Poststroke cognitive impairment and dementia: prevalence, diagnosis, and treatment

Multi-element Exposure and Cognitive Function in Rural Elderly Chinese

To investigate the relationship between selenium (Se) based multi-element combined exposure and cognitive function in rural elderly individuals, a cross-sectional study was conducted. The study involved 416 older adults aged 60 and above, residing in four different areas of Enshi county, China, with varying soil Se levels. Inductively coupled plasma mass spectrometry (ICP-MS) was employed to measure the concentrations of Se, copper (Cu), iron (Fe), zinc (Zn), calcium (Ca), magnesium (Mg), cadmium (Cd), arsenic (As), and lead (Pb) in whole blood. Nine standard cognitive tests were applied to assess cognitive function. Analysis of the least absolute shrinkage and selection operator regression (LASSO), covariance (ANCOVA), and generalized linear model (GLM) were utilized to investigate the relationship between element exposure and cognitive function. The results of LASSO revealed that Se, Cu, Fe, Zn, Ca, and Pb were independently identified to be associated with cognition. Both ANCOVA and GLM demonstrated that Se and Ca were correlated with cognitive function. The multi-element model showed higher composite Z scores of 0.32 (95% CI: 0.09 to 0.55) for log-transformed Se (P = 0.007), 0.75 (95% CI: 0.01 to 1.49) for log-transformed Cu (P = 0.048), and a lower score of - 0.67 (95% CI: - 1.26 to - 0.08) for log-transformed Ca (P = 0.025). Furthermore, there was evidence that Se could counteract the negative impact of Ca on cognitive function (P for interaction = 0.031). Our findings suggested that higher levels of Se and Cu were associated with better cognitive function in the elderly and Se can counteract the cognitive damage caused by Ca.

Neuroanatomical correlates of cognitive impairment following basal ganglia-thalamic post-hemorrhagic stroke: Uncovering network-wide alterations in hemispheric gray matter asymmetry

Cognitive impairment and recovery are central issues in hemorrhagic stroke. This study aimed to investigate whether post-hemorrhagic stroke cognitive impairment (PhSCI) is associated with cortical gray matter (GM) loss and hemispheric asymmetry changes and whether these changes could predict improvements in cognitive function during the recovery. Nineteen patients with PhSCI, comprising 10 with basal ganglia hemorrhage and 9 with thalamic hemorrhage, were recruited. Among them, 9 completed a course of repetitive transcranial magnetic stimulation (rTMS). Additionally, 19 demographically and comorbidity-matched healthy controls were also included. Structural brain MRI and cognitive assessments were performed. Voxel-wise GM volume and hemispheric asymmetry were analyzed. The PhSCI patients exhibited bilateral, yet asymmetric, GM losses in the hippocampus, fusiform, lateral temporal, prefrontal, somatomotor, and inferior parietal regions. The analysis of GM asymmetry revealed that patients showed rightward GM in the lateral temporal, somatomotor, and inferior parietal regions. Among the 9 PhSCI patients who completed rTMS, there was a marginal trend of regional GM increase and leftward GM, and these changes were in parallel with the improvements in cognitive tests. Further lesion connectivity and metanalytic mapping identified two interconnected systems linked to the lesions, which were anchored in the default mode, somatomotor, and salience/cognitive control networks and in the cognitive domains of memory, language, decision-making, and executive function. In conclusion, PhSCI patients exhibited network-wide cortical GM losses, distal to subcortical hemorrhagic lesions, and hemisphere asymmetry changes. These changes appear to predict rTMS-related cognitive improvements, suggesting that even subcortical focal lesions can lead to alterations in distal cortical neuroanatomical architecture. Our preliminary findings provide new insights into the neuroanatomical basis of PhSCI.

Neuroimaging biomarkers of cognitive recovery after ischemic stroke

Post-stroke cognitive impairment affects more than one-third of patients after an ischemic stroke (IS). Identifying markers of potential cognitive recovery after ischemic stroke can guide patients' selection for treatments, enrollment in clinical trials, and cognitive rehabilitation methods to restore cognitive abilities in post-stroke patients. Despite the burden of post-stroke cognitive impairment, biomarkers of cognitive recovery are an understudied area of research. This narrative review summarizes and critically reviews the current literature on the use and utility of neuroimaging as a predictive biomarker of cognitive recovery after IS. Most studies included in this review utilized structural Magnetic Resonance Imaging (MRI) to predict cognitive recovery after IS; these studies highlighted baseline markers of cerebral small vessel disease and cortical atrophy as predictors of cognitive recovery. Functional Magnetic Resonance Imaging (fMRI) using resting-state functional connectivity and Diffusion Imaging are potential biomarkers of cognitive recovery after IS, although more precise predictive tools are needed. Comparison of these studies is limited by heterogeneity in cognitive assessments. For all modalities, current findings need replication in larger samples. Although no neuroimaging tool is ready for use as a biomarker at this stage, these studies suggest a clinically meaningful role for neuroimaging in predicting post-stroke cognitive recovery.

