Canadian Consensus Conference on Diagnosis and Treatment of Dementia (CCCDTD)5: Guidelines for management of vascular cognitive impairment

The Spectrum of Cerebral Small Vessel Disease: Emerging Pathophysiologic Constructs and Management Strategies

Cerebral small vessel disease (CSVD) is a spectrum of disorders that affect small arterioles, venules, cortical and leptomeningeal vessels, perivascular spaces, and the integrity of neurovascular unit, blood brain barrier, and surrounding glia and neurons. CSVD is an important cause of lacunar ischemic stroke and sporadic hemorrhagic stroke, as well as dementia-which will constitute some of the most substantive population and public health challenges over the next century. This article provides an overview of updated pathophysiologic frameworks of CSVD; discusses common and underappreciated clinical and neuroimaging manifestations of CSVD; and reviews emerging genetic risk factors linked to sporadic CSVD.

Imaging Biomarkers of VCI: A Focused Update

Vascular cognitive impairment is common after stroke, in memory clinics, medicine for the elderly services, and undiagnosed in the community. Vascular disease is said to be the second most common cause of dementia after Alzheimer disease, yet vascular dysfunction is now known to predate cognitive decline in Alzheimer disease, and most dementias at older ages are mixed. Neuroimaging has a major role in identifying the proportion of vascular versus other likely pathologies in patients with cognitive impairment. Here, we aim to provide a pragmatic but evidence-based summary of the current state of potential imaging biomarkers, focusing on magnetic resonance imaging and computed tomography, which are relevant to diagnosing, estimating prognosis, monitoring vascular cognitive impairment, and incorporating our own experiences. We focus on markers that are well-established, with a known profile of association with cognitive measures, but also consider more recently described, including quantitative tissue markers of vascular injury. We highlight the gaps in accessibility and translation to more routine clinical practice.

Sex Differences in Healthcare Utilization in Persons Living with Dementia Between 2000 and 2017: A Population-Based Study in Quebec, Canada

Objectives: Describe sex differences in healthcare utilization and mortality in persons with new dementia in Quebec, Canada. Methods: We conducted a repeated cohort study from 2000 to 2017 using health administrative databases. Community-dwelling persons aged 65+ with a new diagnosis of dementia were included. We measured 23 indicators of healthcare use across five care settings: ambulatory care, pharmacological care, acute hospital care, long-term care, and mortality. Clinically meaningful sex differences in age-standardized rates were determined graphically through expert consultations. Results: Women with dementia had higher rates of ambulatory care and pharmacological care, while men with dementia had higher acute hospital care, admission to long-term care, and mortality. There was no meaningful difference in visits to cognition specialists, antipsychotic prescriptions, and hospital death. Discussion: Men and women with dementia demonstrate differences in healthcare utilization and mortality. Addressing these differences will inform decision-makers, care providers and researchers and guide more equitable policy and interventions in dementia care.

European stroke organisation (ESO) guideline on cerebral small vessel disease, part 2, lacunar ischaemic stroke

A quarter of ischaemic strokes are lacunar subtype, typically neurologically mild, usually resulting from intrinsic cerebral small vessel pathology, with risk factor profiles and outcome rates differing from other stroke subtypes. This European Stroke Organisation (ESO) guideline provides evidence-based recommendations to assist with clinical decisions about management of lacunar ischaemic stroke to prevent adverse clinical outcomes. The guideline was developed according to ESO standard operating procedures and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. We addressed acute treatment (including progressive lacunar stroke) and secondary prevention in lacunar ischaemic stroke, and prioritised the interventions of thrombolysis, antiplatelet drugs, blood pressure lowering, lipid lowering, lifestyle, and other interventions and their potential effects on the clinical outcomes recurrent stroke, dependency, major adverse cardiovascular events, death, cognitive decline, mobility, gait, or mood disorders. We systematically reviewed the literature, assessed the evidence and where feasible formulated evidence-based recommendations, and expert concensus statements. We found little direct evidence, mostly of low quality. We recommend that patients with suspected acute lacunar ischaemic stroke receive intravenous alteplase, antiplatelet drugs and avoid blood pressure lowering according to current acute ischaemic stroke guidelines. For secondary prevention, we recommend single antiplatelet treatment long-term, blood pressure control, and lipid lowering according to current guidelines. We recommend smoking cessation, regular exercise, other healthy lifestyle modifications, and avoid obesity for general health benefits. We cannot make any recommendation concerning progressive stroke or other drugs. Large randomised controlled trials with clinically important endpoints, including cognitive endpoints, are a priority for lacunar ischaemic stroke.

Neuropsychological differential diagnosis of Alzheimer's disease and vascular dementia: a systematic review with meta-regressions

Introduction

Diagnostic classification systems and guidelines posit distinguishing patterns of impairment in Alzheimer's (AD) and vascular dementia (VaD). In our study, we aim to identify which diagnostic instruments distinguish them.

