Perivascular spaces, plasma GFAP, and speeded executive function in neurodegenerative diseases.

INTRODUCTION: We investigated the effect of perivascular spaces (PVS) volume on speeded executive function (sEF), as mediated by white matter hyperintensities (WMH) volume and plasma glial fibrillary acidic protein (GFAP) in neurodegenerative diseases. METHODS: A mediation analysis was performed to assess the relationship between neuroimaging markers and plasma biomarkers on sEF in 333 participants clinically diagnosed with Alzheimer's disease/mild cognitive impairment, frontotemporal dementia, or cerebrovascular disease from the Ontario Neurodegenerative Disease Research Initiative. RESULTS: PVS was significantly associated with sEF (c = -0.125 ± 0.054, 95% bootstrap confidence interval [CI] [-0.2309, -0.0189], p = 0.021). This effect was mediated by both GFAP and WMH. DISCUSSION: In this unique clinical cohort of neurodegenerative diseases, we demonstrated that the effect of PVS on sEF was mediated by the presence of elevated plasma GFAP and white matter disease. These findings highlight the potential utility of imaging and plasma biomarkers in the current landscape of therapeutics targeting dementia. HIGHLIGHTS: Perivascular spaces (PVS) and white matter hyperintensities (WMH) are imaging markers of small vessel disease. Plasma glial fibrillary protein acidic protein (GFAP) is a biomarker of astroglial injury. PVS, WMH, and GFAP are relevant in executive dysfunction from neurodegeneration. PVS's effect on executive function was mediated by GFAP and white matter disease.

Predicting Major Adverse Carotid Cerebrovascular Events in Patients with Carotid Stenosis: Integrating a Panel of Plasma Protein Biomarkers and Clinical Features-A Pilot Study.

Background: Carotid stenosis (CS) is an atherosclerotic disease of the carotid artery that can lead to devastating cardiovascular outcomes such as stroke, disability, and death. The currently available treatment for CS is medical management through risk reduction, including control of hypertension, diabetes, and/or hypercholesterolemia. Surgical interventions are currently suggested for patients with symptomatic disease with stenosis >50%, where patients have suffered from a carotid-related event such as a cerebrovascular accident, or asymptomatic disease with stenosis >60% if the long-term risk of death is <3%. There is a lack of current plasma protein biomarkers available to predict patients at risk of such adverse events. Methods: In this study, we investigated several growth factors and biomarkers of inflammation as potential biomarkers for adverse CS events such as stroke, need for surgical intervention, myocardial infarction, and cardiovascular-related death. In this pilot study, we use a support vector machine (SVM), random forest models, and the following four significantly elevated biomarkers: C-X-C Motif Chemokine Ligand 6 (CXCL6); Interleukin-2 (IL-2); Galectin-9; and angiopoietin-like protein (ANGPTL4). Results: Our SVM model best predicted carotid cerebrovascular events with an area under the curve (AUC) of >0.8 and an accuracy of 0.88, demonstrating strong prognostic capability. Conclusions: Our SVM model may be used for risk stratification of patients with CS to determine those who may benefit from surgical intervention.

Current Prognostic Biomarkers for Abdominal Aortic Aneurysm: A Comprehensive Scoping Review of the Literature.

Abdominal aortic aneurysm (AAA) is a progressive dilatation of the aorta that can lead to aortic rupture. The pathophysiology of the disease is not well characterized but is known to be caused by the general breakdown of the extracellular matrix within the aortic wall. In this comprehensive literature review, all current research on proteins that have been investigated for their potential prognostic capabilities in patients with AAA was included. A total of 45 proteins were found to be potential prognostic biomarkers for AAA, predicting incidence of AAA, AAA rupture, AAA growth, endoleak, and post-surgical mortality. The 45 proteins fell into the following seven general categories based on their primary function: (1) cardiovascular health, (2) hemostasis, (3) transport proteins, (4) inflammation and immunity, (5) kidney function, (6) cellular structure, (7) and hormones and growth factors. This is the most up-to-date literature review on current prognostic markers for AAA and their functions. This review outlines the wide pathophysiological processes that are implicated in AAA disease progression.

Association Between Immigration Status and Ambulatory Secondary Stroke Preventive Care in Ontario, Canada.

