Advances in Vascular Cognitive Impairment 2006

Symptomatic Treatment of Vascular Cognitive Impairment (STREAM-VCI): Protocol for a Cross-Over Trial

Background

People with vascular cognitive impairment (VCI) constitute a clinically heterogeneous group, but previous symptomatic drug trials in VCI did not take this clinical heterogeneity into account. Executive dysfunction and memory impairment are the cognitive domains that are most frequently impaired in VCI, and these impairments are likely to reflect vascular damage to specific neurotransmitter systems, which opens the possibility for targeted symptomatic treatment directed at specific neurotransmitters.

Objective

Here we describe the design of the “Symptomatic Treatment of Vascular Cognitive Impairment” (STREAM-VCI) trial. In this proof-of-concept study, we investigate whether people with VCI with executive dysfunction due to vascular damage to the monoaminergic neurotransmitter system differentially respond to a monoaminergic challenge, whereas people with VCI with memory dysfunction associated with vascular damage to the cholinergic system will in turn respond to a cholinergic challenge.

Methods

The STREAM-VCI is a single center, double blind, three-way cross-over trial among 30 people with VCI, in which subjects received a single dose of galantamine, methylphenidate, or placebo on separate occasions. The most important inclusion criteria were a diagnosis of VCI with a Mini-Mental State Examination score of ≥16 and a Clinical Dementia Rating of 0.5-1.0. For each person, the challenges consisted of a single 16 mg dose of galantamine, 10 mg of methylphenidate, and placebo, in random order on three separate visits. Change in performance in executive functioning and memory was assessed directly after the challenge using standardized neuropsychological tests. We will correlate a positive response to the cholinergic and monoaminergic treatment with differences in structural and functional connectivity at baseline using structural magnetic resonance imaging (MRI), diffusion tension MRI, and resting-state functional MRI.

Results

The protocol of this study is approved by the Medical Ethics Committee of VU University Medical Center and the competent authority. The first participant was enrolled in April 2014. In September 2017, enrolment for the study was completed. We expect to publish the results in 2018.

Conclusions

STREAM-VCI is the first study to investigate the association of a response to a cholinergic and monoaminergic treatment with structural and functional connectivity of the monoaminergic and/or cholinergic systems on MRI. We aim to predict on an individual basis which individuals show a positive response to a cholinergic and/or monoaminergic challenge in people with VCI. This may be instrumental in moving in the direction of individually-tailored pharmacological interventions based on MRI measures in people with VCI.

Trial Registration

ClinicalTrials.gov NCT02098824; https://clinicaltrials.gov/ct2/show/NCT02098824 (Archived by WebCite at http://www.webcitation.org/6xhO7Ya1q)

Cognitive decline and cerebral vasoreactivity in asymptomatic patients with severe internal carotid artery stenosis

The aim of the study was to correlate cognitive decline and cerebral vasoreactivity in 150 asymptomatic right-handed patients with severe ≥70% unilateral internal carotid artery (ICA) stenosis and to evaluate the role of intracranial collateral circulation during cognitive testing. Cognitive assessment was performed by means of Montreal Cognitive Assessment (MoCA) and Mini Mental State Exam (MMSE) scales. Cerebrovascular reactivity (CVR) and intracranial collateral circulation were evaluated by means of breath holding index (BHI) and transcranial color Doppler (TCD) sonography. The results were compared with 150 right-handed controls matched for demographic variables and vascular risk factors. Patients with severe unilateral ICA stenosis had MMSE scores within a normal range, but MoCA scores were lower than normal. By examining the side of the observed stenosis, it has been noted that patients with left-sided ICA stenosis had lower MoCA scores in categories of language and episodic memory performance, while patients with right-sided ICA stenosis had lower MoCA scores in a category of visual-spatial skills. All patients had BHI values lower than normal. Subjects with a single intracranial collateral artery recruited had slightly better cognitive results than the patients with two or more collateral arteries activated. Results of the study showed that altered cerebrovascular reactivity and cerebral hypoperfusion might be responsible for the reduction of specific cognitive functions ipsilateral to the ICA stenosis, therefore BHI and MoCA might be useful tools when screening for cognitive decline in asymptomatic patients with severe ICA stenosis.

