Post-Stroke Cognitive Impairment and Dementia

Prospero Homeobox 1 and Doublecortin Correlate with Neural Damage after Ischemic Stroke

OBJECTIVE

Markers of neuroinflammation during ischemic stroke are well characterized, but additional markers of neural damage are lacking. The study identified associations of behavioral disorders after stroke with histologic neural damage and molecular biological change.

METHODS

Eight-week-old, 25 g male mice of the C57BL/6J strain were subjected to middle cerebral artery occlusion (MCAO) to induce ischemic stroke. The control group was a healthy wild type (WT), and the experimental group were designed as a low severity MCAO1 and a high severity MCAO2 based on post-stroke neurological scoring. All groups underwent behavioral tests, realtime polymerase chain reaction, triphenyltetrazolium chloride (TTC) staining and Hematoxylin and Eosin staining. One-way analysis of variance was used to analyze statistical significance between groups.

RESULTS

In TTC staining, MCAO1 showed 29.02% and MCAO2 showed 38.94% infarct volume (p<0.0001). The pro-inflammatory cytokine interleukin (IL)-1β was most highly expressed in MCAO2 (WT 0.44 vs. MCAO1 2.69 vs. MCAO2 5.02, p<0.0001). From the distance to target in the Barnes maze test, WT had a distance of 178 cm, MCAO1 had a distance of 276 cm, and MCAO2 had a distance of 1051 (p=0.0015). The latency to target was 13.3 seconds for WT, 27.9 seconds for MCAO1, and 87.9 seconds for MCAO2 (p=0.0007). Prospero homeobox 1 (Prox1) was most highly expressed in MCAO2 (p=0.0004). Doublecortin (Dcx) was most highly expressed in MCAO2 (p<0.0001).

CONCLUSION

The study demonstrated that histological damage to neural cells and changes in brain mRNA expression were associated with behavioral impairment after ischemic stroke. Prox1 and Dcx may be biomarkers of neural damage associated with long-term cognitive decline, and increased expression at the mRNA level was consistent with neural damage and long-term cognitive dysfunction.

Associations Between Stroke Type, Ischemic Stroke Subtypes, and Post-Stroke Cognitive Trajectories

Background

It is unclear how post-stroke cognitive trajectories differ by stroke type and ischemic stroke subtype. We studied associations between stroke types (ischemic, hemorrhagic), ischemic stroke subtypes (cardioembolic, large artery atherosclerotic, lacunar/small vessel, cryptogenic/other determined etiology), and post-stroke cognitive decline.

Methods

This pooled cohort analysis from four US cohort studies (1971-2019) identified 1,143 dementia-free individuals with acute stroke during follow-up: 1,061 (92.8%) ischemic, 82 (7.2%) hemorrhagic, 49.9% female, 30.8% Black. Median age at stroke was 74.1 (IQR, 68.6, 79.3) years. Outcomes were change in global cognition (primary) and changes in executive function and memory (secondary). Outcomes were standardized as T-scores (mean [SD], 50 [10]); a 1-point difference represents a 0.1-SD difference in cognition. Median follow-up for the primary outcome was 6.0 (IQR, 3.2, 9.2) years. Linear mixed-effects models estimated changes in cognition after stroke.

Results

On average, the initial post-stroke global cognition score was 50.78 points (95% CI, 49.52, 52.03) in ischemic stroke survivors and did not differ in hemorrhagic stroke survivors (difference, -0.17 points [95% CI, -1.64, 1.30]; P=0.82) after adjusting for demographics and pre-stroke cognition. On average, ischemic stroke survivors showed declines in global cognition, executive function, and memory. Post-stroke declines in global cognition, executive function, and memory did not differ between hemorrhagic and ischemic stroke survivors. 955 ischemic strokes had subtypes: 200 (20.9%) cardioembolic, 77 (8.1%) large artery atherosclerotic, 207 (21.7%) lacunar/small vessel, 471 (49.3%) cryptogenic/other determined etiology. On average, small vessel stroke survivors showed declines in global cognition and memory, but not executive function. Initial post-stroke cognitive scores and cognitive declines did not differ between small vessel survivors and survivors of other ischemic stroke subtypes. Post-stroke vascular risk factor levels did not attenuate associations.

Conclusion

Stroke survivors had cognitive decline in multiple domains. Declines did not differ by stroke type or ischemic stroke subtype.

Cerebral hemodynamics and cognitive functions in the acute and subacute stage of mild ischemic stroke: a longitudinal pilot study

The association between cerebral hemodynamics and cognitive impairment has been reported in neurodegenerative and cerebrovascular disorders (CVD). However, it is still unclear whether changes occur in the acute phase of CVD. Here we investigated cognitive and hemodynamic parameters and their association in patients with CVD during the acute and subacute phases. Seventy-three patients with mild stroke, not undergoing endovascular treatment, were recruited. All subjects were devoid of intracranial or external carotid stenosis, significant chronic cerebrovascular pathology, dementia or non-compensated cardiovascular diseases. Patients were evaluated within 7 days from symptoms onset (T1) and after 3 months (T2). Clinical and demographic data were collected. NIHSS, MoCA, FAB, and Word-Color Stroop test (WCST) were used to evaluate disease severity and cognitive functions. Basal hemodynamic parameters in the middle cerebral artery were measured with transcranial Doppler. Differences between T2 and T1, correlations between cognitive and hemodynamic variables at T1 and T2, as well as correlations between the T2-T1 variation in cognitive and hemodynamic parameters were assessed. At T1, cognitive performance of MoCA, FAB, and WCST was lower compared with T2; and pulsatility index, a parameter reflecting distal vascular resistance, was higher. However, no correlations between the changes in cognitive and hemodynamic variables were found; therefore, the two seems to be independent phenomena. In the acute phase, the linear association between cerebral blood flow and cognitive performances was lost, probably due to a differential effect of microenvironment changes and vascular-specific phenomena on cognition and cerebral hemodynamics. This relationship was partially restored in the subacute phase.

High-Frequency Repetitive Transcranial Magnetic Stimulation on Overall Cognition in Patients With Poststroke Cognitive Impairment: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of the study is to comprehensively assess the recovery effects of high-frequency repetitive transcranial magnetic stimulation in patients with poststroke cognitive impairment.

METHODS

Six English and four Chinese databases were searched for relevant studies published up to January 2022. Randomized controlled trials of patients with poststroke cognitive impairment treated with high-frequency repetitive transcranial magnetic stimulation were included. Included studies were assessed for the risk of bias through the Cochrane Intervention Systematic Review Manual 5.1.0. The meta-analysis was performed using RevMan 5.4 software. The PRISMA 2020 guidelines were followed.

RESULTS

Sixty-one randomized controlled trials (4012 patients) were included. Montreal Cognitive Assessment Score, Mini-Mental State Examination score, event-related potential P300 (P300) amplitude, Loewenstein Occupational Therapy Cognitive Assessment score, and total effective rate of cognitive function were higher in the high-frequency repetitive transcranial magnetic stimulation group than in the control group at the end of the treatment period, and scores of Alzheimer Disease Assessment Scale-Cognitive Subscale and P300 latency were lower in the high-frequency repetitive transcranial magnetic stimulation group than in the control group. Fifty studies had selected the dorsolateral prefrontal cortex as the stimulation site for high-frequency repetitive transcranial magnetic stimulation.

CONCLUSIONS

Compared with nonrepetitive transcranial magnetic stimulation or sham repetitive transcranial magnetic stimulation, high-frequency repetitive transcranial magnetic stimulation not only improves the overall cognitive function of poststroke cognitive impairment patients but also has better rehabilitation results.