BACKGROUND AND OBJECTIVES: Secondary stroke preventive care includes evaluation and control of vascular risk factors to prevent stroke recurrence. Our objective was to evaluate the quality of ambulatory stroke preventive care and its variation by immigration status in adult stroke survivors in Ontario, Canada. METHODS: We conducted a population-based administrative database-derived retrospective cohort study in Ontario, Canada. Using immigration records, we defined immigrants as those immigrating after 1985 and long-term residents as those arriving before 1985 or those born in Canada. We included community-dwelling stroke survivors 40 years and older with a first-ever stroke between 2011 and 2017. In the year following their stroke, we evaluated the following metrics of stroke prevention: testing for hyperlipidemia and diabetes; among those with the condition, control of diabetes (hemoglobin A1c ≤7%) and hyperlipidemia (low-density lipoprotein <2 mmol/L); medication use to control hypertension, diabetes, and atrial fibrillation; and visit to a family physician and a specialist (neurologist, cardiologist, or geriatrician). We determined age and sex-adjusted absolute prevalence difference (APD) between immigrants and long-term residents for each metric using generalized linear models with binomial distribution and an identity link function. RESULTS: We included 34,947 stroke survivors (median age 70 years, 46.9% women) of whom 12.4% were immigrants. The receipt of each metric ranged from 68% to 90%. Compared with long-term residents, after adjusting for age and sex, immigrants were slightly more likely to receive screening for hyperlipidemia (APD 5.58%; 95% CI 4.18-6.96) and diabetes (5.49%; 3.76-7.23), have visits to family physicians (1.19%; 0.49-1.90), receive a prescription for antihypertensive (3.12%; 1.76-4.49) and antihyperglycemic medications (9.51%; 6.46-12.57), and achieve control of hyperlipidemia (3.82%; 1.01-6.63). By contrast, they were less likely to achieve diabetes control (-4.79%; -7.86 to -1.72) or have visits to a specialist (-1.68%; -3.12 to -0.24). There was minimal variation by region of origin or time since immigration in immigrants. DISCUSSION: Compared with long-term residents, many metrics of secondary stroke preventive care were better in immigrants, albeit with small absolute differences. However, future work is needed to identify and mitigate the factors associated with the suboptimal quality of stroke preventive care for all stroke survivors.

Retrospective Analysis of the Integration of Palliative Care Into the Care of Stroke Patients Admitted to a Regional Stroke Center.

Background: Palliative care (PC) aims to enhance the quality of life for patients when confronted with serious illness. As stroke inflicts high morbidity and mortality, the integration of PC within acute stroke care remains an important aspect of quality inpatient care. However, there is a tendency to offer PC to stroke patients only when death appears imminent. We aim to understand why this may be by examining stroke patients admitted to a regional stroke centre who subsequently died and their provision of PC. Methods: We conducted a retrospective single-centre cohort study of patients who died during admission to the regional stroke centre at Sunnybrook Health Sciences Centre (SHSC) in Toronto, Ontario, Canada. Baseline demographics were assessed using means, standard deviations (SD), medians, interquartile ranges (IQR), and proportions. Descriptive statistics, univariate, and multivariate analyses were performed to ascertain relationships between collected variables. Results: Univariate modeling demonstrated that older age, being female, no stroke diagnosis at admission to hospital, ischemic stroke, and comorbidities of cancer or dementia were associated with a higher incidence of palliative medicine consultation (PMC), while admission from an acute care hospital and a Glasgow Coma Scale (GCS) coma classification were associated with a lower incidence of PMC. The multivariate model identified the GCS coma-related category as the only significant factor associated with a higher incidence of death but was non-significantly related to a lower incidence of PMC. Conclusion: These results highlight continued missed opportunities for PC in stroke patients and underscore the need to better optimize PMC.

Long-term neuropsychiatric complications of aneurysmal subarachnoid hemorrhage: a narrative review.

This review focuses on the often-neglected long-term neuropsychiatric consequences of aneurysmal subarachnoid hemorrhage (aSAH), beyond traditional randomized trial outcomes of mortality and retreatment. While current guidelines recommend screening for these sequalae, it may not be routinely practiced. This review will underscore the prevalence and management of common neuropsychiatric sequalae, including anxiety, depression, cognitive dysfunction, headaches, seizures, and sexual dysfunction, all of which can significantly impact the quality of life of survivors of aSAH. We emphasize the critical role neurointerventionalists can play by going beyond the customary practice of radiological monitoring for treated aneurysms by screening for and helping guide management of these common neuropsychiatric complications.

