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PubMed1981

A reassessment of sensory evoked potential parameters in multiple sclerosis: a discriminant analysis approach.

The sensitivity of the different parameters (absolute latency, interwave latency, latency asymmetry, amplitude) of both cervical and cerebral responses evoked by stimulation of the median nerve at the wrist was assessed in patients with multiple sclerosis by discriminant analysis. The peak latency of N13 or N20 SEP components or both was found to be more sensitive than their amplitude, provided that a preliminary covariation with the height of the subjects was performed. The measurement of latency asymmetry between the two sides increased the test's sensitivity, while amplitude asymmetry turned out to be of little diagnostic value. A linear discriminant function with four variates (that is mean amplitude, mean latency, latency asymmetry and height of the subject) was computed to summarise the information provided by the different parameters to give a rapid and exact method for the assessment of SEP abnormalities in multiple sclerosis patients.

Adolescent↗
PubMed1981

Discrimination analysis as a tool for classifying the value of biochemical and immunological tests in lung cancer.

The data obtained with routine biochemical, immunological and haematological tests in healthy blood donors and in patients with lung cancer were subjected to discrimination analysis with the aim to select the minimum possible combination of methods with the highest probability of distinguishing between the two groups. Transformation of lymphocytes (TR.LY) after PHA stimulation, formation of E-rosettes (E-ROS), and blood glycoproteins (GP) were shown to permit the most complete differentiation between the group of patients and the blood donors. On the basis of the above-mentioned tests the discrimination rule could be defined: IF 52,73249 - 0.45913 X E-ROS - 0.40752 X TR.LY + 0.02790 X GP greater than or equal to 0, then the investigated person is classified as a cancer patient while at values less than 0 the person is classified as a healthy individual.

Computers↗
PubMed2003

Splice site prediction with quadratic discriminant analysis using diversity measure.

Based on the conservation of nucleotides at splicing sites and the features of base composition and base correlation around these sites we use the method of increment of diversity combined with quadratic discriminant analysis (IDQD) to study the dependence structure of splicing sites and predict the exons/introns and their boundaries for four model genomes: Caenorhabditis elegans, Arabidopsis thaliana, Drosophila melanogaster and human. The comparison of compositional features between two sequences and the comparison of base dependencies at adjacent or non-adjacent positions of two sequences can be integrated automatically in the increment of diversity (ID). Eight feature variables around a potential splice site are defined in terms of ID. They are integrated in a single formal framework given by IDQD. In our calculations 7 (8) base region around the donor (acceptor) sites have been considered in studying the conservation of nucleotides and sequences of 48 bp on either side of splice sites have been used in studying the compositional and base-correlating features. The windows are enlarged to 16 (donor), 29 (acceptor) and 80 bp (either side) to improve the prediction for human splice sites. The prediction capability of the present method is comparable with the leading splice site detector--GeneSplicer.

Algorithms↗
PubMed1985

Depressed patients and non-psychiatric controls: discriminant analysis on social environment variables.

A set of variables from the social environment (e.g. social contacts, confiding relationships, leisure activities, loneliness) was used to differentiate between a consecutive series of 111 patients diagnosed as having a depressive illness and a sample of 98 non-psychiatric controls. The function derived from the discriminant analysis correctly classified 83% of the subjects. The results indicate shortcomings in the social environment of depressives and point to the discriminating power of such variables.

Adjustment Disorders↗
PubMed1978

Differentiation between benign and malignant monoclonal gammopathies by discriminant analysis on serum and bone marrow parameters.

Bone marrow samples of 28 individuals with clinically benign and of 41 patients with malignant monoclonal gammopathy were analyzed for the total number of lymphoplasmocellular elements containing cytoplasmic immunoglobulins and for the monoclonal fraction of these cells. Monoclonal immunoglobulin components were determined in sera. A discriminant analysis was performed on the data: the variables were transformed and in a stepwise procedure used for the construction of a discriminant function which by adividing point allowed a good distinction between the two groups of patients. By use of this discriminant function, 91% of the patients in the sample were correctly classified.

