Changes in memory before and after stroke differ by age and sex, but not by race

Development of a predictive risk stratification tool to identify the population over age 45 at risk for new-onset stroke within 7 years

Background and purpose

With the acceleration of the aging process of society, stroke has become a major health problem in the middle-aged and elderly population. A number of new stroke risk factors have been recently found. It is necessary to develop a predictive risk stratification tool using multidimensional risk factors to identify people at high risk for stroke.

Methods

The study included 5,844 people (age ≥ 45 years) who participated in the China Health and Retirement Longitudinal Study in 2011 and its follow-up up to 2018. The population samples were divided into training set and validation set according to 1:1. A LASSO Cox screening was performed to identify the predictors of new-onset stroke. A nomogram was developed, and the population was stratified according to the score calculated through the X-tile program. Internal and external verifications of the nomogram were performed by ROC and calibration curves, and the Kaplan-Meier method was applied to identify the performance of the risk stratification system.

Results

The LASSO Cox regression screened out 13 candidate predictors from 50 risk factors. Finally, nine predictors, including low physical performance and the triglyceride-glucose index, were included in the nomogram. The nomogram's overall performance was good in both internal and external validations (AUCs at 3-, 5-, and 7-year periods were 0.71, 0.71, and 0.71 in the training set and 0.67, 0.65, and 0.66 in the validation set, respectively). The nomogram was proven to excellently discriminate between the low-, moderate-, and high-risk groups, with a prevalence of 7-year new-onset stroke of 3.36, 8.32, and 20.13%, respectively (P < 0.001).

Conclusion

This research developed a clinical predictive risk stratification tool that can effectively identify the different risks of new-onset stroke in 7 years in the middle-aged and elderly Chinese population.

Cognitive Recovery After Stroke: Memory

Memory impairment occurs in over a third of patients after symptomatic stroke. Memory deficits rarely occur in isolation but are an important component of the poststroke cognitive syndrome because of the strong relationship with the risk of poststroke dementia. In this review, we summarize available data on impairment of episodic memory, with a particular emphasis on the natural history of memory impairment after stroke and the factors influencing trajectory informed by an updated systematic review. We next discuss the pathophysiology of memory impairment and mechanisms of both decline and recovery of function. We then turn to the practical issue of measurement of memory deficits after stroke, emerging biomarkers, and therapeutic approaches. Our review identifies critical gaps, particularly in studies of the natural history that properly map the long-term trajectory of memory and the associations with factors that modulate prognosis. Few studies have used advanced neuroimaging and this, in conjunction with other biomarker approaches, has the potential to provide a much richer understanding of the mechanisms at play and promising therapeutic avenues.

Sex Differences in the Long-Term Consequences of Stroke

Stroke is the fifth leading cause of death and as healthcare intervention improves, the number of stroke survivors has also increased. Furthermore, there exists a subgroup of younger adults, who suffer stroke and survive. Given the overall improved survival rate, bettering our understanding of long-term stroke outcomes is critical. In this review we will explore the causes and challenges of known long-term consequences of stroke and if present, their corresponding sex differences in both old and young survivors. We have separated these long-term post-stroke consequences into three categories: mobility and muscle weakness, memory and cognitive deficits, and mental health and mood. Lastly, we discuss the potential of common preclinical stroke models to contribute to our understanding of long-term outcomes following stroke.

Association of Coronary Artery Bypass Grafting vs Percutaneous Coronary Intervention With Memory Decline in Older Adults Undergoing Coronary Revascularization

IMPORTANCE

It is uncertain whether coronary artery bypass grafting (CABG) is associated with cognitive decline in older adults compared with a nonsurgical method of coronary revascularization (percutaneous coronary intervention [PCI]).

OBJECTIVE

To compare the change in the rate of memory decline after CABG vs PCI.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of community-dwelling participants in the Health and Retirement Study, who underwent CABG or PCI between 1998 and 2015 at age 65 years or older. Data were modeled for up to 5 years preceding and 10 years following revascularization or until death, drop out, or the 2016-2017 interview wave. The date of final follow-up was November 2017.

EXPOSURES

CABG (including on and off pump) or PCI, ascertained from Medicare fee-for-service billing records.

MAIN OUTCOMES AND MEASURES

The primary outcome was a summary measure of cognitive test scores and proxy cognition reports that were performed biennially in the Health and Retirement Study, referred to as memory score, normalized as a z score (ie, mean of 0, SD of 1 in a reference population of adults aged ≥72 years). Memory score was analyzed using multivariable linear mixed-effects models, with a prespecified subgroup analysis of on-pump and off-pump CABG. The minimum clinically important difference was a change of 1 SD of the population-level rate of memory decline (0.048 memory units/y).

