Advances in vascular cognitive impairment 2007

Prediction of poor clinical outcome in vascular cognitive impairment: TRACE-VCI study

INTRODUCTION

Prognostication in memory clinic patients with vascular brain injury (eg possible vascular cognitive impairment [VCI]) is often uncertain. We created a risk score to predict poor clinical outcome.

METHODS

Using data from two longitudinal cohorts of memory clinic patients with vascular brain injury without advanced dementia, we created (n = 707) and validated (n = 235) the risk score. Poor clinical outcome was defined as substantial cognitive decline (change of Clinical Dementia Rating ≥1 or institutionalization) or major vascular events or death. Twenty-four candidate predictors were evaluated using Cox proportional hazard models.

RESULTS

Age, clinical syndrome diagnosis, Disability Assessment for Dementia, Neuropsychiatric Inventory, and medial temporal lobe atrophy most strongly predicted poor outcome and constituted the risk score (C-statistic 0.71; validation cohort 0.78). Of note, none of the vascular predictors were retained in this model. The 2-year risk of poor outcome was 6.5% for the lowest (0-5) and 55.4% for the highest sum scores (10-13).

DISCUSSION

This is the first, validated, prediction score for 2-year clinical outcome of patients with possible VCI.

How Do Different Forms of Vascular Brain Injury Relate to Cognition in a Memory Clinic Population: The TRACE-VCI Study

BACKGROUND

Memory clinic patients frequently present with different forms of vascular brain injury due to different etiologies, often co-occurring with Alzheimer's disease (AD) pathology.

OBJECTIVE

We studied how cognition was affected by different forms of vascular brain injury, possibly in interplay with AD pathology.

METHODS

We included 860 memory clinic patients with vascular brain injury on magnetic resonance imaging (MRI), receiving a standardized evaluation including cerebrospinal fluid (CSF) biomarker analyses (n = 541). The cognitive profile of patients with different forms of vascular brain injury on MRI (moderate/severe white matter hyperintensities (WMH) (n = 398), microbleeds (n = 368), lacunar (n = 188) and non-lacunar (n = 96) infarct(s), macrobleeds (n = 16)) was assessed by: 1) comparison of all these different forms of vascular brain injury with a reference group (patients with only mild WMH (n = 205) without other forms of vascular brain injury), using linear regression analyses also stratified for CSF biomarker AD profile and 2) multivariate linear regression analysis.

RESULTS

The cognitive profile was remarkably similar across groups. Compared to the reference group effect sizes on all domains were <0.2 with narrow 95% confidence intervals, except for non-lacunar infarcts on information processing speed (age, sex, and education adjusted mean difference from reference group (β: - 0.26, p = 0.05). Results were similar in the presence (n = 300) or absence (n = 241) of biomarker co-occurring AD pathology. In multivariate linear regression analysis, higher WMH burden was related to a slightly worse performance on attention and executive functioning (β: - 0.08, p = 0.02) and working memory (β: - 0.08, p = 0.04).

CONCLUSION

Although different forms of vascular brain injury have different etiologies and different patterns of cerebral damage, they show a largely similar cognitive profile in memory clinic patients regardless of co-occurring AD pathology.

Key neuroanatomical structures for post-stroke cognitive impairment

The neuroanatomical substrate of vascular cognitive impairment (VCI) has traditionally included the subcortex of the brain, especially sub-frontal white matter circuits, strategic areas of single infarction that may mediate cognitive impairment such as the dominant thalamus or angular gyrus, and the left hemisphere, and bilateral brain infarcts or volume-driven cortical-subcortical infarctions reaching a critical threshold of tissue loss or injury. We provide an update on the neuroanatomical substrates of VCI and emphasize the following structures or areas: (1) new concepts in relation to hippocampal involvement in VCI based on neuropathological and MRI studies of microinfarcts and the role of traditional cardiovascular risk factors in possibly mediating or potentiating cognitive impairment; (2) advances in our understanding of cerebral microbleeds; and (3) an update on white matter hyperintensities and small vessel disease.

Rationale and design of a double-blind, placebo-controlled, randomized trial to evaluate the safety and efficacy of nimodipine in preventing cognitive impairment in ischemic cerebrovascular events (NICE)

BACKGROUND

Stroke is the second most common cause of mortality and the leading cause of neurological disability, cognitive impairment and dementia worldwide. Nimodipine is a dihydropyridinic calcium antagonist with a role in neuroprotection, making it a promising therapy for vascular cognitive impairment and dementia.

METHODS/DESIGN

The NICE study is a multicenter, randomized, double-blind, placebo-controlled study being carried out in 23 centers in China. The study population includes patients aged 30-80 who have suffered an ischemic stroke (≤7 days). Participants are randomly allocated to nimodipine (90 mg/d) or placebo (90 mg/d). The primary efficacy is to evaluate the level of mild cognitive impairment following treatment of an ischemic stroke with nimodipine or placebo for 6 months. Safety is being assessed by observing side effects of nimodipine. Assuming a relative risk reduction of 22%, at least 656 patients are required in this study to obtain statistical power of 90%. The first patient was recruited in November 2010.

DISCUSSION

Previous studies suggested that nimodipine could improve cognitive function in vascular dementia and Alzheimer's disease dementia. It is unclear that at which time-point intervention with nimodipine should occur. Therefore, the NICE study is designed to evaluate the benefits and safety of nimodipine, which was adminstered within seven days, in preventing/treating mild cognitive impairment following ischemic stroke.

Hidden Dysfunctioning in Subacute Stroke

Background and Purpose— Determining cognitive dysfunctioning (CDF) after stroke is an important issue because it influences choices for management in terms of return to previous activities. Because previous research in subacute stroke has shown important variations in CDF rates, we aimed to describe the frequency and neuropsychological profile of CDF in subacute stroke outside dementia. We used a large battery of tests to screen any potentially hidden CDF.

Methods— Patients with Mini-Mental State Examination scores ≥23 were prospectively and consecutively included 2 weeks after a first-ever ischemic brain infarct. Stroke features were based on MRI. Four domains were evaluated: instrumental and executive functions, episodic memory, and working memory (WM). Patients were scored using means and compared with education- and age-matched control subjects. Then we attributed Z-scores for each test and each domain. The most relevant cognitive tests characterizing CDF were determined using logistic regression.

Results— Among 177 patients (mean age, 50.6 years), 91.5% failed in at least one cognitive domain. WM was the most impaired domain (87.6%) with executive functions (64.4%), episodic memory (64.4%), and instrumental functions (24.9%) being relatively preserved. CDF was associated with age, education, depression, neurological deficit, and leukoaraiosis in bivariate analysis. Using logistic regression, WM tests and age predicted CDF (Modified Paced Auditorial Serial Addition Test: OR=0.96 CI=0.93 to 0.98; Owen-spatial-WM: OR=1.07 CI=1.02 to 1.12; age: OR=0.96 CI=0.93 to 0.98).

Conclusion— CDF appears to be almost constant, although underestimated, in subacute stroke. WM could reflect some hidden dysfunctioning, which may interfere with rehabilitation and return to work. Clinical routine may include WM tests in young patients with mild stroke.