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PubMed2006

A factor analysis of the Wechsler Adult Intelligence Scale 3rd Edition (WAIS-III) in a low IQ sample.

OBJECTIVES: Previous factor analytic studies of the WAIS, WAIS-R and WAIS-III used standardization samples, (representing the general population), clinical populations (e.g. psychiatric) and 'non-clinical' groups (e.g. older adults). These studies endorsed the reliability of the scales in such samples and supported theoretical models of intelligence. The WAIS-III (1997) includes four Indexes based on factor analysis, which provide clinically useful information to practitioners, but have not been validated in a low IQ population. However, the WAIS-III is often administered to individuals with suspected or proven low IQ, as it offers service providers, legislators and the Department of Health with a reliable measure of IQ. The aim of this study was to investigate the factor structure of the WAIS-III in a low IQ sample. METHODS: WAIS-III data was collected from assessments carried out in routine clinical practice from individuals with a full scale IQ of 74 or below (n=105). The data were subjected to factor analysis, using two types of factor analysis: principal axis factoring and principal components analysis. Orthogonal and oblique rotations were applied to the analyses. RESULTS: Only one robust solution could be extracted. This contained two factors, analogous to traditional verbal and performance sub-scales. CONCLUSIONS: This study does not support the four-factor solution which underlies WAIS-III index scores in a low IQ population.

Adolescent↗

PubMed1998

[Spectral interference correction for ICP-AES by factor analysis and a comparison with other methods].

Factor analysis method was used to correct spectral interference in inductively coupled plasma atomic emission spectrometry (ICP-AES) in the present work. The spectral overlap and structural background interferences were investigated and discussed with two real examples. Results show that the factor analysis is comparable to partial least squares (PLS) and the Kalman filtering in correcting the interferences.

English Abstract↗

PubMed2004

The use of phenotypic correlations and factor analysis in determining characters for grain yield selection in chickpea (Cicer arietinum L.).

To our knowledge, this is the first report on the use of factor analysis in determining characters for yield selection in chickpea (Cicer arietinum L.). The present investigation was undertaken to evaluate yield criteria in chickpea using phenotypic correlations and factor analysis. Factor 1 composed of biological yield, reaction to ascochyta blight (Ascochyta rabiei (Pass.) Labr.), plant height, grain yield and harvest index. Factor 2 consisted of branches and pods per plant. Factor 3 encompassed of only the grain weight. The total factors explained 92.9% of the total variance caused in the characters. The grain yield was positively and statistically significant correlated with biological yield, harvest index, plant height, branches and pods per plant, while it was negatively and statistically significant related with reaction to ascochyta blight and grain weight. Biological yield, harvest index, plant height and reaction to ascochyta blight instead of many selection criteria should previously be evaluated in selection to increase the grain yield in chickpea breeding programs. Pods per plant should be handed together with and branches per plant. Apart from the other selection criteria, the grain weight should solely be evaluated to select large grained genotypes.

Ascomycota↗

PubMed1989

[The investigation of asthmatic children by multiple factor analysis. I. The relation between severity of asthma and allergic factors].

In a previous study, we analysed the severity of bronchial asthma in childhood by the class II multiple factor analysis method. At that time, the titers of IgE and IgG4 antibodies to the three major food (cow's milk, egg white, and soybeans) and inhalation antigens such as house dust and mites were, however, left unevaluated because of a lack of independence. The quantification of their relative ratios was introduced into the present study, which made it possible to compare their individual potential as risk factors. Exercise induced asthma had the most outstanding effects on the severity of bronchial asthma, followed by counts of peripheral eosinophils and house dust and mites, in this order. Regarding food antigens, the presence of IgG4 and IgE antibody to egg white was the most critical factor, following by titers of IgG4 to cow's milk and soybeans. Complications with atopic dermatitis and allergic rhinitis little affected the severity. Bronchial asthma becomes manifest through a complicated mechanism involving a variety of causative factors. The results given above suggest that the contribution of individual risk factors can be quantified.

Adolescent↗

PubMed1999

Use of evolutionary factor analysis in the spectroelectrochemistry of Escherichia coli sulfite reductase hemoprotein and a Mo/Fe/S cluster.

