Cognitive impairment and dementia in late-life bipolar disorder

Association of early- and late-life bipolar disorder with incident dementia. A Danish cohort study

BACKGROUND

This study aimed to explore the association between bipolar disorder and the risk of developing dementia, and whether the risk varies with age at the onset of bipolar disorder.

METHODS

In this study, 37,084 individuals with a first-time diagnosis of bipolar disorder diagnosed between 1969 and 2018 and a reference population (n = 189,662) matched on sex, birth year and time of bipolar diagnosis (index date) were followed in nationwide registries for incident dementia until October 2020. Associations were analysed using Cox proportional hazard regression with adjustment for sex, education level, alcohol or drug abuse, traumatic brain injury, ischemic heart disease, stroke and diabetes mellitus.

RESULTS

In total, 6.6 % of individuals with bipolar disorder and 4.0 % in the reference population developed dementia during the mean follow-up of 13.1 years. Compared to the reference population, individuals with bipolar disorder had a higher incidence of dementia during follow-up after adjusting for potential confounders (HR: 2.66, 95 % CI [2.53-2.79]). The strength of this association did not vary among individuals diagnosed with bipolar disorder before and after age 45.

LIMITATIONS

The higher risk of dementia identified for individuals with bipolar disorder could be influenced by detection bias and, despite a large cohort, some of the age-stratified analyses were still affected by lack of statistical power.

CONCLUSION

Individuals with bipolar disorder have a higher risk of developing dementia compared to a reference population without bipolar disorder, independent of the age at the onset of bipolar disorder.

Virtual Reality Cognitive Remediation in Older Adults with Bipolar Disorder: The Effects on Cognitive Performance and Depression in a Feasibility Randomized Controlled Trial

INTRODUCTION

Dementia, depression, and cardiovascular disease are major public health concerns for older adults, requiring early intervention. This study investigates whether a virtual reality cognitive remediation program (VR-CR) can improve cognitive function and depressive symptoms in older adults, and determines the necessary sample size for future studies. Integrated VR and CR interventions have shown promising outcomes in older adults with neurodegenerative and mental health disorders.

METHODS

This secondary analysis of a randomized controlled trial involves adults aged 58-75 years with bipolar disorder, excluding those with acute episodes, epilepsy, or severe eye diseases. The experimental group received standard treatment plus VR-CR, while the control group received only standard treatment.

RESULTS

No baseline differences were found between the experimental and control groups. No significant improvement was observed in the overall cognitive function test (p = 0.897) or in depressive symptoms (p = 0.322). A phase III efficacy study requires a sample size of 28 participants (alpha = 0.05, beta = 0.20).

CONCLUSIONS

VR-CR can potentially treat depressive symptoms in adults and older adults, but the results support conducting phase III studies to further investigate these outcomes. However, the improvement in cognitive performance in the elderly is less pronounced than in younger individuals.

Cognition and gut microbiota in schizophrenia spectrum and mood disorders: A systematic review

FRILEUX, M., BOLTRI M. and al. Cognition and Gut microbiota in schizophrenia spectrum and mood disorders: a Systematic Review. NEUROSCI BIOBEHAV REV (1) 2024 Schizophrenia spectrum disorders and major mood disorders are associated with cognitive impairments. Recent studies suggest a link between gut microbiota composition and cognitive functioning. Here, we review the relationship between gut microbiota and cognition in these disorders. To do this, we conducted a systematic review, searching Cochrane Central Register of Controlled Trials, EBSCOhost, Embase, Pubmed, Scopus, and Web of Science. Studies were included if they investigated the relationship between gut microbiota composition and cognitive function through neuropsychological assessments in patients with bipolar, depressive, schizophrenia spectrum, and other psychotic disorders. Ten studies were identified. Findings underscore a link between gut dysbiosis and cognitive impairment. This relationship identified specific taxa (Haemophilus, Bacteroides, and Alistipes) as potential contributors to bolstered cognitive performance. Conversely, Candida albicans, Toxoplasma gondii, Streptococcus and Deinococcus were associated with diminished performance on cognitive assessments. Prebiotics and probiotics interventions were associated with cognitive enhancements, particularly executive functions. These results emphasize the role of gut microbiota in cognition, prompting further exploration of the underlying mechanisms paving the way toward precision psychiatry.