Advancing Perioperative Neurocognitive Health: A Critical Review of Predictive Tools, Diagnostic Methods, and Interventional Strategies

Perioperative neurocognitive disorders (PNDs) affect a large percentage of people who undergo surgeries that need general anesthesia. There is an increased risk of death and a major disruption to postoperative self-care as a result of this. This study compiles all the relevant materials that the authors have found to investigate postnatal depression and its causes, as well as the methods used to determine the probability and severity of PNDs and how to reduce their risk before surgery. Postnatal depression can have many causes, and this text explores some of them. These include a history of alcohol or opiate use, immunological dysregulation, advanced age, educational background, infections, neurocognitive impairment, and pre-existing chronic inflammatory disorders. It also delves into various methods used to gauge the likelihood and severity of postpartum depression. The following assessment tools were covered: the Clock Drawing Test, Domain-Specific Tests, the Mini-Mental State Examination, and the Montreal Cognitive Assessment. In addition to biochemical markers, neuroimaging techniques play an important role in diagnosis. The Frailty Fried assessment, which measures inertia, sluggishness, lack of physical activity, fatigue, and unintentional weight loss, is a key prognostic sign that is highlighted. There is strong evidence that the index, which is derived from these five characteristics, may accurately predict the likelihood of PNDs. Risk mitigation strategies are also covered in this research. Preoperative brain plasticity-based therapies, such as physical exercise and intensive cognitive training, can significantly reduce the incidence and severity of postoperative neurocognitive disorders. A peripheral nerve block, monitoring cerebral oxygen saturation, dexmedetomidine, and a reduction in anesthesia depth are all ways to improve anesthetic procedures. Methods that lower blood pressure should be avoided, the body temperature should be kept down during surgery, or the time without liquids should be lengthened; all of these raise the risk of postoperative nausea and vomiting and make it worse. Potential approaches include a Mediterranean diet, physical activity, cognitive stimulation, smoking cessation, alcohol reduction, avoidance of anticholinergic medications, and non-steroidal anti-inflammatory drug stewardship, although there is no definitive evidence for successful postoperative neurocognitive rehabilitation procedures. More standardized diagnostic criteria, evaluation methods, and PND classification are urgently needed, according to this study. Different cases of PNDs are characterized by different combinations of tests, cutoff values, and methods because there is a broad variety of diagnostic tests used to make the diagnosis. Until now, PNDs and pre-existing neurocognitive disorders have been diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (DSM-V). With an aging population comes an increase in the occurrence and prevalence of PNDs, which calls for a specific way to classify and describe the condition.

TIMP-3 Alleviates White Matter Injury After Subarachnoid Hemorrhage in Mice by Promoting Oligodendrocyte Precursor Cell Maturation

Subarachnoid hemorrhage (SAH) is associated with high mortality and disability rates, and secondary white matter injury is an important cause of poor prognosis. However, whether brain capillary pericytes can directly affect the differentiation and maturation of oligodendrocyte precursor cells (OPCs) and subsequently affect white matter injury repair has still been revealed. This study was designed to investigate the effect of tissue inhibitor of metalloproteinase-3 (TIMP-3) for OPC differentiation and maturation. PDGFRβret/ret and wild-type C57B6J male mice were used to construct a mouse model of SAH via endovascular perforation in this study. Mice were also treated with vehicle, TIMP-3 RNAi or TIMP-3 RNAi + TIMP-3 after SAH. The effect of TIMP-3 on the differentiation and maturation of OPCs was determined using behavioral score, ELISA, transmission electron microscopy, immunofluorescence staining and cell culture. We found that TIMP-3 was secreted mainly by pericytes and that SAH and TIMP-3 RNAi caused a significant decrease in the TIMP-3 content, reaching a nadir at 24 h, followed by gradual recovery. In vitro, the myelin basic protein content of oligodendrocytes after oxyhemoglobin treatment was increased by TIMP-3 overexpression. The data indicates TIMP-3 could promote the differentiation and maturation of OPCs and subsequently improve neurological outcomes after SAH. Therefore, TIMP-3 could be beneficial for repair after white matter injury and could be a potential therapeutic target in SAH.

Temporal expression profiles of microRNAs associated with acute phase of brain ischemia in gerbil hippocampus

Neuroprotective therapeutic potential for restoring dysregulated microRNA (miRNA) expression has previously been demonstrated in a gerbil cerebral infarction model. However, since temporal changes in miRNA expression profiles following stroke onset are unknown, miRNAs proving to be useful therapeutic targets have yet to be identified. We evaluated cognitive function, hippocampal neuronal cell death, and microarray-based miRNA expression profiles at 5, 9, 18, 36, and 72 h after 5-min whole brain ischemia in gerbils. A decline in cognitive function occurred in parallel with increased neuronal cell death 36-72 h after ischemia. The Jonckheere-Terpstra test was used to analyze miRNA expression trends 5-72 h after ischemia. The expression levels of 63 miRNAs were significantly upregulated, whereas 32 miRNAs were significantly downregulated, monotonically. Of the 32 monotonically downregulated miRNAs, 18 showed the largest decrease in expression 5-9 h after ischemia. A subset of these dysregulated miRNAs (miR-378a-5p, miR-204-5p, miR-34c-5p, miR-211-5p, miR-34b-3p, and miR-199b-3p) could be associated with brain ischemia and neuropsychiatric disorders.

Ion transporter cascade, reactive astrogliosis and cerebrovascular diseases

Cerebrovascular diseases and their sequalae, such as ischemic stroke, chronic cerebral hypoperfusion, and vascular dementia are significant contributors to adult disability and cognitive impairment in the modern world. Astrocytes are an integral part of the neurovascular unit in the CNS and play a pivotal role in CNS homeostasis, including ionic and pH balance, neurotransmission, cerebral blood flow, and metabolism. Astrocytes respond to cerebral insults, inflammation, and diseases through unique molecular, morphological, and functional changes, collectively known as reactive astrogliosis. The function of reactive astrocytes has been a subject of debate. Initially, astrocytes were thought to primarily play a supportive role in maintaining the structure and function of the nervous system. However, recent studies suggest that reactive astrocytes may have both beneficial and detrimental effects. For example, in chronic cerebral hypoperfusion, reactive astrocytes can cause oligodendrocyte death and demyelination. In this review, we will summarize the (1) roles of ion transporter cascade in reactive astrogliosis, (2) role of reactive astrocytes in vascular dementia and related dementias, and (3) potential therapeutic approaches for dementing disorders targeting reactive astrocytes. Understanding the relationship between ion transporter cascade, reactive astrogliosis, and cerebrovascular diseases may reveal mechanisms and targets for the development of therapies for brain diseases associated with reactive astrogliosis.

Prolonged myelin deficits contribute to neuron loss and functional impairments after ischaemic stroke

Ischaemic stroke causes neuron loss and long-term functional deficits. Unfortunately, effective approaches to preserving neurons and promoting functional recovery remain unavailable. Oligodendrocytes, the myelinating cells in the CNS, are susceptible to oxygen and nutrition deprivation and undergo degeneration after ischaemic stroke. Technically, new oligodendrocytes and myelin can be generated by the differentiation of oligodendrocyte precursor cells (OPCs). However, myelin dynamics and their functional significance after ischaemic stroke remain poorly understood. Here, we report numerous denuded axons accompanied by decreased neuron density in sections from ischaemic stroke lesions in human brain, suggesting that neuron loss correlates with myelin deficits in these lesions. To investigate the longitudinal changes in myelin dynamics after stroke, we labelled and traced pre-existing and newly-formed myelin, respectively, using cell-specific genetic approaches. Our results indicated massive oligodendrocyte death and myelin loss 2 weeks after stroke in the transient middle cerebral artery occlusion (tMCAO) mouse model. In contrast, myelin regeneration remained insufficient 4 and 8 weeks post-stroke. Notably, neuronal loss and functional impairments worsened in aged brains, and new myelin generation was diminished. To analyse the causal relationship between remyelination and neuron survival, we manipulated myelinogenesis by conditional deletion of Olig2 (a positive regulator) or muscarinic receptor 1 (M1R, a negative regulator) in OPCs. Deleting Olig2 inhibited remyelination, reducing neuron survival and functional recovery after tMCAO. Conversely, enhancing remyelination by M1R conditional knockout or treatment with the pro-myelination drug clemastine after tMCAO preserved white matter integrity and neuronal survival, accelerating functional recovery. Together, our findings demonstrate that enhancing myelinogenesis is a promising strategy to preserve neurons and promote functional recovery after ischaemic stroke.