The deconvolution of spectroelectrochemical data is often quite difficult if the spectra of intermediates are not known. Factor analysis, however, has been shown to be a powerful technique which can make it possible to deconvolute overlapping spectra. In this work, evolving factor analysis will be used to determine the number of intermediates and the spectra of those species for two typical spectroelectrochemical experiments: linear scan voltammetry and chronoabsorptometry in a thin-layer cell. The first system was the reduction of E. coli sulfite reductase hemoprotein (SiR-HP). Principal factor analysis indicated that three species were present. By using evolving factor analysis, the potential regions where each of the species were present were identified, and their concentrations and spectra were determined by the use of the mass balance equation. The spectra of the one-electron (SiR-HP1-) and two-electron (SiR-HP2-) reduced product were compared with previous work. The second experiment was the chronoabsorptometry of Cl2FeS2MoS2FeCl2(2-) in methylene chloride. This experiment indicated that five species were present during the experiment. The entire set of 61 spectra were fit by assuming that there were 4 species present during the electrolysis. The rate constant for the appearance of subsequent species fit quite well with the rate constant for the disappearance of previous species. The spectra of the intermediates and final product were obtained using evolving factor analysis and a mass balance equation. Identification of the fifth species, which was probably the initial reduction product, Cl2FeS2MoS2FeCl2(3-), was difficult due to its low concentration and the fact that it was present in the same time region as the starting material.

Bacterial Proteins↗

PubMed2003

[Early postoperative pulmonary function study: changing curve and influencing factors analysis].

OBJECTIVE: To investigate the changes and influence factors for early postoperative pulmonary function of thoracotomy. METHODS: Pre- and early postoperative pulmonary function was detected in 64 consecutive cases with optimal thoracotomy. Pain assessment was conducted before pulmonary function test, and the chief complaints of patients were recorded after the procedure. The changing curves of pulmonary function were made and the differences associated with groups, surgical styles, pain assessment, epidural analgesia, chief complaint and preoperative conditions were analyzed using SPSS10.0 medical statistic software. RESULTS: Pulmonary function was severely lowered to (39 +/- 14)% of the base line on the first day. It was rehabilitated gradually, and recovered to (62 +/- 10)% of the base line on the 8th day. Epidural analgesia could improve pain relaxation and pulmonary function in some degree. Single-factor analysis showed that postoperative pain, postoperative day and surgical style were the significant influence factors for early postoperative pulmonary function. Multiple-factor analysis showed that preoperative pulmonary function, age and postoperative pain were the main factors, while surgical style had only weak effect on it. CONCLUSIONS: Early postoperative pulmonary function is severely impaired by thoracotomy. It rehabilitate gradually with time. Improvement of preoperative pulmonary function, reducing surgical procedure injuries, especially injury to respiratory muscle system, and enough postoperative pain relief are the most important means that will reduce pulmonary function impairment and consequently reduce postoperative pulmonary complications.

Analgesia, Epidural↗

PubMed1993

Cross validation of the Hypnotic Induction Profile factor structure: simultaneous confirmatory factor analysis of two published samples.

This study cross-validated factor structure and psychometric characteristics of the Hypnotic Induction Profile (HIP). Earlier studies identified two constructs of the HIP, but their methodology did not allow empirical confirmation of the number of factors. I have used a new methodology, confirmatory factor analysis, and submitted the data from the previous studies to a simultaneous, multisample, factor analysis. The results showed that the HIP indeed consists of two factors. Although the HIP two-factor model is statistically adequate, 7 of the 10 scales have very low item reliability. Issues of measurement error and clinical implications of the study are also discussed in relation to the current findings.

Factor Analysis, Statistical↗

PubMedDate not supplied

Disease patterns of patients with Behçet's disease demonstrated by factor analysis.