One-year recurrence of stroke and death in Lebanese survivors of first-ever stroke: Time-to-Event analysis

BACKGROUND

To date, despite the application of secondary prevention worldwide, first-ever stroke survivors remain at imminent risk of stroke recurrence and death in the short and long term. The present study aimed to assess the cumulative risk rates and identify baseline differences and stroke characteristics of Lebanese survivors.

METHODS

A prospective longitudinal study was conducted among survivors ≥18 years old who were followed-up for 15 months through a face-to-face interview. Kaplan-Meier method was used to calculate the cumulative rates of stroke mortality and recurrence. Cox-regression univariate and multivariable analyses were performed to identify the predictors of both outcomes.

RESULTS

Among 150 subjects (mean age 74 ± 12 years; 58.7% men vs. 44.3% women; 95.3% with ischemic stroke vs. 4.3% with intracerebral hemorrhage), high cumulative risk rates of stroke recurrence (25%) and death (21%) were highlighted, especially in the acute phase. Survival rates were lesser in patients with stroke recurrence compared to those without recurrence (Log rank test p < 0.001). Older age was the main predictor for both outcomes (p < 0.02). Large artery atherosclerosis was predominant in patients with stroke recurrence and death compared to small vessel occlusion (p < 0.02). Higher mental component summary scores of quality of life were inversely associated with stroke recurrence (p < 0.01). Lebanese survivors exhibited the highest percentages of depression and anxiety; elevated Hospital Anxiety and Depression Scale (HADS) scores were seen in those with stroke recurrence and those who died (≥80% with mean HADS scores ≥8). Lower Mini-Mental State Examination scores at the acute phase increased the risk of both outcomes by 10% (p < 0.03). Three out of 13 mortalities (23.1%) were presented with early epileptic seizures (p = 0.012). High educational level was the protective factor against stroke recurrence (p = 0.019). Administration of intravenous thrombolysis decreased the risk of both outcomes by 10% (p > 0.05).

CONCLUSION

Higher rates of stroke recurrence and death were observed in the first year following a stroke in Lebanon. Various factors were identified as significant determinants. Thus, health care providers and officials in Lebanon can use these findings to implement effective preventive strategies to best address the management of these factors to reduce the stroke burden and improve the short and long-term prognosis of stroke survivors.

Obstructive sleep apnea is associated with cognitive impairment in minor ischemic stroke

Objectives

Obstructive sleep apnea (OSA) is commonly seen in stroke patients, and its relationship with cognitive impairment remains poorly understood. This study aimed to explore the roles of OSA in cognition impairment in patients with minor ischemic stroke.

Methods

Patients with minor ischemic stroke were consecutively enrolled from January 2020 to May 2021. Every patient underwent polysomnography (PSG) to assess for OSA. Based on the apnea hypopnea index (AHI), patients were grouped into the no OSA (AHI < 5), mild OSA (5 ≤ AHI < 15), and moderate-to-severe OSA (MS OSA, AHI ≥ 15) groups. Neuropsychological assessments were performed to evaluate cognitive function, and the correlations between cognitive function and OSA were investigated.

Results

Of 94 patients, 35 had no OSA, 32 had mild OSA, and 27 had moderate-to-severe OSA. Compared to the no or mild OSA groups, the moderate-to-severe OSA group performed worse on the Chinese version of the Auditory Verbal Learning Test (CAVLT)-Recognition (p < 0.001), Digital Span Test (DST)-Backward (p < 0.001), Montreal Cognitive Assessment (MoCA) (p < 0.001), and Stroop Color and Word Test (SCWT)-Interference (p < 0.001). The severity of cognitive impairment was assessed using the MoCA, which was negatively related to the AHI (p = 0.041) and lowest SpO2 (p = 0.048).

