SEARCH · PubMed Health

Results for “canonical correlation analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources

PubMed1997

Modeling of progressive glomerular injury in humans with lupus nephritis.

We studied glomerular function longitudinally for 36-120 mo in 21 patients undergoing treatment for diffuse, proliferative lupus nephritis. We determined glomerular filtration rate (GFR) and glomerular oncotic pressure (IIGC) and computed the two-kidney ultrafiltration coefficient (Kf) at 6- to 12-mo intervals. The relationships and cross talk among the three variables over time were then analyzed by eigenfunction regression and canonical correlations. We also performed a morphometric analysis of serial biopsies and computed single-nephron Kf in patent glomeruli at baseline and after 36-94 mo of follow-up. Patients were divisible into progressors (n = 12) or nonprogressors (n = 9) according to the presence or absence, respectively, of an irrevocable decline in GFR over time. Examination of longitudinal variables revealed GFR to be strongly related to Kf in all patients and inversely related to IIGC in progressors. By serial morphometric analysis we observed a threefold increase in the prevalence of global sclerosis in progressors but unchanged prevalence in nonprogressors. Whereas single-nephron Kf of remnant glomeruli increased to supernormal levels in nonprogressors, the absence of this compensatory phenomenon in progressors permitted GFR and Kf to decline in parallel with the declining number of functional glomeruli.

Adolescent↗

PubMedDate not supplied

Preseason hamstring muscle weakness associated with hamstring muscle injury in Australian footballers.

Hamstring muscle strain is the most prevalent injury in Australian Rules Football, accounting for 16% of playing time missed as a result of injury. Thirty-seven professional footballers from an Australian Football League team had preseason measurements of hamstring and quadriceps muscle concentric peak torque at 60, 180, and 300 deg/sec measured on a Cybex 340 dynamometer. Players were studied prospectively throughout the 1995 season. During that time, six players sustained clinically diagnosed hamstring muscle injuries that caused them to miss match-playing time. The injured hamstring muscles were all weaker than in the opposite leg in absolute values and hamstring-to-quadriceps muscle ratios. According to our t-test results, hamstring muscle injury was significantly associated with a low hamstring-to-quadriceps muscle peak torque ratio at 60 deg/sec on the injured side and a low hamstring muscle side-to-side peak torque ratio at 60 deg/sec. Flexibility (as measured by the sit-and-reach test) did not correlate with injury. Discriminant-function analysis using the two significant ratio variables resulted in a canonical correlation with injury of 0.4594 and correctly classified legs into injury groups with 77.4% success. These results indicate that preseason isokinetic testing of professional Australian Rules footballers can identify players at risk of developing hamstring muscle strains.

Adult↗

PubMed1986

Sequential estimation of genetic and phenotypic parameters in multitrait mixed model analysis.

Single-trait and multitrait (2-, 3-, 4-, and 5-trait) restricted maximum likelihood methods were applied to the same set of data with complete information on all traits. Results suggest that parameter estimates from a data set vary depending upon the type of analysis (single- or multitrait model) and upon the other traits included in multitrait analysis. The choice of parameter estimation method for a breeding design should be based on the breeding goal. In parameter estimation or sire evaluation, traits included in a multitrait analysis should correspond to the traits of interest in the breeding goal. Multitrait analysis explores all intercorrelations simultaneously in parameter estimation and thus provides a complete picture of all interrelationships among traits. In contrast, single-trait analysis produces pairwise (simple) correlations and ignores the possible contribution of other related traits under study to the pairwise correlation. The 5-trait model analysis through canonical transformation was about 300% more efficient in terms of computer time than single-trait model analysis of the same 5 traits. In this study, parameter estimates converged faster under multitrait analysis through canonical transformation than under single-trait analysis.

Animals↗

PubMed1999

Three pollination guilds and variation in floral characteristics of Bornean gingers (Zingiberaceae and Costaceae).

