Increased grey matter volumes in the temporal lobe and its relationship with cognitive functioning in euthymic patients with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is characterized by episodic mood dysregulation, although a significant portion of patients suffer persistent cognitive impairment during euthymia. Previous magnetic resonance imaging (MRI) research suggests BD patients may have accelerated brain aging, observed as lower grey matter volumes. How these neurostructural alterations are related to the cognitive profile of BD is unclear.

METHODS

We aim to explore this relationship in euthymic BD patients with multimodal structural neuroimaging. A sample of 27 euthymic BD patients and 24 healthy controls (HC) underwent structural grey matter MRI and diffusion-weighted imaging (DWI). BD patient's cognition was also assessed. FreeSurfer algorithms were used to obtain estimations of regional grey matter volumes. White matter pathways were reconstructed using TRACULA, and four diffusion metrics were extracted. ANCOVA models were performed to compare BD patients and HC values of regional grey matter volume and diffusion metrics. Global brain measures were also compared. Bivariate Pearson correlations were explored between significant brain results and five cognitive domains.

RESULTS

Euthymic BD patients showed higher ventricular volume (F(1, 46) = 6.04; p = 0.018) and regional grey matter volumes in the left fusiform (F(1, 46) = 15.03; pFDR = 0.015) and bilateral parahippocampal gyri compared to HC (L: F(1, 46) = 12.79, pFDR = 0.025/ R: F(1, 46) = 15.25, pFDR = 0.015). Higher grey matter volumes were correlated with greater executive function (r = 0.53, p = 0.008).

LIMITATIONS

We evaluated a modest sample size with concurrent pharmacological treatment.

CONCLUSIONS

Higher medial temporal volumes in euthymic BD patients may be a potential signature of brain resilience and cognitive adaptation to a putative illness neuroprogression. This knowledge should be integrated into further efforts to implement imaging into BD clinical management.

Disrupted network switching in euthymic bipolar disorder: Working memory and self-referential paradigms

BACKGROUND

Patients with bipolar disorder (BD) frequently suffer from neurocognitive deficits that can persist during periods of clinical stability. Specifically, impairments in executive functioning such as working memory and in self-processing have been identified as the main components of the neurocognitive profile observed in euthymic BD patients. The study of the neurobiological correlates of these state-independent alterations may be a prerequisite to develop reliable biomarkers in BD.

METHODS

A sample of 27 euthymic BD patients and 25 healthy participants (HC) completed working memory and self-referential functional Magnetic Resonance Imaging (fMRI) tasks. Activation maps obtained for each group and contrast images (i.e., 2-back > 1-back/self > control) were used for comparisons between patients and HC.

RESULTS

Euthymic BD patients, in comparison to HC, showed a higher ventromedial prefrontal cortex activation during working memory, a result driven by the lack of deactivation in BD patients. In addition, euthymic BD patients displayed a greater dorsomedial and dorsolateral prefrontal cortex activation during self-reference processing.

LIMITATIONS

Pharmacotherapy was described but not included as a confounder in our models. Sample size was modest.

CONCLUSION

Our findings revealed a lack of deactivation in the anterior default mode network (aDMN) during a working memory task, a finding consistent with prior research in BD patients, but also a higher activation in frontal regions within the central executive network (CEN) during self-processing. These results suggest that an imbalance of neural network dynamics underlying external/internal oriented cognition (the CEN and the aDMN, respectively) may be one of the first reliable biomarkers in euthymic bipolar patients.

Factors associated with poor functional outcome in bipolar disorder: sociodemographic, clinical, and neurocognitive variables

OBJECTIVE

The current investigation aimed at studying the sociodemographic, clinical, and neuropsychological variables related to functional outcome in a sample of euthymic patients with bipolar disorder(BD) presenting moderate-severe levels of functional impairment.

METHODS

Two-hundred and thirty-nine participants with BD disorders and with Functioning Assessment Short Test(FAST) scores equal or above 18 were administered a clinical and diagnostic interview, and the administration of mood measure scales and a comprehensive neuropsychological battery. Analyses involved preliminary Pearson bivariate correlations to identify sociodemographic and clinical variables associated with the FAST total score. Regarding neuropsychological variables, a principal component analysis (PCA) was performed to group the variables in orthogonal factors. Finally, a hierarchical multiple regression was run.

RESULTS

The best fitting model for the variables associated with functioning was a linear combination of gender, age, estimated IQ, Hamilton Depression Rating Scale (HAM-D), number of previous manic episodes, Factor 1 and Factor 2 extracted from the PCA. The model, including all these previous variables, explained up to 29.4% of the observed variance.