OBJECTIVE: To explore the main patterns of Behçet's disease (BD) expression, applying factor analysis. METHODS: Sixty-eight BD patients were studied. The following disease manifestations were used for the factor analysis: genital ulcerations, typical skin lesions (erythema nodosum, folliculitis or papulo-pustular rash), uveitis, CNS involvement, joint disease, deep vein and superficial vein thrombosis, and gastrointestinal manifestations. The results were further analyzed according to sex, HLA typing, and childhood vs. adult-onset disease. RESULTS: Five factors were derived, which accounted for 69% of the variance of the matrix. Factor 1 represented the association between folliculitis and genital ulceration. Factor 2 represented the association between papulo-pustular rash and gastrointestinal symptoms. Factor 3 represented the inverse association between superficial vein thrombosis and erythema nodosum. Factor 4 represented the correlation between deep vein thrombosis and neuro-Behçet. Factor 5 represented joint disease. No difference was found between males and females in relation to factors 1, 2 or 5, but factors 3 and 4 had higher scores in male patients (p = 0.1 and p = 0.07, respectively). Factor 3 was significantly higher in patients with HLA-B5, compared to HLA-B5-negative BD patients (p < 0.001). Factors 1 and 3 were higher in patients with adult onset of the disease (p = 0.07, and p = 0.003, respectively), while factor 2 was higher in patients with childhood-onset BD (p = 0.07). CONCLUSIONS: The application of factor analysis revealed possible associations between distinct types of skin lesions, or venous thrombosis, and other disease manifestations of Behçet's syndrome, some of which were sex, age at onset, or HLA-related.

Adolescent↗

PubMed1989

[Clinical assessment of uneven ventilation by factor analysis of Xe-133 washout scintigram].

Factor analysis (FA) was applied to 50 consecutive Xe-133 washout lung scintigrams, and its findings were compared with dynamic scintigrams of Xe-133 washout (DSW). Mean transit time (MTT) of radioactive xenon measured by FA also was compared with that measured by height/area (H/A) or two-compartment analysis (2CA). In 12 patients with normal DSW, FA separated and located two factors: one represented background activity, and the other uniform washout from the lung. In 31 out of 38 patients (82%) with abnormal DSW, FA separated the same areas where the washout was delayed on DSW. In 5 (13%) patients, FA diagnosed more areas of delayed washout than DSW. FA failed in 2 (5%) patients, but this failure was due to small number of counts of pixels. Diagnosis by FA was seemed easier than diagnosis by DSW in 95% of all patients by the authors' impression. MTT by FA (y) correlated with MTT by 2CA (x) in small groups of patients: in 9 patients in whom only one MTT was obtainable by FA (r = 0.75, p = 0.02, y = 4.2x + 1.9), and in 8 patients of normal DSW in whom two MTT's were obtainable by FA (r = 0.77, p = 0.02, y = 0.69x + 6.2, y; shorter MTT by FA between the two). MTT by FA did not correlate with MTT by H/A. In conclusion, FA is useful for diagnosing uneven Xe-133 washout from the lung.

Adolescent↗

PubMed1990

Diagnosis of hepatocellular carcinoma by factor analysis.

We examined the usefulness of factor analysis for the diagnosis of hepatocellular carcinoma by analysis of the data obtained by radionuclide angiography. The data could be separated into two factors, a hepatic phase (hepatic artery and portal vein) and an arterial phase (aorta and kidney). In patients with hepatocellular carcinoma, the factor of the tumor is included in the arterial phase, so that the cancerous region could be differentiated from the noncancerous region. The ratio of the radioactivity of the cancerous region to the noncancerous region was used to estimate the blood flow of the tumor region.

Carcinoma, Hepatocellular↗

PubMed2006

Schizophrenia with prominent catatonic features ('catatonic schizophrenia'). II. Factor analysis of the catatonic syndrome.

Previous factor analyses of catatonia have yielded conflicting results for several reasons including small and/or diagnostically heterogeneous samples and incomparability or lack of standardized assessment. This study examined the factor structure of catatonia in a large, diagnostically homogenous sample of patients with chronic schizophrenia using standardized rating instruments. A random sample of 225 Chinese inpatients diagnosed with schizophrenia according to DSM-IV criteria were selected from the long-stay wards of a psychiatric hospital. They were assessed with a battery of rating scales measuring psychopathology, extrapyramidal motor status, and level of functioning. Catatonia was rated using the Bush-Francis Catatonia Rating Scale. Factor analysis using principal component analysis and Varimax rotation with Kaiser normalization was performed. Four factors were identified with Eigenvalues of 3.27, 2.58, 2.28 and 1.88. The percentage of variance explained by each of the four factors was 15.9%, 12.0%, 11.8% and 10.2% respectively, and together they explained 49.9% of the total variance. Factor 1 loaded on "negative/withdrawn" phenomena, Factor 2 on "automatic" phenomena, Factor 3 on "repetitive/echo" phenomena and Factor 4 on "agitated/resistive" phenomena. In multivariate linear regression analysis negative symptoms and akinesia were associated with 'negative' catatonic symptoms, antipsychotic doses and atypical antipsychotics with 'automatic' symptoms, length of current admission, severity of psychopathology and younger age at onset with 'repetitive' symptoms and age, poor functioning and severity of psychopathology with 'agitated' catatonic symptom scores. The results support recent findings that four main factors underlie catatonic signs/symptoms in chronic schizophrenia.

