Cerebrovascular disease and dementia

Effect of RehaCom cognitive rehabilitation software on working memory and processing speed in chronic ischemic stroke patients

Stroke survivors need assistance to overcome cognitive impairments. Working memory (WM) and processing speed (PS) as two critical cognitive functions are disrupted by stroke. The goal of this study was to investigate the effect of RehaCom rehabilitation software on WM and PS in participants with chronic ischemic stroke with hemiplegia (right/left side). Participants were selected among stroke patients who were referred to our special rehabilitation clinic. Fifty participants were assigned to control (n = 25) and experimental (n = 25) groups. The results of the experimental group were compared with the control group before and after the treatment with RehaCom (ten 45-min sessions across five weeks, two sessions per week). The results showed a significant improvement in WM and PS in the experimental group in comparison with the control group after a 5-week training with RehaCom. In conclusion, our findings indicate that treatment with RehaCom software improves WM and PS in chronic ischemic stroke participants with hemiplegia. The exact mechanism of RehaCom is largely unknown and further studies are needed, but its effects on the function of brain regions involved in modulating cognitive functions such as the prefrontal cortex, cingulate cortex, and parietal cortex may be mechanisms of interest.

Protection against Hypoxia-Reoxygenation Injury of Hippocampal Neurons by H2S via Promoting Phosphorylation of ROCK2 at Tyr722 in Rat Model

The RhoA-ROCK signaling pathway is associated with the protective effects of hydrogen sulfide (H₂S) against cerebral ischemia. H₂S protects rat hippocampal neurons (RHNs) against hypoxia-reoxygenation (H/R) injury by promoting phosphorylation of RhoA at Ser188. However, effect of H₂S on the phosphorylation of ROCK₂-related sites is unclear. The present study was designed to investigate whether H₂S can play a role in the phosphorylation of ROCK₂ at Tyr722, and explore whether this role mediates the protective effect of H/R injury in RHNs. Prokaryotic recombinant plasmids ROCK₂^wild-pGEX-6P-1 and ROCK₂^Y722F-pGEX-6P-1 were constructed and transfected into E. coli in vitro, and the expressed protein, GST-ROCK₂^wild and GST-ROCK₂^Y722F were used for phosphorylation assay in vitro. Eukaryotic recombinant plasmids ROCK₂^Y722-pEGFP-N1 and ROCK₂^Y722F-pEGFP-N1 as well as empty plasmid were transfected into the RHNs. Western blot assay and whole-cell patch-clamp technique were used to detect phosphorylation of ROCK₂ at Tyr722 and BK_Ca channel current in the RHNs, respectively. Cell viability, leakages of intracellular enzymes lactate dehydrogenase (LDH), and nerve-specific enolase (NSE) were measured. The H/R injury was indicated by decrease of cell viability and leakages of intracellular LDH and NSE. The results of Western blot have shown that NaHS, a H₂S donor, significantly promoted phosphorylation of GST-ROCK₂^wild at Tyr722, while no phosphorylation of GST-ROCK₂^Y722F was detected. The phosphorylation of ROCK₂^wild promoted by NaHS was also observed in RHNs. NaHS induced more potent effects on protection against H/R injury, phosphorylation of ROCK₂ at Tyr722, inhibition of ROCK₂ activity, as well as increase of the BK_Ca current in the ROCK₂^Y722-pEGFP-N1-transfected RHNs. Our results revealed that H₂S protects the RHNs from H/R injury through promoting phosphorylation of ROCK₂ at Tyr722 to inhibit ROCK₂ activity and potentially by opening channel currents.

Potential Biomarkers for Post-Stroke Cognitive Impairment: A Systematic Review and Meta-Analysis