Exploring vascular contributions to cognitive impairment and dementia (ENIGMA): protocol for a prospective observational study

BACKGROUND

Post-stroke cognitive impairment (PSCI) is common. However, the underlying pathophysiology remains largely unknown. Understanding the role of microvascular changes and finding markers that can predict PSCI, could be a first step towards better screening and management of PSCI. Capillary dysfunction is a pathological feature of cerebral small vessel disease and may play a role in the mechanisms underlying PSCI. Extracellular vesicles (EVs) are secreted from cells and may act as disease biomarkers. We aim to investigate the role of capillary dysfunction in PSCI and the associations between EV characteristics and cognitive function one year after acute ischemic stroke (AIS) and transient ischemic attack (TIA).

METHODS

The ENIGMA study is a single-centre prospective clinical observational study conducted at Aarhus University Hospital, Denmark. Consecutive patients with AIS and TIA are included and followed for one year with follow-up visits at three and 12 months. An MRI is performed at 24 h and 12 months follow-up. EV characteristics will be characterised from blood samples drawn at 24 h and three months follow-up. Cognitive function is assessed three and 12 months after AIS and TIA using the Repeatable Battery for the Assessment of Neuropsychological Status.

DISCUSSION

Using novel imaging and molecular biological techniques the ENIGMA study will provide new knowledge about the vascular contributions to cognitive decline and dementia.

TRIAL REGISTRATION

The study is retrospectively registered as an ongoing observational study at ClinicalTrials.gov with the identifier NCT06257823.

The prevalence and risk factors study of cognitive impairment: Analysis of the elderly population of Han nationality in Hunan province, China

OBJECTIVE

A large number of studies have found that the prevalence of cognitive impairment varies in different regions. However, data on cognitive impairment in the Chinese population is still lacking. The goal of this study was to assess the prevalence of cognitive impairment among the elderly in a region of China and explore the associated risk factors.

METHODS

We performed a population-based cross-sectional survey from April to June 2022. Residents come from three villages and six urban communities in the county-level city of Liuyang in southern China (N = 3233) and the coverage rate of our study population reached 73%. Participants were assessed with a series of clinical examinations and neuropsychological measures. A total of 2598 participants were selected after filtering out those under 60 years old or with incomplete data. Patients with cognitive impairment included those with mild cognitive impairment (MCI) or dementia who met standard diagnostic criteria.

RESULTS

The prevalence of cognitive impairment, MCI, and dementia among participants aged 60 years and older were 21.48% (95% CI, 19.90-23.10), 15.70% (95% CI, 14.30-17.10), and 5.77 (95% CI, 4.90-6.70), respectively. And residents in villagers were more likely to have cognitive impairment than in urban communities (p < 0.001). Age growth and education level were independent influencing factors for cognitive impairment in all populations (p < 0.001). For lifestyles factors, both smoking and drinking reduced the risk of cognitive impairment (p < 0.05), but when further quantified, the link disappeared. Moreover, having cerebrovascular disease and severe vision impairment were risk factors (p < 0.05).

CONCLUSION

A representative prevalence of cognitive impairment, MCI, and dementia was found in the elderly Han Chinese population in Southern China. And we further explored the role of known risk factors, particularly in physical activity, smoking, and alcohol consumption.

Enhanced angiogenesis in the thalamus induced by a novel TSPO ligand ameliorates cognitive deficits after focal cortical infarction

Neuronal loss in the ipsilateral thalamus after focal cortical infarction participates in post-stroke cognitive deficits, and enhanced angiogenesis in the thalamus is expected to reduce neuronal damage. We hypothesize that novel translocator protein (TSPO) ligand, 2-Cl-MGV-1, can promote angiogenesis, attenuate neuronal loss in the thalamus, and ameliorate post-stroke cognitive deficits. Cortical infarction was induced by distal middle cerebral artery occlusion (dMCAO) in stroke-prone renovascular hypertensive rats. 2-Cl-MGV-1 or dimethyl sulfoxide was administered 24 h after dMCAO and then for 6 or 13 days. Spatial learning and memory were assessed using the Morris water maze. Neuronal loss, TSPO expression, angiogenesis, and intrinsic pathway were determined by immunofluorescence and immunoblotting 7 and 14 days after dMCAO. Cortical infarction caused post-stroke cognitive deficits and secondary neuronal loss with gliosis in the ipsilateral thalamus within 14 days of dMCAO. Increased angiogenesis and elevated expression of vascular TSPO were detected in the ipsilateral thalamus, and treatment with 2-Cl-MGV-1 enhanced angiogenesis by stimulating the PI3K-AKT-mTOR pathway. The effects of 2-Cl-MGV-1 on angiogenesis coincided with reduced neuronal loss in the thalamus and contributed to improvements in post-stroke cognitive deficits. Our findings suggest that 2-Cl-MGV-1 stimulates angiogenesis, ameliorates neuronal loss in the thalamus, and improves post-stroke cognitive deficits.

Remote ischemic conditioning after stroke: Research progress in clinical study

BACKGROUND AND PURPOSE

Stroke is a leading cause of global morbidity and mortality, indicating the necessity and urgency of effective prevention and treatment. Remote ischemic conditioning (RIC) is a convenient, simple, non-intrusive, and effective method that can be easily added to the treatment regime of stroke patients. Animal experiments and clinical trials have proved the neuroprotective effects of RIC on brain injury including (examples of neuroprotective effects). This neuroprotection is achieved by raising brain tolerance to ischemia, increasing local cerebral blood perfusion, promoting collateral circulations, neural regeneration, and reducing the incidence of hematomas in brain tissue. This current paper will summarize the studies within the last 2 years for the comprehensive understanding of the use of RIC in the treatment of stroke.

METHODS

This paper summarizes the clinical research progress of RIC on stroke (ischemic stroke and hemorrhagic stroke (HS)). This paper is a systematic review of research published on registered clinical trials using RIC in stroke from inception through November 2022. Four major databases (PUBMED, WEB OF SCIENCE, EMBASE, and ClinicalTrials.gov) were searched.

RESULTS

Forty-eight studies were identified meeting our criteria. Of these studies, 14 were in patients with acute ischemic stroke with onset times ranging from 6 h to 14 days, seven were in patients with intravenous thrombolysis or endovascular thrombectomy, 10 were in patients with intracranial atherosclerotic stenosis, six on patients with vascular cognitive impairment, three on patients with moyamoya disease, and eight on patients with HS. Of the 48 studies, 42 were completed and six are ongoing.

CONCLUSIONS

RIC is safe, feasible, and effective in the treatment of stroke. Large-scale research is still required to explore the optimal treatment options and mechanisms of RIC in the future to develop a breakthrough in stroke prevention and treatment.

Cognitive outcomes following aneurysmal subarachnoid hemorrhage: Rehabilitation strategies

Despite decreases in mortality rate, the treatment of cognitive deficits following aneurysmal subarachnoid hemorrhage (aSAH) remains a serious challenge for clinicians and survivors alike. Deficits in executive function, language, and memory prevent more than half of survivors from returning to their previous level of work and put a tremendous amount of stress on the individual and their family. New therapies are needed for survivors of aSAH in order to improve cognitive outcomes and quality of life. The aim of this review is to discuss the prevalence and contributing factors of cognitive deficits following aSAH, as well as areas for therapeutic intervention. Due to the limited research on cognitive rehabilitative strategies for aSAH, a literature search of traumatic brain injury (TBI) was used to explore therapies with the potential to improve cognitive outcomes in aSAH. Across cognitive domains, existing rehabilitative and pharmacotherapeutic strategies for TBI show promise to be useful for survivors of aSAH. However, further study of these therapies in addition to consistent assessment of cognitive deficits are required to determine their efficacy in survivors of aSAH.

Effect of Qigong exercise on motor function in stroke patients: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Motor impairment is one of the most common defects after stroke, which could seriously affect the life quality of stroke patients. Exercise intervention gradually becomes a popular alternative rehabilitation therapy because of its safety and applicability.

OBJECTIVES

To systematically assess the effect of Qigong exercise on motor function in stroke patients.

METHODS

Randomized controlled trials that evaluated the effect of Qigong on motor function of stroke patients were obtained from PubMed and Chinese National Knowledge Infrastructure through May 2022. Mean values and standard deviations of the post-intervention score in both experimental group and control group were collected to calculate the mean difference (MD) and corresponkding 95% confidence interval (95% CI) of each study, which were quantificationally summarized using the Review Manager 5.3 software.