CONCLUSIONS

Male gender, older age, lower premorbid IQ, subdepressive symptoms, higher number of manic episodes, and lower performance in verbal memory, working memory, verbal fluency, and processing speed were associated with lower functioning in patients with BD.

Heterogeneity of functional outcomes in patients with bipolar disorder: a cluster-analytic approach

OBJECTIVE

The aim was to examine the heterogeneity of psychosocial outcomes in euthymic bipolar disorder (BD) patients and analyse the potential influence of distinct variables on functioning.

METHOD

Using a hierarchical cluster exploratory analysis, 143 euthymic patients with diagnosis of BD were grouped according to their functional performance based on domains scores of the Functioning Assessment Short Test (FAST). The resulting groups were compared on sociodemographic, clinical and neurocognitive variables to find factors associated with each functional cluster.

RESULTS

Patients were grouped in three functional profiles: patients with good functioning in all the FAST areas, patients with an intermediate profile showing great difficulties in the occupational domain and milder difficulties in most of the rest domains, and a third group with serious difficulties in almost all functional areas. Both functionally impaired groups were characterized by higher subthreshold symptoms (depressive and manic) and higher unemployment rates. The most functionally impaired group also showed lower scores on some measures of processing speed.

CONCLUSION

Two of three functional profiles showed some kind of impairment which was associated with subsyndromal symptoms and cognitive performance. These patterns should be taken into consideration to develop more individualized interventions to restore, or improve, psychosocial outcomes.

Assessing and addressing cognitive impairment in bipolar disorder: the International Society for Bipolar Disorders Targeting Cognition Task Force recommendations for clinicians

OBJECTIVES

Cognition is a new treatment target to aid functional recovery and enhance quality of life for patients with bipolar disorder. The International Society for Bipolar Disorders (ISBD) Targeting Cognition Task Force aimed to develop consensus-based clinical recommendations on whether, when and how to assess and address cognitive impairment.

METHODS

The task force, consisting of 19 international experts from nine countries, discussed the challenges and recommendations in a face-to-face meeting, telephone conference call and email exchanges. Consensus-based recommendations were achieved through these exchanges with no need for formal consensus methods.

RESULTS

The identified questions were: (I) Should cognitive screening assessments be routinely conducted in clinical settings? (II) What are the most feasible screening tools? (III) What are the implications if cognitive impairment is detected? (IV) What are the treatment perspectives? Key recommendations are that clinicians: (I) formally screen cognition in partially or fully remitted patients whenever possible, (II) use brief, easy-to-administer tools such as the Screen for Cognitive Impairment in Psychiatry and Cognitive Complaints in Bipolar Disorder Rating Assessment, and (III) evaluate the impact of medication and comorbidity, refer patients for comprehensive neuropsychological evaluation when clinically indicated, and encourage patients to build cognitive reserve. Regarding question (IV), there is limited evidence for current evidence-based treatments but intense research efforts are underway to identify new pharmacological and/or psychological cognition treatments.

CONCLUSIONS

This task force paper provides the first consensus-based recommendations for clinicians on whether, when, and how to assess and address cognition, which may aid patients' functional recovery and improve their quality of life.

Concordance and Discrepancy Between Subjective and Objective Cognitive Assessment in Bipolar Disorder: What is Influencing this Discrepancy?

Introduction

Evidence has shown that some patients with bipolar disorder have a relatively accurate sense of their cognitive abilities, whereas others may overreported or underreported cognitive difficulties, which causes a discrepancy in this measures.

Objectives

To investigate concordance and discrepancy between subjective and objective cognitive measures, as well as to identify factors that could influence this discrepancy.

Methods

Patients who met DSM IV-TR criteria for bipolar disorder in partial or full remission (HDRS-17 score ≤ 12; YMRS score ≤ 7) were recruited from outpatient clinic at Barcelona and Porto Alegre. Objective cognitive assessment was performed by the Letter-Number Sequencing (LNS-WAIS III). Cognitive Complaints in Bipolar Disorder Rating Scale (COBRA) was used as a subjective cognitive measure.

Results

Were included 179 patients. We found a concordance between COBRA and LNS in 62 cases, and discrepancy in 117 cases (Fig. 1). The incongruent group (COBRA–and LNS + ) have less years of study (8.10 ± 4.01) than the incongruent group (COBRA+ and LNS–) (13.44 ± 4.05, P = 0.001), and than congruent group (COBRA–and NLS–) (13.75 ± 4.04, P = 0.003). Finally, the congruent group (COBRA+ and LNS + ) was the group with higher functioning impairment.

