Schizophrenia Research-Cognition最新文献

Introduction and methods

Based on the limited research focusing on the severity of cognitive deterioration in schizophrenia with preceding toxoplasmosis, we sampled 89 demographically matched paranoid schizophrenia patients (mean age 38.97 years) with (n = 42) and without (n = 47) seroprevalence of IgG type anti T. gondii antibodies as marker of past infection. They underwent examination of verbal memory (10 words Luria test), logical memory and visual memory (BVRT), processing speed (TMT-A/DSST) and executive functions (TMT-B/verbal fluency). We compared the results of both groups, taking into account the normative values for the Bulgarian population where available. We also compared the two groups in terms of clinical severity as evidenced by positive, negative and disorganization sub-scores of the PANSS.

Results

While both groups were expectedly under the population norms for verbal and logical memory, seropositive patients showed significantly bigger impairment in verbal memory (Luria Smax = 72.85 vs 78.51; p = 0.029), psychomotor speed (TMT-A 50.98 s vs 44.64 s; p = 0.017), semantic verbal fluency (27.12 vs 30.02; p = 0.011) and literal verbal fluency (17.17 vs 18.78; p = 0.014) compared to the seronegative ones. In addition to that, they gave less correct answers on the BVRT (2.98 vs 4.09; p = 0.006) while making markedly more errors (13.95 vs 10.21; p = 0.002). Despite not reaching statistical significance, past toxoplasmosis was associated with higher score on the PANSS disorganization sub-scale (16.50 points vs 14.72 points) and with lower educational attainment.

Conclusion

Our results suggest a more profound neuropathological insult(s) resulting in greater cognitive impairment in schizophrenia cases that are exposed to T. gondii infection.

Well characterised cognitive and perceptual impairments in schizophrenia may not be diagnostically specific with some studies suggesting no significant differences between psychotic disorders. This transdiagnostic ambiguity is paralleled in the boundary distinctions between psychotic disorders and the sub-threshold symptomatology of schizotypy. The current study used the CNTRACS test battery to explore if performance deficits in visual integration, relational memory and goal maintenance were specific to schizophrenia or extend to other psychotic disorders; and if task performance varied between individuals with schizophrenia and schizotypy in healthy adults. The sample consisted of healthy controls, and patients who met DSM-IV criteria for schizophrenia, other psychotic disorders and non-psychotic disorders who were tested in person; and an online sample of self-assessed healthy adults. No significant differences were found in performance between patients with schizophrenia and other psychotic disorders in contrast to non-psychotic disorders and healthy controls. The high schizotypy group performed better on the tasks compared to the other psychoses and schizophrenia groups. There were no differences in the healthy control group between individuals with high versus low schizotypy or between in-person and online task performance. These findings support the notion that cognitive and perceptual impairments in schizophrenia extend to other psychotic disorders but are discontinuous with schizotypy. This study provides insights into similarities between schizophrenia and other psychotic disorders with regards to the potential neural substrates underpinning these functions and supports the use of online tools for assessing domains of cognition and perception.

A network of early psychosis-specific intervention programs at the University of Montreal in Montreal, Quebec, Canada, conducted a longitudinal naturalistic five-year study at two Urban Early Intervention Services (EIS). In this study, 198 patients were recruited based on inclusion/exclusion criteria and agreed to participate. Our objectives were to assess the subjective cognition complaints of schizophrenic patients assessed by Subjective Scale to Investigate Cognition in Schizophrenia (SSTICS) in their first-episode psychosis (FEP) in relation to their general characteristics. We also wanted to assess whether there are sex-based differences in the subjective cognitive complaints, as well as differences in cognitive complaints among patients who use alcohol in comparison to those who are abstainers. Additionally, we wanted to monitor the changes in the subjective complaints progress for a period of five years follow-up. Our findings showed that although women expressed more cognitive complaints than men [mean (SD) SSTICS, 28.2 (13.7) for women and 24.7 (13.2) for men], this difference was not statistically significant (r = −0.190, 95 % CI, −0. 435 to 0. 097). We also found that abstainers complained more about their cognition than alcohol consumers [mean (SD) SSTICS, 27.9 (13.4) for abstainers and 23.7 (12.9) for consumers], a difference which was statistically significant (r = −0.166, 95 % CI, −0. 307 to −0.014). Our findings showed a drop in the average score of SSTICS through study follow-up time among FEP patients. In conclusion, we suggest that if we want to set up a good cognitive remediation program, it is useful to start with the patients' demands. This demand can follow the patients' complaints. Further investigations are needed in order to propose different approaches between alcohol users and abstinent patients concerning responding to their cognitive complaints.

Objective

Persons with schizophrenia exhibit greater neurocognitive test score dispersion. Here, we seek to characterize dispersion on the Neurocognitive Composite subtests of the Measurement of Treatment Research to Improve Cognition in Schizophrena Consensus Cognitive Battery (MCCB) and determine the relative effects of different antipsychotic formulations on dispersion and mean performance.

Method

In this post hoc analysis of the DREaM study (NCT02431702), which compared treatment with paliperidone palmitate (PP) long-acting injectable with oral antipsychotic (OAP) treatment over 18 months, dispersion in MCCB neurocognitive subtest performance was calculated for each participant by visit (test occasion).

