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At least 19 recordsLinked to original sources
PubMed2005

[Combined use of factor analysis and cluster analysis in classification of traditional Chinese medical syndromes in patients with posthepatitic cirrhosis].

OBJECTIVE: To explore the significance of the combination of factor analysis and systematic cluster analysis in classification of traditional Chinese medical syndromes in patients with posthepatitic cirrhosis, and to provide a scientific basis for the criterion of the classification. METHODS: We designed a clinical questionnaire according to the clinical characteristics and the demands of traditional Chinese medical information collection for patients with posthepatitic cirrhosis. By means of clinical epidemiological research, with the four diagnosis methods for clinical information collection of traditional Chinese medicine, symptoms, physical signs, tongue conditions and pulse conditions in 310 patients with posthepatitic cirrhosis were collected, and the characteristics of traditional Chinese medical syndromes in these patients were explored with statistical methods, such as factor analysis, varimax and systematic cluster analysis. RESULTS: Analyzed by factor analysis and systematic cluster analysis with SPSS 11.0, the traditional Chinese medical syndromes in 287 of the 310 cases (92.58%) of posthepatitic cirrhosis could be classified. The syndromes could be divided into 7 categories, which were internal accumulation of damp-heat (55 cases), insufficiency of the spleen with overabundance of dampness (74 cases), accumulation of blood stasis plus deficiency of liver-yin and kidney-yin (73 cases), accumulation of blood stasis plus deficiency of both blood and qi (40 cases), deficiency of both blood and qi (16 cases), deficiency of yin and blood heat (6 cases) and stagnation of the liver-qi and deficiency of the spleen (23 cases). The traditional Chinese medical syndromes in the other 23 cases could not be classified. CONCLUSIONS: The clinical information collected with the four diagnostic methods of traditional Chinese medicine can be classified into different categories with the factor analysis and systematic cluster analysis. The factor analysis and systematic cluster analysis can reveal the characteristics and regularity of traditional Chinese medical syndromes in patients with posthepatitic cirrhosis in a way, and have value in researching the syndromes of traditional Chinese medicine.

Adult↗
PubMed2006

[Applying matching matrix, factor analysis and clustering analysis to investigation of characteristics of syndromes of phlegm and blood stasis in patients with coronary heart disease].

OBJECTIVE: To investigate the characteristics of syndromes of phlegm and blood stasis in patients with coronary heart disease by multiple statistical methods of matching matrix, factor analysis and clustering analysis, and to provide some references for classification and normalization of diagnosis of syndromes of phlegm and blood stasis of coronary heart disease. METHODS: The correlations among 46 kinds of symptoms in syndrome of non-phlegm and non-blood stasis, syndrome of blood stasis, syndrome of phlegm and syndrome of phlegm-blood stasis blocking in 200 patients with coronary heart disease were analyzed by matching matrix, factor analysis and clustering analysis. RESULTS: The manifestations of tongue and pulse in syndromes of phlegm and blood stasis were significantly different from those in syndrome of non-phlegm and non-blood stasis. The pathogenesis of viscera in syndromes of phlegm and blood stasis lied in the heart and kidney, and the syndrome of deficiency of heart qi was the most common one while the syndrome of deficiency of kidney qi took the secondary place. The syndrome of phlegm was often accompanied by syndrome of deficiency of spleen qi. Only 15 ones of 46 clinical symptoms showed high frequency in concomitant appearance in syndrome of blood stasis, syndrome of phlegm and syndrome of phlegm-blood stasis blocking. Apart from having the common symptoms in syndrome of deficiency in origin, the syndrome of phlegm especially showed white and greasy fur and slippery pulse as well as distention and fullness of chest and abdominal distension; the syndrome of blood stasis showed purplish tongue and ecchymosis on tongue as well as fixed pain; and the syndrome of phlegm-blood stasis blocking showed the main symptoms of both syndrome of phlegm and syndrome of blood stasis. CONCLUSION: The statistical methods of matching matrix, factor analysis and clustering analysis are convenient, and can definitely indicate the clinical characteristics and syndrome differentiation of viscera of different syndromes of phlegm and blood stasis, which are beneficial to further research of diagnosis and differentiation of such syndromes of coronary heart disease.