Conclusions

A few number of false-negative cases were detected, suggesting that COBRA can be used as a screening instrument. A special attention should be provided for subjects with a few years of study, because possibly these subjects presents more difficulty in express its cognitive difficulties.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

High Cognitive Reserve in Bipolar Disorders as a Moderator of Neurocognitive Impairment

Background

Cognitive reserve (CR) reflects the capacity of the brain to endure neuropathology, minimize clinical manifestations and successfully complete cognitive tasks. The present study aims to determine whether high CR may constitute a moderator of cognitive functioning in bipolar disorder (BD).

Methods

One hundred and two patients with BD and 32 healthy controls were enrolled. All patients met DSM-IV criteria for I or II BD and were euthymic (YMRS ≤ 6 and HDRS ≤ 8) during a 6-month period. All participants were tested with a comprehensive neuropsychological battery, and a Cerebral Reserve Score (CRS) was estimated. Subjects with a CRS below the group median were classified as having low CR, whereas participants with a CRS above the median value were considered to have high CR.

Results

Participants with BD with high CR displayed a better performance in measures of attention (digits forward: F = 4.554, P = 0.039); phonemic and semantic verbal fluency (FAS: F = 9.328, P = 0.004; and Animal Naming: F = 8.532, P = 0.006); and verbal memory (short cued recall of California Verbal Learning Test: F = 4.236, P = 0.046), after multivariable adjustment for potential confounders, including number of admissions and prior psychotic symptoms.

Conclusions

High cognitive reserve may therefore be a valuable construct to explore for predicting neurocognitive performance in patients with BD regarding premorbid status.

Disclosure of interest

Dr. I. Grande has received a Juan Rodés Contract (JR15/00012), Instituto de Salud Carlos III, Spanish Ministry of Economy and Competiveness, Barcelona, Spain and has served as a consultant for Ferrer and as a speaker for AstraZeneca, Ferrer and Janssen-Cilag.

Disclosure of interest

Dr. I. Grande has received a Juan Rodés Contract (JR15/00012), Instituto de Salud Carlos III, Spanish Ministry of Economy and Competiveness, Barcelona, Spain and has served as a consultant for Ferrer and as a speaker for AstraZeneca, Ferrer and Janssen-Cilag.

High cognitive reserve in bipolar disorders as a moderator of neurocognitive impairment

BACKGROUND

Cognitive reserve (CR) reflects the capacity of the brain to endure neuropathology, minimize clinical manifestations and successfully complete cognitive tasks. The present study aims to determine whether high CR may constitute a moderator of cognitive functioning in bipolar disorder (BD).

METHODS

102 patients with BD and 32 healthy controls were enrolled. All patients met DSM-IV criteria for I or II BD and were euthymic (YMRS≤6 and HDRS≤8) during a 6-month period. All participants were tested with a comprehensive neuropsychological battery, and a Cerebral Reserve Score (CRS) was estimated. Subjects with a CRS below the group median were classified as having low CR, whereas participants with a CRS above the median value were considered to have high CR.

RESULTS

Participants with BD with high CR displayed a better performance in measures of attention (digits forward: F=4.554, p=0.039); phonemic and semantic verbal fluency (FAS: F=9.328, p=0.004; and Animal Naming: F=8.532, p=0.006); and verbal memory (short cued recall of California Verbal Learning Test: F=4.236, p=0.046), after multivariable adjustment for potential confounders, including number of admissions and prior psychotic symptoms.

LIMITATIONS

The cross-sectional design of the study does not allow the establishment of causal inferences. Additionally, the small size of the sample may have limited some results.

CONCLUSIONS

High cognitive reserve may therefore be a valuable construct to explore for predicting neurocognitive performance in patients with BD regarding premorbid status.

Functional remediation in bipolar disorder: 1-year follow-up of neurocognitive and functional outcome

BACKGROUND

Few randomised clinical trials have examined the efficacy of an intervention aimed at improving psychosocial functioning in bipolar disorder.

AIMS

To examine changes in psychosocial functioning in a group that has been enrolled in a functional remediation programme 1 year after baseline.

METHOD

This was a multicentre, randomised, rater-masked clinical trial comparing three patient groups: functional remediation, psychoeducation and treatment as usual over 1-year follow-up. The primary outcome was change in psychosocial functioning measured by means of the Functioning Assessment Short Test (FAST). Group×time effects for overall psychosocial functioning were examined using repeated-measures ANOVA (trial registration NCT01370668).

