Executive functioning in schizophrenia: a thorough examination of performance on the Hayling Sentence Completion Test compared to psychiatric and non-psychiatric controls

Factors associated with cognitive dysfunction in treatment-responsive and -resistant schizophrenia: A pilot cross-sectional study

BACKGROUND

Cognitive dysfunction is a core feature of schizophrenia. Although treatment-resistant schizophrenia (TRS) exhibits wide-ranging neuropsychological deficits, factors defining cognitive prognosis in TRS are unclear. We aimed to clarify the association between cognitive dysfunction and factors, such as plasma concentrations of clozapine (CLZ), N-desmethylclozapine (NDMC), and homovanillic acid (HVA), due to differences in antipsychotic responses in patients with schizophrenia.

METHODS

This pilot cross-sectional study included 60 Japanese patients (35 with TRS and 25 with non-CLZ antipsychotic responders (AR)). Cognitive function was evaluated using the Brief Assessment of Cognition Short Form (BAC-SF). Plasma concentrations of HVA, CLZ, and NDMC were analyzed by high-performance liquid chromatography.

RESULTS

The cognitive performance of patients with AR was better than that of patients with TRS in all tasks. No significant cognitive differences were detected between the CLZ responders and non-responders. The severity of negative and extrapyramidal symptoms was found to be potentially negatively associated with BAC-SF composite and several subtest scores. In patients with TRS, chlorpromazine equivalents and the CLZ/NDMC ratio were identified as factors negatively associated with Digit Sequencing and the Symbol Coding subtest scores of the BAC-SF, respectively.

CONCLUSIONS

Our study suggests that patients with TRS experience worse cognitive dysfunction than those with AR, and CLZ responsiveness in TRS may be not associated with cognitive dysfunction. Additionally, higher chlorpromazine equivalents and the CLZ/NDMC ratio may be associated with severity of cognitive dysfunction in patients with TRS. Further studies are required to clarify the relationship between treatment response and cognitive dysfunction in schizophrenia.

Resting-state hyperconnectivity within the default mode network impedes the ability to initiate cognitive performance in first-episode schizophrenia patients

Among multiple cognitive impairments present in schizophrenia, a decline in fast information processing is one of the most severe neuropsychological deficit. Reduced ability to efficiently launch a coherent cognitive activity might be a significant factor contributing to poor results in time-limited tasks obtained by schizophrenia patients. The aim of this study was to identify neurophysiological predictors of expected cognitive initiation failures in a group of first-episode schizophrenia individuals (SZ). To evaluate the effectiveness of initiation, a dynamic analysis of design fluency test was applied, assessing to what extent the productivity was focused within the first interval of the performance, what is a typical way healthy subjects execute this task. Resting-state EEG recordings were obtained from SZ patients (n = 34) and controls (n = 30) to examine functional connectivity between 84 intra-cortical current sources determined by eLORETA (exact low-resolution brain electromagnetic tomography) for six conventionally analyzed frequencies. The nonparametric randomization approach was used to identify hypo- and hyper-connections, i.e. synchronizations significantly differentiating the studied samples in terms of connectivity strength. Generally, SZ patients obtained poor outcomes in fluency test and dynamic analysis of performance confirmed the presence of initiation deficit in clinical sample, which was a single factor explaining the intergroup difference regarding the entire task. In the majority of frequencies, the arrangement of synchronizations in SZ group was dominated by hypo-connections, except for the theta band, in which the strength of synchronizations between posterior cingulate cortex, cuneus and precuneus was significantly higher for SZ group. These theta-band hyper-connections turned out to be significant predictors of cognitive initiation failure in the clinical sample. Additionally, theta hyper-connections correlated negatively with the total number of unique designs generated by patients, however, the strength of this correlation was weaker than regarding initiation index. The results of this study suggest that baseline hyperconnectivity within the posterior hub of the Default Mode Network, containing posterior cingulate gyrus and precuneus, might disturb effective cognitive outcome, not only by interfering with task-positive functional networks but also by delaying the starting phase of performance, which might be specifically deleterious for the execution of time-limited tests.