Conclusions

The findings suggest that OSA has significant effects on cognition impairment in patients with minor ischemic stroke and that hypoxemia may be a potential pathophysiological mechanism of OSA-induced cognitive impairment.

Cardiometabolic and Vascular Disease Factors and Mild Cognitive Impairment and Dementia

INTRODUCTION

There is empirical evidence that cardiovascular risk factors and vascular pathology contribute to cognitive impairment and dementia.

METHODS

We profiled cardiometabolic and vascular disease (CMVD) and CMVD burden in community-living older adults in the Singapore Longitudinal Ageing Study cohort and examined the association of CMVD risk markers with the prevalence and incidence of mild cognitive impairment (MCI) and dementia from a median 3.8 years of follow-up.

RESULTS

Prevalent MCI and dementia, compared with normal cognition, was associated with higher proportions of persons with any CMVD, hypertension, diabetes, coronary heart disease, atrial fibrillation, or stroke. Diabetes, stroke, and the number of CMVD risk markers remained significantly associated with dementia or MCI after adjusting for age, sex, formal education level, APOE-ε4 genotype, and level of physical, social, or productive activities, with odds ratios ranging from 1.3 to 5.7. Among cognitively normal participants who were followed up, any CMVD risk factor, dyslipidemia, diabetes, or heart failure at baseline predicted incident MCI or its progression to dementia after adjusting for potential confounders.

CONCLUSION

Older adults with higher burden of CMVD, driven especially by diabetes, are likely to increase the risk of prevalent and incident MCI and dementia.

Challenges for Diagnostic Clarity for Post-stroke Cognitive Impairment and Behavioural Issues in Middle-Income Countries: Case Studies From Malaysia

Following stroke, individuals require ongoing screening, diagnosis and monitoring for cognitive impairment. Services and policies around these vary widely between settings, and reports from many countries highlight persistent under-diagnosis of cognitive impairment in the months and years after stroke. Missed and delayed diagnosis of post-stroke cognitive impairment, including dementia, are important factors in shaping the experiences of people so affected and their family members, especially in low- and middle-income countries. Drawing upon ethnographic research conducted in Malaysia, this article draws upon three case studies to examine the continued health-seeking behaviour after the appearance of salient cognitive and behavioural symptoms that occurred after stroke. Findings highlight the challenges in getting formal diagnostic clarity for cognitive and behavioural symptoms in a rural setting within a middle-income country. No study participants sought help for memory or cognitive problems, partly due to limited lay awareness of cognitive impairment but more significantly due to health service factors. Despite their elevated risk for dementia, participants were not monitored for cognitive impairment during any follow-up care in various health facilities. Furthermore, caregivers' attempts to seek help when behavioural issues became untenable were met with multiple health system barriers. The journey was complicated by the meanings attached to the reactions towards cognitive symptoms at the community level. We suggest that strategies seek to increase the awareness of post-stroke cognitive and behavioural symptoms, and incorporate clear treatment pathways into the long-term care plans of community-dwelling stroke survivors.

[The role of the inflammatory process in the development of post-stroke cognitive impairment]

Post-stroke cognitive impairment (PCI) is a common complication of stroke. PCI in most cases is associated with an increased risk of progression to dementia, with a progression rate of 8-15% per year. When post-stroke cognitive impairment reaches dementia, patients lose independence, professional and social maladjustment occurs, which, in turn, significantly worsen the quality of life and reduce the rehabilitation potential. According to many experimental and clinical studies, the inflammatory process has an important role in the development of PCI. Several previous studies have looked at the association between inflammatory markers and PCI, with some results conflicting with specific biomarkers. Based on the results of studies, inflammatory markers such as IL-8, IL-12 and ESR were closely associated with PCI, high ESR values are associated with worse cognitive impairment, especially memory. The relationship was not confirmed between the markers IFN-gamma, TNF-α and PCI. With regard to IL-1β, IL-6, IL-10, CRP, the results obtained are not unambiguous. Thus, the inflammatory process in the development of PCI has an important role, including a series of complex reactions, the combined effect of which induces neuronal damage and loss of synapses that ultimately leads to cognitive impairment.

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.

Determinants, Prevalence, and Trajectory of Long-Term Post-Stroke Cognitive Impairment: Results from a 4-Year Follow-Up of the ARCOS-IV Study

BACKGROUND

The long-term (>12 months) prevalence, predictors, and trajectory of post-stroke cognitive deficits are not well established, especially at a community level. This study investigated the longitudinal course and prevalence of cognitive impairment in an incidence cohort, identifying factors associated with declining cognition.