The pollinators of 29 ginger species representing 11 genera in relation to certain floral morphological characteristics in a mixed-dipterocarp forest in Borneo were investigated. Among the 29 species studied, eight were pollinated by spiderhunters (Nectariniidae), 11 by medium-sized Amegilla bees (Anthophoridae), and ten by small halictid bees. These pollination guilds found in gingers in Sarawak are comparable to the pollination guilds of neotropical Zingiberales, i.e., hummingbird-, and euglossine-bee-pollinated guilds. Canonical discriminant analysis revealed that there were significant correlations between floral morphology and pollination guilds and suggests the importance of plant-pollinator interactions in the evolution of floral morphology. Most species in the three guilds were separated on the plot by the first and second canonical variables. Spiderhunter-pollinated flowers had longer floral tubes, while Amegilla-pollinated flowers had wider lips than the others, which function as a platform for the pollinators. Pistils and stamens of halictid-pollinated flowers were smaller than the others. The fact that gingers with diverse morphologies in a forest with high species diversity were grouped into only three pollination guilds and that the pollinators themselves showed low species diversity suggests that many species of rare understory plants have evolved without segregating pollinators in each pollination guild.

Journal Article↗

PubMed1985

Dentoskeletal and tongue soft-tissue correlates: a cephalometric analysis of rest position.

The relationship between dentoskeletal and tongue soft-tissue variables has been quantified in a sample of 60 adult females with normal and anterior open-bite malocclusions. Three lateral rest-position head films were obtained for each subject. A principal component analysis reduced the data base and six significant canonical correlations were identified. The first canonical correlation (r1 = 0.962) represented a size-related correlation factor between the two groups of variables. Subjects with characteristics of a short face syndrome and some evidence of overbite had tongue tips positioned below the lower occlusal plane (r2 = 0.929). In contrast, skeletal open-bite subjects (r4 = 0.759) revealed tongue tips ahead of and above the lower incisor teeth with the mandible in the rest position. Undererupted mandibular teeth (r5 = 0.666) were associated with a reduced tongue height and an inferior epiglottis; short tongue length (r6 = 0.563) correlated with a linear combination of upright central incisors, a small overjet, a low ANB angle, unerupted maxillary and mandibular teeth, and a steep occlusal plane. The multivariate statistical analysis extracted clinically significant associations between tongue soft-tissue and dentoskeletal variables. Tongue posture at rest in skeletal open-bite subjects appeared to be related to incisor position.

Adolescent↗

PubMed1986

Correlation of acute pericoronitis and the position of the mandibular third molar.

Acute pericoronitis is a painful, debilitating infection that is most commonly found among young adults with erupting mandibular third molars. Prophylactic removal of third molars to prevent this disease has been advocated, but this procedure requires an accurate description of the third molar at highest risk for this infection. Clinical and radiographic measurements were compared in 25 diseased subjects and 109 normal subjects. Of 10 variables significantly related to the presence of acute pericoronitis, stepwise discriminant analysis selected 4 variables that produced a canonical correlation coefficient of 0.71. In clinical terms, these variables described the tooth at highest risk for acute pericoronitis as a fully erupted, vertical mandibular third molar that is in contact with the adjacent second molar, at or above the occlusal plane, and partially encapsulated by soft or hard tissues. Prophylactic treatment of these third molars is highly recommended.

Acute Disease↗

PubMed2006

18FDG PET in vascular dementia: differentiation from Alzheimer's disease using voxel-based multivariate analysis.

The brain metabolic pattern of vascular dementia (VaD) remains poorly characterized. Univariate voxel-based analysis ignores the functional correlations among structures and may lack sensitivity and specificity. Here, we applied a novel voxel-based multivariate technique to a large ((18)F)2-fluoro-2-deoxy-D-glucose positron emission tomography data set. The sample consisted of 153 subjects, one-third each being probable subcortical VaD, probable Alzheimer disease (AD) (matched for Mini-Mental-State examination (MMSE) and age), and normal controls (NCs). We first applied principal component (PC) analysis and removed PCs significantly correlated to age. The remainders were used as feature vectors in a canonical variate analysis to generate canonical variates (CVs), that is, linear combinations of PC-scores. The first two CVs efficiently separated the groups. CV(1) separated VaD from AD with 100% accuracy, whereas CV(2) separated NC from demented subjects with 72% sensitivity and 96% specificity. Images depicting CV(1) and CV(2) showed that lower metabolism differentiating VaD from AD mainly concerned the deep gray nuclei, cerebellum, primary cortices, middle temporal gyrus, and anterior cingulate gyrus, whereas lower metabolism in AD versus VaD concerned mainly the hippocampal region and orbitofrontal, posterior cingulate, and posterior parietal cortices. The hypometabolic pattern common to VaD and AD mainly concerned the posterior parietal, precuneus, posterior cingulate, prefrontal, and anterior hippocampal regions, and linearly correlated with the MMSE. This study shows the potential of voxel-based multivariate methods to highlight independent functional networks in dementing diseases. By maximizing the separation between groups, this method extracted a metabolic pattern that efficiently differentiated VaD and AD.

