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Results for “Structural equation modeling”

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PubMed1997

Behaviour problems and relationships with family and peers during adolescence.

This study examines the relationship between (a) characteristics of adolescents' social networks, personal resources, and environmental risks; and (b) adolescents' behaviour problems. A socio-ecological perspective was used to determine whether social support and perceived conflict operate as risk or protective factors. Three samples of adolescents were studied: 63 adolescents in residential care; 29 in day treatment; and 63 who had had no contact with professional care. Interrelations were explored by means of structural equation modelling. Social support in family and peer group may operate as a risk factor or a protective factor depending on other risk factors in these subsystems. Perceived conflict is related to behaviour problems, although the influence differs depending on environmental risk factors and the type of behaviour problems.

Adolescent↗

PubMed1997

Processing time, imagery, and spatial memory.

Measures of cognitive processing time, imagery skill, and spatial memory span were administered to 128 8- to 20-year-olds. Age correlated positively with spatial memory span and accuracy on the imagery tasks but negatively with times on the cognitive processing and imagery tasks. Results of path analyses and structural-equation modeling were consistent with a causal model in which age-related change in speed of processing is associated with more effective imagery. In turn, imagery is associated with spatial memory span. Age was also associated with imagery and spatial span, indicating that other age-related variables need to be incorporated into the causal model.

Adolescent↗

PubMed2000

Sex differences in spatial cognition, computational fluency, and arithmetical reasoning.

Alternative explanations for the male advantage in arithmetical reasoning, as measured by the ability to solve complex word problems, include a male advantage in spatial cognition and a male advantage in computational fluency. The current study was designed to test these competing hypotheses. To this end, 113 male and 123 female undergraduates were administered arithmetical computations and arithmetical reasoning tests, along with an IQ test and a test of spatial cognition. There was no sex difference on the IQ test, but males showed significantly higher mean scores on the arithmetical computations, arithmetical reasoning, and spatial cognition measures. A series of structural equation models indicated that individual differences in arithmetical reasoning were related to individual differences in IQ, spatial abilities, and computational fluency. Moreover, the results suggested that the male advantage in arithmetical reasoning is mediated by the male advantages in both computational fluency and spatial cognition.

Adolescent↗

PubMed1998

Mapping neural interactivity onto regional activity: an analysis of semantic processing and response mode interactions.

Neuroimaging studies of cognition have typically been designed to identify brain regions that are active during a cognitive process. However, identifying how brain regions interact may be equally important. In a recent study we found that the pattern of activation associated with a semantic task differed depending on how subjects made a response, suggesting that there was an interaction between the neural systems underlying response mode and semantic processing (J. M. Jennings et al., 1997, NeuroImage 5, 229-239). This result raises two important questions, which we examined here: (1) How did the regions underlying semantic performance influence one another, or interact, to produce a different pattern of activation in each case? (2) What can be learned about the neurobiology of semantic processing when different regions are identified as a function of response? We addressed these questions using structural equation modeling. This technique produced functional network models representing the effect of different regions on each other during the semantic task for each response. A common network of regions associated with semantic processing was observed and included the left inferior frontal and left superior temporal cortices, with other regions brought into that network depending on response (e.g., right middle frontal). Moreover, changes in the influences among these regions across response condition predicted the pattern of activation found previously. These results show how an arbitrary response can affect the neural pathways associated with a cognitive process, likely due to the parallel and reentrant organization of the brain, and emphasize the importance of examining functional connections when studying cognition.

Adult↗

PubMed2001

Can meaningful effective connectivities be obtained between auditory cortical regions?

Structural equation modeling (SEM) of neuroimaging data can be evaluated both for the goodness of fit of the model and for the strength of path coefficients (as an index of effective connectivity). SEM of auditory fMRI data is made difficult by the necessary sparse temporal sampling of the time series (to avoid contamination of auditory activation by the response to scanner noise) and by the paucity of well-defined anatomical information to constrain the functional model. We used SEM (i.e., a model incorporating latent variables) to investigate how well fMRI data in four adjacent cortical fields can be described as an auditory network. Seven of the 14 models (2 hemispheres x (6 subjects and 1 group)) produced a plausible description of the measured data. Since the auditory model to be tested is not fully validated by anatomical data, our approach requires that goodness of fit be confirmed to ensure generalizability of connectivity patterns. For good-fitting models, connectivity patterns varied significantly across subjects and were not replicable across stimulus conditions. SEM of central auditory function therefore appears to be highly sensitive to the voxel-selection procedure and/or the sampling of the time series.

Adult↗

PubMed2002

Effective connectivity and intersubject variability: using a multisubject network to test differences and commonalities.

