Factor structure of the neurocognitive tests: an application of the confirmative factor analysis in stabilized schizophrenia patients

European Psychiatric Association guidance on assessment of cognitive impairment in schizophrenia

Background

Impairment in a wide range of cognitive abilities has been consistently reported in individuals with schizophrenia. Both neurocognitive and social cognitive deficits are thought to underlie severe functional disabilities associated with schizophrenia. Despite the key role in schizophrenia outcome, cognition is still poorly assessed in both research and clinical settings.

Methods

In this guidance paper, we provide a systematic review of the scientific literature and elaborate several recommendations for the assessment of cognitive functions in schizophrenia both in research settings and in real-world clinical practice.

Results

Expert consensus and systematic reviews provided guidance for the optimal assessment of cognitive functions in schizophrenia. Based on the reviewed evidence, we recommend a comprehensive and systematic assessment of neurocognitive and social cognitive domains in schizophrenia, in all phases of the disorder, as well as in subjects at risk to develop psychosis. This European Psychiatric Association guidance recommends not only the use of observer reports but also self-reports and interview-based cognitive assessment tools. The guidance also provides a systematic review of the state of the art of assessment in the first episode of psychosis patients and in individuals at risk for psychosis.

Conclusion

The comprehensive review of the evidence and the recommendations might contribute to advance the field, allowing a better cognitive assessment, and avoiding overlaps with other psychopathological dimensions. The dissemination of this guidance paper may promote the development of shared guidelines concerning the assessment of cognitive functions in schizophrenia, with the purpose to improve the quality of care and to obtain recovery.

Transdiagnostic validity of the MATRICS Consensus Cognitive Battery across the autism-schizophrenia spectrum

BACKGROUND

Autism Spectrum Disorder (ASD) and schizophrenia are neurodevelopmental disorders which share substantial overlap in cognitive deficits during adulthood. However, treatment evaluation in ASD and treatment comparisons across ASD and schizophrenia are limited by a dearth of empirical work establishing the validity of a standard cognitive battery across ASD and schizophrenia. Promisingly, the MATRICS Consensus Cognitive Battery (MCCB) has been validated in schizophrenia and encompasses cognitive domains that are impacted in ASD. Thus, this study aimed to establish MCCB's generalizability from schizophrenia to ASD.

METHODS

Community-residing adults with schizophrenia (N = 100) and ASD (N = 113) underwent MCCB assessment. Using multigroup confirmatory factor analysis, MCCB's transdiagnostic validity was evaluated by examining whether schizophrenia and ASD demonstrate the same configuration, magnitude, and directionality of relationships within and among measures and their underlying cognitive domains.

RESULTS

Across schizophrenia and ASD, the same subsets of MCCB measures inform three cognitive domains: processing speed, attention/working memory, and learning. Except for group means in category fluency, continuous performance, and spatial span, both groups show vastly comparable factor structures and characteristics.

CONCLUSIONS

To our knowledge, this study is the first to establish the validity of a standard cognitive battery in adults with ASD and furthermore the first to establish a cognitive battery's comparability across ASD and schizophrenia. Cognitive domain scores can be compared across new samples using weighted sums of MCCB scores resulting from this study. These findings highlight MCCB's applicability to ASD and support its utility for standardizing treatment evaluation of cognitive outcomes across the autism-schizophrenia spectrum.

Correlation between Performance-Based and Interview-Based Cognitive Measurements in Patients with Schizophrenia

OBJECTIVE

The Measurement and Treatment Research to improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) is used to measure the cognitive function of patients with schizophrenia. In some situations, interview-based measures such as the Schizophrenia Cognition Rating Scale (SCoRS) may be appropriate. In this study, we analyzed the correlation between performance- and interview-based measurements in patients with schizophrenia.

METHODS

Fifty-six clinically stable patients were recruited. To evaluate cognitive function, we used the MCCB performance-based measure and the SCoRS interview-based measure. Measurements were taken at baseline, and 2 weeks and 3 months later. Spearman correlations were computed between each SCoRS item's interviewer rating and each MCCB score.

RESULTS

The correlation between the MCCB overall T score and the SCoRS global score was the strongest (r=-0.52), while the SCoRS total score and the MCCB Speed of Processing score also correlated (r=-0.48). The SCoRS global score showed statistically significant correlations with all seven MCCB domains and the overall T score.

CONCLUSION

This study reveals correlations between MCCB domains and SCoRS items. Since we find that interview-based measurements are highly correlated with performance-based measurements, we suggest them as a useful cognitive function evaluation tool that can easily be applied in clinical settings.

What is the optimal neuropsychological test battery for schizophrenia in China?

BACKGROUND

The MATRICS consensus cognitive battery (MCCB) has been widely used to evaluate cognitive deficits in schizophrenia (SCZ), however, no study has formally examined the validity of the MCCB in Chinese SCZ. This study compared Chinese SCZ patients with healthy Chinese controls on the MCCB and some additional neurocognitive tests to determine if the Chinese MCCB is an optimal battery to assess the cognitive deficits in Chinese SCZ patients.

METHOD

The study enrolled and examined 230 patients met DSM-IV criteria for SCZ and 656 healthy controls matched for gender, age and education. Besides the MCCB, we also included some additional neurocognitive tests that have been widely used in patients with schizophrenia. We selected MCCB and non-MCCB tests with large effect size, to assemble a new "optimal battery" and compared its performance with that of the standard MCCB.

RESULTS

Comparing the putative "optimal" battery with the original MCCB, more patients with SCZ were identified as cognitively impaired according to the criteria of GDS ≥ 0.50 for the optimal battery (166 vs 135, or 72.2% vs 58.7%). The rate of cognitive impairment according to MCCB GDS in patients with SCZ who were currently working, ever worked and never worked are 45.5%, 61.6% and 70.8% (p = 0.051), whereas the optimal battery GDS showed 56.4%, 74.8%, 91.7% (p = 0.003), respectively.