Reducing the global burden of cerebral venous thrombosis: An international research agenda.

BACKGROUND: Due to the rarity of cerebral venous thrombosis (CVT), performing high-quality scientific research in this field is challenging. Providing answers to unresolved research questions will improve prevention, diagnosis, and treatment, and ultimately translate to a better outcome of patients with CVT. We present an international research agenda, in which the most important research questions in the field of CVT are prioritized. AIMS: This research agenda has three distinct goals: (1) to provide inspiration and focus to research on CVT for the coming years, (2) to reinforce international collaboration, and (3) to facilitate the acquisition of research funding. SUMMARY OF REVIEW: This international research agenda is the result of a research summit organized by the International Cerebral Venous Thrombosis Consortium in Amsterdam, the Netherlands, in June 2023. The summit brought together 45 participants from 15 countries including clinical researchers from various disciplines, patients who previously suffered from CVT, and delegates from industry and non-profit funding organizations. The research agenda is categorized into six pre-specified themes: (1) epidemiology and clinical features, (2) life after CVT, (3) neuroimaging and diagnosis, (4) pathophysiology, (5) medical treatment, and (6) endovascular treatment. For each theme, we present two to four research questions, followed by a brief substantiation per question. The research questions were prioritized by the participants of the summit through consensus discussion. CONCLUSIONS: This international research agenda provides an overview of the most burning research questions on CVT. Answering these questions will advance our understanding and management of CVT, which will ultimately lead to improved outcomes for CVT patients worldwide.

Neuropsychiatric symptoms and brain morphology in patients with mild cognitive impairment, cerebrovascular disease and Parkinson disease: A cross sectional and longitudinal study.

OBJECTIVES: Neuropsychiatric symptoms (NPS) increase risk of developing dementia and are linked to various neurodegenerative conditions, including mild cognitive impairment (MCI due to Alzheimer's disease [AD]), cerebrovascular disease (CVD), and Parkinson's disease (PD). We explored the structural neural correlates of NPS cross-sectionally and longitudinally across various neurodegenerative diagnoses. METHODS: The study included individuals with MCI due to AD, (n = 74), CVD (n = 143), and PD (n = 137) at baseline, and at 2-years follow-up (MCI due to AD, n = 37, CVD n = 103, and PD n = 84). We assessed the severity of NPS using the Neuropsychiatric Inventory Questionnaire. For brain structure we included cortical thickness and subcortical volume of predefined regions of interest associated with corticolimbic and frontal-executive circuits. RESULTS: Cross-sectional analysis revealed significant negative correlations between appetite with both circuits in the MCI and CVD groups, while apathy was associated with these circuits in both the MCI and PD groups. Longitudinally, changes in apathy scores in the MCI group were negatively linked to the changes of the frontal-executive circuit. In the CVD group, changes in agitation and nighttime behavior were negatively associated with the corticolimbic and frontal-executive circuits, respectively. In the PD group, changes in disinhibition and apathy were positively associated with the corticolimbic and frontal-executive circuits, respectively. CONCLUSIONS: The observed correlations suggest that underlying pathological changes in the brain may contribute to alterations in neural activity associated with MBI. Notably, the difference between cross-sectional and longitudinal results indicates the necessity of conducting longitudinal studies for reproducible findings and drawing robust inferences.

Development and internal validation of machine learning-based models and external validation of existing risk scores for outcome prediction in patients with ischaemic stroke.

