Cognitive function following stroke and vascular cognitive impairment

A Comparison of Test-Retest Reliability and Practice Effects of Short Portable Mental State Questionnaire and Montreal Cognitive Assessment in Patients with Stroke

OBJECTIVE

To compare the test-retest reliabilities and minimal detectable change (MDC) of the Short Portable Mental State Questionnaire (SPMSQ) and the Montreal Cognitive Assessment (MoCA) in patients with stroke.

METHODS

63 patients were recruited from 1 medical center. The SPMSQ and MoCA were administered twice, 2 weeks apart.

RESULTS

Both measures showed high intraclass correlation coefficients (SPMSQ: 0.87; MoCA: 0.89) and acceptable MDC%s (SPMSQ: 14.8%; MoCA: 19.6%). A small correlation (r = 0.30) was found between the absolute difference and average in each pair of assessments in the SPMSQ, which was close to the criterion of heteroscedasticity. A small practice effect was observed in the MoCA (Cohen's d = 0.30).

CONCLUSION

The SPMSQ demonstrated smaller random measurement error and an absence of practice effect. When comparing the psychometric properties of the SPMSQ and MoCA as outcome measures for assessing cognitive function in patients with stroke, the SPMSQ appears to be a more suitable choice than the MoCA.

Zinc, Copper, and Calcium: A Triangle in the Synapse for the Pathogenesis of Vascular-Type Senile Dementia

Zinc (Zn) and copper (Cu) are essential for normal brain functions. In particular, Zn and Cu are released to synaptic clefts during neuronal excitation. Synaptic Zn and Cu regulate neuronal excitability, maintain calcium (Ca) homeostasis, and play central roles in memory formation. However, in pathological conditions such as transient global ischemia, excess Zn is secreted to synaptic clefts, which causes neuronal death and can eventually trigger the pathogenesis of a vascular type of senile dementia. We have previously investigated the characteristics of Zn-induced neurotoxicity and have demonstrated that low concentrations of Cu can exacerbate Zn neurotoxicity. Furthermore, during our pharmacological approaches to clarify the molecular pathways of Cu-enhanced Zn-induced neurotoxicity, we have revealed the involvement of Ca homeostasis disruption. In the present review, we discuss the roles of Zn and Cu in the synapse, as well as the crosstalk between Zn, Cu, and Ca, which our study along with other recent studies suggest may underlie the pathogenesis of vascular-type senile dementia.

Drivers of Chronic Pathology Following Ischemic Stroke: A Descriptive Review

Stroke is the third leading cause of death and long-term disability in the world. Considered largely a disease of aging, its global economic and healthcare burden is expected to rise as more people survive into advanced age. With recent advances in acute stroke management, including the expansion of time windows for treatment with intravenous thrombolysis and mechanical thrombectomy, we are likely to see an increase in survival rates. It is therefore critically important to understand the complete pathophysiology of ischemic stroke, both in the acute and subacute stages and during the chronic phase in the months and years following an ischemic event. One of the most clinically relevant aspects of the chronic sequelae of stroke is its extended negative effect on cognition. Cognitive impairment may be related to the deterioration and dysfunctional reorganization of white matter seen at later timepoints after stroke, as well as ongoing progressive neurodegeneration. The vasculature of the brain also undergoes significant insult and remodeling following stroke, undergoing changes which may further contribute to chronic stroke pathology. While inflammation and the immune response are well established drivers of acute stroke pathology, the chronicity and functional role of innate and adaptive immune responses in the post-ischemic brain and in the peripheral environment remain largely uncharacterized. In this review, we summarize the current literature on post-stroke injury progression, its chronic pathological features, and the putative secondary injury mechanisms underlying the development of cognitive impairment and dementia. We present findings from clinical and experimental studies and discuss the long-term effects of ischemic stroke on both brain anatomy and functional outcome. Identifying mechanisms that occur months to years after injury could lead to treatment strategies in the chronic phase of stroke to help mitigate stroke-associated cognitive decline in patients.

Mapping the trajectory of acute mild-stroke cognitive recovery using serial computerised cognitive assessment

INTRODUCTION

Cognitive impairment is common post-stroke. There is a need to understand patterns of early cognitive recovery post-stroke to guide both clinical and research practice. The aim of the study was to map the trajectory of cognitive recovery during the first week to 90-days post-stroke using serial computerised assessment.

METHOD

An observational cohort study recruited consecutive stroke patients admitted to a stroke unit within 48 hours of onset. Cognitive function was assessed using the computerised Cambridge Neuropsychological Test Automated Battery (CANTAB) daily for seven days, then 14, 30 and 90 days post-stroke. The CANTAB measured visual episodic memory and learning, information processing speed, visuo-spatial working memory, complex sustained attention and mental flexibility. Repeated measures MANOVA/ANOVA with Least Squares Difference post-hoc analyses were performed to ascertain significant change over time.

RESULT

Forty-eight participants, mean age 73, primarily mild, ischaemic stroke, completed all assessment timepoints. There was a trajectory of early, global cognitive improvement, indicative of a post-stroke delirium, that largely stabilised between 6 and 14-days post-stroke. Change over time was examined within each cognitive test, with one measure stabilising by day 6 (Reaction Time) and others detecting improving performances up to 14 days post-stroke.

CONCLUSIONS

Serial, computerised cognitive assessment can effectively map post-stroke cognitive recovery and revealed an early phase of global improvement over 14 days that is evidence for an acute post-stroke delirium. Resolution of post-stroke delirium in the second week following mild stroke indicates more extensive neuropsychological testing may be undertaken earlier than previously thought.

The Oxford cognitive screen (OCS) as an acute predictor of long-term functional outcome in a prospective sample of stroke patients

The Oxford Cognitive Screen (OCS) was developed to measure cognitive impairment in stroke. Here, we test if the OCS administered acutely in stroke patients provides useful information in predicting long-term functional outcome. A group of first-time stroke patients (n = 74) underwent an acute behavioral assessment comprising the OCS and the NIHSS within one-week post-stroke. Functional outcome was evaluated using the Stroke Impact Scale 3.0 (SIS 3.0) and the Geriatric Depression Scale (GDS) at 6 and 12-months post-stroke. We compared the predictive ability of the OCS and NIHSS, separately or in combination, to predict different domains of behavioral impairment at a chronic evaluation. The OCS accounted for 61% of variance of SIS physical domain, 61% of memory domain, 79% of language domain, 70% of participation domain and 70% of recovery domain. The OCS accounted for a greater percentage of outcome variance than demographics and NIHSS. The most informative predictive model included the combination of demographics, OCS and NIHSS data. The OCS, performed early after stroke, is a strong independent predictor of long-term functional outcome and significantly improves the prediction of outcome when considered alongside the NIHSS and demographics.

Relationships of Low Serum Levels of Interleukin-10 With Poststroke Anxiety and Cognitive Impairment in Patients With Clinical Acute Stroke

BACKGROUND AND PURPOSE

The relationships among interleukin (IL)-10 levels, anxiety, and cognitive status after stroke remain controversial. We aimed to determine the associations of serum IL-10 levels with poststroke anxiety (PSA) and poststroke cognitive impairment (PSCI).

METHODS

We recruited 350 patients with stroke, of whom only 151 completed a 1-month follow-up assessment. The Mini Mental State Examination (MMSE) and Hamilton Anxiety Scale (HAMA) were used to assess the cognitive status and anxiety, respectively. Serum IL-10 levels were measured within 24 hours of admission.