Adolescent↗

PubMedDate not supplied

Confirmatory factor analysis of the Tampa Scale for Kinesiophobia: invariant two-factor model across low back pain patients and fibromyalgia patients.

OBJECTIVES: (1) To investigate the factor structure of the Tampa Scale for Kinesiophobia (TSK) in a Dutch-speaking sample of chronic low back pain (CLBP) patients using confirmatory factor analysis, (2) to examine whether the internal structure of the TSK extends to another group of fibromyalgia (FM) patients, and (3) to investigate the stability of the factor structure in both patient groups using multi-sample analysis. PATIENTS AND METHODS: TSK-data from 8 studies collected in Dutch and Flemish chronic pain patients were pooled. For 188 CLBP patients and 89 FM patients, complete data were available. Confirmatory factor analyses were performed to assess 4 models of kinesiophobia, and to examine which factor model provided the best fit. Furthermore, a multi-sample analysis was performed to investigate the stability of the factor structure in both patient groups. RESULTS: For both CLBP and FM patients, the 2-factor model containing the factors "activity avoidance" and "pathologic somatic focus" was superior as compared with the 4-factor model containing the factors "harm," "fear of (re)injury." "importance of exercise," and "avoidance of activity". Moreover, the 2-factor model was found to be invariant across CLBP and FM patients, indicating that this model is robust in both pain samples. DISCUSSION: As the 2-factor structure provided the best fit of the data in both patient samples, we recommend to use this version of the TSK and its 2 subscales in both clinical practice and research. Based on the content of the items, the subscales were labeled "Harm" and "Fear-avoidance."

Adult↗

PubMed2005

Confirmatory factor analysis of parents' and teachers' ratings of DSM-IV symptoms of attention deficit hyperactivity disorder in a Spanish sample.

Confirmatory factor analysis examined the factor structure of DSM IV Attention Deficit Hyperactivity Disorder symptoms and analyzed the differences in informants' ratings of ADHD symptoms by children's age and sex. A sample of 1,018 Spanish school children, 574 girls and 444 boys, ages 4 to 12 years, was rated by teachers and parents. Confirmatory factor analysis showed a similar fit for the three-factor model of Inattention, Hyperactivity, and Impulsivity (teachers: CFI = .976, RMR = .041, % of total variance = 83.2; parents: CFI = .969, RMR = .037, % of total variance = 82.7) and for the two-factor model of Inattention and Hyperactivity Impulsivity (teachers: CFI = .958, RMR = .044, % of total variance = 79.3; parents: CFI = .961, RMR = .038, % of total variance, 79.9). The two-factor model was selected as a parsi monious representation of the teachers' and parents' ratings of ADHD symptoms. Analyses of variance indicated significant differences in teachers' and parents' mean ratings across sex and school grades of children.

Attention Deficit Disorder with Hyperactivity↗

PubMed1986

Factor analysis suggesting contrasting determinants for different blood pressure measurements.

A multiple regression analysis was performed on statistically independent factors derived from blood pressure measurements and possible predictive variables in 618 Utah adults. Nine blood pressure factors obtained in a previous study composed the dependent variables; 35 anthropometric, questionnaire, and biochemical variables were reduced by factor analysis to 10 factors and used as independent variables. Body size and obesity had significant independent effects on different types of blood pressure: body size correlated most highly with systolic blood pressure, while obesity correlated most highly with sitting diastolic blood pressure measurements. Smoking did not correlate with sitting blood pressure but did show a significant positive correlation (after controlling for obesity) with tilt and supine diastolic pressure. Alcohol consumption correlated positively with sitting diastolic pressure when the effects of body size and obesity were controlled. No correlations were found between urinary potassium or sodium excretion and any blood pressure factors, but a significant positive correlation was seen between plasma sodium concentration and several different types of diastolic blood pressure measurements. Psychological stress showed a significant independent positive correlation with systolic blood pressure measurements that was strongest in adults over 35 years of age. The multiple correlation values for the multiple regression equations ranged from 0.19 to 0.52.