METHODS

Two hundred fifty-seven participants (mean age = 67.93 ± 13.59) of first-ever stroke survivors, completed cognitive assessments within 2 weeks post stroke, and/or 1, 6, 12, and 48-month. Multivariate linear and logistic models were used to identify baseline predictors (reported as OR with 95% CI) and trajectory of cognitive impairment.

RESULTS

Cognitive functioning significantly declined by 2.8 points by 4 years post stroke. Eighty-four percent of stroke survivors had cognitive impairment indicative of post-stroke dementia (mean Montreal cognitive assessment = 20 ± 4.7) at 4-year. There were significant as-sociations between progressive cognitive decline and the -following factors: male gender (OR 2.9, 95% CI 1.6-5.9, -p = 0.0171), coronary artery disease (OR 2.96, 95% CI 1.35-6.49, p = 0.0070), arrhythmia (OR 2.21, 95% CI 1.07-4.57, p = 0.0317), not in a relationship (OR 2.8, 95% CI 1.4-5.50, p < 0.0001), and not employed (OR 4.9, 95% CI 1.9-12.1, p < 0.0001).

CONCLUSIONS

Cognitive deficits remain highly prevalent at 4-year post stroke. Early identification of those at higher risk of declining cognition is vital to target rehabilitation interventions at the acute stage and improve overall outcomes.

Upper Alpha Based Neurofeedback Training in Chronic Stroke: Brain Plasticity Processes and Cognitive Effects

In the present study, we investigated the effects of upper alpha based neurofeedback (NF) training on electrical brain activity and cognitive functions in stroke survivors. Therefore, two single chronic stroke patients with memory deficits (subject A with a bilateral subarachnoid hemorrhage; subject B with an ischemic stroke in the left arteria cerebri media) and a healthy elderly control group (N = 24) received up to ten NF training sessions. To evaluate NF training effects, all participants performed multichannel electroencephalogram (EEG) resting measurements and a neuropsychological test battery assessing different cognitive functions before and after NF training. Stroke patients showed improvements in memory functions after successful NF training compared to the pre-assessment. Subject B had a pathological delta (0.5-4 Hz) and upper alpha (10-12 Hz) power maximum over the unaffected hemisphere before NF training. After NF training, he showed a more bilateral and "normalized" topographical distribution of these EEG frequencies. Healthy participants as well as subject A did not show any abnormalities in EEG topography before the start of NF training. Consequently, no changes in the topographical distribution of EEG activity were observed in these participants when comparing the pre- and post-assessment. Hence, our results show that upper alpha based NF training had on the one hand positive effects on memory functions, and on the other hand led to cortical "normalization" in a stroke patient with pathological brain activation patterns, which underlines the potential usefulness of NF as neurological rehabilitation tool.

Specific effects of EEG based neurofeedback training on memory functions in post-stroke victims

BACKGROUND

Using EEG based neurofeedback (NF), the activity of the brain is modulated directly and, therefore, the cortical substrates of cognitive functions themselves. In the present study, we investigated the ability of stroke patients to control their own brain activity via NF and evaluated specific effects of different NF protocols on cognition, in particular recovery of memory.

METHODS

N = 17 stroke patients received up to ten sessions of either SMR (N = 11, 12-15 Hz) or Upper Alpha (N = 6, e.g. 10-12 Hz) NF training. N = 7 stroke patients received treatment as usual as control condition. Furthermore, N = 40 healthy controls performed NF training as well. To evaluate the NF training outcome, a test battery assessing different cognitive functions was performed before and after NF training.

RESULTS

About 70 % of both patients and controls achieved distinct gains in NF performance leading to improvements in verbal short- and long-term memory, independent of the used NF protocol. The SMR patient group showed specific improvements in visuo-spatial short-term memory performance, whereas the Upper Alpha patient group specifically improved their working memory performance. NF training effects were even stronger than effects of traditional cognitive training methods in stroke patients. NF training showed no effects on other cognitive functions than memory.

CONCLUSIONS

Post-stroke victims with memory deficits could benefit from NF training as much as healthy controls. The used NF training protocols (SMR, Upper Alpha) had specific as well as unspecific effects on memory. Hence, NF might offer an effective cognitive rehabilitation tool improving memory deficits of stroke survivors.