RESULTS

IL-10 levels were significantly lower in the PSA group than in the non-PSA group, and they were negatively associated with HAMA scores (r=-0.371, p<0.001). After adjusting for all potential confounders, IL-10 levels remained an independent predictor of PSA (odds ratio=0.471, 95% confidence interval=0.237-0.936, p=0.032). IL-10 levels were strongly correlated with behavior during interviews, psychic anxiety, and somatic anxiety. Patients without PSCI had higher IL-10 levels were higher in non-PSCI patients than in PSCI patients, and they were positively associated with MMSE scores in the bivariate correlation analysis (r=0.169, p=0.038), and also with memory capacity, naming ability, and copying capacity. However, IL-10 did not predict PSCI in the univariable or multivariable logistic regression.

CONCLUSIONS

Low IL-10 levels were associated with increased risks of PSA and PSCI at a 1-month follow-up after stroke. Serum IL-10 levels may therefore be helpful in predicting PSA.

The effect of transcranial magnetic stimulation on the recovery of attention and memory impairment following stroke: a systematic review and meta-analysis

BACKGROUND

Previous studies indicated inconsistent results for the treatment effect of repetitive transcranial magnetic stimulation (rTMS) on attention and memory impairment following stroke.

METHODS

Randomized controlled trials (RCTs) on TMS for the treatment of stroke were retrieved from Online databases. Data were analyzed by RevMan 5.3 software.

RESULTS

Ten RCTs performed in China were included, with a total of 591 younger post-stroke patients ranging in age from their 40s to their 60s. The meta-analysis indicated that TMS could significantly improve the recovery of cognitive impairment following a stroke, according to the Montreal Cognitive Assessment (MoCA) score (8 studies, MD = 2.69, 95% CI: 1.44 to 3.95, P < 0.0001), the Rivermead Behavioral Memory Test (RBMT) score (7 studies, MD = 1.74, 95% CI:1.13 to 2.34, P < 0.00001), and the Modified Barthel Index (MBI) for Activities of Daily Living (3 studies, MD = 8.83, 95% CI:5.34 to 12.32, P < 0.00001). Sub-group analysis of MoCA and RBMT suggested that a low-frequency (1 Hz) stimulation exhibited similar effect with a higher-frequency (10 Hz) treatment.

DISCUSSION

TMS might effectively improve the attention and memory impairment of stroke patients without increasing side effects. But this effect needs to be verified by more multi-center, high-quality, large-sample, rigorously designed RCTs.

Vascular Cognitive Impairment After Mild Stroke: Connectomic Insights, Neuroimaging, and Knowledge Translation

Contemporary stroke assessment protocols have a limited ability to detect vascular cognitive impairment (VCI), especially among those with subtle deficits. This lesser-involved categorization, termed mild stroke (MiS), can manifest compromised processing speed that negatively impacts cognition. From a neurorehabilitation perspective, research spanning neuroimaging, neuroinformatics, and cognitive neuroscience supports that processing speed is a valuable proxy for complex neurocognitive operations, insofar as inefficient neural network computation significantly affects daily task performance. This impact is particularly evident when high cognitive loads compromise network efficiency by challenging task speed, complexity, and duration. Screening for VCI using processing speed metrics can be more sensitive and specific. Further, they can inform rehabilitation approaches that enhance patient recovery, clarify the construct of MiS, support clinician-researcher symbiosis, and further clarify the occupational therapy role in targeting functional cognition. To this end, we review relationships between insult-derived connectome alterations and VCI, and discuss novel clinical approaches for identifying disruptions of neural networks and white matter connectivity. Furthermore, we will frame knowledge translation efforts to leverage insights from cutting-edge structural and functional connectomics research. Lastly, we highlight how occupational therapists can provide expertise as knowledge brokers acting within their established scope of practice to drive substantive clinical innovation.

Crosstalk of copper and zinc in the pathogenesis of vascular dementia

Copper and zinc are essential for normal brain functions. Both are localized in presynaptic vesicles and are secreted into synaptic clefts during neuronal excitation. Despite their significance, excesses of copper and zinc are neurotoxic. In particular, excess zinc after transient global ischemia plays a central role in the ischemia-induced neurodegeneration and pathogenesis of vascular type senile dementia. We previously found that sub-lethal concentrations of copper remarkably exacerbated zinc-induced neurotoxicity, and we investigated the molecular pathways of copper-enhanced zinc-induced neurotoxicity. The endoplasmic reticulum stress pathway, the stress-activated protein kinases/c-‍Jun amino-terminal kinases pathway, and mitochondrial energy production failure were revealed to be involved in the neurodegenerative processes. Regarding the upstream factors of these pathways, we focused on copper-derived reactive oxygen species and the disruption of calcium homeostasis. Because excess copper and zinc may be present in the synaptic clefts during ischemia, it is possible that secreted copper and copper-induced reactive oxygen species may enhance zinc neurotoxicity and eventually contribute to the pathogenesis of vascular type senile dementia.

Breathing Exercises for Improving Cognitive Function in Patients with Stroke

Patients with stroke may experience a certain degree of cognitive decline during the period of recovery, and a considerable number of such patients have been reported to show permanent cognitive damage. Therefore, the period of recovery and rehabilitation following stroke is critical for rapid cognitive functional improvements. As dysfunctional breathing has been reported as one of the factors affecting the quality of life post stroke, a number of studies have focused on the need for improving the breathing function in these patients. Numerous breathing exercises have been reported to enhance the respiratory, pulmonary, cognitive, and psychological functions. However, scientific evidence on the underlying mechanisms by which these exercises improve cognitive function is scattered at best. Therefore, it has been difficult to establish a protocol of breathing exercises for patients with stroke. In this review, we summarize the psychological, vascular, sleep-related, and biochemical factors influencing cognition in patients and highlight the need for breathing exercises based on existing studies. Breathing exercises are expected to contribute to improvements in cognitive function in stroke based on a diverse array of supporting evidence. With relevant follow-up studies, a protocol of breathing exercises can be developed for improving the cognitive function in patients with stroke.

Degree and pattern of dual-task interference during walking vary with component tasks in people after stroke: a systematic review

QUESTIONS

What are the degree and pattern of dual-task interference during walking in people after stroke? How do these vary with disease chronicity and different component tasks in people after stroke? How does dual-task interference differ between people after stroke and people without stroke?

DESIGN

Systematic review with meta-analysis of studies reporting gait-related dual-task interference.

PARTICIPANTS

People after stroke and people without stroke.

OUTCOME MEASURES

Measures of walking and secondary (cognitive or manual) task performance under dual-task conditions relative to those under single-task conditions.

RESULTS

Seventy-six studies (2,425 people after stroke and 492 people without stroke) were included. Manual and mental tracking tasks imposed the greatest dual-task interference on gait speed, although there was substantial uncertainty in these estimates. Among mental tracking tasks, the apparently least-complex task (serial 1 subtractions) induced the greatest dual-task interference (-0.17 m/s, 95% CI -0.24 to -0.10) on gait speed, although there was substantial uncertainty in these estimates. Mutual interference (decrement in both walking and secondary component task performances during dual-tasking) was the most common dual-task interference pattern. The results of the sensitivity analyses for studies involving people with chronic stroke were similar to the results of the primary analyses. The amount of dual-task interference from a mental tracking or manual task during walking was similar between people with or without stroke.

CONCLUSIONS

The degree and pattern of dual-task interference vary with the choice of component tasks. When evaluating limitations to functional mobility during dual-tasking conditions and in planning interventions accordingly, clinicians should select dual-task assessments that correspond to the daily habits and physical demands of people after stroke.