Aged↗

PubMed2000

Multivariate predictive relationship between kinematic and functional activation patterns in a PET study of visuomotor learning.

Imaging studies of visuomotor learning have reported practice-related activation in brain regions mediating sensorimotor functions. However, development and testing of functional motor learning models, based on the relationship between imaging and behavioral measures, is complicated by the multidimensional nature of motoric control. In the present study, multivariate techniques were used to analyze [15O]water PET and kinematic correlates of learning in a visuomotor tracing task. Fourteen subjects traced a geometric form over a series of eight tracing trials, preceded and followed by baseline trials in which they passively viewed the geometric form. Simultaneous evaluation of multiple behavioral measures indicated that performance improvement was most strongly associated with a global performance measure and least strongly associated with measures of fine motor control. Results of three independent analytic techniques (i.e., intertrial correlation matrices, power function modeling, iterative canonical variate analysis) indicated that imaging and behavioral measures were most closely related on early learning trials. Performance improvement was associated with covarying increases in normalized activity among superior parietal, postcentral gyrus, and premotor regions and covarying decreases in normalized activity among cerebellar, inferior parietal, pallidal, and medial occipital regions. These findings suggest that performance improvement may be associated with increased activation in neural systems previously implicated in visually guided reaching and decreased activation in neural systems previously implicated in attentive visuospatial processing.

Adult↗

PubMed1994

Positive health practices and perceived health status in adolescents.

The purpose of this study was to examine the relationships among the components of perceived health status and positive health practices in a sample of 211 adolescents, aged 15 to 21, using canonical variate analysis. All subjects completed the General Health Rating Index, which measures current health, prior health, health outlook, and resistance to illness; and the Personal Lifestyle Questionnaire, which measures exercise, nutrition, relaxation, safety, substance use, and health promotion. Four canonical variates emerged in the statistical analysis, two of which had statistically significant canonical correlations. Implications for nursing practice and research are discussed along with the findings.

Adolescent↗

PubMed2004

Proportion and cluster analyses of the skull in various species of the tree shrews.

The skull adaptation was functional-morphologically examined in 14 species of the tree shrews. From the data of the proportion indices, the similarities were confirmed between T. minor and T. gracilis, T. tana and T. dorsalis, and T. longipes and T. glis. We demonstrated that the splanchnocranium was elongated in terrestrial T. tana and T. dorsalis and shortened in arboreal T. minor and T. gracilis from the proportion data. In both dendrogram from the matrix of the Q-mode correlation coefficients and scattergram from the canonical discriminant analysis, the morphological similarities in the skull shape suggested the terrestrial-insectivorous adaptation of T. tana and T. dorsalis, and the arboreal adaptation of T. minor and T. gracilis. Since the osteometrical skull similarities were indicated among the three species of Tupaia by cluster and canonical discriminant analyses, the arbo-terrestrial behavior and its functional-morphological adaptation may be commonly established in T. montana, T. longipes and T. glis.

Animals↗

PubMed2003

Infant EEG spectral coherence data during quiet sleep: unrestricted principal components analysis--relation of factors to gestational age, medical risk, and neurobehavioral status.

EEG spectral coherence data in quiet sleep of 312 infants were evaluated, at 42 weeks post-menstrual age. All were medically healthy and living at home by time of evaluation. The sample consisted of prematurely bom infants with a wide spectrum of underlying risk factors, as well as healthy full-term infants. Initial 3040 coherence variables were reduced by principal components analysis in an unrestricted manner, which avoided the folding of spectral and spatial information into among-subject variance. One hundred fifty factors explained 90% of the total variance; 40 Varimax rotated factors explained 65% of the variance yielding a 50:1 data reduction. Factor loading patterns ranged from multiple spectral bands for a single electrode pair to multiple electrode pairs for a single spectral band and all intermediate possibilities. Simple left-right and anterior-posterior pairings were not observed within the factor loadings. By multiple regression analysis, the 40 factors significantly predicted gestational age at birth. By canonical correlation, significant relationships were demonstrated between the coherence factors and medical risk factors as well as neurobehavioral factors. Using discriminant analysis, the coherence factors successfully discriminated between infants with high and low medical risk status and between those with the best and worst neurobehavioral status. The two factors accounting for the most variance, and chosen across several analyses, indicated increased left central-temporal coherence from 6-24 Hz, and increased frontal-occipital coherence at 10 Hz, for the infants born closest to term with lowest medical risk factors and best neurobehavioral performance.