Adult↗
PubMed1975

[A prognostic index in acute myocardial infarction: discrimination analysis of clinical parameters on admission to hospital (author's transl)].

In 301 patients admitted to an intensive-care unit because of acute myocardial infarction a prognostic analysis was undertaken, based on 21 parameters (history, condition on admission, laboratory results) and related to ultimate outcome. Although some parameters were singly of prognostic value, discrimination analysis markedly improved predictive value. A prognostic index was constructed from seven easily available parameters: age, pulmonary congestion, leucocytosis, peripheral vasoconstriction, systolic blood pressure, site of infarct and hypertension. For those in a low-risk class (index less than 60, death-rate up to 5%), duration of stay in the intensive-care unit may be shortened and rehabilitation measures accelerated. Those at moderate risk (index 60-90, death-rate up to 25%) require careful monitoring. The highest risk classes (index 90-120, death-rate up to 90%; and index more than 120, death-rate more than 90%) require specially intensive and long-term monitoring, and various procedures for assisted circulation and possible cardiacsurgical intervention should be considered from the outset.

Acute Disease↗
PubMed1987

Screening for marasmus: a discriminant analysis as a guide to choose the anthropometric variables.

In a cross-sectional study, children 0-6 yr of age from eight different population groups in Africa and Asia were examined. Clinical assessment defined 8750 children as being well nourished and 194 as having marasmus. Height, weight, arm circumference (AC), and triceps skinfold thickness were measured; the latter two measurements and the clinical assessment were done by the same observer. Based on data from normal children, local growth curves were computed for each group. Each child's growth was expressed in standard deviation scores (SDS) of his own group. On the basis of the results of a discriminant analysis, all variables were ranked by their decreasing power to discriminate between normal and marasmic children. For 83% of the children one measurement (AC/age) is sufficient to classify them definitely; for the others several variables are needed. This strategy yields an overall sensitivity of 80%, a specificity of 97%, and a positive predictive value of 38%.

Africa↗
PubMed1980

The potential of multivariate discriminant analysis in the antenatal detection of neural tube defects.

A method is described which improves the ability to distinguish between normal and neural tube-defective fetuses in utero. Early second trimester amniotic fluid is classified by stepwise discriminant analysis based upon biochemical analysis for alpha-fetoprotein and eight other easily assayed variables; classification is more reliable than using alpha-fetoprotein and gestational age alone.

Amniotic Fluid↗
PubMedDate not supplied

Discriminant analysis of lower respiratory tract components associated with cigarette smoking, based on quantitative sputum cytology.

Cigarette smoking is the major contributor to chronic bronchial irritation, and tobacco smoke is the most common bronchial carcinogen. A newly developed quantitative sputum cytology test was applied to three-day-pooled, spontaneously produced sputa collected from 349 cigarette smokers and 93 patients who had never smoked; the samples were processed by the Saccomanno technique. In addition to identifying malignant and precancerous cells in sputum, this test identifies eight morphologic parameters of bronchial irritation. Cross-sectional analysis of the cytologic data indicated that, within a 99% confidence interval, cigarette smokers had statistically significantly higher levels of all eight components, producing a unique profile. Discriminant analysis revealed that pigmentation of macrophages, alveolar macrophages and mucous spirals (in that order) were the leading components differentiating smokers from nonsmokers. This new quantitative sputum cytology test correlates with the model of lung carcinogenesis. The detection of proliferative cellular alterations, such as benign and early atypical metaplasia, represent the detection of chronic persistent irritation, which is considered to be a reversible change. The ability to monitor individual responses to toxic inhalants (before the development of irreversible disease) by utilizing a noninvasive test represents a unique opportunity to impact the historic course of lung carcinogenesis.

Adult↗
PubMed1989

Effectiveness of discriminant analysis of serum CA 19-9 and elastase 1 in diagnosis of pancreatic carcinoma.