Antipsychotics, Metabolic Adverse Effects, and Cognitive Function in Schizophrenia

Cognitive impairment is a core symptom domain of schizophrenia. The effect of antipsychotics, the cornerstone of treatment in schizophrenia, on this domain is not fully clear. There is some evidence suggesting that antipsychotics may partially improve cognitive function, and that this improvement may vary depending on the specific cognitive domain. However, this research is confounded by various factors, such as age, duration/stage of illness, medication adherence, and extrapyramidal side effects that complicate the relationship between antipsychotics and cognitive improvement. Furthermore, antipsychotics-particularly the second generation, or "atypical" antipsychotics-can induce serious metabolic side effects, such as obesity, dyslipidemia and type 2 diabetes, illnesses which themselves have been linked to impairments in cognition. Thus, the inter-relationships between cognition and metabolic side effects are complex, and this review aims to examine them in the context of schizophrenia and antipsychotic treatment. The review also speculates on potential mechanisms underlying cognitive functioning and metabolic risk in schizophrenia. We conclude that the available literature examining the inter-section of antipsychotics, cognition, and metabolic effects in schizophrenia is sparse, but suggests a relationship between metabolic comorbidity and worse cognitive function in patients with schizophrenia. Further research is required to determine if there is a causal connection between the well-recognized metabolic adverse effects of antipsychotics and cognitive deficits over the course of the illness of schizophrenia, as well as, to determine underlying mechanisms. In addition, findings from this review highlight the importance of monitoring metabolic disturbances in parallel with cognition, as well as, the importance of interventions to minimize metabolic abnormalities for both physical and cognitive health.

Effectiveness of integrated psychological therapy on clinical, neuropsychological, emotional and functional outcome in schizophrenia: a RCT study

Background: Cognitive impairment is considered a central feature of schizophrenia (SZ) and several rehabilitation treatments have been developed to try to improve cognitive deficits.Aims: The aim of the present study was to analyze the effectiveness of integrated psychological therapy (IPT) compared with a standard treatment (TAU) in two groups of patients with SZ, using a comprehensive testing battery of clinical, cognitive, social cognition and functional outcome domains.Methods: Forty-one patients with SZ were assigned to IPT or TAU groups in a randomized controlled trial (RCT). Psychopathological, neuropsychological, emotional and functional outcome variables were assessed at baseline and after 36 weeks of treatment.Results: The IPT group showed significant improvements than the TAU group regarding clinical and functional outcome variables. Moreover, the IPT group improved significantly in the cognitive domains and emotional functioning. Finally, linear regression has highlighted that the improvement of cognitive variables depends on having done the IPT treatment.Conclusions: IPT seems to be effective in improving clinical, neuropsychological, emotional and functional outcome in chronic SZ inpatients. Further studies would be desirable to deepen the effectiveness of IPT in the field of the psychiatric rehabilitation pointing to the possibility of recovery from mental illness.

Brazilian norms and effects of age and education on the Hayling and Trail Making Tests

Abstract Objectives To describe normative data for the Hayling Test and the Trail Making Test (TMT) in a sample of Brazilian adults, and to investigate the effects of age and education on test performance. Method A total of 313 (TMT) and 364 (Hayling) individuals with age ranges of 19-39, 40-59, and 60-75 years, and with at least 5 years of formal education, participated in this study. The tests were administered as part of a large battery of a normative project. Individuals were evaluated individually in silent, ventilated rooms at a university clinic. Instrument protocols were scored by trained research assistants and double-checked to ensure data reliability. Results There were major effects of age on the TMT (Time B, Errors B, B-A) and on the Hayling Test (Errors B/15, B/45), and major effects of education on the TMT (Time B, Errors B, B-A) and on the Hayling Test (Time A, Errors B/15, B/45). Interaction effects were found in Time B and B-A for the Hayling Test and in Time A for the TMT. Conclusions Age and education were critical for performance on both verbal and non-verbal executive functions.

French Version of the Hayling Sentence Completion Test, Part II: Clinical Utility in Schizophrenia and Parkinson's Disease

Objective

We previously developed normative data for a French version of the Hayling Sentence Completion Test (f-HSCT) for adults and elderly people. The present study aimed to evaluate the clinical utility of the f-HSCT norms in two clinical populations in which inhibition dysfunction has been largely documented, i.e., Parkinson's disease (PD) and schizophrenia.

Method

Eighty-five non-demented patients with idiopathic PD and 64 out-patients with schizophrenia completed the automatic and inhibition conditions of the f-HSCT. Time latencies and errors raw data of each patient were compared to the norms previously developed by the authors.

Results

In the automatic condition, errors were rare in both clinical groups and time latencies on this condition felt within the normative data range. Compared with the standardized norms, 46% of patients with PD and 61% of patients with schizophrenia had a deviant performance (i.e., borderline or deficit) for the inhibition error score. The proportion of patients with a deviant performance on the inhibition response time score was similar in both clinical samples (respectively, 25% and 23%). Finally, slightly more than half of patients with PD and more than two-thirds of patients with schizophrenia had a deviant performance on at least one of the f-HSCT inhibition measures.