REGISTRATION

CRD42017059004.

The impact of using implementation intentions as task instructions on prospective memory performance after stroke

Prospective Memory (PM), the ability to remember to carry out intentions in the future, is often impaired after stroke. Little is known about rehabilitation of PM post-stroke with literature limited by small sample sizes and reliance on self-reported memory performance. Implementation intentions may make prospective remembering more automatic and follow a simple if-then structure (if X occurs, then I will do Y), focusing on the cue rather than the task. We aimed to investigate the effect of implementation intentions on PM post-stroke. Twenty-eight individuals with stroke and 27 controls were randomly allocated to a standard instruction or implementation intention condition and completed an assessment battery over two sessions. Implementation intention instructions were provided for PM tasks on the Delayed Message Task, Lexical Decision Prospective Memory Task (LDPMT), and the Virtual Reality Prospective Memory Shopping Task. The implementation intention groups performed better on all PM tasks compared to the standard instruction group, but no results reached statistical significance, likely due to the small sample size. In addition, the implementation intentions group monitored the time significantly more on the LDPMT than those in the standard instruction group.

Copper as a Collaborative Partner of Zinc-Induced Neurotoxicity in the Pathogenesis of Vascular Dementia

Copper is an essential trace element and possesses critical roles in various brain functions. A considerable amount of copper accumulates in the synapse and is secreted in neuronal firings in a manner similar to zinc. Synaptic copper and zinc modulate neuronal transmission and contribute to information processing. It has been established that excess zinc secreted during transient global ischemia plays central roles in ischemia-induced neuronal death and the pathogenesis of vascular dementia. We found that a low concentration of copper exacerbates zinc-induced neurotoxicity, and we have demonstrated the involvement of the endoplasmic reticulum (ER) stress pathway, the stress-activated protein kinases/c-Jun amino-terminal kinases (SAPK/JNK) signaling pathway, and copper-induced reactive oxygen species (ROS) production. On the basis of our results and other studies, we discuss the collaborative roles of copper in zinc-induced neurotoxicity in the synapse and the contribution of copper to the pathogenesis of vascular dementia.

The Role of Processing Speed and Cognitive Control on Word Retrieval in Aging and Aphasia

Purpose When speakers retrieve words, they do so extremely quickly and accurately-both speed and accuracy of word retrieval are compromised in persons with aphasia (PWA). This study examined the contribution of two domain-general mechanisms: processing speed and cognitive control on word retrieval in PWA. Method Three groups of participants, neurologically healthy young and older adults and PWA (n = 15 in each group), performed processing speed, cognitive control, lexical decision, and word retrieval tasks on a computer. The relationship between word retrieval speed and other tasks was examined for each group. Results Both aging and aphasia resulted in slower processing speed but did not affect cognitive control. Word retrieval response time delays in PWA were eliminated when processing speed was accounted for. Word retrieval speed was predicted by individual differences in cognitive control in young and older adults and additionally by processing speed in older adults. In PWA, word retrieval speed was predicted by severity of language deficit and cognitive control. Conclusions This study shows that processing speed is compromised in aphasia and could account for their slowed response times. Individual differences in cognitive control predicted word retrieval speed in healthy adults and PWA. These findings highlight the need to include nonlinguistic cognitive mechanisms in future models of word retrieval in healthy adults and word retrieval deficits in aphasia.

Prognostic rules for predicting cognitive syndromes following stroke: A systematic review

Purpose

Stroke survivors are at high risk of developing cognitive syndromes, such as delirium and dementia. Accurate prediction of future cognitive outcomes may aid timely diagnosis, intervention planning, and stratification in clinical trials. We aimed to identify, describe and appraise existing multivariable prognostic rules for prediction of post-stroke cognitive status.

Method

We systematically searched four electronic databases from inception to November 2019 for publications describing a method to estimate individual probability of developing a cognitive syndrome following stroke. We extracted data from selected studies using a pre-specified proforma and applied the Prediction model Risk Of Bias Assessment Tool (PROBAST) for critical appraisal.

Findings

Of 17,390 titles, we included 10 studies (3143 participants), presenting the development of 11 prognostic rules – 7 for post-stroke cognitive impairment and 4 for delirium. Most commonly incorporated predictors were: demographics, imaging findings, stroke type and symptom severity. Among studies assessing predictive discrimination, the area under the receiver operating characteristic (AUROC) in apparent validation ranged from 0.80 to 0.91. The overall risk of bias for each study was high. Only one prognostic rule had been externally validated.

Discussion/conclusion: Research into the prognosis of cognitive outcomes following stroke is an expanding field, still at its early stages. Recommending use of specific prognostic rules is limited by the high risk of bias in all identified studies, and lack of supporting evidence from external validation. To ensure the quality of future research, investigators should adhere to current, endorsed best practice guidelines for conduct of prediction model studies.

Subacute functional connectivity correlates with cognitive recovery six months after stroke

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Stroke disrupts ipsilesional and inter-hemispheric functional connectivity of DMN.

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Subacute cognition correlated to inter-hemispheric and ipsilesional DMN connectivity.

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Subacute cognition correlated to weaker contralesional SN connectivity.

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Functional connectivity remapping was not observed after six months.

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Cognitive recovery correlated to DMN and SN connectivity from the subacute phase.

Background and purpose

Cognitive impairment is a common consequence of stroke, and the rewiring of the surviving brain circuits might contribute to cognitive recovery. Studies investigating how the functional connectivity of networks change across time and whether their remapping relates to cognitive recovery in stroke patients are scarce. We aimed to investigate whether resting-state functional connectivity was associated with cognitive performance in stroke patients and if any alterations in these networks were correlated with cognitive recovery.

Methods

Using an fMRI ROI-ROI approach, we compared the ipsilesional, contralesional and interhemispheric functional connectivity of three resting-state networks involved in cognition – the Default Mode (DMN), Salience (SN) and Central Executive Networks (CEN), in subacute ischemic stroke patients (time 1, n = 37, stroke onset: 24.32 ± 7.44 days, NIHSS: 2.66 ± 3.45) with cognitively healthy controls (n = 20). Patients were reassessed six months after the stroke event (time 2, n = 20, stroke onset: 182.05 ± 8.17 days) to verify the subsequent reorganization of functional connections and whether such reorganization was associated with cognitive recovery.

Results

At time 1, patients had weaker interhemispheric connectivity in the DMN than controls; better cognitive performance at time 1 was associated with stronger interhemispheric and ipsilesional DMN connectivity, and weaker contralesional SN connectivity. At time 2, there were no changes in functional connectivity in stroke patients, compared to time 1. Better cognitive recovery measured at time 2 (time 2 – time 1) was associated with stronger functional connectivity in the DMN, and weaker interhemispheric subacute connectivity in the SN, both from time 1.

Conclusions

Stroke disrupts the functional connectivity of the DMN, not only at the lesioned hemisphere but also between hemispheres. Six months after the stroke event, we could not detect the remapping of networks. Cognitive recovery was associated with the connectivity of both the DMN and SN of time 1. Our findings may be helpful for facilitating further understanding of the potential mechanisms underlying post-stroke cognitive performance.

