked to original sources

PubMed2005

[Objective measurements of visual acuity by visual evoked potentials].

Electrophysiological measurements of the threshold spatial frequency were conducted in 26 healthy subjects by using visual evoked potentials with the purpose of objective determination of the visual acuity. For that we proposed a universal method of the visual stimulation and EEG processing (using ICA decomposition in particular) to minimize errors arising on account of individual differences in the visual system functioning. As a result, a correlation of 0.74 and a logarithmic dependence were obtained between spatial resolution measured by electrophysiological and psychophysical methods. The proposed methods of objective measurement of visual resolution has a high effectiveness, does not depend on specificity of individual EEG and domination of different channels in the visual system. Therefore it is possible to determinate objectively the visual acuity in humans independently of their responses.

Adolescent↗

PubMed1996

Body composition assessment and minimal weight recommendations for high school wrestlers.

OBJECTIVE: To describe a procedure to estimate a minimal wrestling weight based on percent body fat. BACKGROUND: Weight reduction and weight restriction are health issues that have sparked much debate among those involved with high school wrestling. Recently, programs have been developed to curtail dangerous weight loss practices and severe weight reduction in this population. DESCRIPTION: Skinfold sites, measurement technique, and an equation, based on skinfolds, specific to the high school wrestling population are presented. Recommendations for minimizing error are also presented. CLINICAL ADVANTAGES: This article provides a detailed program for measuring skinfold sites and interpreting these measurements.

Journal Article↗

PubMed2006

CIMT as a behavioral engine in research on physiological adjuvants to neurorehabilitation: the challenge of merging animal and human research.

A physiological adjuvant to neuroplasticity cannot put new knowledge into the brain - it can only augment behavioral rehabilitation, which does replace knowledge in the brain lost due to injury. Clinical trials of adjuvant agents should therefore incorporate behavioral engines: behavioral therapies that have a potent effect and minimize error variance due to variability in subject attributes and the administration of the therapy. We consider in some detail the attributes of behavioral engines with a particular focus on constraint induced movement therapy. Human trials of physiological adjuvants to neuroplasticity are predicated on discoveries from animal research. Because human trials are expensive and carry risk of injury, it behooves us to lay a comprehensive foundation for these trials with animal studies (also incorporating behavioral engines) and to carefully mesh animal and clinical work. We review in detail our own and others' work involving human subjects with brain lesions and animal models of brain injury using donepezil, a central acetyl cholinesterase inhibitor, d-cycloserine, a partial agonist at the NMDA receptor glycine site, d-amphetamine, and methylphenidate in an effort to elucidate the strengths and weakness of animal and human neurorehabilitation science with respect to this mesh between animal and human subject research. We consider modifications in current approaches that might more efficiently advance neurorehabilitation science.

Animals↗

PubMed2006

[Auditory brainstem response in normal guinea pigs and those with gentamicin-induced hearing loss under awake and anesthetic conditions].

OBJECTIVE: To observe the alterations of auditory brainstem response (ABR) in guinea pigs with gentamicin-induced hearing loss under awake and anesthetic conditions. METHODS: We recorded the ABR in 20 normal guinea pigs and 20 with gentamicin-induced hearing loss before and after anesthesia for statistical analysis. RESULTS: No significant difference was observed in the waveform, response threshold (RT), I and III peak latencies (PL), I-III interpeak latencies (IPL) of ABR between awake and anesthetic conditions in normal guinea pigs (P>0.05), nor did gentamicin-induced hearing loss showed obvious impact on the ABR parameters (P>0.05). CONCLUSION: No significant ABR alterations occur under awake and anesthetic conditions in either normal guinea pigs or those with hearing loss, therefore ABR test can be performed without anesthesia to ensure the success and error minimization of the experiment.

Anesthesia↗

PubMed1991

Automated microdensitometric quantification of bone ingrowth into porous implants.

The aim of this study was to develop a technique of automated histometric quantification of bone ingrowth into porous implant bodies that minimizes errors of volume determination arising from the section thickness of histologic specimens. A theoretical and experimental deduction is provided for the calculation of implant and bone layer thicknesses from the grey levels of microradiographs made from thick-section specimens. The presented method allows rapid raising of large amounts of histometric data when a computer-aided video system is available. A histologic preparation of specimens that permits the spatial reconstruction of the examined implant volume and analysis of three-dimensional distribution of bone ingrowth is suggested.