Conclusions

Our results suggest that the f-HSCT has a strong potential for characterizing inhibition of prepotent responses in PD and schizophrenia. Furthermore, it requires only a short administration time so it may be ideal to detect response inhibition in clinical populations with cognitive fatigue.

Verbal Initiation, Suppression, and Strategy Use and the Relationship with Clinical Symptoms in Schizophrenia

OBJECTIVES

Individuals with schizophrenia have difficulties on measures of executive functioning such as initiation and suppression of responses and strategy development and implementation. The current study thoroughly examines performance on the Hayling Sentence Completion Test (HSCT) in individuals with schizophrenia, introducing novel analyses based on initiation errors and strategy use, and association with lifetime clinical symptoms.

METHODS

The HSCT was administered to individuals with schizophrenia (N=77) and age- and sex-matched healthy controls (N=45), along with background cognitive tests. The standard HSCT clinical measures (initiation response time, suppression response time, suppression errors), composite initiation and suppression error scores, and strategy-based responses were calculated. Lifetime clinical symptoms [formal thought disorder (FTD), positive, negative] were calculated using the Lifetime Dimensions of Psychosis Scale.

RESULTS

After controlling for baseline cognitive differences, individuals with schizophrenia were significantly impaired on the suppression response time and suppression error scales. For the novel analyses, individuals with schizophrenia produced a greater number of initiation errors and subtly wrong errors, and produced fewer responses indicative of developing an appropriate strategy. Strategy use was negatively correlated with FTD symptoms in individuals with schizophrenia.

CONCLUSIONS

The current study provides further evidence for deficits in the initiation and suppression of verbal responses in individuals with schizophrenia. Moreover, an inability to attain a strategy at least partly contributes to increased semantically connected errors when attempting to suppress responses. The association between strategy use and FTD points to the involvement of executive deficits in disorganized speech in schizophrenia. (JINS, 2016, 22, 735-743).

Executive dysfunction in psychosis following traumatic brain injury (PFTBI)

INTRODUCTION

Executive dysfunction is well established in patients with traumatic brain injury and in schizophrenia (SCZ). However, assessments of executive function in psychosis following traumatic brain injury (PFTBI) are limited and inconsistent, and often do not reflect the deficits demonstrated in patients with traumatic brain injury (TBI) or SCZ. We sought to determine the extent of executive dysfunction in PFTBI relative to three comparison cohorts.

METHOD

Measures of executive function were administered to dually diagnosed patients with PFTBI (n = 10) including tests of mental inhibition and switching, processing speed, and attention: the Stroop Task, Trail Making Test (TMT), and the Attention subtest of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Demographically comparable patients with TBI (n = 10), SCZ (n = 23), and healthy controls (n = 23) underwent an identical battery.

RESULTS

Significant executive dysfunction was evident in patients with PFTBI on all measures. Relative to all three comparison cohorts patients with PFTBI performed most poorly.

CONCLUSIONS

These data present novel evidence of substantially impaired executive function across four task types in PFTBI and suggest that TBI and psychosis have an additive influence on executive function deficits. Treatment programs requiring substantial executive engagement are not suitable for patients dually diagnosed with PFTBI.

The Experience of Cognitive Impairment in People with Psychosis

Cognitive impairment has been widely studied in people with psychosis. However, research is lacking into the subjective experience of cognitive impairment, its impact and ways in which individuals cope. This study aimed to provide an account of the experience of cognitive impairment in people with a diagnosis of schizophrenia, including what difficulties people experience, how these difficulties are understood, how people respond to these difficulties and how they perceive others' views of these difficulties. A semi-structured interview was carried out with eight participants with a diagnosis of schizophrenia focusing on participants' experiences of difficulties with cognitive functioning. Interpretative phenomenological analysis was used to analyse interview transcripts. Experience of cognitive impairment was understood in terms of six master themes: impaired controlled thinking, physical sensations and impaired movement, explanations for the impairment and comparisons to the past, managing the impairment, how others see the impairment and anticipating the future. This study is the first rigorous qualitative study of the subjective experience of cognitive impairment in people with psychosis, and it provides greater context for empirical findings. The results have significant implications for clinical psychology, including education about cognitive difficulties and the importance of cognitive functioning to formulation. New areas for research include coping strategies in relation to functioning and future perspectives, ascertaining staff understanding of cognitive impairment, and reflective conversation style as an intervention for metacognitive difficulties. Key Practitioner Message Difficulties with cognitive functioning should be considered in clinical practitioners' formulations of clients' difficulties in the context of psychosis. Services should consider providing service user and carer education about cognitive impairment in psychosis. Staff may need further training in order to support people with psychosis who have difficulties with cognitive functioning.