What are the causes of pre-existing dementia in patients with intracerebral haemorrhages?

In intracerebral haemorrhage, the most frequent underlying vasculopathies are cerebral amyloid angiopathy and hypertensive vasculopathy. Although both are associated with cognitive impairment, no study has focused on pre-existing dementia in patients with intracerebral haemorrhage. Therefore, we aimed to determine prevalence and mechanisms of pre-existing dementia in a large cohort of patients with an intracerebral haemorrhage. In a cohort of 417 patients, we evaluated the cognitive status before intracerebral haemorrhage with the Informant Questionnaire on Cognitive Decline in the Elderly. The cut-off to diagnose cognitive impairment with no dementia was 53 and 64 for pre-existing dementia. We determined factors associated with pre-existing dementia in multivariate analyses in the overall cohort and among patients with lobar only or deep only intracerebral haemorrhages. We performed post-mortem examinations when possible. Of 417 patients (median age 72 years, interquartile range 58-79), 58 (14%; 95% CI 11-18%) patients had cognitive impairment with no dementia and 65 had pre-existing dementia (16%; 95% CI 12-19%). In lobar intracerebral haemorrhage, the prevalence was 23%, and factors associated with pre-existing dementia were increasing age (odds ratio: 1.09 per year; 95% CI 1.02-1.15), having <8 years of education (odds ratio: 8.37; 95% CI 1.91-36.65) and increasing cortical atrophy (odds ratio: 3.34 per step; 95% CI 1.40-7.96). The five autopsied patients had Alzheimer's disease with cerebral amyloid angiopathy. In deep intracerebral haemorrhage, factors associated with pre-existing dementia were presence of old territorial vascular lesions (odds ratio: 4.52; 95% CI 1.18-17.42) and increasing severity of leucoaraiosis (odds ratio: 4.11 per step; 95% CI 1.73-9.75); the autopsied patient had small-vessel disease without Alzheimer's disease. These findings support the fact that pre-existing dementia is frequent in patients with intracerebral haemorrhage and may be the consequence of two different mechanisms: neurodegeneration with Alzheimer's disease and cerebral amyloid angiopathy in lobar intracerebral haemorrhage versus vascular process in deep intracerebral haemorrhage. These findings may contribute to the improvement of prevention and management of patients with intracerebral haemorrhages.

Vascular cognitive syndromes: relation to stroke etiology and topography

BACKGROUND

Cognitive syndromes (CS) after stroke may be important to measure and monitor for management and emerging therapies.

AIM

To describe the spectrum and frequency of CSs in the first month after stroke and to relate these to stroke etiology and topography.

METHODS

A validated cognitive examination was administered during the first month of stroke presentation and analyzed according to five large-scale networks for cognition and correlated with neuropsychological tests. A multivariate analysis was performed to determine association of CSs with etiology (TOAST classification), topography and neurological deficit by National Institute of Health Stroke Score (NIHSS).