Post-Stroke Working Memory Dysfunction: A Meta-Analysis and Systematic Review

This review investigates the severity and nature of post-stroke working memory deficits with reference to the multi-component model of working memory. We conducted a systematic search in PubMed up to March 2019 with search terms for stroke and memory. Studies on adult stroke patients, that included a control group, and assessed working memory function, were selected. Effect sizes (Hedges' g) were extracted from 50 studies (in total 3,084 stroke patients) based on the sample size, mean and standard deviation of patients and controls. Performance of stroke patients was compared to healthy controls on low-load (i.e. capacity) and high-load (executively demanding) working memory tasks, grouped by modality (verbal, non-verbal). A separate analysis compared patients in the sub-acute and the chronic stage. Longitudinal studies and effects of lesion location were systematically reviewed. Stroke patients demonstrated significant deficits in working memory with a moderate effect size for both low-load (Hedges' g = -.58 [-.82 to -.43]) and high-load (Hedges' g = -.59 [-.73 to -.45]) tasks. The effect sizes were comparable for verbal and non-verbal material. Systematically reviewing the literature showed that working memory deficits remain prominent in the chronic stage of stroke. Lesions in a widespread fronto-parietal network are associated with working memory deficits. Stroke patients show decrements of moderate magnitude in all subsystems of working memory. This review clearly demonstrates the global nature of the impairment in working memory post-stroke.

Factors predicting rehabilitation outcomes after severe acquired brain injury in trauma, stroke and anoxia populations: A cohort study

Severe acquired brain injury has long-term physical and cognitive effects. Identifying patient variables predictive of recovery in different brain injury populations would generate improved prognostic information and help rehabilitation teams set appropriate therapeutic goals. This cohort study of 447 NHS neurorehabilitation inpatients aimed to identify functional and cognitive predictors of recovery following severe acquired brain injury caused by trauma, stroke and anoxia. Motor and cognitive impairment ratings were collected at admission and discharge using the Functional Independence Measure and Functional Assessment Measure (FIM+FAM), and injury-related and demographic data were collated from medical records. Predictors of physical, cognitive and overall recovery were identified via hierarchical regression analyses. Several key findings emerged. Firstly, on-admission motor skills predicted functional and overall outcomes across groups. Secondly, on-admission social interaction skills predicted cognitive discharge outcomes in stroke and trauma, and overall outcomes for stroke, but did not predict anoxia outcomes. Thirdly, age predicted all forms of recovery for stroke only. Further group-specific factors were also identified as predicting motor and cognitive recovery, indicating that factors key to the rehabilitation trajectory may differ between populations. These variables should be considered in rehabilitation goal planning, although further research is required to explore their contributions to recovery.

Self-reported prospective memory after stroke

Prospective Memory (PM) is the memory for completing future intentions. This study aimed to compare self-reported PM of individuals with stroke to healthy controls, to determine if PM is impaired after stroke. Additionally, self-reported PM for individuals with stroke was compared to significant-other reports, ascertaining a level of self-awareness of PM function. Twenty-eight individuals with stroke, 25 significant-others, and 27 healthy controls completed the Brief Assessment of PM (BAPM) and the Prospective and Retrospective Memory Questionnaire (PRMQ) as part of a larger study. Individuals with stroke reported significantly more Basic Activities of Daily Living (BADL) PM failures compared to controls on Part A of the BAPM. On Part B, individuals with stroke reported BADL PM failures to be less problematic/important than controls, suggesting a lack of self-awareness into the consequences of PM failure. Individuals with stroke also reported significantly more PM and RM failures compared to controls on the PRMQ. No significant differences were found between individuals with stroke and their significant-others on both the BAPM and PRMQ. Results of this study helped to clarify the previous research and highlighted that individuals with stroke reported more PM failures than controls but underestimated the importance of such memory lapses.

Body mass index across adult life and cognitive function in the American elderly

This study aimed to examine the associations of body mass index (BMI) across adult life with cognitive function in 2,637 participants aged 60 years or over from NHANES 2011-2014. The primary outcome was a composite score based on test scores on word list learning, animal naming, and digit symbol substitution. Exposures of interest included BMI at age 25, BMI 10 years before the survey, BMI at the survey (current BMI), and BMI burden calculated from age 25 to age at survey. BMI at age 25 was inversely associated with the composite score (β=-0.0271±0.0130 per kg/m², P=0.038) and positively with low cognitive performance (odd ratio=1.04, 95% confidence interval: 1.01-1.07, P=0.010), defined as below 20 percentile of the composite score. Similar results were observed for BMI 10 years before the survey and BMI burden. Current BMI was positively associated with the composite score (β=0.0369±0.0113, P=0.001) and inversely associated with low cognitive performance (odd ratio=0.96, 95% confidence interval: 0.94-0.99, P=0.004). In conclusion, high BMI in early adult life is associated with low cognitive function in late life, which underscores the importance of a healthy body weight across the life course. The association between BMI and cognitive function at late life requires further investigation.

Predictable hematological markers associated with cognitive decline in valid rodent models of cognitive impairment

Endogenous (hyperglycemia) and exogenous (therapeutic, prophylactic, street drugs) factors can considerably contribute to cognitive impairment (CI). Currently, there are few invasive and/or noninvasive markers that correlate with CI and those that do exist require expensive or invasive techniques to predict and accurately measure the cognitive decline. Therefore, we sought to determine hematological markers as predictors of CI in two different chemically induced valid rodent models of CI (streptozotocin induced hyperglycemic model and chemotherapy [doxorubicin/cyclophosphamide] treated rodent model). Hematological markers were analyzed in the above rodent models of CI CI and compared to their respective control groups. There was a significant increase in creatinine kinase, lactate dehydrogenase and aspartate aminotransferase (AST) in the chemotherapy group. Blood urea nitrogen (BUN), alkaline phosphatase (ALP), bilirubin, creatinine and glucose levels were significantly increased in the streptozotocin group. Interestingly, triglycerides were significantly elevated in both the streptozotocin and chemotherapy groups. Previous studies with human subjects have shown a potential link between the increase in triglyceride levels and CI. Likewise, our data indicate a notable correlation with an increase in triglycerides to cognitive impairment in the rodent models. This suggests elevated levels of triglycerides could prove to be a potential noninvasive hematological marker for the increased risk of CI. Further studies are warranted to determine the causal relationship between elevated triglyceride levels and CI.

Hemoglobin, anemia, and poststroke cognitive impairment: A cohort study

OBJECTIVES

Several studies have demonstrated that anemia was associated with cognitive impairment. The aim of this study was to explore the relationship between hemoglobin and cognitive impairment in patient with acute ischemic stroke.

METHODS

In total, 326 patients with acute ischemic stroke were followed up for 1 month. The main outcome was the incidence and severity of poststroke cognitive impairment (PSCI) assessed by Mini-Mental State Examination (MMSE). The impact of hemoglobin levels and anemia on PSCI was assessed by multiple regression models controlling for potential confounders.

RESULTS

During the 1-month follow-up, 193 (59.2%) patients developed PSCI. Anemia was independently associated with PSCI (OR = 3.637; 95% CI, 1.216-10.881; P = .021) after adjusting for demographics, vascular risk factors, stroke severity, and functional outcome. When the hemoglobin levels stratified into tertiles, higher hemoglobin levels were associated with better cognitive function. This result was however not significant after adjusting for the same confounders above.

CONCLUSIONS

Low hemoglobin levels are associated with an increased risk of PSCI. Targeted interventions in this population may reduce the incidence of PSCI and require further evaluation.