The accuracies of assays of serum CA 19-9 and elastase 1 in the diagnosis of pancreatic carcinoma were investigated by the cutoff method and discriminant analysis of data on 98 patients with pancreatitis, 65 patients with pancreatic carcinoma, 107 patients with benign diseases of other organs, and 108 patients with cancer of other organs. Comparison of the diagnostic accuracies of the cutoff method and multivariate analysis of CA 19-9 and elastase 1 showed that the latter was better for diagnosis in terms of its specificity. The performance of multivariate analysis was validated on independent data consisting of 52 patients with pancreatitis, 27 patients with pancreatic carcinoma, 79 patients with benign diseases of other organs, and 29 patients with cancer of other organs. Multivariate analysis of CA 19-9 and elastase 1 was very useful for differentiation of patients with and without pancreatic carcinoma: 24 (88.9%) of 27 patients with pancreatic carcinoma were correctly classified. Moreover, by this method, all patients with pancreatic carcinoma of less than 2 cm in longest diameter and 81.3% of those without jaundice were correctly classified.

Adult↗
PubMedDate not supplied

The performance of logistic discrimination on myocardial infarction data, in comparison with some other discriminant analysis methods.

The Imminent Myocardial Infarction study Rotterdam (IMIR), concerns patients who visit their general practitioners and have complaints suspected to be of cardiac origin. The study aims to develop a protocol for diagnosing myocardial infarction without laboratory assistance. We use the IMIR data, consisting of continuous and binary variables, to compare the diagnostic performance of logistic discrimination with some other discriminant analysis techniques. We discuss which characterizations of mixed data sets may give indications for an appropriate choice from among the alternative methods for discrimination.

Humans↗
PubMed1978

The use of discriminant analysis to define obesity in children aged 7-11 years.

All the elementary schoolchildren (ages 7-11 years) in the city of Aosta were diagnosed clinically for obesity and measured for height, weight and triceps and subscapular skinfolds. A statistical discriminant analysis revealed that, on the basis of these measurements, this population of children could be divided into a group of normal children and one or more distinct populations of obese children. To the extent that these groups reveal qualitative phenotypic differences, they should simplify genetic studies of obesity.

Body Height↗
PubMed1991

Schizophrenia, bipolar disorder and depression. A discriminant analysis, using 'lifetime' psychopathology ratings.

Discriminant and canonical variate analyses were performed using 302 patients, on whom ratings of lifetime psychopathology and course of illness has been made. DSM-III diagnoses were used to form the criterion groups. Bipolar disorder emerged as a distinct grouping, but there are reasons for dissatisfaction with its definition. The remaining patients formed a 'schizodepressive continuum', but this also had a tendency to bimodality. It is possible that the distinction between schizophrenia and depression was obscured by inadequacies in the data and the inclusion of excessive numbers of patients with schizoaffective depression in this study.

Adolescent↗
PubMed1986

Sex determination of prehistoric central California skeletal remains using discriminant analysis of the femur and humerus.

A large sample (n = 370) of Central California prehistoric skeletal remains was analyzed for sexual dimorphism of long bones using nine femoral and nine humeral dimensions. Sex of all individuals was assessed using traits of the os pubis. Discriminant analysis was done separately for the robust Early Horizon sample and the Middle/Late Horizon sample. Use of multiple variables did not produce appreciably better results over the use of several of the best variables, analyzed singly. Attention is focused on measurements of maximum diameter femoral head, femoral bicondylar width, and diameter of the humeral head (transverse or vertical). These variables produce excellent separation of the sexes with about 90% accuracy for the Middle/Late Horizon sample. They have been overlooked in the recent literature in which the relative values of length versus midshaft dimensions are debated. The measurements found to be superior in this study are taken at the ends of the bones where durability of these regions is indicated by large sample sizes found in this study. We suggest workers redirect their focus from the midshaft to the ends of the long bones. The discriminant analyses presented here have greater accuracy than most claims for either long bone or cranial sex determination. These standards, based on two samples with differing robusticity, may have applicability for workers in other areas who lack large skeletal samples.