RESULTS

There was a significant group×time interaction for overall psychosocial functioning, favouring patients in the functional remediation group (F = 3.071, d.f. = 2, P = 0.049).

CONCLUSIONS

Improvement in psychosocial functioning is maintained after 1-year follow-up in patients with bipolar disorder receiving functional remediation.

Neurocognitive impairment across the bipolar spectrum

Bipolar disorder is a severe mental illness that affects nearly 4.4% of the general population when bipolar spectrum disorders are taken into account. Neurocognitive impairment is thought to be a core deficit of this illness since it is present during euthymia. In fact, 40-60% of euthymic patients present with neurocognitive disturbances. Not only the clinical factors but also disturbances in neurocognition can influence the functional outcome of BD patients. Hence, further research is needed in order to clarify the relationship between these variables. Despite the growing body of evidence that has emerged during the last decade, no unique neurocognitive profile has been proposed yet for either BD subtype. The majority of the studies recluted heterogeneous samples (including both bipolar I and II) or focused on BD-I patients only. The aim of this review is to give an overall picture of the main neurocognitive disturbances found in the bipolar spectrum and particularly in BD-II, where the findings are more ambiguous. An extensive review of all the literature has been done regarding this subtype (from 1980 until July 2009). Data available until now suggest that deficits are present across the bipolar spectrum (BD-I and BD-II), but they seem slightly more severe in BD-I. The extent to which either subtype share-or not-some similarities is still unknown. More studies are required but it would also be interesting to reach a consensus in the neuropsychological assessment of BD to facilitate comparisons between the different studies.

[Bipolar disorder, cognitive functioning and hypothalamic-pituitary-thyroid axis]

In psychoneuroendocrinology there's a scarcity of knowledge of hypothalamic-pituitary-thyroid axis (HPT) in relation to bipolar disorder (BD) and neuropsychological functions. The aim of this study is to review the current state of the following issues: (1) neuropsychological dysfunctions in BD, as well as their hypothetic aetiology; (2) response of HPT in each phase of BD, and, finally, (3) connection between alterations in HPT and neuropsychological deficits.

Functioning and disability in bipolar disorder: an extensive review

BACKGROUND

Bipolar disorder has generally been regarded as having a better functional outcome than schizophrenia. However, studies have suggested low functioning in bipolar patients even when they are in clinical remission. Our aim was to determine the degree of functioning and disability in bipolar patients. Secondly, we reviewed factors potentially associated with the low functioning of bipolar patients.

METHOD

The authors conducted an extensive Medline and Pubmed search of the published literature from 1980 up to December 2007, using a variety of search terms to find relevant articles. Bibliographies of retrieved papers were further analysed for publications of interest. Articles that reported clinically significant findings on functioning and disability, and research reports were reviewed in detail.

RESULTS

From these articles, we determined that bipolar disorder is associated with significant impairment in work, family and social life, beyond the acute phases of the illness. The aspects that appear to increase the risk of low functioning and disability in bipolar patients are mainly subsyndromal symptoms and neurocognitive impairment, among others.

CONCLUSIONS

Suitable pharmacological and psychological interventions may improve the level of functioning and reduce the disability in bipolar patients. Potential targets to be considered for intervention should be residual symptoms, comorbid conditions and neurocognitive deficits. Further research is required to better identify the factors that best predict functioning in bipolar patients.

Comparison of the Hypomania Check List-32 scale with the Mood Disorder Questionnaire on Spanish Sample

Hypomania is perhaps the most difficult psychiatric syndrome to rule out retrospectively. However, the retrospective detection of hypomania is crucial for a correct diagnosis of bipolar disorder, and particularly bipolar II, and for the implementation of the right pharmacological treatment. Unfortunatelly, still nowadays, the misdiagnosis of bipolar II disorder as unipolar depression is very frequent, and may carry serious consequences for the patients. The availability of a good screening tool for past hypomania episodes would be extremely helpful.

The psychometric study of the development of the HCL-32 scale in Spain exhibits high internal consistency and similar stability over time, in comparison with other instruments such as the MDQ and suggests that this scale may be very useful for the detection of bipolar disorder and past hypomania.