Early Inflammatory Signatures Predict Subsequent Cognition in Long-Term Virally Suppressed Women With HIV

Immunologic function is an important determinant of cognition. Here we examined the contribution of early immune signatures to cognitive performance among HIV-infected, virally suppressed women (HIV+VS) and in HIV-uninfected (HIV-) women. Specifically, we measured serum inflammatory markers, developed combinatory immune signatures, and evaluated their associations with cognition. Forty-nine HIV+VS women in the Women’s Interagency HIV Study (WIHS) who achieved viral suppression shortly after effective antiretroviral therapy (ART) initiation, and 56 matched HIV− women were selected. Forty-two serum inflammatory markers were measured within 2 years of effective ART initiation for HIV+VS women, and at an initial timepoint for HIV− women. The same inflammatory markers were also measured approximately 1, 7, and 12 years later for all women. Of the 105 women with complete immune data, 83 (34 HIV+VS, 49 HIV−) also had cognitive data available 12 years later at ≥1 time points (median = 3.1). We searched for combinatory immune signatures by adapting a dynamic matrix factorization analytic method that builds upon Tucker decomposition followed by Ingenuity^® Pathway Analysis to facilitate data interpretation. Seven combinatory immune signatures emerged based on the Frobenius residual. Three signatures were common between HIV+VS and HIV− women, while four signatures were unique. These inflammatory signatures predicted subsequent cognitive performance in both groups using mixed-effects modeling, but more domain-specific associations were significant in HIV+VS than HIV− women. Leukocyte influx into brain was a major contributor to cognitive function in HIV+VS women, while T cell exhaustion, inflammatory response indicative of depressive/psychiatric disorders, microglial activity, and cytokine signaling predicted both global and domain-specific performance for HIV− women. Our findings suggest that immune signatures may be useful diagnostic, prognostic, and immunotherapeutic targets predictive of subsequent cognitive performance. Importantly, they also provide insight into common and distinct inflammatory mechanisms underlying cognition in HIV− and HIV+VS women.

Validation of a New Cognitive Screening Method for Stroke Patients

Objective

Two million adults under fifty years of age have a cerebral stroke every year worldwide. Neuropsychological assessment is the best way to identify poststroke cognitive dysfunction, but it is often time-consuming and can be tiring for the patient, and hospitals vary in their availability of neuropsychological expertise. A valid and reliable cognitive screening method could be advantageous in identifying patients who need comprehensive neuropsychological examination. Our purpose in this study was to validate a newly developed cognitive screening method as an identifier of cognitive dysfunction after stroke in working-aged patients.

Methods

We analyzed new cognitive screening method concurrent validity by comparing it in two groups formed on the basis of a comprehensive neuropsychological examination for 77 stroke patients. We identified the best balance of sensitivity and specificity by using receiver operating characteristic curve analysis and investigated the impact of the sociodemographic variables to the screening method total score variation.

Results

We found a significant correlation between the method's total score and performance in neuropsychological examination. The cognitive method's internal consistency was strong; Cronbach's alpha for all items was .818. The best balance of sensitivity (88%) and specificity (50%) was found at a total score cut point of 138. Subjects' age and length of education were each responsible for 10% of total score variation.

Conclusions

This study shows promising results for this new cognitive screening tool's ability to identify poststroke cognitive decline and patients' need for further detailed neuropsychological examination.

High levels of plasma fibrinogen are related to post-stroke cognitive impairment

INTRODUCTION

Studies have shown that high levels of the fibrinogen (FIB) are related to cognitive deficits. However, the relationship between fibrinogen and cognitive deficit after stroke remains unclear. Therefore, we explored the relationship between plasma fibrinogen and post-stroke cognitive impairment (PSCI).

METHODS

This study is carried out in the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China. A total of 210 patients with acute ischemic stroke were enrolled in this study. Ultimately, 134 patients completed 3-month follow-up. Blood samples were collected at hospital admission. Cognitive function was evaluated 3 months after stroke. All patients underwent the Mini-Mental State Examination (MMSE) after 3 months.

RESULTS

Higher levels of fibrinogen were observed in patients with post-stroke cognitive impairment compared with the non-PSCI group (p < .001). Additionally, elevated plasma fibrinogen levels were independently associated with PSCI (odds ratio [OR] = 2.000, 95% CI 1.062-3.770 p = .032). The plasma fibrinogen levels were negatively correlated with the 3-month MMSE scores (r = -.171, p = .048). In a multivariate linear regression, FIB was negatively associated with the 3-month MMSE scores after adjustment for the other variables (β = -0.782, p = .035).

CONCLUSION

High levels of plasma fibrinogen were associated with the presence and severity of PSCI.

Cognitive functions and white matter lesions on magnetic resonance images in a sample of normal Iranian population with cardiovascular risk factors

PURPOSE

Due to a suggestive three-way relationship between brain structural disorders, microvascular lesions, and cognitive impairments, we aimed to examine the association of the volume and number of white matter hyperintensity lesions and lacunar infarcts with cognitive impairment among patients with cardiovascular risk factors in a sample of the Iranian population.

MATERIALS AND METHODS

This study was conducted on a total number of 156 normal subjects aged 30-74 years with cardiovascular risk factors. We used the Framingham general cardiovascular risk factors prediction model to calculate the likelihood of each risk factor. The total number of lacunar infarcts and the volume of white matter hyperintensity lesion were calculated in brain magnetic resonance imaging. Cognition status was assessed using the Montreal Cognitive Assessment questionnaire.

RESULTS

An adverse association was revealed between Montreal Cognitive Assessment score and different cardiovascular risk profiles including the Framingham body mass index score ( p < 0.001) and the Framingham lipid score ( p < 0.001). The total volume of white matter hyperintensity was negatively associated with total Montreal Cognitive Assessment cognition score ( p < 0.001). Our study also showed an adverse association between total number of lacunar infarcts and total Montreal Cognitive Assessment cognition score ( p = 0.038) and with some cognition components including memory ( p = 0.013), attention ( p = 0.037), abstraction ( p = 0.046), and orientation ( p = 0.002).

CONCLUSION

Periventricular lesions are associated with impaired memory, language, and visuoconstruction while subcortical lesions are associated with impairment in naming, attention, language, and abstraction functions in normal subjects with cardiovascular risk factors but without cardiovascular or cerebrovascular disorders.

Association between vitamin D status and cognitive impairment in acute ischemic stroke patients: a prospective cohort study

Objective

Previous studies found that low vitamin D levels were modestly associated with risk of stroke and poor functional outcome after stroke. In addition, vitamin D deficiency has been linked with cognitive decline. Our study aimed to explore the potential relationship between vitamin D levels in the short-term acute phase of ischemic stroke and cognitive impairment at 1 month.

Methods

In total, 354 ischemic stroke patients were consecutively enrolled in the study and received 1-month follow-up. The serum levels of vitamin D were measured within 24 hours after admission. Cognitive function was evaluated by the Mini-Mental State Examination (MMSE) at 1 month after acute ischemic stroke. Cognitive impairment was defined according to different education levels.

Results

According to MMSE scores, 114 participants (32.2%) had cognitive impairment at 1 month. Patients with vitamin D deficiency were more likely to have cognitive impairment than those with vitamin D insufficiency and vitamin D sufficiency (P<0.001). After adjusting for potential confounders in our Cox proportional hazards model, vitamin D deficiency was independently associated with the development of cognitive impairment in acute ischemic stroke patients.

Conclusion

Independent of established risk factors, vitamin D deficiency in the short-term phase of ischemic stroke was associated with a higher incidence of 1-month cognitive impairment.

Low Tri-iodothyronine Syndrome Is Associated With Cognitive Impairment in Patients With Acute Ischemic Stroke: A Prospective Cohort Study

OBJECTIVE

Low tri-iodothyronine (T3) syndrome is a predictor of poor prognosis in patients with stroke. Poststroke cognitive impairment (PSCI) is a common and important complication after stroke. The association between low T3 syndrome and PSCI is unclear. We aimed to explore the potential relationship between low T3 syndrome and PSCI in the acute phase of ischemic stroke at a 1-month follow-up visit.