Absorptiometry, Photon↗

PubMed1991

[Three-dimensional reconstructions in neuroanatomy].

Computer-aided 3D reconstructions of neurofunctional systems and structures are generated as a reference for neuroimaging (CT, MRI, PET). The clinical application of these 3D reconstructions requires a coordinate system and conditions resembling the intravital neuroanatomy as far as possible. In this paper the neuroanatomical Reference System (NeuRef) of the Department of Neuroanatomy of Hannover Medical School is presented. This consists of methods to record brain structures from serial sections with minimal error (less than 1 mm) and to display 3D brain models derived from such a data base. In addition, NeuRef is able to generate sections through, for instance, the visual and pyramidal system and to transfer these data onto a corresponding CT image. Therefore, this method can serve as a diagnostic aid in neuroradiology, in operation planning, and radiotherapy. It can also be used in PACS.

Brain↗

PubMed1991

What effect does glucose have on measured creatinine in the peritoneal equilibration test?

Very high glucose concentrations falsely elevate measured creatinine. An appropriate correction factor may be applied to obtain an accurate creatinine value; however, the glucose interference is of a low magnitude in most dialysate samples at a 4-hour dwell time. Clinical interpretation of the peritoneal equilibration test using uncorrected creatinine values to determine the dialysate-to-plasma ratio at 4 hours is associated with minimal error.

Colorimetry↗

PubMed1990

ARIC hemostasis study--II. Organizational plan and feasibility study.

In our previous paper, we reported the development of a blood collection and processing system (BCPS) suitable for the ARIC multicenter hemostasis study. As an additional step of preparation for the ARIC study, we incorporated this BCPS into an organizational plan to increase efficiency and minimize errors. We initially designed organizational trays for blood collection tubes and aliquot tubes and developed a coordinated step-by-step plan for the orderly processing of blood samples. Once the plan was considered workable, we carried out a pilot study to test the feasibility of this integrated organizational plan. Included in the pilot study were 95 healthy subjects randomly selected from 4 ARIC field centers, whose age and gender were comparable to those projected for the ARIC population. We determined the time lapse of filling the first tube as an index of blood flow. The overall mean time-lapse was 23 s (S.D. = 5). There was no significant difference among the field centers. We also determined the entire time lapse required for completing the sample processing. The total processing time was always less than 60 min. By performing the processing of samples in pairs, all the samples from two subjects could be completely processed in 70 min. This greatly increased the efficiency of field center operation. We evaluated the potential in vitro hemostasis activation by measuring plasma beta-thromboglobulin and platelet factor 4 levels. The geometric means of both proteins were comparable to our previously reported results. Fibrinogen, factor VII, factor VIII, von Willebrand factor, antithrombin III, protein C and activated partial thromboplastin time were analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriosclerosis↗

PubMed1990

[Experimental criteria for interpretation of bacterial sensitivity to dioxidine determined by diffusion from the disks].

Antibacterial activity of dioxidine against aerobic and facultative anaerobic organisms under conditions of anaerobiosis i. e. conditions really observed for example in abscess cavities or necrotic tissues is 30 to 100 times as high as that under aerobic conditions. There is a relationship between sensitivity of bacteria to dioxidine under aerobic and anaerobic conditions which is expressed by the regression equation. Therefore, comparison of the MICs determined under anaerobic conditions with the growth inhibition zones formed by disks with the drug under aerobic conditions is possible. The MIC of dioxidine was determined under anaerobic conditions for 179 clinical strains of aerobic and facultative anaerobic bacteria and the growth inhibition zones of the same bacteria under aerobic conditions were evaluated with the use of disks containing 100, 75, 50, 25, 20, and 15 micrograms of the drug. The border line. MIC differentiating between resistant and sensitive strains was chosen to be equal to 4 micrograms/ml. Differentiation of the strains into sensitive and resistant ones by the values of the growth inhibition zones was performed with the method of error minimization described by C. Metzler and R. De Haan in 1974. Disks containing 25 micrograms of the drug allowed one to differentiate the strains under aerobic conditions into sensitive and resistant ones: the growth inhibition zones greater than 11 mm corresponded to the sensitive strains (the MIC smaller than 4 micrograms/ml) and the growth inhibition zones smaller than 11 mm corresponded to the resistant strains (the MIC greater than 4 micrograms/ml).

