Schizophrenia Research-Cognition最新文献

Working memory (WM) impairments are well recognized in schizophrenia patients (PSZ) and contribute to poor psycho-social outcomes in this population. Distinct neural networks underlay the ability to encode and recall visual and spatial information raising the possibility that profile of visual working memory performance may help pinpoint dysfunctional neural correlates in schizophrenia. This study assessed the resolution and associative aspects of visual working memory deficits in schizophrenia and whether these deficits arise during encoding or maintenance processes. A total of 60 participants (30 PSZ and 30 healthy controls) matched in age, gender and education assessed on a modified object in place (OiPT), a delayed non-match-to-sample (DNMST) and a delayed spatial estimation (DSET) task. Patients demonstrated lower accuracy than controls in binding visual features of the same object and recognizing novel objects as well as lower precision recalling the location of a memorized target. Moreover, response choice set size affected recognition accuracy more in PSZ than controls. However, delay duration affected spatial recall precisions, binding, and recognition accuracy equally in the two groups. Our results suggest that visual working memory (vWM) impairments in schizophrenia predominantly reflect spatial and non-spatial binding deficits, with largely preserved discrete feature information. Moreover, these impairments likely arise more during encoding than during maintenance. These binding deficits may reflect impaired effective neural functional connectivity observed in schizophrenia.

Objective

Introspective Accuracy (IA) is a metacognitive construct that refers to alignment of self-generated accuracy judgments, confidence, and objective information regarding performance. IA not only refers to accuracy and confidence during tasks, but also predicts functional outcomes. The consistency and magnitude of IA deficits suggest a sustained disconnect between self-assessments and actual performance. The cognitive origins of IA are unclear and are not simply due to poor performance. We tried to capture task and diagnosis-related differences through examining confidence as a timeseries.

Method

This relatively large sample (N = 171; Bipolar = 71, Schizophrenia = 100) study used item by item confidence judgments for tasks including the Wisconsin Card Sorting Task (WCST) and the Emotion Recognition task (ER-40). Using a seasonal decomposition approach and AutoRegressive, Integrative and Moving Averages (ARIMA) time-series analyses we tested for the presence of randomness and perseveration.

Results

For the WCST, comparisons across participants with schizophrenia and bipolar disorder found similar trends and residuals, thus excluding perseverative or random responding. However, seasonal components were weaker in participants with schizophrenia, reflecting a reduced impact of feedback on confidence. In contrast, for the ER40, which does not require identification of a sustained construct, seasonal, trend, and residual analyses were highly comparable.

Conclusion

Seasonal analysis revealed that confidence judgments in participants with schizophrenia on tasks requiring responses to feedback reflected diminished incorporation of external information, not random or preservative responding. These analyses highlight how time series analyses can specify potential faulty processes for future intervention.

As core symptoms of schizophrenia, cognitive deficits contribute substantially to poor outcomes. Early life stress (ELS) can negatively affect cognition in patients with schizophrenia and healthy controls, but the exact nature of the mediating factors is unclear. Therefore, we investigated how ELS, education, and symptom burden are related to cognitive performance.

The sample comprised 215 patients with schizophrenia (age, 42.9 ± 12.0 years; 66.0 % male) and 197 healthy controls (age, 38.5 ± 16.4 years; 39.3 % male) from the PsyCourse Study. ELS was assessed with the Childhood Trauma Screener (CTS). We used analyses of covariance and correlation analyses to investigate the association of total ELS load and ELS subtypes with cognitive performance.

ELS was reported by 52.1 % of patients and 24.9 % of controls. Independent of ELS, cognitive performance on neuropsychological tests was lower in patients than controls (p < 0.001). ELS load was more closely associated with neurocognitive deficits (cognitive composite score) in controls (r = −0.305, p < 0.001) than in patients (r = −0.163, p = 0.033). Moreover, the higher the ELS load, the more cognitive deficits were found in controls (r = −0.200, p = 0.006), while in patients, this correlation was not significant after adjusting for PANSS.

ELS load was more strongly associated with cognitive deficits in healthy controls than in patients. In patients, disease-related positive and negative symptoms may mask the effects of ELS-related cognitive deficits. ELS subtypes were associated with impairments in various cognitive domains. Cognitive deficits appear to be mediated through higher symptom burden and lower educational level.