Characterizing mild cognitive impairment to predict incident dementia in adults with bipolar disorder: What should the benchmark be?

Objective: Although mild cognitive impairment (MCI) is generally considered a risk state for dementia, its prevalence and association with dementia are impacted by the number of tests and cut-points used to assess cognition and define "impairment," and sources of norms. Here, we investigate how these methodological variations impact estimates of incident dementia in adults with bipolar disorder (BD), a vulnerable population with pre-existing cognitive deficits and increased dementia risk. Method: Neuropsychological data from 148 adults with BD and 13,610 healthy controls (HC) were drawn from the National Alzheimer's Coordinating Center. BD participants' scores were standardized against published norms and again using regression-based norms generated from HC within the same catchment area as individual BD patients ("site-specific norms"), varying the number of within-domain tests (one vs. two) and the cut-points (-1 vs. -1.5 SD) used to operationalize MCI. Results: Site-specific norms were more sensitive to incident dementia (88.6%-94.3%) than published norms (74.3%-88.6%), but only when using a "single test" definition of impairment. Specificity (22.1%-74.3%), accuracy (37.8%-68.9%), and positive predictive values (26.1%-38.3%) were overall poor. Applying a "single test" definition of impairment resulted in better negative predictive values using site-specific (92.3%-93.3%) than published norms (83.6%-86.2%), and a substantial increase in relative risk of incident dementia relative to published norms. Conclusions: Neuropsychologists should define "impairment" as scores below -1.0 or -1.5 SD on at least two within-domain measures when using published norms to interpret cognitive performance in adults with BD.

The prevalence and characteristics of MCCB cognitive impairment in unmedicated patients with bipolar II depression and major depressive disorder

BACKGROUND

Cognitive impairment has been acknowledged as a core clinical manifestation of bipolar disorder (BD) as well as major depressive disorder (MDD). Determining the prevalence and characteristics of cognitive impairment is important for clinical interventions. This study investigated the prevalence and characteristics of cognitive impairment based on the Measurement and Treatment Research to Improve Cognition Schizophrenia Consensus Cognitive Battery (MCCB) in both BD and MDD.

METHOD

One hundred and forty-nine BD II depression, 147 MDD, and 124 demographically matched healthy controls (HC) underwent MCCB cognitive assessment. The prevalence of MCCB cognitive impairment and group difference comparisons were performed. Additionally, association analysis was performed to investigate the relationship between cognitive performance and clinical variables.

RESULTS

Compared to the HC group, both BD II depression and MDD groups had a significantly reduced performance for all MCCB cognitive domains (all p < 0.05). The numerical scores for visual learning were lower in the BD II depression group compared to the MDD group. 32.89% of the BD II depression patients had clinically significant impairment (>1.5 SD below the normal mean) in two or more MCCB domains compared to 23.13% for MDD patients.

CONCLUSIONS

A high percent of patients in the BD II depression and MDD group exhibited MCCB cognitive impairments with clinical significance. Cognitive impairments were more common in BD II depression patients compared to MDD patients, particularly for visual learning. These findings suggest that clinicians should be aware of the severe cognitive impairment in mood disorders and establish effective cognitive screening and intervention strategies.

Add-on memantine may improve cognitive functions and attenuate inflammation in middle- to old-aged bipolar II disorder patients

OBJECTIVES

Chronic inflammation and neuroprogression underlie bipolar disorder (BP) and associated cognitive deficits. Memantine (MM) exerts neuroprotective effects by reducing neuroinflammation. Therefore, we investigated whether add-on low-dose MM (5 mg/day) in BP-II patients may improve cognition and inflammation.

METHODS

We combined two 12-week randomized, double-blind, placebo-controlled studies (NCT01188148 and NCT03039842) for analysis. Each participant was allocated to the MM or placebo group. Symptom severity, neuropsychological tests, and the cytokine plasma levels [tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), interleukin-8 (IL-8), transforming growth factor-β1 (TGF-β1), and brain-derived neurotrophic factor (BDNF)] were evaluated at baseline and endpoint. A subgroup analysis of middle- to old-aged BP-II patients was also performed.