Animals↗
PubMed1983

Determinants of organ malfunction or death in patients with intra-abdominal sepsis. A discriminant analysis.

One hundred and six patients found at operation to have intra-abdominal sepsis were prospectively followed up to determine the incidence of organ malfunction and death. These outcomes were correlated with age, preexisting disease, underlying cause of sepsis, shock, nutritional status, and alcoholism. Organ malfunction occurred in 31 patients (29%), 19 (61%) of whom died. Two (3%) of 75 patients without organ malfunction died. Discriminant analysis revealed a significantly increased risk of death in patients with shock at any time, age greater than 65 years, alcoholism, bowel infarction, or malnutrition. A discriminant equation based only on preoperative variables correctly assigned the outcome of death or survival in 97 (92%) of the patients based on probabilities derived from this analysis. At present, this information is primarily of interest for researchers comparing outcomes in groups of patients, but with additional refinements it may become clinically useful for individual patients.

Abdomen↗
PubMed1999

Dental arch size in healthy human permanent dentitions: ethnic differences as assessed by discriminant analysis.

Race and ethnicity variably influence the form of the human craniofacial complex. In the present study, the effects of ethnicity and sex on the global size of normal adult dental arches were analyzed. The dental arches of 47 northern Chilean mestizos (25 men, 22 women) and 95 northern Italian Caucasians (50 men, 45 women) were cast in stone. All subjects had a complete dentition in both arches. In all models the coordinates of dental cusp tips were digitized using an image analyzer. The center of gravity of each tooth was computed and arches were interpolated using a polynomial model (y = ax + bx2 + cx3 + dx4). In all arches, the intercanine, intermolar, and mid-intercanine to mid-intermolar distances were computed from the dental centers of gravity. These arch distances were entered in a linear discriminant function analysis. The polynomial model accurately interpolated data points in all instances, and most of the dental arch form was determined by the first and second degree coefficients. On average, Italian Caucasian arches were smaller than Chilean mestizo arches. Male mean distances were larger than female distances regardless of ethnic group or arch. The linear discriminant analysis performed between male and female arches within ethnic groups was significant only for both Italian Caucasian arches, but the percentage errors for the classification of a new individual were very high (about 30%). Conversely, Italian Caucasian arches could always be discriminated from Chilean mestizo arches of the same sex with a much smaller error.

Adult↗
PubMed1979

Factors in the drug involvement of inner city junior high school youths: a discriminant analysis.

Data from a survey of youths attending an inner city junior high school were examined to learn how their demographic characteristics, socio-cultural experiences and the drug use existing among their neighbourhood peers related to their involvement with substances. Discriminant analysis uncovered two important factors that were associated with the youths' drug taking: (1) a street scene, social/recreational drug use factor and (2) a cluster reflecting friends' use of alcohol/marijuana and other drugs. The implications of these results for drug abuse prevention programming are explored.

Adolescent↗
PubMed1982

Factor and discriminant analysis of the Bem Sex-Role Inventory.

Several studies have recently recommended that items which fail to load substantially (< .40) on one of several primary factors characterizing the Bem Sex-Rote Inventory (BSRI) could be deleted without substantial loss of interpretability. This recommendation is questioned on the basis that the extent of interrelatedness of the items is an insufficient indicator of the contribution each item makes towards the classification (identifying sex-types by Bem's median split technique) efficiency of the inventory. Empirical support of this contention was provided by conducting several discriminant analyses (predicting sex-types) on a sample of 1117 BSRI protocols and excluding the various items suggested by the earlier research. These results were then compared with the results of a discriminant analysis using the 40 masculine and feminine items. The analyses using less. than all 40 items produced substantially poorer discrimination than when all 40 items were included. The results Suggest that decisions to exclude items on the basis of factor analysis may be inappropriate and risk serious loss of power in classifying individuals by sex-type.

Journal Article↗