Cross-cultural comparisons on Wisconsin Card Sorting Test performance in euthymic patients with bipolar disorder

Double dissociation between P300 components and task switch error type in healthy but not psychosis participants

Event-related potentials (ERPs) during oddball tasks and the behavioral performance on the Penn Conditional Exclusion Task (PCET) measure context-appropriate responding: P300 ERPs to oddball targets reflect detection of input changes and context updating in working memory, and PCET performance indexes detection, adherence, and maintenance of mental set changes. More specifically, PCET variables quantify cognitive functions including inductive reasoning (set 1 completion), mental flexibility (perseverative errors), and working memory maintenance (regressive errors). Past research showed that both P300 ERPs and PCET performance are disrupted in psychosis. This study probed the possible neural correlates of 3 PCET abnormalities that occur in participants with psychosis via the overlapping cognitive demands of the two study paradigms. In a two-tiered analysis, psychosis (n = 492) and healthy participants (n = 244) were first divided based on completion of set 1 - which measures subjects' ability to use inductive reasoning to arrive at the correct set. Results showed that participants who failed set 1 produced lower parietal P300, independent of clinical status. In the second tier of analysis, a double dissociation was found among healthy set 1 completers: frontal P300 amplitudes were negatively associated with perseverative errors, and parietal P300 was negatively associated with regressive errors. In contrast, psychosis participants showed global P300 reductions regardless of PCET performance. From this we conclude that in psychosis, overall activations evoked by the oddball task are reduced while the cognitive functions required by PCET are still somewhat supported, showing some level of independence or compensatory physiology in psychosis between neural activities underlying the two tasks.

Aberrant Functional Connectivity of Sensorimotor Network and Its Relationship With Executive Dysfunction in Bipolar Disorder Type I

Background

The key pathophysiological mechanism of executive dysfunction in patients with bipolar disorder type I (BD-I) is still unclear. Previous studies have demonstrated that it may be related to the disbalance of the sensory motor network (SMN).

Objective

This study was designed to explore the aberrant functional connectivity (FC) of SMN in BD-I patients and its potential associations with executive dysfunction.

Methods

Eighteen BD-I patients and 20 healthy controls (HCs) underwent resting-state fMRI scans. The intranetwork and internetwork functional connectivities of SMN were extracted by independent component analysis (ICA). Clinical symptoms were assessed by the Bech–Rafaelsen Mania Rating Scale (BRMS) and Positive and Negative Syndrome Scale (PANSS). Executive function was measured by digit span tasks and a verbal fluency test. Finally, linear regression and correlation analyses were applied to measure the potential associations between clinical symptoms, intranetwork and internetwork functional connectivities, and executive function performance.

Results

(1) Patients with BD-I showed increased connectivity in the right paracentral lobule and the right postcentral gyrus within the SMN, and the increased connectivity value was positively correlated with the BRMS score (P < 0.05) but negatively correlated with digit span forward scores (P < 0.05). (2) Compared with HC, the connectivity value increased between the SMN and dorsal attention network (DAN) (P < 0.01) and between the default mode network (DMN) and DAN (P < 0.05) but decreased between the DAN and auditory network (AN) (P < 0.05) and between the SMN and DMN (P < 0.01) in patients with BD-I. (3) Digit span forward scores and education of all participants were negatively correlated with FC between SMN and DAN. Age of all subjects was positively correlated with FC between SMN and DMN.

Conclusion

Our findings suggest that the sensorimotor network of BD-I has abnormal functional connections within and between networks, and the abnormal FC value correlated with clinical symptoms and executive function, which provide new information for exploring the neural physiopathology of executive dysfunction in BD-I patients.

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.

Bipolar disorder and obsessive compulsive disorder: The comorbidity does not further impair the neurocognitive profile

BACKGROUND

The comorbidity of bipolar disorder (BD) and obsessive-compulsive disorder (OCD) has been widely described. Several studies have investigated the cognitive profiles of BD and OCD patients, but studies that compare BD, BD-OCD, and OCD patients in neuropsychological domains do not exist. The purpose of this study was to compare set-shifting, decision making, and central coherence among BD, BD-OCD, and OCD patients.