RESULTS

Nineteen randomized controlled trials enrolling 1487 stroke patients were included. Pooled results indicated that Qigong exercise had beneficial effect on balance function (Berg Balance Scale [MD: 7.56, 95% CI: 4.09-11.02]), limb motor function (Fugl-Meyer Assessment [total score: MD: 7.54, 95% CI: 6.38-8.69; upper limb: MD: 3.57, 95% CI: 0.71-6.43; lower limb: MD: 2.44, 95% CI: 0.59-4.29]) and walking function (6-min walking test [MD: 62.21, 95% CI: 11.70-112.73]) of stroke patients. It was also found to be associated with an improvement in trunk function as indicated by the Trunk Impairment Scale.

CONCLUSIONS

Available evidence supported potential benefits of Qigong exercise for improving motor functions of stroke patients. As a safe and widely applicable exercise, Qigong is worthy of further promotion in the rehabilitation of stroke patients.

Association of socioeconomic status and poststroke cognitive function: A systematic review and meta-analysis

BACKGROUND

Stroke survivors are at high risk of coping with cognitive problems after stroke. In recent decades, the relationship between socioeconomic status (SES) and health-related outcomes has been a topic of considerable interest. Learning more about the potential impact of SES on poststroke cognitive dysfunction is of great importance.

OBJECTIVE

The purpose of this systematic review and meta-analysis was to summarize the association between SES and poststroke cognitive function by quantifying the effect sizes of the existing studies.

METHOD

We searched studies from PubMed, Ovid, Embase, Cochrane, Scopus, and PsychINFO up to January 30th 2024 and the references of relevant reviews. Studies reporting the risk of poststroke cognitive dysfunction as assessed by categorized SES indicators were included. The Newcastle-Ottawa scale and the Agency for Healthcare Research and Quality were used to evaluate the study quality. Meta-analyses using fixed-effect models or random-effect models based on study heterogeneity were performed to estimate the influence of SES on cognitive function after stroke, followed by subgroup analyses stratified by study characteristics.

RESULTS

Thirty-four studies were eligible for this systematic review and meta-analysis. Of which, 19 studies reported poststroke cognitive impairment (PSCI) as the outcome, 13 reported poststroke dementia (PSD), one reported both PSCI and PSD, and one reported vascular cognitive impairment no dementia. The findings showed that individuals with lower SES levels had a higher risk of combined poststroke cognitive dysfunction (odds ratio (OR) = 1.91, 95% confidence interval (CI) = 1.59-2.29), PSCI (OR = 2.09, 95% CI = 1.57-2.78), and PSD (OR = 1.95, 95% CI = 1.48-2.57). Subgroup analyses stratified by SES indicators demonstrated the protective effects of education and occupation against the diagnoses of combined poststroke cognitive dysfunction, PSCI, and PSD.

CONCLUSIONS

Stroke survivors belonging to a low SES are at high risk of poststroke cognitive dysfunction. Our findings add evidence for public health strategies to reduce the risk of poststroke cognitive dysfunction by reducing SES inequalities.

Nonlinear relationship between triglycerides and cognitive function after acute ischemic stroke among older adults

Background

Although studies have explored the association between triglyceride levels and cognitive function after acute ischemic stroke (AIS), the results have been conflicting. Therefore, the purpose of this study was to investigate the relationship between triglyceride levels and cognitive function after AIS among older adults.

Methods

This is an observational cross-sectional study. From November 2022 to June 2023, we consecutively collected patients diagnosed with AIS in China. Triglyceride levels were measured within 24 h of admission. The Mini-Mental State Examination (MMSE) was used to assess cognitive function. Nonlinear associations between triglyceride levels and cognitive function were assessed using smooth curve fitting and threshold effect analysis.

Results

In this study, a total of 221 patients (mean ± SD: 70.64 ± 7.43 years) with AIS were consecutively recruited, among whom 144 (65.16%) were male. Among the 221 recruited patients, 102 (46.15%) had cognitive impairment. Triglyceride levels and cognitive impairment were found to have a nonlinear association after controlling for potential confounders, with an inflection point at 0.8 mmol/L. Below the inflection point, triglyceride levels were positively correlated with MMSE scores (β = 14.11, 95% confidence interval [CI] = 2.33-25.89, P = 0.020). However, above the inflection point, the correlation between MMSE score and triglyceride levels was not statistically significant (β = 1.04, 95% CI = -1.27 - 3.34, P = 0.380).

Conclusion

There is a nonlinear association between triglyceride levels and cognitive function after AIS in older adults. Triglyceride was positively connected with cognitive function when it was less than 0.8 mmol/L.

Serum autophagy-related gene 5 level in stroke patients: correlation with CD4+ T cells and cognition impairment during a 3-year follow-up

Autophagy-related gene (ATG) 5 regulates blood lipids, chronic inflammation, CD4+ T-cell differentiation, and neuronal death and is involved in post-stroke cognitive impairment. This study aimed to explore the correlation of serum ATG5 with CD4+ T cells and cognition impairment in stroke patients. Peripheral blood was collected from 180 stroke patients for serum ATG5 and T helper (Th) 1, Th2, Th17, and regulatory T (Treg) cell detection via enzyme-linked immunosorbent assays and flow cytometry. The Mini-Mental State Examination (MMSE) scale was completed at enrollment, year (Y)1, Y2, and Y3 in stroke patients. Serum ATG5 was also measured in 50 healthy controls (HCs). Serum ATG5 was elevated in stroke patients compared to HCs (P<0.001) and was positively correlated to Th2 cells (P=0.022), Th17 cells (P<0.001), and Th17/Treg ratio (P<0.001) in stroke patients but not correlated with Th1 cells, Th1/Th2 ratio, or Treg cells (all P>0.050). Serum ATG5 (P=0.037), Th1 cells (P=0.022), Th17 cells (P=0.002), and Th17/Treg ratio (P=0.018) were elevated in stroke patients with MMSE score-identified cognition impairment vs those without cognition impairment, whereas Th2 cells, Th1/Th2 ratio, and Treg cells were not different between them (all P>0.050). Importantly, serum ATG5 was negatively linked with MMSE score at enrollment (P=0.004), Y1 (P=0.002), Y2 (P=0.014), and Y3 (P=0.001); moreover, it was positively related to 2-year (P=0.024) and 3-year (P=0.012) MMSE score decline in stroke patients. Serum ATG5 was positively correlated with Th2 and Th17 cells and estimated cognitive function decline in stroke patients.

Experimental Ischemic Stroke Induces Secondary Bihemispheric White Matter Degeneration and Long-Term Cognitive Impairment

Clinical studies have identified widespread white matter degeneration in ischemic stroke patients. However, contemporary research in stroke has predominately focused on the infarct and periinfarct penumbra regions. The involvement of white matter degeneration after ischemic stroke and its contribution to post-stroke cognitive impairment and dementia (PSCID) has remained less explored in experimental models. In this study, we examined the progression of locomotor and cognitive function up to 4 months after inducing ischemic stroke by middle cerebral artery occlusion in young adult rats. Despite evident ongoing locomotor recovery, long-term cognitive and affective impairments persisted after ischemic stroke, as indicated by Morris water maze, elevated plus maze, and open field performance. At 4 months after stroke, multimodal MRI was conducted to assess white matter degeneration. T2-weighted MRI (T2WI) unveiled bilateral cerebroventricular enlargement after ischemic stroke. Fluid Attenuated Inversion Recovery MRI (FLAIR) revealed white matter hyperintensities in the corpus callosum and fornix across bilateral hemispheres. A positive association between the volume of white matter hyperintensities and total cerebroventricular volume was noted in stroke rats. Further evidence of bilateral white matter degeneration was indicated by the reduction of fractional anisotropy and quantitative anisotropy at bilateral corpus callosum in diffusion-weighted MRI (DWI) analysis. Additionally, microglia and astrocyte activation were identified in the bilateral corpus callosum after stroke. Our study suggests that experimental ischemic stroke induced by MCAO in young rat replicate long-term cognitive impairment and bihemispheric white matter degeneration observed in ischemic stroke patients. This model provides an invaluable tool for unraveling the mechanisms underlying post-stroke secondary white matter degeneration and its contribution to PSCID.