Cluster Analysis↗
PubMed2004

Mixture modelling for cluster analysis.

Cluster analysis via a finite mixture model approach is considered. With this approach to clustering, the data can be partitioned into a specified number of clusters g by first fitting a mixture model with g components. An outright clustering of the data is then obtained by assigning an observation to the component to which it has the highest estimated posterior probability of belonging; that is, the ith cluster consists of those observations assigned to the ith component (i = 1,..., g). The focus is on the use of mixtures of normal components for the cluster analysis of data that can be regarded as being continuous. But attention is also given to the case of mixed data, where the observations consist of both continuous and discrete variables.

Australia↗
PubMed1994

Improvements to the quality of MRI cluster analysis.

Cluster analysis techniques are gaining widespread use for segmentation of MRI data, especially for volume measurement and 3-D display purposes. This paper describes four improvements to such techniques: (1) The use of intensity simulations to model cluster plots; (2) Correction of image nonuniformity; (3) Anisotropic smoothing of data; and (4) Automatic isolation of tissues of interest. Simulation of cluster plots allows an informed choice of pulse sequence(s) and acquisition parameters to be made. Correction of image nonuniformity and anisotropic smoothing reduce the spread of signal intensity from a single tissue thus producing significantly more compact clusters, whilst the isolation of tissues of interest prevents overlap of clusters from the tissues of interest with those not under consideration. These techniques may be used to improve the results of cluster analysis or traded off, for example to allow lower signal-to-noise images, shorter repetition time images, or fewer images to be used for segmentation.

Cluster Analysis↗
PubMed1996

Cluster analysis.

Cluster analysis was performed on flow cytometry data generated from the reactivities of the 302 workshop monoclonal antibodies with 36 target cell preparations. The antibodies were assigned to 42 preliminary clusters that were subjected to further examination in subsequent stages of the workshop.

Animals↗
PubMed1984

Statistical factor analysis and cluster analysis in the etiology of climacteric symptoms.

Factor analysis and cluster analysis were applied to a set of 17 climacteric symptoms data obtained from 194 premenopausal and postmenopausal women. Six distinct factors were extracted and the women were divided into 7 groups by hierarchical cluster analysis in terms of their factor scores. Only one representative factor was identified in 3 groups out of the 7. These 3 groups including 87 women were tentatively designated as vasomotor symptom, neurotic, and sensory disturbance groups. These results confirmed statistically that at least 3 simple etiological factors exist among climacteric symptoms.

Adult↗
PubMedDate not supplied

[The malariological zoning of the Guyana portion of the nosogeographical range of malaria based on cluster analysis].

Cluster analysis of malaria incidence in Guyana revealed a relationship between population migration intensity and increased rate of P falciparum infection. Such a relationship was not detected for P. vivax malaria. Seasonal differences in malaria incidence are explained by changes in vector ratio. Malariogenic stratification helped clear out the role of three main malaria vectors in different regions of Guyana.

Adolescent↗
PubMed2005

Parametric image of myocardial blood flow generated from dynamic H2(15)O PET using factor analysis and cluster analysis.