Methods

We searched PubMed and PsychInfo for empirical studies published until December 2020, which investigated differences in cognitive, behavioral, psychiatric, and functional measures in patients older than 64 years and reported information on VaD subtype, age, education, dementia severity, and proportion of women. We systematically reviewed these studies and conducted Bayesian hierarchical meta-regressions to quantify the evidence for differences using the Bayes factor (BF). The risk of bias was assessed using the Newcastle-Ottawa-Scale and funnel plots.

Results

We identified 122 studies with 17,850 AD and 5,247 VaD patients. Methodological limitations of the included studies are low comparability of patient groups and an untransparent patient selection process. In the digit span backward task, AD patients were nine times more probable (BF = 9.38) to outperform VaD patients (β g = 0.33, 95% ETI = 0.12, 0.52). In the phonemic fluency task, AD patients outperformed subcortical VaD (sVaD) patients (β g = 0.51, 95% ETI = 0.22, 0.77, BF = 42.36). VaD patients, in contrast, outperformed AD patients in verbal (β g = -0.61, 95% ETI = -0.97, -0.26, BF = 22.71) and visual (β g = -0.85, 95% ETI = -1.29, -0.32, BF = 13.67) delayed recall. We found the greatest difference in verbal memory, showing that sVaD patients outperform AD patients (β g = -0.64, 95% ETI = -0.88, -0.36, BF = 72.97). Finally, AD patients performed worse than sVaD patients in recognition memory tasks (β g = -0.76, 95% ETI = -1.26, -0.26, BF = 11.50).

Conclusion

Our findings show inferior performance of AD in episodic memory and superior performance in working memory. We found little support for other differences proposed by diagnostic systems and diagnostic guidelines. The utility of cognitive, behavioral, psychiatric, and functional measures in differential diagnosis is limited and should be complemented by other information. Finally, we identify research areas and avenues, which could significantly improve the diagnostic value of cognitive measures.

Cognitive Dysfunction and Affective Mood Disorder Screening in Patients With Chronic Inflammatory Bowel Disease: Protocol for a Prospective Case-Control Study

BACKGROUND

Mild cognitive impairment (MCI) and Alzheimer's disease (AD) might be more frequent in patients with inflammatory bowel disease (IBD), but the relationship between these 2 entities is yet to be entirely established. Certain blood biomarkers (eg, serum amyloid A [SAA] and serum homocysteine [Hcy], which increase in IBD and MCI; brain-derived neurotrophic factor [BDNF], which decreases in MCI and AD but is not clearly modified in IBD; and S100 calcium-binding protein B [S100B], which increases in the blood-brain barrier and neuronal lesions) might predict the stage of MCI or dementia or progression to a further state. The gut-brain axis (GBA) might be the key to the development of MCI in patients with IBD, along with systemic inflammation and the possible and unknown adverse effects of disease-modifying medication.

OBJECTIVE

The aim of this study is to investigate whether GBA interactions play a role in MCI development in patients with IBD.

METHODS

A case-control study will be conducted on at least 100 patients diagnosed with IBD, matched with 100 healthy individual controls. The matching will include sex, age, and education. Patients will be fully examined, and a full interview and a neurological and cognitive examination will be performed. The primary clinical outcomes will be cognitive test scores (Montreal Cognitive Assessment, Trail Making Test, Digit Symbol Substitution Test, forward and backward digit span testing). Depression, stress, and anxiety screening will also be performed. Blood samples from all participants will be collected, and aliquots will be immediately stored in a biobank. Primary laboratory outcomes will include serum levels of presumed cognitive dysfunction blood biomarkers SAA, Hcy, S100B, and BDNF. Follow-up will be performed at 12, 24, 36, and 48 months.

RESULTS

Data collection started in December 2021 and is ongoing. So far, 53 patients with IBD have been recruited and 50 HC matched. Data collection should end in January 2030. Intermediary analysis will be performed in April 2024. We expect patients with IBD to have lower scores on cognitive testing and a positive correlation between disease length and cognitive impairment level. In addition, the levels of stress, anxiety, and depression should be higher in the IBD group. The serum levels of the 4 biomarkers could correlate or anticorrelate with cognitive scores and serve as predictive factors for MCI or dementia development. A higher level of education, a younger age, the absence of malabsorption, and good disease control might serve as protectors against MCI.

CONCLUSIONS

GBA interactions, along with systemic inflammation and the adverse effects of medication, might be a cause of MCI and AD development in patients with IBD. Serum biomarkers could prove cheap and useful predictors of MCI development.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05760729; https://clinicaltrials.gov/study/NCT05760729.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/50546.