Electroencephalography↗

PubMed1994

Assessment of cognitive appraisal and coping linkages using two forms of canonical correlation.

As a conceptual framework for research on stress and coping, the transactional model of Lazarus and Folkman is process-oriented and requires methodologies that capture the process nature of cognitive appraisal and coping across stages of a transaction. Two forms of canonical correlation were used to analyze strength of association measures between pairs of cognitive appraisal and coping variable sets for 138 student subjects. Analysis indicated that, when an environmental transaction includes more than one time period, the generalized canonical correlation approach may offer some advantages in assessing linkage strength over the pairwise method.

Adaptation, Psychological↗

PubMed1991

Structural equation analysis of an exercise/sleep health practices model on quality of life of elderly persons.

An exercise/sleep model from past research was tested for relationships with a quality of life measure of the health status of 126 elderly persons. Past statistical analyses of this relationship used canonical correlation statistical analyses. In the following study, when structural equation analysis (LISREL VII) was applied to the same data, an altered model resulted: an exercise-only model. To examine this relationship further, researchers should employ a longitudinal design with a more comprehensive model and larger sample of elderly persons.

Activities of Daily Living↗

PubMed1988

Latency and accuracy of word recognition in dementia of the Alzheimer type.

The sensitivity of reaction time (RT) measurement in assessing cognitive decline in dementia of the Alzheimer type (DAT) was evaluated. Sixteen DAT patients and 16 normal elderly controls, matched for age and education, read 50 stimulus words presented individually on a cathode-ray tube. DAT patients exhibited a significantly greater cognitive impairment as shown by multivariate analysis of variance (p less than 0.0001). Canonical variate correlations revealed RT (0.961) to be more sensitive to decline in cognitive functioning in dementia than the measure of number of reading errors (0.559). Results confirm that RT is a highly sensitive measure of central nervous system integrity, which allows for a more refined investigation of a patient's cognitive deficit than is obtainable with traditional test measures. These findings suggest that chronometric measures should be incorporated in clinical and research studies attempting to document the existence and severity of cognitive impairment in neurodegenerative disease.

Aged↗

PubMed2006

Parental and coach support or pressure on psychosocial outcomes of pediatric athletes in soccer.

OBJECTIVE: The purpose of this article was to examine supportive and/or pressuring influences of parents and coaches on young athletes' maladaptive perfectionist tendencies, relationships to friends, and competency perceptions in soccer. Previous research has revealed that parents and coaches may give rise to both enjoyable and stressful sport experiences for the pediatric athlete and that parents and coaches are thus able to influence whether young people decide to quit sport or continue participating. Less is known about the relation of supportive versus pressuring parental and coach behaviors on the quality of athletes' achievement striving, relationships to friends in sport, and their competence perceptions. Such knowledge may help create a better psychological sport experience for pediatric athletes. DATA SOURCES/SYNTHESIS: A questionnaire-based cross-sectional field study was carried out among 677 young Norwegian soccer players (aged 10 to 14 years; 504 boys, 173 girls; mean age: boys = 11.9 years, SD = 2.9; girls = 11.2 years, SD = 2.1) taking part in the Norway Cup international youth soccer tournament in 2001. Multivariate analysis of variance (MANOVA) with follow-up canonical correlation was used to examine multivariate relationships between supportive and pressuring behavior and athletes' psychosocial experiences. RESULTS: Joint pressuring behaviors from parents and coaches related positively to maladaptive achievement striving, as indicated by overconcern for mistakes, doubt about one's soccer actions, and lowered perceptions of soccer competence. Mirroring these findings, predominantly supportive coach-created psychological climates were related to a linear pattern of psychological outcomes comprising high-quality friendships, positive competency perceptions, and the absence of specific worries related to achievement striving. CONCLUSIONS: Supportive, mastery-oriented coach influence seems beneficial for constructive psychosocial outcomes in pediatric athletes, and athletes experiencing a joint social pressure to excel from coaches and parents may benefit less psychosocially through sport.

Achievement↗

PubMed1998

Recursive MUSIC: a framework for EEG and MEG source localization.