RESULTS

We recruited 155 BP-II patients (23 of which were middle- to old-aged) for the MM group and 170 patients (20 of which were middle- to old-aged) for the placebo group. Add-on MM did not result in significant improvements in cognitive functions in all BP-II patients, but a group difference in TNF-α levels was found in the MM group (P=0.04). Specifically, in middle- to old-aged BP-II patients, there was a significant time and group interaction effect on omission T-scores, hit reaction time T-scores, and hit reaction time standard error T-scores on continuous performance tests (CPTs) in the MM group (P=0.007, 0.02, and 0.01, respectively), and a decrease in plasma TNF-α levels (P=0.04).

LIMITATIONS

The sample size of middle- to old-aged BP-II patients were limited.

CONCLUSION

Add-on MM may attenuate inflammation in BP-II and improve cognition in middle- to old-aged BP-II patients.

How Does Dementia Begin to Manifest in Bipolar Disorder? A Description of Prodromal Clinical and Cognitive Changes

BACKGROUND

Older adults with bipolar disorder (BD) have increased dementia risk, but signs of dementia are difficult to detect in the context of pre-existing deficits inherent to BD.

OBJECTIVE

To identify the emergence of indicators of early dementia in BD.

METHODS

One hundred and fifty-nine non-demented adults with BD from the National Alzheimer's Coordinating Center (NACC) data repository underwent annual neuropsychological assessment up to 14 years (54.0 months average follow-up). Cognitive performance was examined longitudinally with linear mixed-effects models, and yearly differences between incident dementia cases and controls were examined in the six years prior to diagnosis.

RESULTS

Forty participants (25.2%) developed dementia over the follow-up period ('incident dementia cases'). Alzheimer's disease was the most common presumed etiology, though this was likely a result of sampling biases within NACC. Incident dementia cases showed declining trajectories in memory, language, and speeded attention two years prior to dementia onset.

CONCLUSION

In a sample of BD patients enriched for Alzheimer's type dementia, prodromal dementia in BD can be detected up to two years before onset using the same cognitive tests used in psychiatrically-healthy older adults (i.e., measures of verbal recall and fluency). Cognition in the natural course of BD is generally stable, and impairment or marked decline on measures of verbal episodic memory or semantic retrieval may indicate an early neurodegenerative process.

Dopamine D3 receptor: A neglected participant in Parkinson Disease pathogenesis and treatment?

Parkinson disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms which relentlessly and progressively lead to substantial disability and economic burden. Pathologically, these symptoms follow the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) associated with abnormal α-synuclein (α-Syn) deposition as cytoplasmic inclusions called Lewy bodies in pigmented brainstem nuclei, and in dystrophic neurons in striatal and cortical regions (Lewy neurites). Pharmacotherapy for PD focuses on improving quality of life and primarily targets dopaminergic pathways. Dopamine acts through two families of receptors, dopamine D1-like and dopamine D2-like; dopamine D3 receptors (D3R) belong to dopamine D2 receptor (D2R) family. Although D3R's precise role in the pathophysiology and treatment of PD has not been determined, we present evidence suggesting an important role for D3R in the early development and occurrence of PD. Agonist activation of D3R increases dopamine concentration, decreases α-Syn accumulation, enhances secretion of brain derived neurotrophic factors (BDNF), ameliorates neuroinflammation, alleviates oxidative stress, promotes neurogenesis in the nigrostriatal pathway, interacts with D1R to reduce PD associated motor symptoms and ameliorates side effects of levodopa (L-DOPA) treatment. Furthermore, D3R mutations can predict PD age of onset and prognosis of PD treatment. The role of D3R in PD merits further research. This review elucidates the potential role of D3R in PD pathogenesis and therapy.