METHODS

In total, 314 ischemic stroke patients were consecutively enrolled in the study and followed up at 1 month. Thyroid hormones were measured within 24 hours after admission. Cognitive function was evaluated by the Mini-Mental State Exam (MMSE) 1 month after acute ischemic stroke. Cognitive impairment was defined as an MMSE score of less than 27. Cognitive impairment severity was categorized as severe, mild, or none (MMSE score <23, 23-26, or ≥27, respectively).

RESULTS

According to the MMSE score, 182 participants (58.0%) had cognitive impairment 1 month after stroke. Patients with low T3 syndrome were more prone to have cognitive impairment than patients with normal levels of T3 (p < 0.001). After adjusting for potential confounders in our logistic model, low T3 syndrome was independently associated with PSCI (odds ratio 4.319, 95% confidence interval 1.553-12.013, p = 0.005).

CONCLUSION

Low T3 syndrome in the acute phase of ischemic stroke was associated with a higher prevalence of 1-month PSCI, independently of established risk factors.

Psychometric Properties of the Chinese (Putonghua) Version of the Oxford Cognitive Screen (OCS-P) in Subacute Poststroke Patients without Neglect

Background

Oxford Cognitive Screen is designed for assessing cognitive functions of poststroke patients. This study was aimed to assess the psychometric properties of the Chinese (Putonghua) version of the Oxford Cognitive Screen-Putonghua (OCS-P) for use among poststroke patients without neglect.

Methods

Expert review panel evaluated content validity of the Chinese-translated items. After pilot tested the translated items, the patients and healthy participants completed the OCS-P as well as the Montreal Cognitive Assessment (MoCA-ChiB) and Goldenberg's test. A group of patients completed OCS-P for the second time within seven days. Data analyses included confirmatory factor analysis, item difficulty and item-total correlation, inter- and intrarater reliability, internal consistency, and between-group discrimination.

Results

One hundred patients and 120 younger (n = 60) or older (n = 60) healthy participants completed all the tests. Modifications were required for items in the “Picture Naming”, “Orientation”, and “Sentence Reading” subscales. Confirmatory factor analysis revealed a three-factor structure for the OCS-P subscales. The internal consistency coefficients for the three identified test dimensions were 0.30 to 0.52 (Cronbach's alpha). Construct validity coefficients between the OCS-P and MoCA-ChiB subscales were 0.45 < r < 0.79 (p < 0.001) and the “Praxis” subscale of OCS-P and Goldenberg's test was r = 0.72 (p < 0.001). The interrater reliability coefficients for the subscales were in general higher than the intrarater reliability coefficients. The “Picture Naming” and “Numerical Cognition” subscales were the most significant (p = 0.003) for differentiating patient participants from their older healthy counterpart.

Conclusion

This study generated satisfactory evidence on the content validity, substantive validity, construct validity, inter- and intrarater reliability, and known-group discrimination of the OCS-P. They support its application among poststroke patients who speak Putonghua. Future studies could review the existing five-dimension domains for improving its structural validity and internal consistency as well as generate evidence of the OCS-P for use among the poststroke patients with neglect.

Abnormal functional corticomuscular coupling after stroke

Motor dysfunction is a major consequence after stroke and it is generally believed that the loss of motor ability is caused by the impairments in neural network that controls movement. To explore the abnormal mechanisms how the brain controls shoulder abduction and elbow flexion in "flexion synergy" following stroke, we used the functional corticomuscular coupling (FCMC) between the brain and the muscles as a tool to identify the temporal evolution of corticomuscular interaction between the synkinetic and separate phases. 59-channel electroencephalogram (EEG) over brain scalp and 2-channel electromyogram (EMG) from biceps brachii (BB)/deltoid (DT) were recorded in sixteen stroke patients with motor dysfunction and eight healthy controls during a task of uplifting the arm (stage 1) and maintaining up to the chest (stage 2). As a result, compared to healthy controls, stroke patients had abnormally reduced coherence in EEG-BB combination and increased coherence in EEG-DT combination. Compared to synkinetic stroke patients, separate ones exhibited higher coupling at gamma-band during stage 1 and higher at beta-band during stage 2 in EEG-BB combination, but lower at beta-band during stage 2 in EEG-DT combination. Therefore, we infer that the disorders of efferent control and afferent proprioception in sensorimotor system for stroke patients effect on the oscillation at beta and gamma bands. Patients need integrate more information for shoulder abduction to compensate for the functional loss of elbow flexion in the recovery process, so that partial cortical cortex controlling on the elbow flexion may work on the shoulder abduction during "flexion synergy". Such researches could provide new perspective on the temporal evolution of corticomuscular interaction after stroke and add to our understanding of possible pathomechanisms how the brain abnormally controls shoulder abduction and elbow flexion in "flexion synergy".

Acute single channel EEG predictors of cognitive function after stroke

BACKGROUND

Early and accurate identification of factors that predict post-stroke cognitive outcome is important to set realistic targets for rehabilitation and to guide patients and their families accordingly. However, behavioral measures of cognition are difficult to obtain in the acute phase of recovery due to clinical factors (e.g. fatigue) and functional barriers (e.g. language deficits). The aim of the current study was to test whether single channel wireless EEG data obtained acutely following stroke could predict longer-term cognitive function.

METHODS

Resting state Relative Power (RP) of delta, theta, alpha, beta, delta/alpha ratio (DAR), and delta/theta ratio (DTR) were obtained from a single electrode over FP1 in 24 participants within 72 hours of a first-ever stroke. The Montreal Cognitive Assessment (MoCA) was administered at 90-days post-stroke. Correlation and regression analyses were completed to identify relationships between 90-day cognitive function and electrophysiological data, neurological status, and demographic characteristics at admission.

RESULTS

Four acute qEEG indices demonstrated moderate to high correlations with 90-day MoCA scores: DTR (r = -0.57, p = 0.01), RP theta (r = 0.50, p = 0.01), RP delta (r = -0.47, p = 0.02), and DAR (r = -0.45, p = 0.03). Acute DTR (b = -0.36, p < 0.05) and stroke severity on admission (b = -0.63, p < 0.01) were the best linear combination of predictors of MoCA scores 90-days post-stroke, accounting for 75% of variance.

CONCLUSIONS

Data generated by a single pre-frontal electrode support the prognostic value of acute DAR, and identify DTR as a potential marker of post-stroke cognitive outcome. Use of single channel recording in an acute clinical setting may provide an efficient and valid predictor of cognitive function after stroke.

The prognosis of stroke survivors primarily discharged to their homes

OBJECTIVES

Stroke is one of the leading causes for nursing home placement (NHP). We have studied the prognosis and risk factors regarding NHP for stroke patients initially discharged to their homes.

MATERIALS AND METHODS

All stroke patients in the municipality of Stavanger, Norway, between January 1, 1996, and March 31, 2004, were included and followed until death or May 31, 2012. Time intervals for NHP and death were compared to an age- and sex-matched, stroke-free control cohort. Logistic regression analysis was used to assess risk factors for NHP.