Aims: We developed new machine learning (ML) models and externally validated existing statistical models [ischaemic stroke predictive risk score (iScore) and totalled health risks in vascular events (THRIVE) scores] for predicting the composite of recurrent stroke or all-cause mortality at 90 days and at 3 years after hospitalization for first acute ischaemic stroke (AIS). Methods and results: In adults hospitalized with AIS from January 2005 to November 2016, with follow-up until November 2019, we developed three ML models [random forest (RF), support vector machine (SVM), and extreme gradient boosting (XGBOOST)] and externally validated the iScore and THRIVE scores for predicting the composite outcomes after AIS hospitalization, using data from 721 patients and 90 potential predictor variables. At 90 days and 3 years, 11 and 34% of patients, respectively, reached the composite outcome. For the 90-day prediction, the area under the receiver operating characteristic curve (AUC) was 0.779 for RF, 0.771 for SVM, 0.772 for XGBOOST, 0.720 for iScore, and 0.664 for THRIVE. For 3-year prediction, the AUC was 0.743 for RF, 0.777 for SVM, 0.773 for XGBOOST, 0.710 for iScore, and 0.675 for THRIVE. Conclusion: The study provided three ML-based predictive models that achieved good discrimination and clinical usefulness in outcome prediction after AIS and broadened the application of the iScore and THRIVE scoring system for long-term outcome prediction. Our findings warrant comparative analyses of ML and existing statistical method-based risk prediction tools for outcome prediction after AIS in new data sets.

Diagnosis and Management of Cerebral Venous Thrombosis: A Scientific Statement From the American Heart Association.

Cerebral venous thrombosis accounts for 0.5% to 3% of all strokes. The most vulnerable populations include young individuals, women of reproductive age, and patients with a prothrombotic state. The clinical presentation of cerebral venous thrombosis is diverse (eg, headaches, seizures), requiring a high level of clinical suspicion. Its diagnosis is based primarily on magnetic resonance imaging/magnetic resonance venography or computed tomography/computed tomographic venography. The clinical course of cerebral venous thrombosis may be difficult to predict. Death or dependence occurs in 10% to 15% of patients despite intensive medical treatment. This scientific statement provides an update of the 2011 American Heart Association scientific statement for the diagnosis and management of cerebral venous thrombosis. Our focus is on advances in the diagnosis and management decisions of patients with suspected cerebral venous thrombosis. We discuss evidence for the use of anticoagulation and endovascular therapies and considerations for craniectomy. We also provide an algorithm to optimize the management of patients with cerebral venous thrombosis and those with progressive neurological deterioration or thrombus propagation despite maximal medical therapy.

World Stroke Organization Brain & hEart globAl iniTiative Program.

INTRODUCTION: The World Stroke Organization (WSO) Brain & Heart Task Force developed the Brain & hEart globAl iniTiative (BEAT), a pilot feasibility implementation program to establish clinical collaborations between cardiologists and stroke physicians who work at large healthcare facilities. METHODS: The WSO BEAT pilot project focused on atrial fibrillation (AF) and patent foramen ovale (PFO) detection and management, and poststroke cardiovascular complications known as the stroke-heart syndrome. The program included 10 sites from 8 countries: Brazil, China, Egypt, Germany, Japan, Mexico, Romania, and the USA The primary composite feasibility outcome was the achievement of the following 3 implementation metrics (1) developing site-specific clinical pathways for the diagnosis and management of AF, PFO, and the stroke-heart syndrome; (2) establishing regular Neurocardiology rounds (e.g., monthly); and (3) incorporating a cardiologist to the stroke team. The secondary objectives were (1) to identify implementation challenges to guide a larger program and (2) to describe qualitative improvements. RESULTS: The WSO BEAT pilot feasibility program achieved the prespecified primary composite outcome in 9 of 10 (90%) sites. The most common challenges were the limited access to specific medications (e.g., direct oral anticoagulants) and diagnostic (e.g., prolonged cardiac monitoring) or therapeutic (e.g., PFO closure devices) technologies. The most relevant qualitative improvement was the achievement of a more homogeneous diagnostic and therapeutic approach. CONCLUSION: The WSO BEAT pilot program suggests that developing neurocardiology collaborations is feasible. The long-term sustainability of the WSO BEAT program and its impact on quality of stroke care and clinical outcomes needs to be tested in a larger and longer duration program.

Association of plasma biomarkers with cognition, cognitive decline, and daily function across and within neurodegenerative diseases: Results from the Ontario Neurodegenerative Disease Research Initiative.