Anti-Bacterial Agents↗

PubMed1990

Assignment of assay values to Coulter controls and calibrators.

The whole blood reference specimens are carefully selected in order to minimize errors in either reference methods or the assay method that might be produced by interferants in the specimens. Fundamental to the process of assigning values to calibrators and controls is the rule that fresh whole blood from normal donors be used as the transfer medium between reference measurement methods and the automated blood cell counter that will be used to assay the stabilized whole blood product. Increasing recognition is being given to the need to adopt K2EDTA salts as global standards for reference specimen anticoagulant. The reference methods used by Coulter closely follow the methods recommended by the Cytometry Panel of the International Committee for Standardization in Haematology and by the National Committee for Clinical Laboratory Standards. Methods used for the statistical control of value assignment are appropriate for commercial rather than institutional use. Simplification of methods is possible because of high levels of test replication and the homogeneous nature of stabilized blood products.

Automation↗

PubMed1990

Practical aspects of vascular imaging using MRI.

MRI is an accurate means of noninvasively assessing vascular abnormalities. However, multiple potential pitfalls exist. In order to minimize error, a knowledge of the flow phenomena seen on various pulse sequences, along with an understanding of pulse sequence modifications that alter these flow phenomena, is necessary. With such an understanding, the current utility of MRI for solving commonly encountered clinical problems of the vascular tree is addressed. Emphasis is placed on a "how-I-do-it" approach, realizing that the reader will make modifications where necessary due to differences in hardware, software, and experience. As appropriate, references to the literature are made in an attempt to justify the use of MRI for the particular problems being discussed.

Blood Vessels↗

PubMedDate not supplied

Design of a microprocessor-based sphygmomanometer.

This paper describes the implementation on a microprocessor of a new method for the indirect measurement and recording of the systolic and diastolic blood pressure in humans. The technique is based on a statistical analysis of the cardiac pulse pressure signal. Polynomial relations are derived between the amplitude of the pulsatile pressure waveforms at the systolic and diastolic points and the amplitude of pulse signals detected when the artery is fully occluded. With the dual objective of automating the measurement procedure and minimizing errors, an electronic analog-digital sphygmomanometer that contains suitable electronic instrumentation was developed. The functions of processing the pressure signal, automating the measurement, and recording the results are performed and controlled by a microprocessor. A laboratory prototype embodying this approach was constructed and its performance and reliability were verified using a series of clinical tests. The test results indicate that the device is accurate within acceptable bounds for automated blood pressure instruments.

Analog-Digital Conversion↗

PubMed1989

[Clinical evaluation of the GaALAs laser treatment for hypersensitive dentin].

The methods available for treatment of hypersensitive dentin include the application of heavy metal salts such as diamine silver fluoride to the tooth, iontophoresis, Hyper-Band patching and restoration with various filling materials following cavity lining. Laser beam therapy, which has recently been used in dental treatment, is also expected to be applied to the treatment of hypersensitive dentin. In the present study, we obtained interesting results from the clinical use of a GaAlAs semiconductor Laser (Semilaser Nanox LX-800, GC Co.). The subjects were 63 patients with hypersensitive dentin: 8 patients without the exposed root, 40 with the exposed root, 21 treated with filling materials, 5 given Hyper-Band treatment, 14 with wedge-shaped defect, attrition or abrasion, and one with primary caries. Twenty-six fell into two or more categories. The effect of treatment was assessed by a single examiner in order to minimize error of estimates. Each lesion was directly irradiated for less than 3 minutes, and assessment of the result was conducted according to the criteria and method of Suzuki and Ishikawa. The results were as follows: The treatment was markedly effective in 44 (69.8%), effective in 12 (19.0%) and not effective in 7 (11.1%) of 63 patients. No case of exacerbation was found. The efficacy rate was 88.9%.

Dental Caries↗

PubMed1989

[Quantitative measure of the output of the deep abdominal vessels with a new device Duplex. Preliminary results].