Adolescent↗

PubMed1985

Factor analysis of 81mKr lung ventilation studies.

Factor analysis of dynamic structures (FADS) summarizes data depending on time and space in a few elementary components. Each of them associates a time-activity curve (factor) and the spatial distribution of the corresponding events. The aim was to evaluate the patterns, the number of components, and their possible link to physiology when FADS was applied to scintigraphic images representing a composite of a 81mKr ventilation cycle. In a study of 26 patients (10 normal, 16 pathologic), components were found that represent: (1) a rapid and steeply changing ventilation factor, corresponding mainly to bases in normal subjects and whole lung fields in patients, (2) a slower expiration and shorter inspiration ventilation factor distributed throughout both lung fields in all patients, (3) a constant activity curve, with an inspiratory activity peak distributed over both lung fields and the large airways, and (4) a factor including a phase shift with respect to the first; this was found significantly more often in patients with pathology.

Factor Analysis, Statistical↗

PubMed2004

[Models of confirmatory factor analysis of the emotional stability criteria of flying students].

OBJECTIVE: To established models of confirmatory factor analysis of the emotional stability criteria of flying students, and to provide an available criteria tool for evaluating the emotional stability. METHOD: "Criterion Assessment Scale of Emotional Stability of Flying Cadets" (ACSEFC) including 9 items were compiled first by interviewing with skillful pilots or flying instructors, and then the emotional stability of 153 flying students was evaluated by these pilots or instructors. RESULT: There were high level (P<0.05) of correlation coefficients between 8 items except for item 1; three-factor design appears to be the best choice for the nine items by exploratory factor analysis; model 4 appears to have the best effect by confirmatory factor analysis. CONCLUSION: The evaluation of emotional stability of flying students can be divided into 3 parts: general manifest emotion, tense before flying and flying emotion stability.

Aerospace Medicine↗

PubMed2004

The quality of life for cancer children (QOLCC) in Taiwan (part I): reliability and construct validity by confirmatory factor analysis.

Part 1, the current paper describes the development and testing of a quality-of-life (QOL) assessment specifically designed for Taiwanese pediatric cancer patients (7-18 years) and their parents/caregivers. The assessment instrument was established based on a qualitative study, then refined using recognized item-analysis methods and pilot tested on a group of 25 patients. The final assessment instrument included three versions of the same instrument, a patient self-report (QOLCC-7-12, for children aged 7-12 years; QOLCC-ADO for adolescent aged 13-18 years) and a parent proxy-report (QOLCC-PAR). The final seven-subscale tool has a total of 34 items and was tested among 106 young cancer patients and 106 their parents. Psychometric properties of the measure were tested using item analysis, Cronbach's alpha, and a confirmatory factor analysis. Results suggest acceptable reliability and goodness of fit of this seven-scale measure. In order to test the factor validity of QOLCC, an independent group of 42 children with cancer participated. The results of confirmatory factor analysis shows the goodness of fit in QOLCC.

Adolescent↗

PubMed1984

The physique of sportsmen: a study using factor analysis.

A range of anthropometric measurements was taken on 116 sportsmen who were successfully involved in a variety of sports. The measurements included 11 skeletal lengths, 4 bone widths, 14 trunk and limb circumferences, and 15 skinfold thicknesses. The greatest inter-subject variability occurred in the skinfold measurements. The variability of limb bone lengths and muscle circumferences was generally high, particularly in the case of lower thigh circumference and leg bone lengths. The variability of trunk length and biacromial diameter was low. Alpha factor analysis produced seven factors as follows (the percentage of the total variance explained is in parenthesis): 1) circumferences and bone widths (32%), 2) skeletal lengths, particularly of limb bones (17%), 3) skinfolds on the trunk (10%), 4) leg and triceps skinfolds (8%), 5) muscle size specific to the legs (6%), 6) trunk length (5%), and 7) pelvic depth (4%). These seven factors were stable across other factoring solutions. Canonical factor analysis produced five additional factors corresponding to proximal limb-bone lengths, distal limb-bone lengths, hip width, shoulder width, and a further skinfold factor. Step-wise multiple regression analysis of factor scores indicated that 83% of the variance could be accounted for by six anthropometric measurements and 95% by a total of twelve measurements.

Adolescent↗