PDE5 inhibitor drugs for use in dementia

Alzheimer's disease and related dementias (ADRD) remain a major health-care challenge with few licensed medications. Repurposing existing drugs may afford prevention and treatment. Phosphodiesterase-5 (PDE5) is widely expressed in vascular myocytes, neurons, and glia. Potent, selective, Food and Drug Administration-approved PDE5 inhibitors are already in clinical use (sildenafil, vardenafil, tadalafil) as vasodilators in erectile dysfunction and pulmonary arterial hypertension. Animal data indicate cognitive benefits of PDE5 inhibitors. In humans, real-world patient data suggest that sildenafil and vardenafil are associated with reduced dementia risk. While a recent clinical trial of acute tadalafil on cerebral blood flow was neutral, there may be chronic actions of PDE5 inhibition on cerebrovascular or synaptic function. We provide a perspective on the potential utility of PDE5 inhibitors for ADRD. We conclude that further prospective clinical trials with PDE5 inhibitors are warranted. The choice of drug will depend on brain penetration, tolerability in older people, half-life, and off-target effects.

HIGHLIGHTS

Potent phosphodiesterase-5 (PDE5) inhibitors are in clinical use as vasodilators.In animals PDE5 inhibitors enhance synaptic function and cognitive ability.In humans the PDE5 inhibitor sildenafil is associated with reduced risk of Alzheimer's disease.Licensed PDE5 inhibitors have potential for repurposing in dementia.Prospective clinical trials of PDE5 inhibitors are warranted.

Decision making under uncertainty in the diagnosis and management of Alzheimer's Disease in primary care: A study protocol applying concepts from neuroeconomics

Background

The current management of patients with Dementia, primarily with Alzheimer's Disease (AD) is rapidly evolving. However, limited information is available about the current gaps and decision-making in primary care.

Objectives

To evaluate factors associated with gaps, risk preferences regarding diagnostic and therapeutic choices in the management of patients with AD by primary care physicians (PCP) from across Canada.

Methods

We propose a non-interventional, cross-sectional pilot study involving 120 primary care physicians referred from the College of Family Physicians of Canada to assess diagnostic and therapeutic decisions in the management of ten simulated AD-related case-scenarios commonly encountered in clinical practice. We initially describe the current landscape and gaps regarding diagnostic and therapeutic challenges in the management of patients with AD in primary care. Then, we provide concepts from behavioral economics and neuroeconomics applied to medical decision-making. Specifically, we include standardized tests to measure risk aversion, physicians' reactions to uncertainty, and questions related to risk preferences in different domains. Finally, we summarize the protocol to be implemented to address our goals. The primary study outcome is the proportion of participants that elect to defer initial investigations to the specialist and the associated factors. Secondary outcomes include the proportion of PCP willing to order cerebral spinal fluid studies, PET scans, or initiate treatment according to the simulated case-scenarios. The study will be conducted in English and French.

Conclusions

The study findings will contribute a better understanding of relevant factors associated with diagnostic and therapeutic decisions of PCP in the management of AD, identifying participant's preferences and evaluating the role of behavioral aspects such tolerance to uncertainty, aversion to ambiguity, and therapeutic inertia.

[PAPPS update on older people 2022]

This article examines the latest available evidence on preventive activities in the elderly, including sleep disorders, physical exercise, deprescription, cognitive disorders and dementias, nutrition, social isolation and frailty.

Clinical Trials of New Drugs for Vascular Cognitive Impairment and Vascular Dementia

Population aging has challenged the treatment of cognitive impairment or dementia. Vascular dementia is the second leading cause of dementia after Alzheimer’s disease. Cognitive consequences after ischemic brain injury have been recognized as a preferred target for therapeutic strategies, prompting the search for potential agents. The keyword “vascular dementia” was used to search ClinicalTrials.gov to determine agents represented in phases I, II, III, and IV. The agents were classified on the basis of their mechanisms. Of the 17 randomized controlled trials meeting our inclusion criteria, 9 were completed in the past 10 years, and 8 are ongoing or in the planning stages. We also identified one trial in phase I, nine in phase II, six in phase III, and one in phase IV. Fewer trials of new drugs for improving cognition or ameliorating the behavioral and psychological symptoms of dementia target vascular dementia than Alzheimer’s dementia. Drug trials on vascular dementia overlap with drug trials targeting functional outcomes in cerebrovascular disease. International pharmaceutical companies’ investment in new drugs targeting VCI and vascular dementia remains insufficient.

Role of White Matter Hyperintensities and Related Risk Factors in Vascular Cognitive Impairment: A Review

White matter hyperintensities (WMHs) of presumed vascular origin are one of the imaging markers of cerebral small-vessel disease, which is prevalent in older individuals and closely associated with the occurrence and development of cognitive impairment. The heterogeneous nature of the imaging manifestations of WMHs creates difficulties for early detection and diagnosis of vascular cognitive impairment (VCI) associated with WMHs. Because the underlying pathological processes and biomarkers of WMHs and their development in cognitive impairment remain uncertain, progress in prevention and treatment is lagging. For this reason, this paper reviews the status of research on the features of WMHs related to VCI, as well as mediators associated with both WMHs and VCI, and summarizes potential treatment strategies for the prevention and intervention in WMHs associated with VCI.