Cognitive impairment in late life bipolar disorder: Risk factors and clinical outcomes

BACKGROUND

Late Life Bipolar Disorder (LLBD) is associated with a high prevalence of cognitive impairments, but few studies have examined their risk factors and clinical correlates METHODS: Participants with bipolar disorder older than 60 (n = 86) were recruited from psychiatric outpatient and inpatients units. Patients were assessed with various instruments, including the Clinical Dementia Rating scale, the Montreal Cognitive Assessment and the Cumulative Illness Rating Scale. The distribution of disorder-specific and general risk factors was compared between patients with LLBD plus cognitive impairments (mild cognitive impairment or dementia) and those with LLBD but no cognitive impairment. Analyses were first conducted at the bivariate level, then using multiple regression. The association with disability, aggressive behavior and suicidal ideation was also explored.

RESULTS

Cognitive impairments in LLBD were associated with a diagnosis of type 1 bipolar disorder (OR = 6.40, 95%CI: 1.84 - 22.31, p = 0.004), fewer years of education (OR = 0.79, 95%CI: 0.69 - 0.91, p = 0.001) and higher severity of physical diseases (OR 26.54, 95%CI: 2.07 - 340.37, p = 0.01). Moreover, cognitive impairments were associated with an increased likelihood of disability and recent aggressive behavior, but not suicidal ideation.

LIMITATIONS

retrospective design, conflation of MCI and dementia, not all subjects were in euthymia CONCLUSIONS: In LLBD, the presence of cognitive impairments was associated with a diagnosis of type I bipolar disorder, lower education and more severe physical comorbidities. In turn, MCI or dementia were associated with increased disability and aggressive behavior. These findings may aid the identification of patients at risk for cognitive deterioration in everyday clinical practice.

Cognitive impairment in late-life bipolar disorder is not associated with Alzheimer's disease pathological signature in the cerebrospinal fluid

OBJECTIVES

Cognitive impairment is a common feature of late-life bipolar disorder (BD). Yet, there is limited information on the biological mechanisms associated with this process. It is uncertain whether cognitively impaired patients with BD may present the Alzheimer's disease (AD) bio-signature in the cerebrospinal fluid (CSF), defined as a combination of low concentrations of the amyloid-beta peptide (Aβ1-42 ) and high concentrations of total tau (T-tau) and tau phosphorylated at threonine 181 (P-tau). In this study, we sought to determine whether cognitive impairment in elderly patients with BD is associated with the AD CSF bio-signature.

METHODS

Seventy-two participants were enrolled in the study. The test group comprised older adults with BD and mild cognitive impairment (BD-MCI; n = 16) and the comparison groups comprised patients with dementia due to AD (n = 17), patients with amnestic MCI (aMCI; n = 14), and cognitively healthy older adults (control group; n = 25). CSF samples were obtained by lumbar puncture and concentrations of Aβ1-42 , T-tau and P-tau were determined.

RESULTS

CSF concentrations of all biomarkers were significantly different in the AD group compared to all other groups, but did not differentiate BD-MCI subjects from aMCI subjects and controls. BD-MCI patients had a non-significant reduction in CSF Aβ1-42 compared to controls, but this was still higher than in the AD group. Concentrations of T-tau and P-tau in BD-MCI patients were similar to those in controls, and significantly lower than those in AD.

CONCLUSIONS

Cognitively impaired patients with BD do not display the so-called AD bio-signature in the CSF. We therefore hypothesize that cognitive deterioration in BD is not associated with the classical pathophysiological mechanisms observed in AD, i.e., amyloid deposition and hyperphosphorylation of microtubule-associated tau protein.

The use of the Clock Drawing Test in bipolar disorder with or without dementia of Alzheimer’s type

There is limited data regarding the cognitive profile from screening tests of older adults with bipolar disorder (BD) with dementia. Objective To investigate the Clock Drawing Test (CDT) among older adults with BD with and without Alzheimer’s disease (AD). Method 209 older adults (79 with BD without dementia and 70 controls; 60 with AD, being 27 with BD) were included to evaluate the performance of three CDT scoring scales, beyond the Mini-Mental State Examination (MMSE) and verbal fluency (VFT). Results Patients with BD without dementia presented with lower scores in MMSE, VF and one CDT scoring scale than controls. Patients with BD and AD presented with lower scores in VF and CDT scoring scales than patients with only AD. All CDT scales presented similar sensitivity and specificity for BD and non-BD groups. Conclusion Elderly subjects with BD showed greater impairment in CDT in both groups of normal cognition and AD.