Bipolar disorder and schizophrenia share a similar deficit in semantic inhibition: a meta-analysis based on Hayling Sentence Completion Test performance

Bipolar disorder (BD) is associated with deficits in executive function similar to that found in schizophrenia (SZ). However, very few studies have examined whether a specific component of executive function, namely, semantic inhibition, is differentially impaired in BD and SZ. The present study reports the results of a meta-analysis of performance on a theory-driven test of semantic inhibition, namely, the Hayling Sentence Completion Test (HSCT), in patients with BD and SZ, and to examine differential group impairments. The Comprehensive Meta-Analysis Software package was used to calculate the mean effect sizes for group differences on different measures of HSCT. A total of 13 studies were included in the meta-analysis. Effect sizes for six HSCT measures were calculated. These included: Total Latency of Task A, Total Latency of Task B, Suppression Time, Total Error of Task B, Type A Error of Task B, and Type B Error of Task B. When compared with healthy controls, medium-to-large effect sizes were observed in both groups for each HSCT measure. Interestingly, the effect sizes for BD and SZ groups were comparable. These results suggest that patients with SZ and patients with BD are impaired in both task initiation and task inhibition of executive function and these impairments are similar in magnitude for both disorders.

Cognitive impairment in bipolar disorder and schizophrenia: a systematic review

AIMS

Previous comparisons of cognitive decline among patients with bipolar disorder (BD) and schizophrenia (SZ) have found somehow quite similar profiles of deficits, but results have varied between studies. Therefore an extensive and thoughtful systematic review of the matter is warranted.

METHODS

Studies were found through systematic search (PubMed) following PRISMA guidelines. To be included, studies must have assessed the following cognitive functions: executive functions, memory, IQ, attention-concentration, and perceptuomotor function. In order to make comparison between the two entities, studies should include BD patients with operationally defined euthymia, schizophrenic patients in remission, and third group of healthy control patients. Comparisons were made after controlling for years of schooling and residual affective symptoms.

RESULTS

We found that overall both SZ and BD patients present deficits on all neurocognitive measures compared to healthy controls. In particular, SZ patients show more severe and pervasive cognitive deficits while BD patients present a milder and more confined impairment. In addition, evidence from the literature suggests that SZ and BD patients share a similar cognitive impairment profile with different degrees of deficits. Therefore, the difference between the two groups seems to be more quantitative (degree of deficit) rather than qualitative (profile), supporting a dimensional approach to the two clinical entities. Limitations of the present review includes the impossibility to control for effects of medication, varying time required for assessment across studies, illness diagnosis reliability, and course severity.

CONCLUSION

Patients with BD might exhibit a cognitive impairment that could be similar to SZ in terms of their profile, although patients with SZ may have more severe and widespread impairments.

The DISC1 promoter: characterization and regulation by FOXP2

Disrupted in schizophrenia 1 (DISC1) is a leading candidate susceptibility gene for schizophrenia, bipolar disorder and recurrent major depression, which has been implicated in other psychiatric illnesses of neurodevelopmental origin, including autism. DISC1 was initially identified at the breakpoint of a balanced chromosomal translocation, t(1;11) (q42.1;14.3), in a family with a high incidence of psychiatric illness. Carriers of the translocation show a 50% reduction in DISC1 protein levels, suggesting altered DISC1 expression as a pathogenic mechanism in psychiatric illness. Altered DISC1 expression in the post-mortem brains of individuals with psychiatric illness and the frequent implication of non-coding regions of the gene by association analysis further support this assertion. Here, we provide the first characterization of the DISC1 promoter region. Using dual luciferase assays, we demonstrate that a region -300 to -177 bp relative to the transcription start site (TSS) contributes positively to DISC1 promoter activity, while a region -982 to -301 bp relative to the TSS confers a repressive effect. We further demonstrate inhibition of DISC1 promoter activity and protein expression by forkhead-box P2 (FOXP2), a transcription factor implicated in speech and language function. This inhibition is diminished by two distinct FOXP2 point mutations, R553H and R328X, which were previously found in families affected by developmental verbal dyspraxia. Our work identifies an intriguing mechanistic link between neurodevelopmental disorders that have traditionally been viewed as diagnostically distinct but which do share varying degrees of phenotypic overlap.