In terms of thought disorder, the language of patients with schizophrenia itself could be a valuable resource. Some valuable studies on the language of patients with schizophrenia have been performed. However, most such studies have been confined to English-speaking countries, or at least those where Indo-European languages are spoken. Therefore, we investigated linguistic anomalies in the language of Korean patients with schizophrenia. Short texts written by 69 patients with schizophrenia from a single mental hospital and matched normal control participants were analyzed. We evaluated these texts in terms of semantic and syntactic errors. Then, we compared the error rates adjusted for text length between patients and normal control participants. We also divided the patients with schizophrenia into two groups by their duration of illness and compared these two groups to investigate the relationship between the duration of illness and linguistic anomalies. The patients with schizophrenia committed a total of 1.86 (2.52) semantic errors and 1.37 (1.79) syntactic errors per 100 characters, which were significantly more frequent than errors committed by normal control participants. Furthermore, there was a notably high number of semantic errors relative to syntactic errors in the language of patients with schizophrenia. Our study results are consistent with previous studies from English-speaking countries, implying that the linguistic anomalies of patients with schizophrenia are not confined to a single language. Because language is essential in mental function, further research on linguistic anomalies in patients with schizophrenia is recommended.

Purpose

Cognitive Adaptation Training (CAT) is a psychosocial intervention with demonstrated effectiveness. However, no validated fidelity instrument is available. In this study, a CAT Fidelity Scale was developed and its psychometric properties, including interrater reliability and internal consistency, were evaluated.

Methods

The fidelity scale was developed in a multidisciplinary collaboration between international research groups using the Delphi method. Four Delphi rounds were organized to reach consensus for the items included in the scale. To examine the psychometric properties of the scale, data from a large cluster randomized controlled trial evaluating the implementation of CAT in clinical practice was used. Fidelity assessors conducted 73 fidelity reviews at four mental health institutions in the Netherlands.

Results

After three Delphi rounds, consensus was reached on a 44-item CAT Fidelity Scale. After administration of the scale, 24 items were removed in round four resulting in a 20-item fidelity scale. Psychometric properties of the 20-item CAT Fidelity Scale shows a fair interrater reliability and an excellent internal consistency.

Conclusions

The CAT fidelity scale in its current form is useful for both research purposes as well as for individual health professionals to monitor their own adherence to the protocol. Future research needs to focus on improvement of items and formulating qualitative anchor point to the items to increase generalizability and psychometric properties of the scale. The described suggestions for improvement provide a good starting point for further development.

Impaired cognitive control, for instance increased distractibility in simple conflict tasks such as Stroop, is considered one of fundamental cognitive deficits in schizophrenia patients. Relatively less is known about patients proneness to distraction in more complex, longer-lasting cognitive tasks. We applied the four-term analogies with and without distraction to 51 schizophrenia patients in order to examine whether they display increased distractibility during analogical reasoning, and to test which kind of distractors (semantic, categorical, or perceptual) elicits their strongest distraction, as compared to 51 matched controls. We found that (a) both groups reasoned by analogy comparably well when distraction was absent; (b) in both groups distraction significantly decreased performance; (c) schizophrenia patients were significantly more distracted than the controls; (d) in both groups the semantic distractors were selected more frequently than the categorical distractors, while the perceptual distractors were virtually ignored; as well as (e) in both groups distractibility in the four-term analogies was unrelated with distractibility in the simple perceptual conflict task, suggesting that these two distraction types tap into different cognitive mechanisms. Importantly, a significantly stronger distractibility in the schizophrenia group could not be explained by their lower intelligence, because the two groups were matched on the fluid reasoning test. We conclude that during complex cognitive processing schizophrenia patients become captured by irrelevant semantic associations. The patients are also less willing to critically evaluate their responses.

Goal Management Training (GMT) improved self-reported executive functioning in a recent randomized, controlled trial in early intervention for psychosis participants. Little is known about the mechanism for this benefit, so this study investigates objectively measured executive function, the difference between subjective and objective executive function, independent living and employment status as potential moderators of efficacy of GMT.

Baseline scores from 81 participants (GMT n = 39 vs Treatment-as-usual; TAU n = 42) were analyzed in a linear mixed model analysis for repeated measures as predictors of improvement on the self-reported Behavior Rating Inventory of Executive Function–Adult version (BRIEF-A) immediately and 30 weeks after GMT. Potential moderators were scores from objective measures of executive functioning, discrepancy between subjective and objective measures, independent living and employment status. Discrepancy was assessed by comparing four clusters of participants with differing patterns of scores.

The effect of GMT remained significant regardless of initial objective executive functioning at baseline. Those with higher subjective complaints at baseline in two clusters with (i) both objective and subjective executive dysfunction, and (ii) mostly subjective executive dysfunction experienced greater change after treatment. Living arrangements or participation in education or work did not significantly moderate the effects of GMT.

Poor performance on neuropsychological tasks is not an obstacle to making use of GMT, but further knowledge is needed about the benefits of strategy training for individuals with a combination of poor performance with few subjective complaints.

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.