RESULTS

Of a total of 2105 patients, one or more patients with CS was present in 1569/1796 (87%) stroke patients vs 112/309 (36%, P < or = 0.001) transient ischemic attack (TIA) patients. The frequency of frontal network syndromes (FNS) was 908/1796 (51%), left hemisphere network (LH) syndromes 646/1796 (36%), right hemisphere (RH) network syndromes 275/1796 (15.3%), occipitotemporal network (OT) syndromes 107/1796 (6%), hippocampal limbic (HL) network syndromes 397/1796 (22%) and miscellaneous (M) syndromes 481/1796 (27%). Stroke etiology and their signature CS by multivariate analyses revealed significant associations for LH with cardioembolism (OR 1.61, P = 0.0029), FNS and 'other' etiology (OR 1.96, P < or = 0.0001) and HL also for 'other' etiology (OR 1.57, P = 0.0026). Coma (OR 2.95, P < or = 0.0001) and encephalopathy (OR 2.82, P < or = 0.0001) were both associated significantly with hemorrhage. A left hemisphere lesion was associated with LH CSs (OR 9.26, P < or = 0.0001). An FNS was associated with frontal lesions (OR 5.19, <0.0001) as well as subcortical lesions (OR 1.91, P < or = 0.0001). The M group of CS was associated with subtentorial (OR 1.86, P = 0.0283) and right hemisphere lesions (OR 2.47, P < or = 0.0001). The LH and RH syndromes had the highest NIHSS and differed significantly from all others.

CONCLUSIONS

(1) CSs are present in the vast majority of stroke patients. (2) Particular stroke etiological subtypes are associated with specific CS. (3) Certain signature CS results from lesions that relate to the major anatomical cognitive networks.

Comprehensive cognitive neurological assessment in stroke

BACKGROUND

Cognitive syndromes (CS) after stroke may be important to measure and monitor for management and emerging therapies.

AIM

To incorporate known behavioral neurological and neuropsychiatric syndromes into a bedside cognitive assessment in patients with stroke.

METHODS

A validated cognitive examination (comprehensive cognitive neurological test in stroke, Coconuts) was administered during the first month of stroke presentation and analyzed according to five large-scale networks for cognition and correlated with neuropsychological tests. Validity testing of the test was performed for overall sensitivity, specificity, positive predictive value and negative predictive value to stroke in comparison with MRI diagnosis of stroke as well as discriminant validity, construct validity and inter-rater reliability.

RESULTS

Overall the sensitivity of the Coconuts scale was 91% and specificity 35%, PPV 88% and NPV 41% vs stroke lesions using MRI. Cognitive syndrome frequencies: frontal network syndrome frequency was 908/1796 (51%), left hemisphere network syndrome frequency was 646/1796 (36%), right hemisphere network included 275/1796 (15.3%), occipitotemporal network for complex visual processing 107/1796 (6%), the hippocampal limbic network for amnesias and emotional disorders 397/1796 (22%) and miscellaneous network syndromes 481/1796 (27%).

CONCLUSION

The Coconuts is a valid and practical test of a comprehensive array of known behavioral neurological and neuropsychiatric syndromes in patients with stroke.

Antihypertensive treatment in elderly hypertensives without a history of stroke and the risk of cognitive disorders

OBJECTIVES

The role of the antihypertensive therapy in preventing cognitive disorders in elderly persons without a history of stroke is a matter of debate. This review focuses on the pathogenesis of the cognitive disorders in elderly hypertensives and on the risk factors of their occurrence.

METHODS

Relevant papers were identified by searches in PubMed from 1946 until October 2007, using the key words 'vascular risk factors', 'vascular cognitive impairment', 'vascular dementia', 'neuroimaging in hypertension' and 'antihypertensive treatment'.

RESULTS

Blood pressure lowering in elderly patients with long-standing hypertension below a certain critical level may increase the risk of cerebral hypoperfusion and cognitive decline, particularly in cases with additional vascular risk factors. Cerebral white matter lesions have been found in the majority of elderly hypertensives. They have been shown to correlate with cognitive disorders.

CONCLUSIONS

Appropriate neuropsychological assessment and follow-up of the cognitive functions could be considered with the aim to individualize the antihypertensive therapy and slow down cognitive decline. Prospective studies are needed to confirm such a treatment strategy.

Cardiac dysfunction and cognition in older adults with heart failure

OBJECTIVES

To characterize cognition in patients with moderate to severe heart failure and examine the association between 2 measures of systemic perfusion (ie, ejection fraction and cardiac index) and cognition.