Deep abdominal vessels blood flow can be measured noninvasively with the relation Q = V x A, where Q = flow, V = blood velocity and A = area of the considered vessel. In most Duplex devices, V is only calculated as a mean by the Doppler effect and A estimated by an echograph. Our newly developed multi-gated pulsed Doppler provides the velocity profile across the vessel, so minimizing errors in flow determination. On fifty healthy volunteers, we found flow of 717 +/- 238 ml/min for the portal vein, 1594 +/- 293 ml/min for the upper abdominal aorta and 794 +/- 168 ml/min for the lower aorta. These results are obtained through many technical and practical problems, but are feasible, even if still subject to errors. Further investigation will determine if the technique is also suitable for patients. Better assessment of deep abdominal vessels hemodynamics may be expected.

Adult↗

PubMedDate not supplied

Neuro-oncological problems in the histological diagnosis of stereotactic biopsies.

Stereotactic biopsy, together with CT and MRI, plays a very important role in the diagnosis of intracranial neoplasms and in their subsequent treatment. Serial neuroimaging-driven biopsies are considered the method of choice when dealing with gliomas, due to their well know morphological dishomogeneity; peritumoral tissues can also be investigated. Oncotype diagnosis, identification of malignancy grading and delimitation of the tumor are evaluated both with the quick perioperatory method of smears and then, in order to minimize errors, definitively evaluated on the paraffin-embedded specimens. Despite these precautions, several specific criteria must be taken into account in order to achieve the correct diagnosis.

Biopsy↗

PubMed1989

Measurement of regional myocardial blood flow in hypertrophic cardiomyopathy: application of the first-pass flow model using [13N]ammonia and PET.

Positron emission tomography (PET) has become an important tool in the study of regional myocardial blood flow. The purpose of the present study was to measure regional myocardial blood flow using dynamic [13N]ammonia PET and the first-pass flow model. Thirteen patients with hypertrophic cardiomyopathy, and with a considerably thickened ventricular wall (25 mm or greater), were selected for the study in order to minimize errors due to spillover of radioactivity from blood to the myocardium and to the underestimation of myocardial activity caused by the partial volume effect. Arterial input function was determined by assigning a region of interest to the left atrial cavity on the PET images. Using left atrial and myocardial time-activity curves, regional myocardial blood flow was calculated using the first-pass flow model. Mean myocardial blood flow ranged from 47.8 to 76.5 ml/min per 100 g (63.0 +/- 9.4). Regional myocardial blood flow in the septum was significantly lower than in the anterior and lateral walls of the left ventricle (P less than .01). These results indicate the potential usefulness of dynamic PET in the measurement of regional myocardial blood flow in man.

Adult↗

PubMed1988

The use of ambulatory blood pressure monitoring to improve the accuracy and reduce the numbers of subjects in clinical trials of antihypertensive agents.

A low-cost ambulatory blood pressure measuring device has been developed from a commercially available stationary apparatus. The device, which has been compared for accuracy with a mercury manometer, has functioned satisfactorily as an ambulatory monitor for 4 years. To minimize errors, blood pressure readings were made in the sitting position at half-hourly intervals over the waking day. The utility of the device in clinical trials has been investigated. On repeated readings no placebo effect on blood pressure was detectable and the mean difference between two readings in 42 subjects was 1.9/-0.33 mmHg. The standard deviation of the difference were 8.1/5.6 mmHg. This should make it possible to detect differences of 8/5 mmHg between two treatments in about 16 subjects. There was no detectable tendency for blood pressure to change during the day but the variability between readings was substantially increased if the observation periods were reduced to 4 h.

Adult↗

PubMed1985

A comprehensive computer system for anesthetic record retrieval.

We have developed computer software to store data on all surgical and obstetrical anesthetics administered by our department. The computer system provides information for monitoring the residency training program, department and operating room management, professional fee billing, and research. It imposes little additional workload on our clinical personnel, who use simple codes to record the necessary data directly on the anesthetic record. Department secretarial staff transcribe data from the anesthesia and operating room records into the computer file, which is then available for producing scheduled reports and for answering inquiries from a video terminal. The system employs extensive manual and computer verification to minimize errors and omissions in the data. We report design details and more than 3.5 years experience with this system, which is now used at four affiliated teaching hospitals, has over 50,000 cases on file, and adds more than 1800 cases monthly.

Anesthesia↗