This article is about intersubject variability in the functional integration of activity in different brain regions. Previous studies of functional and effective connectivity have dealt with intersubject variability by analyzing data from different subjects separately or pretending the data came from the same subject. These approaches do not allow one to test for differences among subjects. The aim of this work was to illustrate how differences in connectivity among subjects can be addressed explicitly using structural equation modeling. This is enabled by constructing a multisubject network that comprises m regions of interest for each of the n subjects studied, resulting in a total of m x n nodes. Constructing a network of regions from different subjects may seem counterintuitive but embodies two key advantages. First, it allows one to test directly for differences among subjects by comparing models that do and do not allow a particular connectivity parameter to vary over subjects. Second, a multisubject network provides additional degrees of freedom to estimate the model's free parameters. Any neurobiological hypothesis normally addressed by single-subject or group analyses can still be tested, but with greater sensitivity. The common influence of experimental variables is modeled by connecting a virtual node, whose time course reflects stimulus onsets, to the sensory or "input" region in all subjects. Further experimental changes in task or cognitive set enter through modulation of the connections. This approach allows one to model both endogenous (or intrinsic) variance and exogenous effects induced by experimental design. We present a functional magnetic resonance imaging study that uses a multisubject network to investigate intersubject variability in functional integration in the context of single word and pseudoword reading. We tested whether the effect of word type on the reading-related coupling differed significantly among subjects. Our results showed that a number of forward and backward connections were stronger for reading pseudowords than words, and, in one case, connectivity showed significant intersubject variability. The discussion focuses on the implications of our findings and on further applications of the multisubject network analysis.

Adult↗

PubMed2003

Smoking in Cape Town: community influences on adolescent tobacco use.

BACKGROUND: This paper examines the effect of pro- and antisocial opinions about communities on cigarette use by Black, Colored, and White 8th- and 11th-grade students in Cape Town, South Africa. METHODS: This analysis consists of 1,328 students who completed a questionnaire in 1997 on sociodemographic characteristics, substance abuse, adolescent behaviors, and opinions about their communities. Structural equation modeling (SEM) was used to assess hypotheses related to the social development model positing direct and indirect associations between community constructs and smoking within the previous 31 days. RESULTS: White students had the highest proportion (36.3%, P < 0.01) of past-31-days smokers compared to Colored (29.7%) and Black (9.7%) students. SEM analysis showed that among all groups the strongest association (beta = 0.29, Whites, P < 0.01; beta =.14, Coloreds, P < 0.01; beta = 0.05, Blacks, P < 0.05) with recent cigarette smoking was the personal knowledge of adults who engaged in antisocial behavior. CONCLUSIONS: Youth smoking behavior may be affected by antisocial adult behavior, subjective adult norms, and community affirmation. Thus, in addition to other factors, social norms and community influence should be considered in preventing adolescent smoking.

Adolescent↗

PubMed1992

Determinants of isometric muscle strength in men of different ages.

Values of maximal isometric strength of five muscle groups and associated factors including occupational status, life style and health were studied in three groups of men aged from 31 to 35, 51 to 55, and 71 to 75 years. The results indicated significant differences between the age groups in isometric handgrip, elbow flexion, knee extension, trunk extension and trunk flexion strength. In the youngest group, the manual workers tended to have higher strength values in all muscle groups than the lower and higher status white collar workers, whereas among the middle-aged and oldest men the manual workers tended to have the poorest performance. Good self-rated health and the intensity of physical exercise during leisure were positively associated with muscle strength in the youngest and middle-aged groups whereas in the oldest group the most important variable was home gymnastics. The multivariate structural equation models of isometric strength differed somewhat among the age groups and in these models the above-mentioned variables accounted for from 33% to 43% of the variance in isometric strength within the age groups. The results illustrated the most important factors associated with isometric strength in samples of men of different ages and also provided suggestions as to how these determinants might influence comparisons between different age groups in respect of muscle strength.

Adult↗

PubMed1995

Social skills in schizophrenia: assessing the relationship between social skills, psychopathology and community functioning.

Social skills training (SST) has been widely used in attempts to rehabilitate chronic schizophrenic patients. The key assumption underlying SST is that social skills deficits are important determinants of the social isolation, poor social role functioning, and low quality of life characteristic of schizophrenic patients. To test this assumption, 89 patients meeting DSM-III-R criteria for schizophrenia were assessed on behavioural and self-report measures of social skills. A structured clinical interview, a self-report inventory of distress during social interaction, and self-monitoring of time in social interaction were used to assess social functioning. Positive psychotic symptoms were assessed in a standardised clinical interview. A structural equation modelling analysis showed that observed social skills predicted social functioning, and that this association was statistically independent of severity of psychotic symptoms. This finding is consistent with the hypothesis that social skills are important in the social functioning of patients with schizophrenia.