METHODS

A battery of neuropsychological tests was administered to 68 patients (22 BD, 26 BD-OCD, 20 OCD). The Young Mania Rating Scale and Hamilton Depression Rating Scale were used to evaluate manic and depressive symptoms, and OCD severity was assessed with the Yale Brown Obsessive Compulsive Scale.

RESULTS

No significant differences emerged in decision-making and cognitive flexibility, whereas BD patients had lower scores in the Accuracy Index on Rey-Osterrieth Complex Figure Test and poor response speed on Hayling Sentence Completion Test Part A than OCD patients.

LIMITATIONS

The small sample size with different BD patients, the cross-sectional design, and the study clinical nature.

CONCLUSIONS

The most striking result is that, contrary to our hypothesis, comorbidity does not further impair the neurocognitive profile. The clinical relevance of our work could be a shift from the current cognitive rehabilitation model focusing on individualized pathways towards a new overlapping model for all three patient groups. This could make the cognitive rehabilitation faster and less costly. Notwithstanding, these disorders do not only need cognitive training but also various psycho-educative approaches and treatment according to their different clinical profile.

Cytokines and C-reactive protein alterations with respect to cognitive impairment in schizophrenia and bipolar disorder: A systematic review

BACKGROUND

The aim of this article was to perform a systematic review of studies investigating the association between peripheral levels of cytokines and C-reactive protein (CRP), cytokine gene polymorphisms and cognition in patients with schizophrenia and bipolar disorder (BD).

METHODS

The following databases: PubMed, CINAHL Complete, Academic Search Complete, ERIC and Health Source: Nursing/Academic Edition databases were searched according to the PRISMA guidelines. We included studies that investigated the association between peripheral levels of CRP and cytokines, cytokine gene polymorphisms and cognitive performance in schizophrenia and/or BD patients. Subsequently, quality assessment of eligible publications was performed. Results were synthesized by discussing main findings around correlations between inflammatory markers and cognition.

RESULTS

Most consistent results indicate worse cognitive performance in schizophrenia patients with higher CRP levels. Less consistent evidence suggests better cognitive functioning of schizophrenia patients with higher levels of tumour necrosis factor-α (TNF-α). Evidence for the involvement of other cytokines in cognitive impairment in patients with schizophrenia is less convincing due to discordant results or scarcity of studies. Due to low number of studies, it is difficult to draw conclusions on the involvement of CRP and cytokine alterations in the development of cognitive deficits in BD. Single studies suggest the role of CRP, interleukin(IL)-1 receptor antagonist, IL-6 and TNF-α with its receptors in the development of cognitive impairment in BD.

CONCLUSIONS

Peripheral inflammation might be related to cognitive deficits in schizophrenia and BD. Unequivocal conclusions cannot be made due to methodological heterogeneity and low number of studies investigating particular cytokines.

The link between high-sensitivity C-reactive protein and orbitofrontal cortex in euthymic bipolar disorder

OBJECTIVE

C-reactive protein (CRP), a marker of underlying low-grade inflammation, has been associated with the pathophysiology of bipolar disorder. Additionally, bipolar disorder may be accompanied by functional or structural cerebral alterations. We attempted to discover whether serum high-sensitivity CRP (hs-CRP) levels are linked to the structural volume change of a specific brain region along with cognitive performance.

METHODS

We recruited 17 physically healthy patients with bipolar I disorder (DSM-IV), aged 18-45 years and euthymic, to undergo the Wisconsin Card Sorting Test (WCST) and volumetric magnetic resonance imaging at 1.5 T. The analytic method was based on the hidden Markov random field model with an expectation-maximization algorithm, and the volume of each brain region was presented as a percentage of the total intracranial volume.

RESULTS

Among the various regions, only the orbitofrontal cortex had a significantly negative correlation with serum hs-CRP levels after adjustment for age and gender (left and right orbitofrontal cortex: r = -0.62, p < 0.01, and r = -0.67, p < 0.005, respectively). Regarding cognitive function, poor WCST performance was also associated with certain subregions of the orbitofrontal cortex.

CONCLUSION

Elevation of serum hs-CRP levels, an indicator of inflammation, may be associated with reduced volume of the orbitofrontal cortex. Persistent inflammation in the euthymic phase of bipolar disorder may involve the pathogenesis or pathophysiology of alteration of the frontal pathway.