INTRODUCTION: We investigated whether novel plasma biomarkers are associated with cognition, cognitive decline, and functional independence in activities of daily living across and within neurodegenerative diseases. METHODS: Glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), phosphorylated tau (p-tau)181 and amyloid beta (Aß)42/40 were measured using ultra-sensitive Simoa immunoassays in 44 healthy controls and 480 participants diagnosed with Alzheimer's disease/mild cognitive impairment (AD/MCI), Parkinson's disease (PD), frontotemporal dementia (FTD) spectrum disorders, or cerebrovascular disease (CVD). RESULTS: GFAP, NfL, and/or p-tau181 were elevated among all diseases compared to controls, and were broadly associated with worse baseline cognitive performance, greater cognitive decline, and/or lower functional independence. While GFAP, NfL, and p-tau181 were highly predictive across diseases, p-tau181 was more specific to the AD/MCI cohort. Sparse associations were found in the FTD and CVD cohorts and for Aß42/40 . DISCUSSION: GFAP, NfL, and p-tau181 are valuable predictors of cognition and function across common neurodegenerative diseases, and may be useful in specialized clinics and clinical trials.

Current Biomarkers for Carotid Artery Stenosis: A Comprehensive Review of the Literature.

Carotid artery stenosis (CAS), an atherosclerotic disease of the carotid artery, is one of the leading causes of transient ischemic attacks (TIA) and cerebrovascular attacks (CVA). The atherogenic process of CAS affects a wide range of physiological processes, such as inflammation, endothelial cell function, smooth muscle cell migration and many more. The current gold-standard test for CAS is Doppler ultrasound; however, there is yet to be determined a strong, clinically validated biomarker in the blood that can diagnose patients with CAS and/or predict adverse outcomes in such patients. In this comprehensive literature review, we evaluated all of the current research on plasma and serum proteins that are current contenders for biomarkers for CAS. In this literature review, 36 proteins found as potential biomarkers for CAS were categorized in to the following nine categories based on protein function: (1) Inflammation and Immunity, (2) Lipid Metabolism, (3) Haemostasis, (4) Cardiovascular Markers, (5) Markers of Kidney Function, (6) Bone Health, (7) Cellular Structure, (8) Growth Factors, and (9) Hormones. This literature review is the most up-to-date and current comprehensive review of research on biomarkers of CAS, and the only review that demonstrated the several pathways that contribute to the initiation and progression of the disease. With this review, future studies can determine if any new markers, or a panel of the proteins explored in this study, may be contenders as diagnostic or prognostic markers for CAS.

Perivascular spaces mediate a relationship between diabetes and other cerebral small vessel disease markers in cerebrovascular and neurodegenerative diseases.

Type 2 diabetes mellitus (T2DM) and hypertension are risk factors for cerebral small vessel disease (SVD); however, few studies have characterised their relationships with MRI-visible perivascular spaces (PVS). MRI was used to quantify deep (d) and periventricular (p) white matter hyperintensities (WMH), lacunes, PVS in the white matter (wmPVS) or basal ganglia (bgPVS), and diffusion metrics in white matter. Patients with T2DM had greater wmPVS volume and there were greater wmPVS volumes in patients with T2DM and hypertension together. Counterfactual moderated mediation models found indirect effects of T2DM on volumes of other SVD and diffusion markers that were mediated by wmPVS: pWMH, dWMH, periventricular lacunes, and deep lacunes, and progression of deep lacunes over 1 year, in patients with hypertension, but not in patients without hypertension. Studying the regulation of cortical perivascular fluid dynamics may reveal mechanisms that mediate the impact of T2DM on cerebral small vessels.

White matter hyperintensities and smaller cortical thickness are associated with neuropsychiatric symptoms in neurodegenerative and cerebrovascular diseases.

BACKGROUND: Neuropsychiatric symptoms (NPS) are a core feature of most neurodegenerative and cerebrovascular diseases. White matter hyperintensities and brain atrophy have been implicated in NPS. We aimed to investigate the relative contribution of white matter hyperintensities and cortical thickness to NPS in participants across neurodegenerative and cerebrovascular diseases. METHODS: Five hundred thirteen participants with one of these conditions, i.e. Alzheimer's Disease/Mild Cognitive Impairment, Amyotrophic Lateral Sclerosis, Frontotemporal Dementia, Parkinson's Disease, or Cerebrovascular Disease, were included in the study. NPS were assessed using the Neuropsychiatric Inventory - Questionnaire and grouped into hyperactivity, psychotic, affective, and apathy subsyndromes. White matter hyperintensities were quantified using a semi-automatic segmentation technique and FreeSurfer cortical thickness was used to measure regional grey matter loss. RESULTS: Although NPS were frequent across the five disease groups, participants with frontotemporal dementia had the highest frequency of hyperactivity, apathy, and affective subsyndromes compared to other groups, whilst psychotic subsyndrome was high in both frontotemporal dementia and Parkinson's disease. Results from univariate and multivariate results showed that various predictors were associated with neuropsychiatric subsyndromes, especially cortical thickness in the inferior frontal, cingulate, and insula regions, sex(female), global cognition, and basal ganglia-thalamus white matter hyperintensities. CONCLUSIONS: In participants with neurodegenerative and cerebrovascular diseases, our results suggest that smaller cortical thickness and white matter hyperintensity burden in several cortical-subcortical structures may contribute to the development of NPS. Further studies investigating the mechanisms that determine the progression of NPS in various neurodegenerative and cerebrovascular diseases are needed.