Activities of Daily Living↗

PubMed1991

AIDS-related health behavior: coping, protection motivation, and previous behavior.

The purpose of this study was to examine Rogers' protection motivation theory and aspects of Janis and Mann's conflict theory in the context of AIDS-related health behavior. Subjects were 84 heterosexual men and women and 147 homosexual men with multiple sexual partners; LISREL's path-analysis techniques were used to evaluate the goodness of fit of the structural equation models. Protection motivation theory did fit the data but had considerably more explanatory power for heterosexual than for homosexual subjects (49 vs. 22%, respectively). When coping styles were added, different patterns of findings were found among both groups. Adding variables such as social norms and previous behavior increased the explained variance to 73% for heterosexual subjects and to 44% for homosexual subjects. It was concluded that although protection motivation theory did fit the data fairly adequately, expanding the theory with other variables--especially those related to previous behavior--could improve our understanding of AIDS-related health behavior.

Acquired Immunodeficiency Syndrome↗

PubMed1993

The effect of maternal depression on maternal ratings of child behavior.

There have been continuing concerns about the extent to which maternal depression may influence maternal reports of child behavior. To examine this issue, a series of structural equation models of the relationships between maternal depression and errors in maternal reports of child behavior was proposed and tested. These models assumed that (a) maternal depression was unrelated to maternal reporting behavior; (b) maternal depression causally influenced maternal reporting accuracy; (c) maternal depression was correlated with reporting accuracy. These models were fitted to data on maternal depression and multiple-informant (mother, teacher, child) reports of conduct disorder and attention deficit behaviors for a birth cohort of 12- and 13-year-old New Zealand children. The results of model fitting suggested the presence of small to moderate correlations (r = +.13 to +.40) between maternal depression and maternal reporting errors, indicating the presence of a tendency for increasing maternal depression to be associated with a tendency for mothers to over-report child behavior problems. However, independently of any effects of maternal depression on maternal reporting errors there was evidence of small but significant associations (r = .10 to .17; p < .05) between maternal depression and child conduct disorder and attention deficit behaviors.

Adolescent↗

PubMed1996

The role of adolescent peer affiliations in the continuity between childhood behavioral adjustment and juvenile offending.

This research reports on a structural equation model analysis of the relationships between childhood behavioral adjustment, adolescent peer affiliations, and adolescent offending using data gathered during the course of a 16-year longitudinal study of a birth cohort of New Zealand children. The model developed contained parameters that estimated (a) the continuities between early behavior and later offending, (b) the associations between early behavior and adolescent peer affiliations, and (c) the potentially reciprocal relationship between adolescent peer affiliations and adolescent offending behaviors. This analysis suggested that, when due allowance was made for reporting error, there was evidence of relatively strong continuity (r = .50) between early behavior and later offending. The model estimates suggested that these continuities arose from both direct continuities in behavior over time and from the effects of adolescent peer affiliations in reinforcing and sustaining earlier behavioral tendencies. The implications of the analysis for the understanding of the role of adolescent peer affiliations in behavioral continuities and discontinuities are discussed.

Adolescent↗

PubMed1995

Early disruptive behavior, IQ, and later school achievement and delinquent behavior.

A series of structural equation model is developed to examine the relationship between early externalizing behaviors (conduct problems, attention deficit) and IQ measured at age 8 years, academic achievement over the period 10 to 13 years, and delinquent behavior to the age of 15 in a birth cohort of New Zealand children. These models indicated that early externalizing behaviors and IQ were related to later academic achievement and delinquent behavior by two quite distinct but highly correlated developmental sequences. In one sequence early conduct problems were predictive of later delinquency but were not directly related to later academic achievement. In the other sequence, attention deficit and IQ were prognostic of later school achievement but were not directly related to delinquency. Further, the apparent correlations between academic achievement and delinquency were adequately explained by the common and correlated effects of early behavior and IQ on later achievement and delinquency. These conclusions remained unchanged when the sample was stratified by gender, and when further explanatory factors were introduced into the model.

Achievement↗

PubMed1989

The relationships between neuroticism and depressive symptoms.

A structural equation model designed to estimate the reciprocal associations which may exist between mental state and personality trait variables is presented. This model is applied to measures of neuroticism and depression obtained for a sample of over 1000 women studied over a two year period. The fitted model suggests that while measures of neuroticism are contaminated by the effects of short term mental state on the reporting of personality, there is still a fairly substantial relationship between trait neuroticism (corrected for the effects of mental state contamination) and reports of depressive symptoms.