Stroke is a primary debilitating disease in adults, occurring in 15 million individuals each year and causing high mortality and disability rates. The latest estimate revealed that stroke is currently the second leading cause of death worldwide. Post-stroke cognitive impairment (PSCI), one of the major complications after stroke, is frequently underdiagnosed. However, stroke has been reported to increase the risk of cognitive impairment by at least five to eight times. In recent decades, peripheral blood molecular biomarkers for stroke have emerged as diagnostic, prognostic, and therapeutic targets. In this study, we aimed to evaluate some blood-derived proteins for stroke, especially related to brain damage and cognitive impairments, by conducting a systematic review and meta-analysis and discussing the possibility of these proteins as biomarkers for PSCI. Articles published before 26 July 2021 were searched in PubMed, Embase, the Web of Science, and the Cochrane Library to identify all relevant studies reporting blood biomarkers in patients with stroke. Among 1820 articles, 40 were finally identified for this study. We meta-analyzed eight peripheral biomarker candidates: homocysteine (Hcy), high-density lipoprotein cholesterol (HDL-C), C-reactive protein (CRP), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG), uric acid, and glycated hemoglobin (HbA1c). The Hcy, CRP, TC, and LDL-C levels were significantly higher in patients with PSCI than in the non-PSCI group; however, the HDL-C, TG, uric acid, and HbA1c levels were not different between the two groups. Based on our findings, we suggest the Hcy, CRP, TC, and LDL-C as possible biomarkers in patients with post-stroke cognitive impairment. Thus, certain blood proteins could be suggested as effective biomarkers for PSCI.

Predictors of dementia after first ischemic stroke

Various mechanisms contribute to dementia after first ischemic stroke as lesions on strategic areas of cognition and stroke premorbidity.

Objectives

Assessing clinical and neuroimaging predictors of dementia after first ischemic stroke and its relation to stroke location, subtypes and severity.

Methods

Eighty first ischemic stroke patients were included. Forty patients with dementia after first stroke and forty patients without dementia according to DSM-IV diagnostic criteria of vascular dementia. All patients were subjected to general and neurological assessment, National Institute Health Stroke Scale (NIHSS) for stroke severity, Montreal Cognitive Assessment (MoCA) scale for cognition assessment, MRI brain and Trial of Org 10172 in acute stroke treatment (TOAST) classification for stroke subtypes.

Results

Left hemispheric ischemic stroke, strategic infarctions, diabetes mellitus and stroke of anterior circulation were found to be independent risk factors for dementia after first ischemic stroke (OR=3.09, 95%CI 1.67-10.3, OR=2.33, 95%CI 1.87-8.77, OR=1.88, 95%CI 1.44-4.55, OR=1.86, 95%CI 1.45-6.54, respectively). Hypertension, dyslipidemia, smoking, ischemic heart disease, high NIHSS score and large vessel infarction were significantly higher among post stroke dementia patients. However, on binary logistic regression, they did not reach to be independent risk factors.

Conclusion

Stroke location (left stroke, strategic infarction, anterior circulation stroke) and diabetes mellitus could be predictors of dementia after first ischemic stroke, but stroke severity, stroke subtypes, hypertension, dyslipidemia, smoking and ischemic heart could not.

Stroke injury, cognitive impairment and vascular dementia

The global burden of ischaemic strokes is almost 4-fold greater than haemorrhagic strokes. Current evidence suggests that 25–30% of ischaemic stroke survivors develop immediate or delayed vascular cognitive impairment (VCI) or vascular dementia (VaD). Dementia after stroke injury may encompass all types of cognitive disorders. States of cognitive dysfunction before the index stroke are described under the umbrella of pre-stroke dementia, which may entail vascular changes as well as insidious neurodegenerative processes. Risk factors for cognitive impairment and dementia after stroke are multifactorial including older age, family history, genetic variants, low educational status, vascular comorbidities, prior transient ischaemic attack or recurrent stroke and depressive illness. Neuroimaging determinants of dementia after stroke comprise silent brain infarcts, white matter changes, lacunar infarcts and medial temporal lobe atrophy. Until recently, the neuropathology of dementia after stroke was poorly defined. Most of post-stroke dementia is consistent with VaD involving multiple substrates. Microinfarction, microvascular changes related to blood–brain barrier damage, focal neuronal atrophy and low burden of co-existing neurodegenerative pathology appear key substrates of dementia after stroke injury. The elucidation of mechanisms of dementia after stroke injury will enable establishment of effective strategy for symptomatic relief and prevention. Controlling vascular disease risk factors is essential to reduce the burden of cognitive dysfunction after stroke. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

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Ischaemic injury is common among long-term stroke survivors

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About 25% stroke survivors develop dementia with a much greater proportion developing cognitive impairment

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Risk factors of dementia after stroke include older age, vascular comorbidities, prior stroke and pre-stroke impairment

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Current imaging and pathological studies suggest 70% of dementia after stroke is vascular dementia

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Severe white matter changes and medial temporal lobe atrophy as sequelae after ischaemic injury are substrates of dementia

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Controlling vascular risk factors and prevention strategies related to lifestyle factors would reduce dementia after stroke

Multimorbidity patterns are differentially associated with functional ability and decline in a longitudinal cohort of older women

BACKGROUND

we aimed to identify multimorbidity patterns and relate these patterns to functional ability and decline.