Algorithm-based parametric imaging of myocardial blood flow (MBF), as measured by H2(15)O PET, has been the goal of many research efforts. A method for generating parametric images of regional MBF by factor and cluster analysis on H2(15)O dynamic myocardial PET was validated by its comparison with gold-standard MBF values determined invasively using radiolabelled microspheres. Right and left ventricular blood pool activities and their factor images were obtained by the application of factor analysis to dynamic frames. By subtraction of the factor images multiplied by their corresponding values on the factors from the original dynamic images for each frame, pure tissue dynamic images were obtained, from which arterial blood activities were excluded. Cluster analysis that averaged pixels having time-activity curves with the same shape was applied to pure tissue images to generate parametric MBF images. The usefulness of this method for quantifying regional MBF was evaluated using canine experiment data. H2(15)O PET scans and microsphere studies were performed on seven dogs at rest and after pharmacological stress. The image qualities and the contrast of parametric images obtained using the proposed method were significantly improved over either the tissue factor images or the parametric images obtained using a conventional method. Regional MBFs obtained using the proposed method correlated well with those obtained by the region of interest method (r = 0.94) and by the microsphere technique (r = 0.90). A non-invasive method is presented for generating parametric images of MBF from H2(15)O PET, using factor and cluster analysis.

Animals↗
PubMed2000

Principal component analysis and cluster analysis for the characterization of dental composites.

Various experimental dental materials were characterized using chemometric methods. The main aim of the study was to ascertain which composite materials present the best properties for use in restorative dentistry. Bisphenol-alpha-glycidyl methacrylate-based composites containing hydroxyapatite as a filler and a coupling agent were prepared using a photocuring polymerization procedure. Several chemical and mechanical properties of experimental composites were measured and the corresponding data were further studied using principal component analysis and cluster analysis. Results from the characterization allowed the most appropriate materials to be selected. Various composites presented acceptable general properties suggesting their suitability as substitutes for commercial materials in dentistry.

Cluster Analysis↗
PubMed2001

Use of multiple correspondence analysis and cluster analysis to study dietary behaviour: food consumption questionnaire in the SU.VI.MAX. cohort.

Although the effects of individual foods or nutrients on the development of diseases and their risk factors have been investigated in many studies, little attention has been given to the effect of overall dietary patterns. The main objectives of this study were to identify dietary patterns and groups of subjects with similar food consumption habits, i.e. 'dietary profiles', using multiple correspondence analysis and cluster analysis. A food frequency questionnaire was sent to a large population-based sample (2923 women and 2,180 men), recruited among the 'SUpplementation en VItamines et Minéraux AntioXydants' (SU.VI.MAX.) cohort participants in France. The food items were dichotomised in order to focus the study on the highest levels of consumption. Multiple correspondence analysis allows the construction of principal components, which optimally summarise the data, and enables the construction of graphical displays. An interesting property of these graphical displays is that associations between food items can be observed on various projection planes, each category of each food item being located at the centre of gravity of the subjects corresponding to this category. An ascending hierarchical classification was unsuccessfully tried in order to determine clusters from these principal components. Therefore, a 'dissection' of the cloud of points was performed according to the orientation of the axes, providing a readily interpretable eight-dietary profiles typology for each sex. This statistical approach allows identification of particular dietary patterns and dietary profiles, which might be more appropriate in studies of diet-disease associations than the single food or nutrient approach that has dominated past epidemiological research.

Adult↗
PubMed1980

Classification of organic brain syndromes by cluster analysis.

Cluster analysis was carried out on a sample of 92 patients with behavior disorders caused by degenerative, vascular, (alcohol) toxic, and other diseases of the brain. Rating variables of the AMDP system concerning mental state, social behavior, need for special care, sleep disorders, autonomic, physical, and neurologic symptoms were used in the absence of severe degrees of disordered consciousness such as stupor, coma, delirium tremens, and gross cerebral lesions. Results suggested the existence of four major groups of global cognitive impairment combined with neurasthenia and irritability in the first, hypochondriasis and depression in the second, withdrawal symptoms in the third, and severe disorientation in the fourth. At the seven-group level the groups were further distinguished according to severe withdrawal, amnestic syndrome, and dementia by various social and illness behaviors, sleep-wakefulness pattern, hypo- or hyperactivity, additional physical, and neurologic symptoms. Other minor types of organic brain syndromes were identified as individual cases by hallucinations or other circumscribed cognitive, psychomotor, affect, motivation, personality, and/or behavior disorder, symptomatic manic, or schizophreniform psychosis. The findings lent support to old classifications and new ones of organic mental syndromes (DSM-III).