Depression↗

PubMed1996

The development of health protective behaviors among college students.

This study uses structural equation modeling and a panel design to explain participation in health protective behavior (HPB) among college students. The direct, indirect, and total effects of gender, social influences (parental and peer behavior), social attachments (activity involvement, social support, and romantic involvement), social triggers (personal health, acute illnesses, and personal or family health crisis), health value, and effort to improve health behavior on HPB are examined. A path model with a high goodness of fit and an R2 of .418 shows that gender; health value, and effort to change health behaviors are the most powerful predictors of HPB participation, while parents and peers influence HPB indirectly through influence on health value and effort to change. Neither the social attachment nor social trigger items influenced HPB in this sample. Implications of these findings are discussed.

Female↗

PubMed1996

Role of anxiety sensitivity in pain-related fear and avoidance.

Anxiety sensitivity (AS) is the fear of anxiety-related bodily sensations, arising from beliefs that the sensations have harmful consequences. There has been a good deal of research on the role of AS in anxiety disorders, and only recently have investigators begun to assess its role in other conditions. In a preliminary report, Asmundson and Norton (1995) found that chronic back-pain patients with high AS (n = 14), compared to those with lower AS (n = 56), reported greater pain-related fear, and tended to have greater avoidance. The present study further investigated the role of AS in pain-related fear and escape/avoidance. Patients with chronic musculoskeletal pain (N = 259) completed measures of AS, pain severity, and pain-related fear and escape/avoidance. Structural equation modeling supported the prediction that AS directly exacerbates fear of pain, even after controlling for the effects of pain severity on fear of pain. Support also was found for the prediction that AS indirectly promotes pain-related escape/avoidance via its influence on fear of pain. This indirect effect was significant even when controlling for the direct influence of pain severity on pain-related escape/avoidance. These results suggest that AS plays an important role in pain-related fear and escape/avoidance in people with chronic pain.

Adult↗

PubMed1996

The heritability of human longevity: a population-based study of 2872 Danish twin pairs born 1870-1900.

The aim of this study was to explore, in a large and non-censored twin cohort, the nature (i.e., additive versus non-additive) and magnitude (i.e., heritability) of genetic influences on inter-individual differences in human longevity. The sample comprised all identified and traced non-emigrant like-sex twin pairs born in Denmark during the period 1870-1900 with a zygosity diagnosis and both members of the pairs surviving the age of 15 years. A total of 2872 pairs were included. Age at death was obtained from the Danish Central Person Register, the Danish Cause-of-Death Register and various other registers. The sample was almost non-censored on the date of the last follow-up (May 1, 1994), all but 0.6% had died, leaving a total of 2872 pairs for analysis. Proportions of variance attributable to genetic and environmental factors were assessed from variance-covariance matrices using the structural equation model approach. The most parsimonious explanation of the data was provided by a model that included genetic dominance (non-additive genetic effects caused by interaction within gene loci) and non-shared environmental factors (environmental factors that are individual-specific and not shared in a family). The heritability of longevity was estimated to be 0.26 for males and 0.23 for females. The small sex-difference was caused by a greater impact of non-shared environmental factors in the females. Heritability was found to be constant over the three 10-year birth cohorts included. Thus, longevity seems to be only moderately heritable. The nature of genetic influences on longevity is probably non-additive and environmental influences non-shared. There is no evidence for an impact of shared (family) environment.

Aged↗

PubMed1995

Etiology of individual differences in reading performance: a test of sex limitation.

To test the hypothesis that the etiology of individual differences in reading performance differs in males and females, reading performance data from twin pairs tested in the Colorado Learning Disabilities Research Center were fitted to structural equation models of sex limitation. The sample included 513 pairs of twins in which at least one member of each pair has a positive school history of reading problems [228 monozygotic (MZ), 176 same-sex dizygotic (DZ), and 109 opposite-sex DZ pairs] and 302 matched control pairs [148 MZ, 98 same-sex DZ, and 56 opposite-sex DZ pairs]. Estimates of the genetic correlation between performance in males and females were obtained by analysis of data from both same-sex and opposite-sex twin pairs (Neale and Cardon, 1992). The full model fit the data well (chi 2 = 17.74, df = 16, p = 0.340), and the resulting genetic parameter estimates were highly similar in males and females in both the proband and the control samples. The correlations between genetic influences in males and females do not differ among groups (change in chi 2 = 0.95, df = 1, p > or = 0.25), and the resulting pooled estimate is about .5. Thus, results of this analysis suggest that the etiology of individual differences in reading performance may differ to some extent in males and females.

Adolescent↗