Stroke disease-specific quality of life trajectories and their associations with caregivers' anxiety, depression, and burden in stroke population: a longitudinal, multicentre study

AIMS

The aims of this study were to: (i) test if there are clusters of stroke survivors who experience distinct trajectories of quality of life (QOL) from hospital rehabilitation discharge to 12-month follow-up; (ii) test if any sociodemographic or clinical variables predict this class membership; and (iii) examine the associations between the clusters of stroke survivors' and their caregivers' trajectories of anxiety, depression, and burden over time.

METHODS AND RESULTS

A total of 415 stroke survivors and their caregivers were recruited in Italy for this 1-year, longitudinal, multicentre prospective study, filling out a survey at five time points. We found two distinct trajectories of change in stroke survivors' psychological QOL (i.e. Memory, Communication, Emotion, and Participation). The first trajectory (86% of the survivors) included those who started with greater levels of QOL and improved slightly to markedly in all psychological domains, while the second trajectory (14% of the survivors) comprised those who started with lower overall levels of psychological QOL and experienced a worsening or no changes at all in these dimensions up to 12-month follow-up. Very few clinical and sociodemographic variables at baseline predicted class membership. Finally, caregivers of those patients who experienced no change or a worsening in psychological QOL reported greater distress and burden over time.

CONCLUSION

Our results highlight the need for more tailored interventions to improve patients' psychological QOL and consequently their caregivers' well-being. This requires a shift from a stroke survivor-centred approach to a stroke survivor- and caregiver-centred one.

Intermittent theta burst stimulation combined with cognitive training improves cognitive dysfunction and physical dysfunction in patients with post-stroke cognitive impairment

OBJECTIVE

Post-stroke cognitive impairment (PSCI) is a common complication of stroke. Intermittent theta burst stimulation (iTBS) can inducing motor learning. We observed the effects of combination of iTBS with cognitive training on physical/cognitive dysfunctions in PSCI patients.

METHODS

PSCI patients treated with basic treatment & cognitive training (Control group)/iTBS & cognitive training (iTBS group) were enrolled, with Mini-mental State Examination (MMSE)/Montreal Cognitive Assessment (MoCA)/Frontal Assessment Battery (FAB)/barthel index (BI)/Upper Limb Fugl-Meyer Assessment (U-FMA)/Action Research Arm Test (ARAT) scores compared. Gait spatiotemporal parameters/dynamic parameters were analyzed by 3D gait analysis. Correlations between MMSE/MoCA scores and gait parameters in PSCI patients after iTBS & cognitive training were analyzed by Spearman analysis.

RESULTS

Increased MMSE/MoCA/FAB/BI/U-FMA/ARAT scores, step speed, step frequency, stride length, step width, step length on the affected side, percentage of swing phase on the affected side, hip joint flexion angle on the affected side, knee joint flexion angle on the affected side, and ankle plantar flexion angle on the affected side and reduced gait period on the affected side and percentage of stance phase on the affected side were found in patients of both groups after treatment, with the effects in the iTBS group more profound.

CONCLUSION

iTBS & cognitive training obviously improved the cognitive function scores/upper limb function scores/gait parameters in PSCI patients versus cognitive training treatment. After combination therapy, the MMSE/MoCA scores of PSCI patients were significantly correlated with gait parameters. This provided more data support for iTBS & cognitive training application in the rehabilitation treatment of PSCI patients.

Neuroprotective effects of Aucubin against cerebral ischemia-reperfusion injury

AIMS

To study the role of Aucubin (AU) in cerebral ischemia-reperfusion injury and investigate the potential mechanisms.

METHODS

For the in vitro experiment, primary microglia were cultured and stimulated by Lipopolysaccharides (LPS) and treated with AU. Male C57/BL6J mice were used and middle cerebral artery occlusion (MCAO) model was performed to induce cerebral ischemia-reperfusion injury. For the short-term effects, mice administrated with AU (40 mg/kg) for 3 days after MCAO were evaluated for the infarct volume and neurological deficits. The neuroinflammatory factors and microglia activation were determined by Real-time PCR, western blot and immunofluorescence staining. For the long-term effects, MCAO mice were injected daily with AU (5 mg/kg or 10 mg/kg) for 28 days. Behavior tests were used to assess the neurological deficits of MCAO mice, and white matter integrity was determined by myelin basic protein (MBP) staining and black-gold staining.

RESULTS

AU suppressed LPS-induced activation of microglia and pro-inflammatory cytokines release, and downregulated the NF-κB and MAPK pathways in primary microglia. In addition, AU attenuated ischemic injury and inhibited the neuro-inflammatory response in MCAO mice. Moreover, AU induced prolonged improvements in sensorimotor function and memory function following MCAO, and preserved white matter integrity in the long-term experiments.

CONCLUSIONS

AU protected against ischemic injury, which might be correlated with the downregulation of NF-κB and MAPK signaling pathways. Furthermore, AU alleviated cognitive impairment after stroke and restored white matter integrity. Our data indicated that AU might be a potential compound for the treatment of stroke and post-stroke cognitive impairment.

Trans- and Cis-Phosphorylated Tau Protein: New Pieces of the Puzzle in the Development of Neurofibrillary Tangles in Post-Ischemic Brain Neurodegeneration of the Alzheimer's Disease-like Type

Recent evidence indicates that experimental brain ischemia leads to dementia with an Alzheimer's disease-like type phenotype and genotype. Based on the above evidence, it was hypothesized that brain ischemia may contribute to the development of Alzheimer's disease. Brain ischemia and Alzheimer's disease are two diseases characterized by similar changes in the hippocampus that are closely related to memory impairment. Following brain ischemia in animals and humans, the presence of amyloid plaques in the extracellular space and intracellular neurofibrillary tangles was revealed. The phenomenon of tau protein hyperphosphorylation is a similar pathological feature of both post-ischemic brain injury and Alzheimer's disease. In Alzheimer's disease, the phosphorylated Thr231 motif in tau protein has two distinct trans and cis conformations and is the primary site of tau protein phosphorylation in the pre-entanglement cascade and acts as an early precursor of tau protein neuropathology in the form of neurofibrillary tangles. Based on the latest publication, we present a similar mechanism of the formation of neurofibrillary tangles after brain ischemia as in Alzheimer's disease, established on trans- and cis-phosphorylation of tau protein, which ultimately influences the development of tauopathy.

The role of gut microbiota in cerebrovascular disease and related dementia

In recent years, increasing evidence suggests that commensal microbiota may play an important role not only in health but also in disease including cerebrovascular disease. Gut microbes impact physiology, at least in part, by metabolizing dietary factors and host-derived substrates and then generating active compounds including toxins. The purpose of this current review is to highlight the complex interplay between microbiota, their metabolites. and essential functions for human health, ranging from regulation of the metabolism and the immune system to modulation of brain development and function. We discuss the role of gut dysbiosis in cerebrovascular disease, specifically in acute and chronic stroke phases, and the possible implication of intestinal microbiota in post-stroke cognitive impairment and dementia, and we identify potential therapeutic opportunities of targeting microbiota in this context. LINKED ARTICLES: This article is part of a themed issue From Alzheimer's Disease to Vascular Dementia: Different Roads Leading to Cognitive Decline. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.6/issuetoc.

Improving post-acute stroke follow-up care by adopting telecare consultations in a nurse-led clinic: Study protocol of a hybrid implementation-effectiveness trial

AIM

To evaluate the clinical effectiveness and implementation strategies of telecare consultations in post-stroke nurse-led clinics.

BACKGROUND

Telecare consultations could be an alternative to conventional in-person consultations and improve continuity of care for stroke survivors following their discharge from hospital. Previous studies utilizing telecare consultations only focused on testing their clinical effectiveness on stroke survivors; the appropriateness and feasibility of adopting this new delivery modality in a real-world setting were not examined.

DESIGN

A Type II hybrid effectiveness-implementation design will be adopted.