RESULTS

Of 1680 participants (mean age at procedure, 75 years; 41% female), 665 underwent CABG (168 off pump) and 1015 underwent PCI. In the PCI group, the mean rate of memory decline was 0.064 memory units/y (95% CI, 0.052 to 0.078) before the procedure and 0.060 memory units/y (95% CI, 0.048 to 0.071) after the procedure (within-group change, 0.004 memory units/y [95% CI, -0.010 to 0.018]). In the CABG group, the mean rate of memory decline was 0.049 memory units/y (95% CI, 0.033 to 0.065) before the procedure and 0.059 memory units/y (95% CI, 0.047 to 0.072) after the procedure (within-group change, -0.011 memory units/y [95% CI, -0.029 to 0.008]). The between-group difference-in-differences estimate for memory decline for PCI vs CABG was 0.015 memory units/y (95% CI, -0.008 to 0.038; P = .21). There was statistically significant increase in the rate of memory decline after off-pump CABG compared with after PCI (difference-in-differences: mean increase in the rate of decline of 0.046 memory units/y [95% CI, 0.008 to 0.084] after off-pump CABG), but not after on-pump CABG compared with PCI (difference-in-differences: mean slowing of decline of 0.003 memory units/y [95% CI, -0.024 to 0.031] after on-pump CABG).

CONCLUSIONS AND RELEVANCE

Among older adults undergoing coronary revascularization with CABG or PCI, the type of revascularization procedure was not significantly associated with differences in the change of rate of memory decline.

Temporal Trends in Stroke-Related Memory Change: Results From a US National Cohort 1998-2016

BACKGROUND AND PURPOSE

Findings from the Framingham Heart Study suggest that declines in dementia incidence rates over recent decades are partially due to decreases in stroke incidence and mortality; however, whether trends of declining dementia rates extend to survivors of incident stroke remains unclear. We investigated evidence for temporal trends in memory change related to incident stroke in a nationally representative cohort.

METHODS

Adults age 50+ in the HRS (Health and Retirement Study) were followed across three successive 6-year epochs (epoch 1: 1998-2004, n=16 781; epoch 2: 2004-2010, n=15 345; and epoch 3: 2010-2016; n=15 949). Participants were included in an epoch if they were stroke-free at the start of that epoch. Annual rates of change in a composite z-standardized memory score were compared using demographic-adjusted linear regression models for stroke-free participants, those who survived after stroke, and those who died after stroke, considering memory change before stroke, at the time of stroke, and for years following stroke.

RESULTS

Crude stroke incidence rates decreased from 8.5 per 1000 person-years in epoch 1 to 6.8 per 1000 person-years in epoch 3. Rates of memory change before and following stroke onset were similar across epochs. Memory decrement immediately after stroke onset attenuated from -0.37 points (95% CI, -0.44 to -0.29) in epoch 1 to -0.26 (95% CI, -0.33 to -0.18) points in epoch 2 and -0.25 (95% CI, -0.33 to -0.17) points in epoch 3 (P value for linear trend=0.02).

CONCLUSIONS

Decreases in stroke-related dementia in recent years may be partially attributable to smaller memory decrements immediately after stroke onset. Findings suggest reductions in stroke incidence and improvements in stroke care may also reduce population burden of dementia. Further investigations into whether temporal trends are attributable to improvements in stroke care are needed.

Stroke disease-specific quality of life trajectories after rehabilitation discharge and their sociodemographic and clinical associations: A longitudinal, multicentre study

AIM

To investigate the longitudinal growth trajectories of disease-specific quality of life (QoL) dimensions and their associations over 1 year.

DESIGN

A longitudinal design. Data were collected between February 2015-May 2017.

METHODS

Four hundred and fifteen stroke survivors (mean age 70.6 years; 81% ischaemic stroke) were recruited after discharge from rehabilitation hospitals and were followed up every 3 months for 1 year. Changes in Stroke Impact Scale (SIS) dimension scores were evaluated using hierarchical linear models (HLMs) and linear, logarithmic, quadratic, and cubic time slope.

RESULTS

We observed a significant linear and quadratic increase in most SIS dimensions from the baseline to 12-month follow-up, especially in physical dimensions. The communication dimension was stable over time, while the memory dimension increased only linearly. Higher physical dimension scores were significantly associated with lower age, hypercholesterolaemia, and better physical functioning at baseline, while higher communication was associated with lower age, better physical functioning, and a diagnosis of peripheral vascular disease. Better memory was associated with lower age, married status, better physical functioning, and left-hemisphere stroke. Better participation was associated with lower age and better physical functioning. No significant associations were observed for emotion.

CONCLUSIONS

This study provides important information about the trajectories of stroke survivors' specific QoL and their associated variables.

IMPACT

Stroke has a great impact on stroke survivors' QoL. Disease-specific QoL significantly increases from the baseline to 12-month follow-up, especially in physical dimensions. Lower age, hypercholesterolaemia, better physical functioning, and diagnosis of peripheral vascular disease seem to be associated with better QoL. Through the analyses of associated variables, we identified stroke survivors who are more at risk and who need more tailored interventions to improve their physical, psychological, emotional, and social dimensions.

Comparison of Methods for Algorithmic Classification of Dementia Status in the Health and Retirement Study

Supplemental Digital Content is available in the text.

Background:

Dementia ascertainment is time-consuming and costly. Several algorithms use existing data from the US-representative Health and Retirement Study (HRS) to algorithmically identify dementia. However, relative performance of these algorithms remains unknown.