The multiple signal classification (MUSIC) algorithm can be used to locate multiple asynchronous dipolar sources from electroencephalography (EEG) and magnetoencephalography (MEG) data. The algorithm scans a single-dipole model through a three-dimensional (3-D) head volume and computes projections onto an estimated signal subspace. To locate the sources, the user must search the head volume for multiple local peaks in the projection metric. This task is time consuming and subjective. Here, we describe an extension of this approach which we refer to as recursive MUSIC (R-MUSIC). This new procedure automatically extracts the locations of the sources through a recursive use of subspace projections. The new method is also able to locate synchronous sources through the use of a spatio-temporal independent topographies (IT) model. This model defines a source as one or more nonrotating dipoles with a single time course. Within this framework, we are able to locate fixed, rotating, and synchronous dipoles. The recursive subspace projection procedure that we introduce here uses the metric of canonical or subspace correlations as a multidimensional form of correlation analysis between the model subspace and the data subspace. By recursively computing subspace correlations, we build up a model for the sources which account for a given set of data. We demonstrate here how R-MUSIC can easily extract multiple asynchronous dipolar sources that are difficult to find using the original MUSIC scan. We then demonstrate R-MUSIC applied to the more general IT model and show results for combinations of fixed, rotating, and synchronous dipoles.

Algorithms↗

PubMed2004

T-138C polymorphism of matrix gla protein promoter alters its expression but is not directly associated with atherosclerotic vascular calcification.

Matrix Gla protein (MGP) is a crucial inhibitor of vessel and cartilage calcification. We investigated the association of T-138C MGP promoter polymorphism with the degree of atherosclerosis, vascular calcification and patients' clinical background including calcification of the trachea and costal cartilage. Analysis of 108 autopsy cases was carried out by polymorphism-specific PCR on formalin-fixed paraffin-embedded samples. Statistical correlations among eight risk factors and five markers related to atherosclerosis and extra-bone tissue calcification were multivariantly analyzed. We found very high canonical correlations between the factors and the markers, and Pearson's correlation analysis revealed six significant correlations between age and the Gore index; age and costal cartilage calcification; sex and costal cartilage calcification; hypertension and the Gore index; hypertension and the calcification factor of the Gore index; and hyperlipidemia and costal cartilage calcification. The promoter activity of the -138T allele was significantly higher than that of the -138C allele; treatment with 12-O-tetradecanonylphorbol 13-acetate (TPA) significantly activated the former, but had almost no effect on the latter. The C genotype was significantly common among Japanese subjects, (TT 45.5%, TC 37.6% and CC 16.8%) compared with that reported in the Netherlands, Northern Ireland and France. No significant correlation was observed, however, between T-138C MGP promoter polymorphism and the markers. Although the C genotype (TC+CC) tended to show a higher calcification factor than the TT genotype, no significant difference was observed among the genotypes in the Gore index or in the calcification factor. Although MGP promoter activity and the binding of the AP-1 transcription factor were clearly different between T-138 and C-138 MGP promoter polymorphism in vitro, T-138C polymorphism was, statistically, not an independent factor of atherosclerosis or atherosclerotic vascular calcification in the abdominal aorta.

Adolescent↗

PubMed1997

Dosage adjustment of antiinfective therapy in patients with renal impairment.

Schematic dosage adjustments for aminoglycosides, vancomycin, and ciprofloxacin were derived from published data on the prolongation of elimination half-lives in patients with renal impairment. Therapeutic drug monitoring was retrospectively evaluated with 84 severely ill patients, 29 of whom needed renal replacement therapy (35%). Mortality (n = 27) and antiinfective failures were high (n = 23). Toxicity was suspected in 5 patients, though it was demonstrated only in 1 case. As compared to the patients with normal renal function, patients with renal impairment exhibited peak levels that tended to be lower, although their trough levels tended to be higher; the aminoglycoside troughs even were significantly elevated in renal replacement patients (1.0 mg/l (0.6-1.4) versus 0.6 mg/l (0.3-0.8)). Seen in relation to toxicity, antiinfective failure was by far the greater problem even with dosage adjustments at high trough levels. Multivariate analysis showed antiinfective failure to be significantly correlated to 10 canonical variables (age, weight, leucocyte count, peak level, trough level, initial creatinine, increase in creatinine, fever, change of dosage, and renal replacement therapy). Among these variables, it were neither drug levels nor renal replacement, but only persistent fever and deteriorating renal function that independently contributed to antiinfective failure. For adjustment of antiinfective therapy, paradoxically we conclude that trough concentrations higher than normal must be allowed for to avoid underdosage in renal replacement patients.

Aminoglycosides↗