METHODS

Eligible stroke survivor participants will be randomly assigned to the intervention group (telecare consultation) or control group (usual in-person clinic consultation). Both groups will receive the same nursing intervention but delivered through different channels. The Reach, Effectiveness, Adoption, Implementation, Maintenance framework will be used to evaluate the clinical effectiveness and implementation outcomes. The primary outcome is the non-inferiority of the degree of disability between the two groups at 3 months into the intervention and at 3 months post-intervention. The paper complies with the SPIRIT guidelines for study protocols adapted for designing and reporting parallel group randomized trials.

CONCLUSION

The findings of this study will provide key insights into the processes for implementing and adopting telecare consultations into long-term services for post-stroke patients.

IMPACT

This study contributes to the translation of telecare consultations for stroke survivors into real-life settings. If effective, this program may provide guidance for expanding telecare consultations to other post-stroke nurse-led clinics or to patients with other chronic diseases.

TRIAL REGISTRATION

This study has been registered at clinicaltrials.gov (identifier: NCT05183672). Registered on 10 January 2022.

Astrocytic endothelin-1 overexpression impairs learning and memory ability in ischemic stroke via altered hippocampal neurogenesis and lipid metabolism

Vascular etiology is the second most prevalent cause of cognitive impairment globally. Endothelin-1, which is produced and secreted by endothelial cells and astrocytes, is implicated in the pathogenesis of stroke. However, the way in which changes in astrocytic endothelin-1 lead to poststroke cognitive deficits following transient middle cerebral artery occlusion is not well understood. Here, using mice in which astrocytic endothelin-1 was overexpressed, we found that the selective overexpression of endothelin-1 by astrocytic cells led to ischemic stroke-related dementia (1 hour of ischemia; 7 days, 28 days, or 3 months of reperfusion). We also revealed that astrocytic endothelin-1 overexpression contributed to the role of neural stem cell proliferation but impaired neurogenesis in the dentate gyrus of the hippocampus after middle cerebral artery occlusion. Comprehensive proteome profiles and western blot analysis confirmed that levels of glial fibrillary acidic protein and peroxiredoxin 6, which were differentially expressed in the brain, were significantly increased in mice with astrocytic endothelin-1 overexpression in comparison with wild-type mice 28 days after ischemic stroke. Moreover, the levels of the enriched differentially expressed proteins were closely related to lipid metabolism, as indicated by Kyoto Encyclopedia of Genes and Genomes pathway analysis. Liquid chromatography-mass spectrometry nontargeted metabolite profiling of brain tissues showed that astrocytic endothelin-1 overexpression altered lipid metabolism products such as glycerol phosphatidylcholine, sphingomyelin, and phosphatidic acid. Overall, this study demonstrates that astrocytic endothelin-1 overexpression can impair hippocampal neurogenesis and that it is correlated with lipid metabolism in poststroke cognitive dysfunction.

Physiotherapy Approach to an Internal Capsule Infarct With Upper Motor Neuron Facial Nerve Palsy: A Case Report

The internal capsule (IC) is a vital brain structure housing descending and ascending fiber tracts, with traditional assumptions about the corticobulbar and corticospinal tracts descending through the genu and anterior third of the posterior limb of internal capsule (PLIC), respectively. However, observations of IC infarctions reveal that symptoms often deviate from the expected fiber pattern, prompting a deeper exploration of these complexities. The posterior limb of the IC receives its blood supply from the lenticulostriate branches of the middle cerebral artery and the anterior choroidal artery (AChA). AChA infarctions present a diverse array of symptoms beyond the classic triad, reflecting the intricate vascular supply and lesion patterns within this region. We present a case of a 74-year-old male farmer with right-hand dominance, who experienced a fall resulting in head and right lower limb injuries. Subsequently, he developed weakness in his left upper and lower limbs, facial deviation, slurred speech, and swelling in the right lower limb. Following these symptoms, his family promptly brought him to the hospital on November 30, 2023. Extensive investigations, including magnetic resonance imaging (MRI), revealed a hyper-acute infarct in the posterior limb of the left IC. The patient was admitted to the intensive care unit (ICU) for three days and later shifted to the neurology ward where medical management was commenced, including physiotherapy protocol that was started on December 2, 2023. Physiotherapy interventions were designed to address the patient's weakness, altered sensation, and diminished reflexes. Therapeutic goals focused on preventing complications, improving posture, enhancing range of motion (ROM), and mitigating breathing difficulties and mobility issues. The physiotherapy aimed to enhance the patient's overall physical and mental well-being, emphasizing independence and improved quality of life. Regular assessments and adjustments to the therapeutic interventions were made based on the patient's progress. This case underscores the importance of tailored physiotherapy interventions in addressing the diverse manifestations of IC infarctions, contributing to a comprehensive understanding of rehabilitation strategies in neurologically compromised individuals.

Neurological Consequences of Cardiac Arrhythmias: Relationship Between Stroke, Cognitive Decline, and Heart Rhythm Disorders

Cardiac arrhythmias are one of the most common disorders with high morbidity and mortality. The effect of cardiac arrhythmias on the brain is very pronounced due to the high sensitivity of the brain to oxygen and blood supply. This mortality is preventable by early diagnosis and treatment which improves the patient's quality of life. Intervening at the right time, post arrhythmia is significant in preventing deaths and improving patient outcomes. Multiple pathophysiological mechanisms are studied for the brain-axis implications, that have the potential to be targeted by novel therapies. In this review, we describe the pathophysiological mechanisms and recent advances in detail to understand the functional aspects of the brain-heart axis and neurological implications post-stroke, caused by cardiac disorders.  This paper aims to discuss the current literature on the neurological consequences of cardiac arrhythmias and delve into a deeper understanding of the brain-heart axis, imbalances, and decline, with the aim of summarizing everything and all about the neurological consequences of cardiac arrhythmias.

Age at cardiovascular disease onset, dementia risk, and the role of lifestyle factors

INTRODUCTION

We first examined the role of age at cardiovascular disease (CVD) onset for incident dementia, and then examined whether lifestyle factors at guideline-recommended levels in individuals with CVD mitigates dementia risk.

METHODS

We used population-based data (Whitehall II: n = 10,308/baseline 1985-1988/examinations every 4-5 years). Lifestyle factors (non-smoking, body mass index [BMI], physical activity, diet) were extracted post-CVD.

RESULTS

Over a median of 31.6 years, 3275 (32.1%) developed CVD. At age 70, risk of dementia was higher in individuals with CVD onset before (hazard ratio [HR] of incident dementia for participants with CVD before age 60, using participants without CVD at age 70 as the reference: 1.56, 95% confidence interal [CI] 1.18-2.08) but not after 60 years. In participants with CVD, a greater number of lifestyle factors at recommended levels post-CVD was associated with a lower dementia risk (per lifestyle factor at recommended level HR: 0.73, 95% CI 0.59-0.92).

DISCUSSION

Our results suggest that early onset CVD is associated with a higher dementia risk at older ages. In those with CVD, the dementia risk was lower if lifestyle factors are at recommended levels following CVD diagnosis.

HIGHLIGHTS

CVD in midlife but not in late life is associated with a higher risk of dementia. Dementia risk in CVD patients is lower if their lifestyle factors are at recommended levels. These findings provide evidence to promote CVD prevention in midlife or earlier. Study findings also show the importance of a healthy lifestyle in those with CVD.

Psychedelics for acquired brain injury: a review of molecular mechanisms and therapeutic potential

Acquired brain injury (ABI), such as traumatic brain injury and stroke, is a leading cause of disability worldwide, resulting in debilitating acute and chronic symptoms, as well as an increased risk of developing neurological and neurodegenerative disorders. These symptoms can stem from various neurophysiological insults, including neuroinflammation, oxidative stress, imbalances in neurotransmission, and impaired neuroplasticity. Despite advancements in medical technology and treatment interventions, managing ABI remains a significant challenge. Emerging evidence suggests that psychedelics may rapidly improve neurobehavioral outcomes in patients with various disorders that share physiological similarities with ABI. However, research specifically focussed on psychedelics for ABI is limited. This narrative literature review explores the neurochemical properties of psychedelics as a therapeutic intervention for ABI, with a focus on serotonin receptors, sigma-1 receptors, and neurotrophic signalling associated with neuroprotection, neuroplasticity, and neuroinflammation. The promotion of neuronal growth, cell survival, and anti-inflammatory properties exhibited by psychedelics strongly supports their potential benefit in managing ABI. Further research and translational efforts are required to elucidate their therapeutic mechanisms of action and to evaluate their effectiveness in treating the acute and chronic phases of ABI.