METHODS

we included 7,270 participants of the older cohort of the Australian Longitudinal Study on Women's Health, who were surveyed every 3 years from 2002 to 2011. We used factor analysis to identify multimorbidity patterns from 31 self-reported chronic conditions among women aged 76-81 in 2002. We applied a linear increments model to account for attrition and related the multimorbidity patterns to functional ability and decline at subsequent surveys, as measured by activities of daily living (ADL) and instrumental activities of daily living (IADL). For each pattern, we determined mean ADL and IADL scores in the middle and highest third of factor score in comparison to a reference group.

RESULTS

we identified three multimorbidity patterns, labelled musculoskeletal/somatic (MSO), neurological/mental health (NMH) and cardiovascular (CVD). High factor scores for NMH, MSO and CVD were associated with significantly higher mean ADL and IADL scores (poorer functional ability) in 2005 compared with the reference group of low factor scores for all three factors. The CVD pattern was associated with the greatest decline in ADL between 2005 and 2011, whereas the NMH pattern was associated with the greatest decline in IADL.

CONCLUSIONS

distinct multimorbidity patterns were differentially associated with functional ability and decline. Given the paucity of studies on multimorbidity patterns, future studies should seek to assess the reproducibility of our findings in other populations and settings, and investigate the potential implications for improved prediction of functional decline.

Young-onset dementia epidemiology applied to neuropsychiatry practice

A substantial number of adults suffer young-onset dementia (YOD). The diversity of types and syndromes makes recognition and diagnosis difficult. An algorithmic approach to interpreting clinical data, informed by clinical epidemiology, integrates data pertaining to defining syndromes and their chronology and tempo, family history, and other neuropsychiatric features and neurologic signs, is used to reach a preliminary diagnosis and direct diagnostic tests and their interpretation. Screening for YOD in the psychiatric context is a rational process in which vigilance is combined with careful searches for red flags that signal a neurodegenerative etiology.

Understanding and preventing the development of post-stroke dementia

Post-stroke dementia (PSD) is a clinical entity but it now appears that most of PSD may be categorized as vascular dementia. The well-established relationship between vascular factors and dementia provides a rationale for the implementation of intervention and prevention efforts. Larger primary prevention trials related to lifestyle factors are warranted in association with dementia. Published clinical trials have not been promising and there is meager information on whether PSD can be prevented through the use of pharmacological agents. Control of vascular disease risk and prevention of recurrent strokes are obviously key to reducing the burden of cognitive decline and dementia after stroke. However, modern imaging and analysis techniques will help to elucidate the mechanism of PSD and establish better treatment.

The occurrence of cerebrovascular atherosclerosis in Alzheimer's disease patients

Background:

Both Alzheimer’s disease (AD) and cerebrovascular atherosclerosis (CA) contributed to dementia in an aged population. Whether they share the same mechanism is unknown.

Aim:

Our goal was to explore the occurrence rates of CA in AD patients.

Method:

Here we examined the degree of CA in different groups of AD patients with contrast angiography. Ninety-three AD patients were recruited to the present study. Contrast computed tomography scanning and contrast angiography were performed for CA analyses.

Result:

We found that the cerebrovascular plaques were common in AD patients, which was partly correlated with the severity of AD (as determined by cognitive decline).

Conclusion:

We concluded that vascular dementia may partly correlate with AD pathology.

Patients with chronic kidney disease are at an elevated risk of dementia: a population-based cohort study in Taiwan

Background

Chronic kidney disease (CKD) is more prevalent in Taiwan than in most countries. This population-based cohort study evaluated the dementia risk associated with CKD.

Methods

Using claims data of 1,000,000 insured residents covered in the universal health insurance of Taiwan, we selected 37049 adults with CKD newly diagnosed from 2000–2006 as the CKD cohort. We also randomly selected 74098 persons free from CKD and other kidney diseases, frequency matched with age, sex and the date of CKD diagnosed. Incidence and hazard ratios (HRs) of dementia were evaluated by the end of 2009.