RESULTS

A total of 452 patients were included. A total of 48 patients (10.6%) were directly placed in a nursing home, while 401 patients (88.7%) were discharged to their homes; 180 patients (44.7%) directly and 221 patients (55.3%) after temporary rehabilitation. Of the patients discharged to their homes, 29.7% needed NHP at a later time point as compared to 19.9% of the controls (P<.001). Logistic regression analysis showed that only age (P<.001) was a risk factor for NHP. Stroke patients discharged home and stroke patients admitted directly to nursing home were significantly younger at time of NHP; stroke patients discharged home died significantly earlier than the controls.

CONCLUSIONS

Almost 90% of the stroke patients could be discharged to their homes, but they needed more often NHP in the long run than the stroke-free controls. Stroke patients discharged to their homes were younger at the time of NHP and death indicating that the stroke deficit may contribute to increased morbidity and mortality in this patient group.

Neuroprotective effect of minocycline on cognitive impairments induced by transient cerebral ischemia/reperfusion through its anti-inflammatory and anti-oxidant properties in male rat

Memory deficit is the most visible symptom of cerebral ischemia that is associated with loss of pyramidal cells in CA1 region of the hippocampus. Oxidative stress and inflammation may be involved in the pathogenesis of ischemia/reperfusion (I/R) damage. Minocycline, a semi-synthetic tetracycline derived antibiotic, has anti-inflammatory and antioxidant properties. We evaluated the neuroprotective effect of minocycline on memory deficit induced by cerebral I/R in rat. I/R was induced by occlusion of common carotid arteries for 20min. Minocycline (40mg/kg, i.p.) was administered once daily for 7days after I/R. Learning and memory were assessed using the Morris water maze test. Nissl staining was used to evaluate the viability of CA1 pyramidal cells. The effects of minocycline on the microglial activation was also investigated by Iba1 (Ionized calcium binding adapter molecule 1) immunostaining. The content of malondialdehyde (MDA) and pro-inflammatory cytokines (IL-1β and TNF-α) in the hippocampus were measured by thiobarbituric acid reaction substances method and ELISA, respectively. Minocycline reduced the increase in escape latency time and in swimming path length induced by cerebral I/R. Furthermore, the ischemia-induced reduction in time spent in the target quadrant during the probe trial was increased by treatment with minocycline. Histopathological results indicated that minocycline prevented pyramidal cells death and microglial activation induced by I/R. Minocycline also reduced the levels of MDA and pro-inflammatory cytokines in the hippocampus in rats subjected to I/R. Minocycline has neuroprotective effects on memory deficit induced by cerebral I/R in rat, probably via its anti-inflammatory and antioxidant properties.

Blood cholesterol in late-life and cognitive decline: a longitudinal study of the Chinese elderly

Background

Previous studies regarding the lipid-cognition relation in older adults are limited and have generated mixed results. We thus examined whether higher blood cholesterol concentrations were associated with faster cognitive decline in a community-based longitudinal study of Chinese elderly.

Methods

The study included 1,159 Chinese adults aged over 60 years (women: 48.7%, mean age: 79.4 years), who were free of dementia, Parkinson disease and stroke at the baseline. Blood concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), were assessed at the baseline. Global cognitive functions were assessed using the Chinese Mini-Mental State Examination (MMSE) at in 2009, 2012 and 2014. Association between blood cholesterol and repeated cognitive function was analyzed with linear mixed models, adjusting for sociodemographic information, behavior and lifestyle, depression symptoms, physical examination, hypertension, and laboratory indexes.

Results

Higher baseline TC and LDL-C concentrations were significantly associated with greater cognitive decline. Adjusted mean difference in cognitive decline rate, comparing two extreme quartiles, was 0.28 points (MMSE score) per year (95% confident interval (CI): -0.54,–0.02; P-trend = 0.005) for TC and 0.42 points per year (95% CI: -0.69, -0.16; P-trend = 0.006) for LDL-C. In a subgroup analysis, the associations between all lipids and cognitive decline appeared to be more pronounced among individuals aged 100 years or older (n = 90), relative to others.

Conclusions

Higher blood concentrations of TC and LDL-C in late-life were associated with faster global cognitive decline.

Electronic supplementary material

The online version of this article (doi:10.1186/s13024-017-0167-y) contains supplementary material, which is available to authorized users.

The role of objective cognitive dysfunction in subjective cognitive complaints after stroke

BACKGROUND AND PURPOSE

Objective cognitive performance (OCP) is often impaired in patients post-stroke but the consequences of OCP for patient-reported subjective cognitive complaints (SCC) are poorly understood. We performed a detailed analysis on the association between post-stroke OCP and SCC.

METHODS

Assessments of OCP and SCC were obtained in 208 patients 3 months after stroke. OCP was evaluated using conventional and ecologically valid neuropsychological tests. Levels of SCC were measured using the CheckList for Cognitive and Emotional (CLCE) consequences following stroke inventory. Multivariate hierarchical regression analyses were used to evaluate the association of OCP with CLCE scores adjusting for age, sex and intelligence quotient. Analyses were performed to examine the global extent of OCP dysfunction (based on the total number of impaired neuropsychological tests, i.e. objective cognitive impairment index) and for each OCP test separately using the raw neuropsychological (sub)test scores.

RESULTS

The objective cognitive impairment index for global OCP was positively correlated with the CLCE score (Spearman's rho = 0.22, P = 0.003), which remained significant in multivariate adjusted models (β = 0.25, P = 0.01). Results for the separate neuropsychological tests indicated that only one task (the ecologically valid Rivermead Behavioural Memory Test) was independently associated with the CLCE in multivariate adjusted models (β = -0.34, P < 0.001).

CONCLUSIONS

Objective neuropsychological test performance, as measured by the global dysfunction index or an ecologically valid memory task, was associated with SCC. These data suggest that cumulative deficits in multiple cognitive domains contribute to subjectively experienced poor cognitive abilities in daily life in patients post-stroke.

The test accuracy of the Montreal Cognitive Assessment (MoCA) by stroke lateralisation

BACKGROUND

The Montreal Cognitive Assessment (MoCA) is an increasingly popular screening tool for detecting cognitive impairment post-stroke. However its' test accuracy by stroke lateralisation is as yet unknown.

AIM

Our aim was to investigate whether the test accuracy of the MoCA differs by stroke lateralisation across different cognitive domains.

METHODS

We retrospectively examined the cognitive profiles of 228 subacute stroke patients (86 Left, 142 Right), comparing MoCA-total and domain-specific scores with performance on detailed neuropsychological assessment.

RESULTS

The prevalence of cognitive impairment detected on neuropsychological assessment was high and relatively comparable between the right and left hemisphere stroke groups (91% and 93% respectively). Notably however, 29% of the right stroke group and 6% of the left stroke group achieved a "cognitively-intact" MoCA score (≥25). A high proportion of right stroke patients who had an overall MoCA-intact score were found to be impaired in intellectual functioning, processing speed, executive functions and non-verbal memory on neuropsychological assessment. Furthermore, a high proportion of patients who scored full-marks within a MoCA-specified domain, irrespective of their overall score, were found to have impairment on corresponding neuropsychological assessment for both stroke groups.

CONCLUSIONS

Particular care needs to be taken in interpreting MoCA-intact performance for right hemisphere patients due to its poor sensitivity to right hemisphere deficits. Scoring maximum points within a MoCA-specified domain also does not necessarily indicate intact cognitive functioning in that domain. Clinicians should consider supplementing their MoCA assessment with additional tools to increase the test accuracy of detecting relevant cognitive impairments post-stroke.

Neuropsychological Outcome and its Predictors Across the First Year after Ischaemic Stroke

Background: Neuropsychological deficits occur in over half of the stroke survivors and are associated with the reduced functioning and a decline in quality of life. However, the trajectory of recovery and predictors of neuropsychological outcomes over the first year post stroke are poorly understood.