Results

Over 18 months, mean neurocognitive performance improved in a manner consistent with the expected effects of practice in both groups (p < 0.05); this improvement was observed during the first 9 months (PP: p < 0.05, OAP: p < 0.001), followed by stable performance over the second 9 months (PP: p = 0.821, OAP: p = 0.375). Rates of change did not differ between groups (treatment-by-visit interaction: p = 0.548). In contrast, analyses of dispersion focusing on contrasts between baselines and end points of the first and second 9 months revealed different patterns. Over the first 9 months, dispersion in both groups lessened to a similar extent. However, over the second 9 months, dispersion remained stable in the PP group, whereas neurocognitive performance became significantly more variable in the OAP group (p < 0.01).

Conclusion

Dispersion of neurocognitive test scores provides a different index of cognitive change than that provided by composite scores. Long-term maintenance of therapeutic levels provided by PP over time may limit (relative to oral AP) the extent to which cognitive performance becomes more variable.

Cognitive impairments in schizophrenia are well-documented, present across several cognitive domains and found to be relatively stable over time. However, there is a high degree of heterogeneity and indications of domain-specific developmental courses. The present study investigated the 10-year cognitive course in participants with first-episode schizophrenia (FES) and healthy controls on eight cognitive domains and a composite score, looking at group- and individual-level changes.

A total of 75 FES participants and 91 healthy controls underwent cognitive assessment at baseline and follow-up. Linear mixed models were used for group-level analyses and reliable change index (RCI) analyses were used to investigate individual change. The prevalence of clinically significant impairment was explored at both time points, using a cut-off of < −1.5 SD, with significant cognitive impairment defined as impairment on ≥2 domains.

Group-level analyses found main effects of group and time, and time by group interactions. Memory, psychomotor processing speed and verbal fluency improved, while learning, mental processing speed and working memory were stable in both groups. FES participants showed deteriorations in attention and cognitive control. Individual-level analyses mainly indicated stability in both FES and controls, except for a higher prevalence of decline in cognitive control in FES. At baseline, 68.8 % of FES participants had clinically significant impairment, compared to 62.3 % at follow-up.

We mainly found long-term stability and modest increases in cognition over time in FES, as well as a high degree of within-group heterogeneity. We also found indications of deterioration in participants with worse cognitive performance at baseline.

Schizophrenia, a debilitating disorder with typical manifestation of clinical symptoms in early adulthood, is characterized by cognitive impairments in executive processes such as in working memory (WM). However, there is a rare case of individuals with early-onset schizophrenia (EOS) starting before their 18th birthday, while WM and its neural substrates are still undergoing maturation. Using the WM n-back task with functional magnetic resonance imaging, we assessed the functional neurodevelopment of WM in adolescents with EOS and age- and gender-matched typically developing controls. Participants underwent neuroimaging in the same scanner twice, once at age 17 and at 21 (mean interscan interval = 4.3 years). General linear model analysis was performed to explore WM neurodevelopmental changes within and between groups. Psychopathological scores were entered in multiple regressions to detect brain regions whose longitudinal functional change was predicted by baseline symptoms in EOS. WM neurodevelopment was characterized by widespread functional reductions in frontotemporal and cingulate brain areas in patients and controls. No between-group differences were found in the trajectory of WM change. Baseline symptom scores predicted functional neurodevelopmental changes in frontal, cingulate, parietal, occipital, and cerebellar areas. The adolescent brain undergoes developmental processes such as synaptic pruning, which may underlie the refinement WM of network. Prefrontal and parietooccipital activity reduction is affected by clinical presentation of symptoms. Using longitudinal neuroimaging methods in a rare diagnostic sample of patients with EOS may help the advancement of neurodevelopmental biomarkers intended as pharmacological targets to tackle WM impairment.

This study examined social cognitive heterogeneity in Norwegian sample of individuals with schizophrenia (n = 82). They were assessed with three social cognitive tests: Emotion in Biological Motion (emotion processing), Relationships Across Domains (social perception), and Movie for the Assessment of Social Cognition (theory of mind). Hierarchical and k-means cluster analyses using standardized scores on these three tests provided two clusters. The first cluster (68 %) had mild social cognitive impairments (<0.5 standard deviations below healthy comparison participants). The second cluster (32 %) had severe social cognitive impairments (>2 standard deviations below healthy comparison participants). Validity of the two social cognitive subgroups was indicated by significant differences in functioning, symptom load and nonsocial cognition. Our study shows that social cognitive tests can be used for clinical and cognitive subtyping. This is of potential relevance for treatment.

Schizophrenia patients are known to have deficits in contextual vision. However, results are often very mixed. In some paradigms, patients do not take the context into account and, hence, perform more veridically than healthy controls. In other paradigms, context deteriorates performance much more strongly in patients compared to healthy controls. These mixed results may be explained by differences in the paradigms as well as by small or biased samples, given the large heterogeneity of patients' deficits. Here, we show that mixed results may also come from idiosyncrasies of the stimuli used because in variants of the same visual paradigm, tested with the same participants, we found intact and deficient processing.