Rare neurovascular genetic and imaging markers across neurodegenerative diseases.

INTRODUCTION: Cerebral small vessel disease (SVD) is common in patients with cognitive impairment and neurodegenerative diseases such as Alzheimer's and Parkinson's. This study investigated the burden of magnetic resonance imaging (MRI)-based markers of SVD in patients with neurodegenerative diseases as a function of rare genetic variant carrier status. METHODS: The Ontario Neurodegenerative Disease Research Initiative study included 520 participants, recruited from 14 tertiary care centers, diagnosed with various neurodegenerative diseases and determined the carrier status of rare non-synonymous variants in five genes (ABCC6, COL4A1/COL4A2, NOTCH3/HTRA1). RESULTS: NOTCH3/HTRA1 were found to significantly influence SVD neuroimaging outcomes; however, the mechanisms by which these variants contribute to disease progression or worsen clinical correlates are not yet understood. DISCUSSION: Further studies are needed to develop genetic and imaging neurovascular markers to enhance our understanding of their potential contribution to neurodegenerative diseases.

Association of Dual-Task Gait Cost and White Matter Hyperintensity Burden Poststroke: Results From the ONDRI.

BACKGROUND: Acute change in gait speed while performing a mental task [dual-task gait cost (DTC)], and hyperintensity magnetic resonance imaging signals in white matter are both important disability predictors in older individuals with history of stroke (poststroke). It is still unclear, however, whether DTC is associated with overall hyperintensity volume from specific major brain regions in poststroke. METHODS: This is a cohort study with a total of 123 older (69 ± 7 years of age) participants with history of stroke were included from the Ontario Neurodegenerative Disease Research Initiative. Participants were clinically assessed and had gait performance assessed under single- and dual-task conditions. Structural neuroimaging data were analyzed to measure both, white matter hyperintensity (WMH) and normal appearing volumes. Percentage of WMH volume in frontal, parietal, occipital, and temporal lobes as well as subcortical hyperintensities in basal ganglia + thalamus were the main outcomes. Multivariate models investigated associations between DTC and hyperintensity volumes, adjusted for age, sex, years of education, global cognition, vascular risk factors, APOE4 genotype, residual sensorimotor symptoms from previous stroke and brain volume. RESULTS: There was a significant positive global linear association between DTC and hyperintensity burden (adjusted Wilks' λ = .87, P = .01). Amongst all WMH volumes, hyperintensity burden from basal ganglia + thalamus provided the most significant contribution to the global association (adjusted ß = .008, η2 = .03; P = .04), independently of brain atrophy. CONCLUSIONS: In poststroke, increased DTC may be an indicator of larger white matter damages, specifically in subcortical regions, which can potentially affect the overall cognitive processing and decrease gait automaticity by increasing the cortical control over patients' locomotion.

Men Are at Higher Risk of Screening Positive for Vascular Cognitive Impairment Compared to Women after Stroke and Transient Ischemic Attack.

While women have greater incidence of dementia, men have higher prevalence of vascular risk factors. This study examined sex differences in risk of screening positive for cognitive impairment after stroke. Ischemic stroke/TIA patients (N = 5969) participated in this prospective, multi-centered study, which screened for cognitive impairment using a validated brief screen. Men showed a higher risk of screening positive for cognitive impairment after adjusting for age, education, stroke severity, and vascular risk factors, suggesting that other factors may be contributing to increased risk among men (OR = 1.34, CI 95% [1.16, 1.55], p < 0.001). The effect of sex on cognitive impairment after stroke warrants further attention.