CONCLUSIONS

Our study needs validation with independent samples but suggests that the current "optimal" cognitive battery could be more sensitive than the widely used MCCB in detecting SCZ related cognitive impairment in China.

Factor analyzing the Norwegian MATRICS Consensus Cognitive Battery

AIM

The MATRICS Consensus Cognitive Battery (MCCB) assesses seven cognitive domains with 10 subtests. This domain structure has not been demonstrated. Three factors have been produced in US samples. We examined the dimensional structure of the Norwegian MCCB. In addition, we studied the contribution of each subtest to the battery sum score.

METHODS

The participants were 131 patients with schizophrenia spectrum disorders and 300 healthy controls. Their Norwegian MCCB test scores were subject to exploratory and confirmatory factor analysis and regression analysis.

RESULTS

The theoretical MCCB factor structure was not shown. In the patient group, three-factor and two-factor models had acceptable fit. In both groups, the Symbol Coding, Spatial Span, Letter-Number Span, and Visual Learning subtests contributed most to the sum score.

CONCLUSION

The theoretical domain structure of the MCCB could not be demonstrated in these Norwegian participants. Consonant with US studies, models with three and two factors had mediocre fit, and in the schizophrenia spectrum disorder group only. In both groups, the subtests Symbol Coding, Working Memory, and Learning were the most sensitive in tapping general neurocognitive performance, supporting US results. We conclude that in both Norway and the USA, the MCCB generates the same cognitive domains through factor analysis, but that these domains are not the ones suggested by the MATRICS project.

Normatization of the symbol digit modalities test-oral version in a Latin American country

The aim of this study was to standardize the Symbol Digit Modalities Test (SDMT)-Oral version in a healthy population living in Argentina and to analyze the influence that age, gender, and education have on the SDMT. Secondarily, it is intended to analyze the performance of patients with multiple sclerosis (MS) on this test. Two hundred ninety-seven healthy participants were evaluated; they had an average age of 39.28 years and 13.87 years of schooling; 77.8% were women. The sample was segmented according to age in three groups: younger than 35 years old, 36 to 50 years old, and 51 to 70 years old. The sample was also segmented according to years of schooling in three groups: 11 years or less, 12 to 16 years, and more than 16 years. All participants were evaluated with the oral version of the SDMT. A clinical sample of 111 patients with MS was also assessed. The mean on the SDMT for the total sample was 51.34 (SD=12.76). The differences were significant between all groups, p<.05, according to age. The participants with a higher level of education performed better than did those with moderate education and those with less schooling, p<.05. There was a significant difference between patients with MS and healthy controls, p<.01. The SDMT is influenced by age as well as by schooling, although not by gender. The norms displayed here will be useful to accurately evaluate the yield of the patients in the neuropsychological clinic when comparing them with their group of reference. It was also demonstrated that the SDMT can discriminate between patients with MS and healthy people.

Reliability, validity and treatment sensitivity of the Schizophrenia Cognition Rating Scale

Cognitive functioning can be assessed with performance-based assessments such as neuropsychological tests and with interview-based assessments. Both assessment methods have the potential to assess whether treatments for schizophrenia improve clinically relevant aspects of cognitive impairment. However, little is known about the reliability, validity and treatment responsiveness of interview-based measures, especially in the context of clinical trials. Data from two studies were utilized to assess these features of the Schizophrenia Cognition Rating Scale (SCoRS). One of the studies was a validation study involving 79 patients with schizophrenia assessed at 3 academic research centers in the US. The other study was a 32-site clinical trial conducted in the US and Europe comparing the effects of encenicline, an alpha-7 nicotine agonist, to placebo in 319 patients with schizophrenia. The SCoRS interviewer ratings demonstrated excellent test-retest reliability in several different circumstances, including those that did not involve treatment (ICC> 0.90), and during treatment (ICC>0.80). SCoRS interviewer ratings were related to cognitive performance as measured by the MCCB (r=-0.35), and demonstrated significant sensitivity to treatment with encenicline compared to placebo (P<.001). These data suggest that the SCoRS has potential as a clinically relevant measure in clinical trials aiming to improve cognition in schizophrenia, and may be useful for clinical practice. The weaknesses of the SCoRS include its reliance on informant information, which is not available for some patients, and reduced validity when patient's self-report is the sole information source.

Association of genetic variations in DTNBP1 with cognitive function in schizophrenia patients and healthy subjects

The dystrobrevin-binding protein 1 gene (DTNBP1) has been regarded as a susceptibility gene for schizophrenia. Recent studies have investigated its role on cognitive function that is frequently impaired in schizophrenia patients, and generated inconsistent results. The present study was performed to elucidate effects of genetic variations in DTNBP1 on various cognitive domains in both schizophrenia patients and healthy subjects. Comprehensive neuropsychological tests were administered to 122 clinically stable schizophrenia patients and 119 healthy subjects. Based on positive findings reported in previous association studies, six SNPs were selected and genotyped. Compared to healthy subjects, schizophrenia patients showed expected lower performance for all of the cognitive domains. After adjusting for age, gender, and educational level, four SNPs showed a nominally significant association with cognitive domains. The association of rs760761 and rs1018381 with the attention and vigilance domain remained significant after applying the correction for multiple testing (P < 0.001). Similar association patterns were observed both, in patients and healthy subjects. The observed results suggest the involvement of DTNBP1 not only in the development of attention deficit of schizophrenia, but also in the inter-individual variability of this cognitive domain within the normal functional range.