High-Serum Brain-Derived Neurotrophic Factor Levels Are Associated With Decreased Risk of Poststroke Cognitive Impairment

BACKGROUND

BDNF (brain-derived neurotrophic factor) is widely implicated in the pathophysiological process of stroke, but the effect of BDNF on poststroke cognitive impairment (PSCI) remains unclear. We aimed to investigate the association between baseline serum BDNF and the risk of PSCI at 3 months in a multicenter study based on a preplanned ancillary study of the CATIS trial (China Antihypertensive Trial in Acute Ischemic Stroke).

METHODS

We examined serum BDNF levels at baseline and used the Mini-Mental State Examination and Montreal Cognitive Assessment to evaluate cognitive function at 3-month follow-up after ischemic stroke. PSCI was defined as Mini-Mental State Examination score <27 or Montreal Cognitive Assessment score <25. Logistic regression analyses were performed to evaluate the association between serum BDNF and the risk of 3-month PSCI.

RESULTS

In this ancillary study, a total of 660 patients with ischemic stroke with hypertension were included, and 593 patients (mean age, 59.90±10.44 years; 410 males and 183 females) were finally included in this analysis. According to mini-mental state examination score, after adjustment for age, sex, education, baseline National Institutes of Health Stroke Scale score, APOE ɛ4 carriers, and other potential confounders, the odds ratio of PSCI for the highest tertile of BDNF was 0.60 ([95% CI, 0.39-0.94]; P=0.024) compared with the lowest tertile. Multiple-adjusted spline regression model showed a linear association of serum BDNF levels with PSCI at 3 months (P value for linearity=0.010). Adding serum BDNF to conventional prognostic factors slightly improved the risk reclassification of PSCI (net reclassification improvement: 27.46%, P=0.001; integrated discrimination index: 1.02%, P=0.015). Similar significant findings were observed when PSCI was defined by the Montreal Cognitive Assessment score.

CONCLUSIONS

Elevated serum BDNF levels were associated with a decreased risk of PSCI at 3 months, suggesting that serum BDNF might be a potential predictive biomarker for PSCI among patients with ischemic stroke with hypertension.

Bioinformatics identification of potential biomarkers and therapeutic targets for ischemic stroke and vascular dementia

Ischemic stroke and vascular dementia, as common cerebrovascular diseases, with the former causing irreversible neurological damage and the latter causing cognitive and memory impairment, are closely related and have long received widespread attention. Currently, the potential causative genes of these two diseases have yet to be investigated, and effective early diagnostic tools for the diseases have not yet emerged. In this study, we screened new potential biomarkers and analyzed new therapeutic targets for both diseases from the perspective of immune infiltration. Two gene expression profiles on ischemic stroke and vascular dementia were obtained from the NCBI GEO database, and key genes were identified by LASSO regression and SVM-RFE algorithms, and key genes were analyzed by GO and KEGG enrichment. The CIBERSORT algorithm was applied to the gene expression profile species of the two diseases to quantify the 24 subpopulations of immune cells. Moreover, logistic regression modeling analysis was applied to illustrate the stability of the key genes in the diagnosis. Finally, the key genes were validated using RT-PCR assay. A total of 105 intersecting DEGs genes were obtained in the 2 sets of GEO datasets, and bioinformatics functional analysis of the intersecting DEGs genes showed that GO was mainly involved in the purine ribonucleoside triphosphate metabolic process，respiratory chain complex，DNA-binding transcription factor binding and active transmembrane transporter activity. KEGG is mainly involved in the Oxidative phosphorylation, cAMP signaling pathway. The LASSO regression algorithm and SVM-RFE algorithm finally obtained three genes, GAS2L1, ARHGEF40 and PFKFB3, and the logistic regression prediction model determined that the three genes, GAS2L1 (AUC: 0.882), ARHGEF40 (AUC: 0.867) and PFKFB3 (AUC: 0.869), had good diagnostic performance. Meanwhile, the two disease core genes and immune infiltration were closely related, GAS2L1 and PFKFB3 had the highest positive correlation with macrophage M1 (p < 0.001) and the highest negative correlation with mast cell activation (p = 0.0017); ARHGEF40 had the highest positive correlation with macrophage M1 and B cells naive (p < 0.001), the highest negative correlation with B cell memory highest correlation (p = 0.0047). RT-PCR results showed that the relative mRNA expression levels of GAS2L1, ARHGEF40, and PFKFB3 were significantly elevated in the populations of both disease groups (p < 0.05). Immune infiltration-based models can be used to predict the diagnosis of patients with ischemic stroke and vascular dementia and provide a new perspective on the early diagnosis and treatment of both diseases.

Role of residential greenspace in the trajectory of major neurological disorders: A longitudinal study in UK Biobank

BACKGROUND

Stroke and dementia are major neurological disorders that contribute significantly to disease burden and are interlinked in terms of risk. Nevertheless, there is currently no study investigating the influence of residential greenspace on the trajectory of these neurological disorders.

METHODS

This longitudinal study utilized data from the UK Biobank. Exposure to residential greenspace was measured by the percentage of total greenspace coverage within a 300-meter buffer zone surrounding the participants' residences. A multistate model was employed to illustrate the trajectory of major neurological disorders, and a piecewise Cox regression model was applied to explore the impact of residential greenspace on different time courses of disease transitions.

RESULTS

With 422,649 participants and a median follow-up period of 12.5 years, 8568 (2.0 %), 5648 (1.3 %), and 621 (0.1 %) individuals developed incident stroke, dementia, and comorbidity of both conditions, respectively. An increase in residential greenspace by one interquartile range was associated with reduced risks of transitions from baseline to stroke, dementia, and death, as well as from stroke to comorbidity. The corresponding hazard ratios (HRs) were 0.967 (95 % CI: 0.936, 0.998), 0.928 (0.892, 0.965), 0.925 (0.907, 0.942), and 0.799 (0.685, 0.933), respectively. Furthermore, the protective effect of residential greenspace on the transition from stroke or dementia to comorbidity was particularly pronounced within the first year and over 5 years after stroke and during the 2 to 3 years after dementia onset, with HRs of 0.692 (0.509, 0.941), 0.705 (0.542, 0.918), and 0.567 (0.339, 0.949), respectively.

CONCLUSION

This study observed a protective role of residential greenspace in the trajectory of major neurological disorders and contributed to identifying critical progression windows. These findings underscore the significance of environment-health interactions in the prevention of neurological disorders.

Risk factors for post-cerebral infarction cognitive dysfunction in older adults: a retrospective study

OBJECTIVE

Our research aims to elucidate the significance of type 2 diabetes (T2D) and provides an insight into a novel risk model for post-cerebral infarction cognitive dysfunction (PCICD).

METHODS

Our study recruited inpatients hospitalized with cerebral infarction in Xijing hospital, who underwent cognitive assessment of Mini-Mental State Examination (MMSE) from January 2010 to December 2021. Cognitive status was dichotomized into normal cognition and cognitive impairment. Collected data referred to Demographic Features, Clinical Diseases, scale tests, fluid biomarkers involving inflammation, coagulation function, hepatorenal function, lipid and glycemic management.

RESULTS

In our pooled dataset from 924 eligible patients, we included 353 in the final analysis (age range 65-91; 30.31% female). Multivariate logistic regression analysis was performed to show that Rural Areas (OR = 1.976, 95%CI = 1.111-3.515, P = 0.020), T2D (OR = 2.125, 95%CI = 1.267-3.563, P = 0.004), Direct Bilirubin (OR = 0.388, 95%CI = 0.196-0.769, P = 0.007), Severity of Dependence in terms of Barthel Index (OR = 1.708, 95%CI = 1.193-2.445, P = 0.003) that were independently associated with PCICD, constituting a model with optimal predictive efficiency.

CONCLUSION

To the best of our knowledge, this study provides a practicable map of strategical predictors to robustly identify cognitive dysfunction at risk of post-cerebral infarction for clinicians in a broad sense. Of note, our findings support that the decline in serum direct bilirubin (DBil) concentration is linked to protecting cognitive function.