Adult↗
PubMed2006

[Principal component analysis and cluster analysis of inorganic elements in Panax quinque folium. L].

The contents of elements such as Mg, Al, P, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd and Pb in twelve Panax quinque folium. L samples were determined by means of ICP/MS. The results were used for the development of element fingerprint chromatogram. The principal component analysis of SPSS was applied for the study of characteristic elements in Panax quinque folium. L. Five principal components which accounted for over 90% of the total variance were extracted from the original data. The analysis results show that Fe, Al, V, Mn, Mg, Sr, Mo, Ca and Cu may be the characteristic elements in Panax quinque folium. L. The results of Q-type cluster analysis show that the samples could be clustered reasonably into five groups, and the elemental distribution characteristics are related to the breeds of Panax quinque folium. L.

Cluster Analysis↗
PubMed2001

Principal component analysis and cluster analysis for measuring the local organisation of human atrial fibrillation.

The distribution of atrial electrogram types has been proposed to characterise human atrial fibrillation. The aim of this study was to provide computer procedures for evaluating the local organisation of intracardiac recordings during AF as an alternative to off-line manual classification. Principal component analysis (PCA) reduced the data set to a few representative activations, and cluster analysis (CA) measured the average dissimilarity between consecutive activations of an intracardiac signal. The data set consisted of 106 bipolar signals recorded on 11 patients during electrophysiological studies for catheter ablation. Performances of PCA and CA in distinguishing between organised (type I) and disorganised (type II/III, Wells criteria) were assessed, in comparison with manual reading, by evaluating the predictive parameters of the classification analysis. Both methods gave high accuracy (92% for PCA and 89% for CA), confirming the feasibility of on-line characterisation of AF. Sensitivity was lower than specificity (81% against 98% for PCA, and 77% against 97% for CA), with seven out of eight misclassifications of PCA in common with CA. Differences between manual and computer analysis may be related to the higher resolution of PCA and CA in the measurement of the organisation of atrial activations. These procedures are suitable for providing automatic (by CA) or semi-automatic (by PCA) measures of the extent of local organisation of AF in the pre-ablation treatment phase.

Atrial Fibrillation↗
PubMed1978

Classification of suicide attempters by cluster analysis.

Cluster analytic procedures for classification were carried out on a sample of 236 suicide attempters. Rating variables concerned previous suicidal behaviour, details of the recent attempt and its motivation, mental state, and demographic characteristics. Results suggested the existence of three groups of attempters. The first comprised patients taking overdoses, on the whole showing less risk to life, less psychiatric disturbance, and more evidence of interpersonal rather than self-destructive motivation. The second groups, fewer in number, made severe attempts with more self-destructive motivation, by violent methods rather than overdose. The third and smallest group had a previous history of many attempts and gestures, made relatively mild attempts and were overtly hostile, engendering reciprocal hostility in the treating psychiatrist. These groups show some resemblance to those found in other studies.

Adult↗
PubMed1999

Determination of behavioural traits of pure-bred dogs using factor analysis and cluster analysis; a comparison of studies in the USA and UK.

The questionnaire survey of Hart and Hart (1985, Journal of the American Veterinary Medical Association 186, 1811-1815) ranked the 56 most popular breeds of dog in the USA on 13 behavioural traits and is compared here with results of a similar survey conducted on the 49 most popular breeds in the UK. Of the 36 breeds in common between the studies, 24 were similar for the traits aggressivity, reactivity and ease of housetraining between the two countries. However, the characteristics of nine breeds (Airedale Terrier, Old English Sheepdog, Welsh Corgi, Irish Setter, Standard Poodle, Beagle, Samoyed, Boxer, Dalmatian) differed markedly between the two countries, and a further three (Chihuahua, Scottish Terrier, Standard Dachshund) showed smaller, but probably meaningful, shifts. These differences should be recognised when giving advice to prospective owners, and when treating unwanted behaviour in these breeds.

Aggression↗