Method: Neuropsychological performance, assessed using the CNS-Vital signs, was examined at 1 month, 6 months and 12 months after ischaemic stroke (IS) in a sample drawn from a population-based study (N = 198).

Results: While mean scores across neuropsychological domains at each time-point fell in the average range, one in five individuals produced very low-range scores for verbal memory, attention and psychomotor speed. Significant improvements were seen for executive functioning, psychomotor speed and cognitive flexibility within 6 months post stroke, but no gains were noted from 6 to 12 months. Stroke-related neurological deficits and depression at baseline significantly contributed to the prediction of neuropsychological function at 12 month follow-up.

Conclusions: In a significant minority of IS survivors, focal deficits are evident in psychomotor speed, verbal memory, executive functions and attention. Significant improvements in these domains were only evident in the first 6 months post stroke. Initial stroke-related neurological deficits and concurrent depression may be the best predictors of later cognitive functioning.

Prospective Memory After Stroke: A Scoping Review

The aim of this paper was to review the limited, but growing, literature on prospective memory (PM) following stroke using a scoping study methodology. Multiple databases were systematically searched and yielded 11 studies that were classified as observational (n = 7) or intervention studies (n = 4) and reviewed for quality. PM impairment after stroke was more commonly identified using behavioural measures compared to self-report measures. There were mixed findings regarding the extent and nature of PM impairment poststroke; however, more studies reported impairment for time-based PM, compared to both event- and activity-based PM. Studies examining rehabilitative techniques for PM resulted in mixed findings and were limited as most were case studies of poor methodological quality. Overall previous research in this area was limited as most studies were often underpowered due to small sample sizes, or used single-item measures which may not be robust enough to reliably measure PM impairment. Additionally, the methods used to measure PM were varied and many studies did not control for retrospective memory impairment, which could impact the results, as PM has both a retrospective (remembering both the action and when it needs to be completed) and prospective component (remembering to perform the action when appropriate). In conclusion, PM impairment is apparent poststroke, specifically for time-based PM. However, more research is needed to determine why PM impairment occurs, and how it can be improved.

Depressive signs and cognitive performance in patients with a right hemisphere stroke

PURPOSE

This study investigated the influence of suggestive signs of depression (SSD) in right-hemisphere brain-damaged (RHD) patients following a stroke on their cognitive performance measured by a brief neuropsychological assessment battery.

METHODS

Forty-two adults with RHD after a single episode of stroke and 84 matched controls participated in this study. They were assessed by means of the Geriatric Depression Scale and by Brief Neuropsychological Assessment Battery NEUPSILIN.

RESULTS

Almost half of the patients showed SSD. The RHD group with SSD (RHD+) showed poorer performance in at least one task among all evaluated cognitive domains (concentrated attention, visual perception, working memory, episodic verbal memory and semantic memory, auditory and written language, constructional praxia and verbal fluency).

CONCLUSION

The association of depression and RHD seems to enhance the occurrence and the severity of cognitive déficits. A brief neuropsychological assessment can be useful to identify cognitive impairment caused by this neuropsychiatric disorder.

Quality of life and associated factors among poststroke clinic attendees at a University Teaching Hospital in Nigeria

BACKGROUND

Quality of life (QOL) measures are effective in quantifying disease burden after stroke, more so than levels of debility. The objective of this study is to determine QOL and associated factors of stroke survivors in Lagos, Nigeria.

MATERIALS AND METHODS

Seventy stroke survivors (study sample) and seventy stable hypertensive patients (control sample) attending clinics at a Nigerian hospital were recruited for the study. Respondents were assessed using sociodemographic/clinical questionnaires, modified mini-mental state examination, modified Rankin Scale, schedule for clinical assessment in neuropsychiatry, and World Health Organization-QOL-BREF.

RESULTS

Mean ages of the study and control respondents were 57.43 (±9.67) years and 57.33 (±9.33) years, respectively. Each sample comprised 38 male and 32 female respondents. Stroke survivors were significantly more likely to: be unemployed (P = 0.001), pay more for healthcare (P = 0.001), consume alcohol (P = 0.02), and have physical impairments (P = 0.001) compared with control. The mean QOL scores of stroke survivors were significantly lower than controls across all spheres. Stroke survivors who were unemployed, younger, female, paying more for healthcare, more disabled, with right stroke lateralization, having comorbidities, and sexual dysfunction had significantly poorer QOL specific grades. Depression or anxiety poststroke was also associated with reduced QOL means scores.

CONCLUSION

Besides, clinical variables such as levels of disability and stroke lesion lateralization, other factors such as unemployment, health costs, age, gender, and emotional problems influenced QOL after stroke.

Domain-specific versus generalized cognitive screening in acute stroke

Cognitive assessments after stroke are typically short form tests developed for dementia that generates pass/fail classifications (e.g. the MoCA). The Oxford Cognitive Screen (OCS) provides a domain-specific cognitive profile designed for stroke survivors. This study compared the use of the MoCA and the OCS in acute stroke with respect to symptom specificity and aspects of clinical utility. A cross-sectional study with a consecutive sample of 200 stroke patients within 3 weeks of stroke completing MoCA and OCS. Demographic data, lesion side and Barthel scores were recorded. Inclusivity was assessed in terms of completion rates and reasons for non-completion were evaluated. The incidence of cognitive impairments on both the MoCA and OCS sub-domains was calculated and differences in stroke specificity, cognitive profiles and independence of the measures were addressed. The incidence of acute cognitive impairment was high: 76 % of patients were impaired on MoCA, and 86 % demonstrated at least one impairment on the cognitive domains assessed in the OCS. OCS was more sensitive than MoCA overall (87 vs 78 % sensitivity) and OCS alone provided domain-specific information on prevalent post-stroke cognitive impairments (neglect, apraxia and reading/writing ability). Unlike the MOCA, the OCS was not dominated by left hemisphere impairments but gave differentiated profiles across the contrasting domains. The OCS detects important cognitive deficits after stroke not assessed in the MoCA, it is inclusive for patients with aphasia and neglect and it is less confounded by co-occurring difficulties in these domains.

On the importance of cognitive profiling: A graphical modelling analysis of domain-specific and domain-general deficits after stroke

Cognitive problems following stroke are typically analysed using either short but relatively uninformative general tests or through detailed but time consuming tests of domain specific deficits (e.g., in language, memory, praxis). Here we present an analysis of neuropsychological deficits detected using a screen designed to fall between other screens by being 'broad' (testing multiple cognitive abilities) but 'shallow' (sampling the abilities briefly, to be time efficient) - the BCoS. Assessment using the Birmingham Cognitive Screen (BCoS) enables the relations between 'domain specific' and 'domain general' cognitive deficits to be evaluated as the test generates an overall cognitive profile for individual patients. We analysed data from 287 patients tested at a sub-acute stage of stroke (<3 months). Graphical modelling techniques were used to investigate the associative structure and conditional independence between deficits within and across the domains sampled by BCoS (attention and executive functions, language, memory, praxis and number processing). The patterns of deficit within each domain conformed to existing cognitive models. However, these within-domain patterns underwent substantial change when the whole dataset was modelled, indicating that domain-specific deficits can only be understood in relation to linked changes in domain-general processes. The data point to the importance of using over-arching cognitive screens, measuring domain-general as well as domain-specific processes, in order to account for neuropsychological deficits after stroke. The paper also highlights the utility of using graphical modelling to understand the relations between cognitive components in complex datasets.