A comparison of cognitive structure in schizophrenia patients and healthy controls using confirmatory factor analysis

Abstract

There is evidence that cognitive task performance breaks down into the same broad domains in schizophrenia as in healthy populations. However, this does not mean that the domains are independent of one another or that the interrelationships among domains are the same between groups. We used confirmatory factor analysis (CFA) to compare the latent structure of a broad neuropsychological battery in schizophrenia patients (n =148) and healthy controls (n =157). Main analyses examined the fit of a hierarchical six-factor model, in which associations among the factors were assumed to reflect their strong shared relationship to a general cognitive ability factor. The model incorporated the factors of verbal comprehension, perceptual organization, verbal memory, spatial memory, processing speed, and executive/working memory. The hierarchical model provided a good overall fit to data from both groups. However multiple groups CFA revealed significant differences in factor loadings between groups, reflecting a more generalized latent structure of cognitive ability in schizophrenia. This was also evident in higher bivariate correlations among cognitive domain composite scores calculated from the observed test data. Cognitive ability, as reflected in test performance, appears to be more unitary in schizophrenia than in healthy subjects. This finding may have measurement and treatment implications.

Investigation of cognition in schizophrenia: psychometric properties of instruments for assessing working memory updating

“…Through confirmatory factor analysis and application of gradual restrictions on the model's parameters, the researchers found that the schizophrenia group showed more homogenous cognition than the control group. In our study, although cognitive performance in schizophrenia has been suggested to be fractionated 40,41 , our results corroborate prior studies 42 suggesting that people with schizophrenia have a more unitary cognitive structure. This unitary cognitive performance may be a reflection of the variable cortical and subcortical dysfunction present in schizophrenia 43 or the existence of a more widespread range of test performance among patients than in healthy controls 42 .…”

“…In our study, although cognitive performance in schizophrenia has been suggested to be fractionated 40,41 , our results corroborate prior studies 42 suggesting that people with schizophrenia have a more unitary cognitive structure. This unitary cognitive performance may be a reflection of the variable cortical and subcortical dysfunction present in schizophrenia 43 or the existence of a more widespread range of test performance among patients than in healthy controls 42 . That's why focus on group average performance, or use of samples with individuals who are at different phases of the illness, may mask the existence of different cognitive profiles amongst patient subgroups 44 .…”

“…Dickinson et al 42 tested a two-level hierarchical cognitive model. At the first level, the model conceives of six latent dimensions (verbal comprehension, perceptual organization, visual memory, verbal memory, processing speed and executive functions/working memory); at the second level is a second-order general factor that determines the variance of the six first-order factors.…”

Recent developments in neuropsychological endophenotypes for schizophrenia: Development of the MATRICS battery, liability syndromes and the near future

“…A subsequent study showed that 63.6% of the diagnosis-related variance was attributable to a common factor, with much smaller percentages attributable to performance in other cognitive domains, such as verbal memory (13.8%) and processing speed (9.1%) [33]. The same group demonstrated that, compared to healthy controls, schizophrenia patients showed higher correlations between composite scores of neuropsychological functions in a study of confirmatory factor analysis, consistent with the hypothesis that patients demonstrated a more generalized cognitive ability (or deficit) than controls [34].…”

A Brief Cognitive Assessment Tool for Schizophrenia: Construction of a Tool for Clinicians

“…In particular, whether performance on all cognitive domains predicts general cognitive function in aggregate or whether generalized cognitive ability hierarchically informs the performance on subdomains of cognition. While some research and expert opinion support a domain model of cognitive deficit in schizophrenia, 7,19,20 recent factor and structural equation analyses from large studies with comprehensive neuropsychological batteries 9,16,[21][22][23] have demonstrated that a single factor of global cognitive function better explains the deficit pattern of schizophrenia (one of these analyses was conducted on the CATIE data set used in this study 16 ). Specifically, these studies have shown that the best fit for the neurocognitive performance data of people with schizophrenia is either a 1-factor model where the factor of global cognitive ability explains the majority of the variance in performance on the specific tests included in the battery without significant input from cognitive subdomains 21,23 or the global factor hierarchically influences performance on the subdomains, which in turn predict performance on the individual tests in the battery.…”