Methods:

We compared performance across five algorithms (Herzog–Wallace, Langa–Kabeto–Weir, Crimmins, Hurd, Wu) overall and within sociodemographic subgroups in participants in HRS and Wave A of the Aging, Demographics, and Memory Study (ADAMS, 2000–2002), an HRS substudy including in-person dementia ascertainment. We then compared algorithmic performance in an internal (time-split) validation dataset including participants of HRS and ADAMS Waves B, C, and/or D (2002–2009).

Results:

In the unweighted training data, sensitivity ranged from 53% to 90%, specificity ranged from 79% to 97%, and overall accuracy ranged from 81% to 87%. Though sensitivity was lower in the unweighted validation data (range: 18%–62%), overall accuracy was similar (range: 79%–88%) due to higher specificities (range: 82%–98%). In analyses weighted to represent the age-eligible US population, accuracy ranged from 91% to 94% in the training data and 87% to 94% in the validation data. Using a 0.5 probability cutoff, Crimmins maximized sensitivity, Herzog–Wallace maximized specificity, and Wu and Hurd maximized accuracy. Accuracy was higher among younger, highly-educated, and non-Hispanic white participants versus their complements in both weighted and unweighted analyses.

Conclusion:

Algorithmic diagnoses provide a cost-effective way to conduct dementia research. However, naïve use of existing algorithms in disparities or risk factor research may induce nonconservative bias. Algorithms with more comparable performance across relevant subgroups are needed.

Sex differences in risk factors for vascular contributions to cognitive impairment & dementia

Vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia. While males overall appear to be at a slightly higher risk for VCID throughout most of the lifespan (up to age 85), some risk factors for VCID more adversely affect women. These include female-specific risk factors associated with pregnancy related disorders (e.g. preeclampsia), menopause, and poorly timed hormone replacement. Further, presence of certain co-morbid risk factors, such as diabetes, obesity and hypertension, also may more adversely affect women than men. In contrast, some risk factors more greatly affect men, such as hyperlipidemia, myocardial infarction, and heart disease. Further, stroke, one of the leading risk factors for VCID, has a higher incidence in men than in women throughout much of the lifespan, though this trend is reversed at advanced ages. This review will highlight the need to take biological sex and common co-morbidities for VCID into account in both preclinical and clinical research. Given that there are currently no treatments available for VCID, it is critical that we understand how to mitigate risk factors for this devastating disease in both sexes.

Racial and ethnic disparities in stroke outcomes: a scoping review of post-stroke disability assessment tools

Purpose: To identify how post-stroke disability outcomes are assessed in studies that examine racial/ethnic disparities and to map the identified assessment content to the International Classification of Functioning, Disability, and Health (ICF) across the time course of stroke recovery. Methods: We conducted a scoping review of the literature. Articles published between January 2001 and July 2017 were identified through Scopus, PubMed, CINAHL, and PsycINFO according to predefined inclusion and exclusion criteria. Results: We identified 1791 articles through database and hand-searching strategies. Of the articles, 194 met inclusion criteria for full-text review, and 41 met inclusion criteria for study inclusion. The included studies used a variety of outcome measures encompassing domains within the ICF: body functions, activities, participation, and contextual factors across the time course of stroke recovery. We discovered disproportionate representation among racial/ethnic groups in the post-stroke disability disparities literature. Conclusions: A wide variety of assessments are used to examine disparities in post-stroke disability across the time course of stroke recovery. Several studies have identified disparities through a variety of assessments; however, substantial problems abound from the assessments used including inconsistent use of assessments, lacking evidence on the validity of assessments among racial/ethnic groups, and inadequate representation among all racial/ethnic populations comprising the US. Implications for Rehabilitation An enhanced understanding of racial/ethnic disparities in post-stroke disability outcomes is inherently important among rehabilitation practitioners who frequently engage with racial/ethnic minority populations across the time course of stroke recovery. Clinicians should carefully consider the psychometric properties of assessment tools to counter potential racial bias. Clinicians should be aware that many assessments used in stroke rehabilitation lack cultural sensitivity and could result in inaccurate assessment findings.

Transcranial Direct Current Stimulation Improves Audioverbal Memory in Stroke Patients

OBJECTIVE

The aim of this study was to investigate whether anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance in stroke patients.

DESIGN

Twelve stroke patients with audioverbal memory impairment participated in a single-masked, crossover, and sham-controlled experiment. The anodal or sham transcranial direct current stimulation was applied during the Rey Auditory Verbal Learning Test, which evaluates the ability to recall a list of 15 heard words over five trials. The number of correctly recalled words was compared between the anodal and sham conditions and the influence of transcranial direct current stimulation on serial position effect of the 15 words was also examined.

RESULTS

The increase in the number of correctly recalled words from the first to the fifth trial was significantly greater in the anodal condition than in the sham condition (P < 0.01). There was a significant difference (P < 0.01) between the anodal and sham conditions in the number of correctly recalled words within the first five words (primacy region) over the second to fifth trial trials, but not in the middle (next five words) or recency (last five words) regions.

CONCLUSIONS

Anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance and induced the primacy effect in stroke patients.