Executive function in first-episode schizophrenia: a three-year prospective study of the Hayling Sentence Completion Test

In recent decade, deficits in the mechanism of Supervisory Attentional System (SAS) have become increasingly influential in explaining the nature of dysexecutive syndrome experienced by schizophrenic patients. The SAS model is characterized by having a detailed sub-classification of specific executive function components, among which semantic inhibition has been investigated using the Hayling Sentence Completion Test (HSCT). Several studies thus far have indicated that schizophrenic patients show impairment in HSCT performance. However, HSCT data concerning first-episode patients is still scarce. Besides, as previous HSCT studies were all cross-sectional in nature, they were not able to assess changes in HSCT performance over time. In order to address the paucity of knowledge about the longitudinal trajectories and correlates of semantic inhibition deficits in early schizophrenia, this paper reports a three-year prospective study of HSCT performance in medication-naïve, first-episode patients with schizophrenia-spectrum disorders. HSCT performance was assessed in 34 patients at four times over a period of three years, while the 34 healthy controls were assessed once. We found that medication-naïve patients demonstrated impairment in the inhibition condition in HSCT as compared to controls, but not in the initiation condition. Such HSCT impairment gradually improved in the three years following the first psychotic episode; however, HSCT performance did not predict improvement in negative or positive symptoms over the three-year period. The present findings suggest that semantic inhibition impairment is a specific deficit in schizophrenia that may require early intervention efforts, with the goal of facilitating more successful verbal communication and thereby better interpersonal functioning.

A video ethnography approach for linking naturalistic behaviors to research constructs of neurocognition in schizophrenia

Few methods are available to explore the impact of neurocognition in schizophrenia on behaviors performed in usual contexts. The authors developed a video ethnography approach to examine the relationship between naturalistic behaviors and research constructs of neurocognition. Video ethnographers accompanied subjects through usual routines gathering continuous video data. Researchers developed codes to measure four behavioral domains observed on video. This paper describes the psychometric characteristics to be considered in the development of observational approaches. It also highlights differences between behaviors performed in usual environments and neuropsychological constructs. The authors demonstrate that everyday behaviors that have been shown to correspond to neurocognitive skills in a pilot feasibility study can be identified and rated. They further suggest that observational methods could provide novel strategies for linking research findings and clinical concerns.

Cognitive flexibility in verbal and nonverbal domains and decision making in anorexia nervosa patients: a pilot study

BACKGROUND

This paper aimed to investigate cognitive rigidity and decision making impairments in patients diagnosed with Anorexia Nervosa Restrictive type (AN-R), assessing also verbal components.

METHODS

Thirty patients with AN-R were compared with thirty age-matched healthy controls (HC). All participants completed a comprehensive neuropsychological battery comprised of the Trail Making Test, Wisconsin Card Sorting Test, Hayling Sentence Completion Task, and the Iowa Gambling Task. The Beck Depression Inventory was administered to evaluate depressive symptomatology. The influence of both illness duration and neuropsychological variables was considered. Body Mass Index (BMI), years of education, and depression severity were considered as covariates in statistical analyses.

RESULTS

The AN-R group showed poorer performance on all neuropsychological tests. There was a positive correlation between illness duration and the Hayling Sentence Completion Task Net score, and number of completion answers in part B. There was a partial effect of years of education and BMI on neuropsychological test performance. Response inhibition processes and verbal fluency impairment were not associated with BMI and years of education, but were associated with depression severity.

CONCLUSIONS

These data provide evidence that patients with AN-R have cognitive rigidity in both verbal and non-verbal domains. The role of the impairment on verbal domains should be considered in treatment. Further research is warranted to better understand the relationship between illness state and cognitive rigidity and impaired decision-making.

Use of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to investigate group and gender differences in schizophrenia and bipolar disorder

OBJECTIVE

Gender differences exist in schizophrenia and bipolar disorder (BD), therefore the aim of the present study was to clarify the role of gender in cognitive deficits in these disorders.

METHODS

Cognitive performance was examined in schizophrenia (24M : 14F) and BD (16M : 24F) patients compared with age-, IQ- and gender-matched control participants (21M : 22F). The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to assess five cognitive domains: immediate memory/learning, visuospatial ability, language, attention, and delayed memory, which are summed to provide a Total score.

RESULTS

In comparison to controls, schizophrenia patients showed deficits on all domains, while BD patients had impaired immediate memory/learning, language and Total score. Schizophrenia patients showed deficits compared to BD in the Total score, immediate and delayed memory and visuospatial ability. The Total and domain scores were not different in men and women across or within groups. There were gender effects on four of the 12 individual cognitive tasks, in which female patients outperformed male patients. Further, there were gender differences across groups for three of the individual tasks: female schizophrenia patients showed poorer story memory and story recall compared to male schizophrenia patients; female BD patients had enhanced figure copy performance compared to male BD patients.

CONCLUSIONS

The RBANS highlighted the cognitive deficits in schizophrenia and BD patients compared to controls and also each other. There were no overall gender differences in cognition.