BACKGROUND

Decreased systemic perfusion has been implicated as an etiologic factor in the development of cognitive deficits in cardiovascular disease.

METHOD

Thirty-one patients with moderate to severe heart failure and 31 patients with cardiovascular disease and no heart failure completed a medical history interview and neuropsychologic assessment. Participants with heart failure additionally underwent an echocardiogram to assess cardiac function.

RESULTS

Patients with heart failure performed significantly worse than the cardiovascular disease-no heart failure group on several measures of executive functioning and psychomotor speed. Among the heart failure group, lower ejection fraction was associated with weaker global cognition, performance on several, but not all, measures of executive functioning, and was marginally associated with delayed memory. Decreased cardiac index was associated with poorer immediate memory and weakly associated with global cognition.

CONCLUSIONS

Findings suggest that depressed systemic perfusion is associated with cognitive deficits among patients with heart failure. Research including measures of cardiac function, cerebral perfusion, and cognition will be necessary to clarify the causal nature of the suggested mechanism.

Neuroimaging predictors of cognitive impairment in confluent white matter lesion: volumetric analyses of 99 brain regions

BACKGROUND

Although confluent white matter lesion (WML) is associated with cognitive impairment, the mechanism explaining this association is controversial. We aimed to investigate comprehensively the MRI predictors of cognitive impairment in confluent WML.

METHODS

Among 45 lacunar stroke patients who had confluent WML, we evaluated the association of executive function [Mattis Dementia Rating Scale - Initiation/Perseveration subscale (MDRS I/P)] and global cognition [Mini-Mental State Examination (MMSE)] with the volume of WML, measures of lacunes and microbleeds, and the volumes of 99 other specific brain regions.

RESULTS

Regression analyses showed that WML volume predicted performance on the MDRS I/P (beta = -0.34, p = 0.016) independent of age. Volumes of cortical gray matter (cGM; beta = 0.41, p = 0.003), the lateral fronto-orbital gyrus (beta = 0.38, p = 0.01), superior frontal gyrus (beta = 0.29, p = 0.04), lateral ventricle (beta = -0.30, p = 0.04), and posterior limb of the internal capsule (beta = 0.43, p = 0.002) predicted MDRS I/P performance independent of WML volume. Volumes of cGM, and the lateral fronto-orbital gyrus predicted MMSE performance as well.

CONCLUSION

Atrophy along the frontosubcortical pathways and cGM predict cognition in confluent WML independent of WML volume.

Hypertension, vascular cognitive disorders and neuroprotection

OBJECTIVE

The role of the antihypertensive therapy in preventing vascular cognitive disorders in elderly persons without a history of stroke is a matter of debate. This review focuses on cognitive disorders in elderly hypertensive patients.

METHODS

Relevant papers were identified by searches in PubMed from 1946 until February 2007 using the keywords 'cerebral blood flow autoregulation', 'vascular cognitive disorders', 'neuroimaging in hypertension', 'antihypertensive treatment' and 'neuroprotection in cerebral ischemia'.

RESULTS

Excessive blood pressure lowering in patients with long-standing hypertension may increase the risk of cerebral hypoperfusion, white matter lesions and consequent cognitive decline. White matter lesions have been found in the majority of patients with long-standing hypertension. They correlate with vascular cognitive disorders, particularly impairments of attention and executive function, while memory is relatively preserved. Cerebral small vessel disease in elderly patients should be taken into account when antihypertensive treatment is considered. Renin-angiotensin blockade, some calcium channel blockers and statins are thought to possess neuroprotective action.

CONCLUSION

For prevention of cerebral hypoperfusion in elderly hypertensives blood pressure lowering should be cautiously controlled. The increased risk of white matter lesions is an indication for early neuroprotection. The combination of renin-angiotensin blockade or calcium channel blockers with statins may become a promising preventive strategy against cognitive decline in elderly hypertensives. Cerebral white matter protection is a future challenge.