Results

Subjects in the CKD cohort were more prevalent with comorbidities than those in the non-CKD cohort (p <0.0001). The dementia incidence was higher in the CKD cohort than in the non-CKD cohort (9.30 vs. 5.55 per 1,000 person-years), with an overall HR of 1.41 (95% confidence interval (CI), 1.32-1.50), controlling for sex, age, comorbidities and medicaitions. The risk was similar in men and women but increased sharply with age to an HR of 133 (95% CI, 68.9-256) for the elderly. However, the age-specific CKD cohort to non-CKD cohort incidence rate ratio decreased with age, with the highest ratio of 16.0 (95% CI, 2.00-128) in the youngest group. Among comorbidities and medications, alcoholism and taking benzodiazepines were also associated with dementia with elevated adjusted HRs of 3.05 (95% CI 2.17-4.28) and 1.23 (95% CI 1.14-1.32), respectively.

Conclusions

Patients with CKD could have an elevated dementia risk. CKD patients with comorbidity deserve attention to prevent dementia.

Using informant reports to detect cognitive decline in mild cognitive impairment

BACKGROUND

The use of informant rating scales in older adults at risk of dementia may assist with early detection and intervention strategies. This study aims to evaluate whether informants rate greater cognitive change in patients with mild cognitive impairment (MCI) compared to cognitively intact individuals, and to determine the relationship between informant ratings of cognitive change and neuropsychological performance.

METHODS

One hundred and nine health-seeking older adults underwent clinical and neuropsychological assessments, and informants completed the Cambridge Behavioral Inventory-Revised (CBI-R). Patients were rated according to MCI criteria, including amnestic and non-amnestic subtypes, or as being cognitively intact. CBI-R ratings were evaluated with respect to MCI diagnosis and neuropsychological performance.

RESULTS

Compared to cognitively intact individuals, informants rated patients with MCI as having significantly more change in overall functioning (p < 0.05) as well as in specific domains of memory and orientation (p < 0.01), everyday skills (p < 0.05), and motivation (p < 0.05), even after controlling for depressive symptom severity. In further analyses, the non-amnestic MCI subgroup only had more informant-rated mood changes compared to the amnestic subgroup. In relation to neuropsychological performance, informant ratings were related to poorer visual memory, verbal learning and memory, language, and psychomotor speed, with correlations ranging from -0.19 to -0.43 (p < 0.05).

CONCLUSIONS

These findings indicate that informants are sensitive to subtle early cognitive change in individuals with MCI, and that their ratings are related to objectively measured neuropsychological performance. Thus, the CBI-R may be valuable in assisting early screening and intervention processes.

Cognitive impairment of vascular origin: neuropathology of cognitive impairment of vascular origin

The term cognitive impairment of vascular origin is used to designate global cognitive deficits as well as focal neurological deficits such as aphasia, apraxia and agnosia of vascular/circulatory origin. It has been useful for identifying early clinical and neuroradiological alterations that might permit therapeutic strategies geared to curbing the progression of cerebrovascular disease. Multi-infarct encephalopathy, infarcts in strategic areas, lacunae and lacunar status, Binswanger's encephalopathy, hippocampal sclerosis, cortical granular atrophy and watershed infarcts are common lesions. Hypertension and vascular diseases such as arteriosclerosis, small blood vessel disease, inflammatory diseases of the blood vessels, Sneddon syndrome, cerebral amyloid angiopathies, cerebral autosomic dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and Maeda's syndrome are causative of cognitive impairment of vascular origin. Other less common causes are hereditary endotheliopathy with retinopathy, neuropathy and strokes (HERNS), cerebro-retinian vasculopathy (CRV), hereditary vascular retinopathy (HVR) (all three linked to 3p21.1-p21.3), hereditary infantile hemiparesis with arteriolar retinopathy and leukoencephalopathy (HIHRATL) (not linked to 3p21), fibromuscular dysplasia, and moya-moya disease. Lack of uniformity of clinical manifestations, the variety of vascular diseases and circulatory factors, the diverse, but often convergent, neuropathological substrates, and the common association with unrelated neurodegenerative diseases in the elderly, make it hard to assume a single clinical approach in the diagnosis and treatment of cognitive impairment of vascular origin. Rather, environmental and genetic risk factors, underlying vascular diseases, associated systemic, metabolic and neurodegenerative diseases and identification of extent and distribution of lesions with morphological and functional neuroimaging methods should be applied in every individual patient.