The results of our study suggest the usefulness of the HCL-32 to screen out previous hypomanic symptoms in psychiatric patients, thus leading to better detection results than with the MDQ, although with the possibility of obtaining more false positives. HCL-32 has been shown to be a useful instrument for the detection of hypomania in patients with an affective disorder. The Spanish version exhibits good psychometric properties in relation to sensitivity and specificity. Given the difficulties involved in both the retrospective and cross-sectional diagnosis of hypomania, a key aspect of appropriate management of bipolar disorders, this questionnaire represents a potential improvement in clinicians’ ability to detect and correctly treat bipolar disorder, and in some aspects such as internal consistency, obtains better results than the MDQ.

Clinical Factors as Predictors on Functional Impairment in Bipolar Disorder

Introduction:

Recent studies have suggested that functional impairment in bipolar disorder may be strongly associated with residual depressive symptoms. However, there is a notable disparity between functional recovery and symptomatic recovery. This study was carried out to investigate clinical factors as potential predictors on functional impairment in a well defined euthymic bipolar sample.

Methods:

Seventy-one patients were recruited from the Bipolar Disorder Program at the Clinic Hospital of Barcelona. A Structured Clinical Interview for DSM-IV-TR, HAM-D and YMRS were used to diagnostic assessment and euthymia criteria. The Functioning Assessment Short Test (FAST) was employed to assess functional impairment. The FAST is a reliable and valid, interview-administered scale, rapid and easy to apply (3-6 min). It consists of 24 items which allow to assess six specific areas of functioning such as autonomy, occupational functioning, cognitive functioning, financial issues, interpersonal relationships, and leisure time.

Results:

The sample comprised 36 (51%) men, aged 48±13.56 years. Several clinical variables were associated with poor functioning on a linear regression model, such as age, depressive symptoms, number of previous mixed episodes and number of previous hospitalizations. This model explained 44% of the variance (F=12.54, df=58, p< 0.001).

Discussion:

In this study, specific clinical and socio-demographic characteristics were identified as predictors of functional impairment in remitted bipolar patients. Poor functioning was identified in patients with older age and more severe illness course.

Functional outcome in bipolar disorder: the role of clinical and cognitive factors

INTRODUCTION

Few studies have examined the clinical, neuropsychological and pharmacological factors involved in the functional outcome of bipolar disorder despite the gap between clinical and functional recovery.

METHODS

A sample of 77 euthymic bipolar patients were included in the study. Using an a priori definition of low versus good functional outcome, based on the psychosocial items of the Global Assessment of Functioning (GAF, DSM-IV), and taking also into account their occupational adaptation, the patients were divided into two groups: good or low occupational functioning. Patients with high (n = 46) and low (n = 31) functioning were compared on several clinical, neuropsychological and pharmacological variables and the two patient groups were contrasted with healthy controls (n = 35) on cognitive performance.

RESULTS

High- and low-functioning groups did not differ with respect to clinical variables. However, bipolar patients in general showed poorer cognitive performance than healthy controls. This was most evident in low-functioning patients and in particular on verbal memory and executive function measures.

CONCLUSIONS

Low-functioning patients were cognitively more impaired than highly functioning patients on verbal recall and executive functions. The variable that best predicted psychosocial functioning in bipolar patients was verbal memory.

Neuropsychological performance in depressed and euthymic bipolar patients

INTRODUCTION

Recent studies have suggested that the presence of persistent cognitive dysfunctions in bipolar patients is not restricted to acute episodes, but they persist even during remission states. Nevertheless, there are several methodological pitfalls in most studies, such as unclear remission criteria, diagnostic heterogeneity or small sample sizes.

PATIENTS AND METHODS

Several domains of cognitive function were examined in 30 depressed bipolar patients [DSM-IV criteria for major depression, Hamilton Depression Scale (HDRS) > or =17] and 30 euthymic bipolar patients (at least 6 months of remission, HDRS < or =8 and Young Mania Rating Scale, YMRS < or =6). Psychosocial functioning was assessed through General Assessment of Functioning.

RESULTS

The two groups showed a similar pattern of neuropsychological performance. However, the depressed group was significantly impaired on the Controlled Oral Word Association Test, FAS (COWAT), a measure of verbal fluency, compared with the euthymic group. On the other hand, functional outcome in euthymic patients was related to verbal fluency, even after controlling for residual depressive symptoms.

CONCLUSIONS

Neuropsychological performance was similar in both groups, except for verbal fluency, which was lower in the depressed group. Poor verbal fluency was related to a poor social outcome in euthymic patients. Further research including longitudinal designs aimed at evaluating changes in cognition in these patients is warranted.