Electroacupuncture attenuates middle cerebral artery occlusion-induced learning and memory impairment by regulating microglial polarization in hippocampus

BACKGROUND

As a traditional medical therapy, electroacupuncture (EA) has been demonstrated to have beneficial effects on ischemic stroke-induced cognitive impairment. However, the underlying mechanism is largely unclear.

METHODS

Adult rats received occlusion of the middle cerebral artery and reperfusion (MCAO/R) to establish the ischemic stroke model. Morris water maze test was performed following EA stimulation at the GV20, PC6, and KI1 acupoints in rats to test the learning and memory ability. Western blot, immunofluorescent staining, and enzyme-linked immunosorbent assay were conducted to assess the cellular and molecular mechanisms.

RESULTS

EA stimulation attenuated neurological deficits. In the Morris water maze test, EA treatment ameliorated the MCAO/R-induced learning and memory impairment. Moreover, we observed that MCAO/R induced microglial activation and polarization in the ischemic hippocampus, whereas, EA treatment dampened microglial activation and inhibited M1 microglial polarization but enhanced M2 microglial polarization. EA treatment inhibited the increased expression of proinflammatory cytokines and enhanced the increased expression of anti-inflammatory cytokines. Finally, we found that EA treatment dampened microglial p38 mitogen-activated protein kinase (MAPK) phosphorylation.

CONCLUSION

Collectively, our data suggested that EA treatment ameliorated cognitive impairment induced by MCAO/R and the underlying mechanism may be p38-mediated microglia polarization and neuroinflammation.

Risk factors and predictive markers of post-stroke cognitive decline-A mini review

Stroke is one of the top causes of death and disability worldwide. Cognitive impairments are found in more than 70% of individuals who have survived a stroke. Cognitive decline is a major contributor to disability, dependency, and morbidity. The prevalence and severity of dementia vary depending on different characteristics of the stroke and other clinical risk factors. Here we discuss the effects of stroke territory, patients' age, sex, cerebral blood flow, acute reperfusion therapy, and cognitive reserve of post-stroke cognitive decline. Potential predictive molecular and genetic biomarkers of post-stroke cognitive impairments are also discussed.

The Luigi Sacco Hospital VAS-COG stroke care pathway: A five-year experience

Background

Psycho-cognitive consequences are a frequent cause of disability in stroke survivors but are often underdiagnosed also because of lack of services dedicated to these aspects. We started assessing systematically cognitive and behavioral functions in acute stroke patients and to follow them up. Here, we report a retrospective analysis of the organization of the Sacco VAS-COG stroke care pathway and the refinements implemented during 5 years of activity.

Methods

The protocol includes baseline collection of clinical history, general and neurologic examinations, functional, neuropsychological, and neuroimaging assessment. At follow-up, a diagnosis of cognitive decline was made based on best clinical judgment in the first period (January 2018 to May 2019, namely VAS-COG protocol 1.0) and then based on an extensive neuropsychological battery (May 2019 to January 2023, namely VASCOG protocol 2.0); psychiatric and behavioral disturbances are investigated through suitable scales.

Results

From January 2018 to December 2022, 834 patients (mean age 76±13.6 years; 46.6 % females) with acute cerebrovascular events were admitted to the stroke unit, mostly (80 %) for ischemic strokes. Pre-event cognitive impairment was not assessable in 78 patients (9.3 %) because no reliable informant was present and was reported in 327/756 (43 %) patients. During follow-up, post-stroke cognitive impairment was detected in 124/217 (57.1 %) patients in VAS-COG protocol 1.0 and in 137/201(68.2 %) patients in VAS-COG protocol 2.0, while 95/218 (43.2 %) patients were found to be depressed and patients presented on average 2.5 neuropsychiatric symptoms on Neuropsychiatric Inventory-questionnaire.

Conclusions

The VAS-COG stroke care pathway represents a model for patients and for their families.

Interactions between tDCS treatment and COMT Val158Met in poststroke cognitive impairment

OBJECTIVE

This study aimed to explore the effect of catechol-O-methyltransferase (COMT) Val158Met and brain-derived neurotrophic factor (BDNF) Val66Met to post-stroke cognitive impairment (PSCI) and the interaction with transcranial direct current stimulation (tDCS).

METHODS

Seventy-six patients with PSCI were randomly assigned to Group (1) (n = 38) to receive anodal tDCS of left dorsolateral prefrontal cortex or Group (2) (n = 38) to receive sham stimulation. The intensity of the tDCS was 2 mA, and the stimulations were applied over the left DLPFC for 10 sessions. The Montreal Cognitive Assessment (MoCA) and backward digit span test (BDST) were assessed before, immediately after, and one month after stimulation.

RESULTS

After stimulation, patients in the tDCS group showed better improvement in both MoCA and BDST than those in the sham group. The results of GLMs also supported the main effects of tDCS on general cognitive function and working memory. Then we found that COMT genotype may have a main effect on the improvement of MoCA and BDST, and there may be an interaction between COMT genotype and tDCS in enhancing BDST. In contrast, BDNF genotype showed no significant main or interaction effects on any scales.

CONCLUSIONS

These findings demonstrate that tDCS can improve cognition after stroke. Gene polymorphisms of COMT can affect the efficacy of tDCS on PSCI, but BDNF may not.

SIGNIFICANCE

This study found that COMT Val158Met has an interaction on the efficacy of prefrontal tDCS in cognitive function, which provides reference for future tDCS research and clinical application.

Therapeutic robots for post-stroke rehabilitation

Stroke is a prevalent, severe, and disabling health-care issue on a global scale, inevitably leading to motor and cognitive deficits. It has become one of the most significant challenges in China, resulting in substantial social and economic burdens. In addition to the medication and surgical interventions during the acute phase, rehabilitation treatment plays a crucial role in stroke care. Robotic technology takes distinct advantages over traditional physical therapy, occupational therapy, and speech therapy, and is increasingly gaining popularity in post-stroke rehabilitation. The use of rehabilitation robots not only alleviates the workload of healthcare professionals but also enhances the prognosis for specific stroke patients. This review presents a concise overview of the application of therapeutic robots in post-stroke rehabilitation, with particular emphasis on the recovery of motor and cognitive function.

Impact of early cognitive impairment on outcome trajectory in patients with intracerebral hemorrhage

OBJECTIVE

To assess the prevalence and factors associated with early cognitive impairment in intracerebral hemorrhage (ICH) patients and to describe short-term recovery trajectories among ICH patients with early cognitive impairment.

METHODS

We prospectively enrolled ICH patients without baseline dementia in our institutions. Cognitive function was assessed using mini-mental state examination (MMSE), and functional outcome was evaluated at discharge, 3, and 6 months after symptoms onset using the modified Rankin Scale (mRS). We used multinomial logistic regression models to investigate potential risk factors and generalized linear models to analyze the functional outcome data.

RESULTS

Out of 181 patients with ICH, 167 were included in the final analysis. Early cognitive impairment occurred in 60.48% of patients with ICH. Age (odds ratio [OR] per 1-year increase, 1.037; 95% confidence interval [CI], 1.003-1.071; p = 0.034), National Institutes of Health Stroke Scale (NIHSS) score (OR per 1-point increase, 1.146; 95% CI, 1.065-1.233; p < 0.001) and lobar ICH location (OR, 4.774; 95% CI, 1.810-12.593; p = 0.002) were associated with early cognitive impairment in ICH patients. Patients with ≥10 years of education were less likely to experience early cognitive impairment (OR, 0.323; 95% CI, 0.133-0.783; p = 0.012). Participants with early cognitive impairment had a higher risk of poor outcome (OR, 4.315; 95% CI, 1.503-12.393; p = 0.005) than those without. Furthermore, there was a significantly faster functional recovery rate for those without early cognitive impairment compared with those with at 3 and 6 months (p < 0.05).

INTERPRETATION

Early cognitive impairment was prevalent and associated with poor outcomes in ICH patients, which decelerated short-term functional recovery.

Absence in CX3CR1 receptor signaling promotes post-ischemic stroke cognitive function recovery through suppressed microglial pyroptosis in mice

BACKGROUND

Post-stroke cognitive impairment (PSCI) is a major source of morbidity and mortality after stroke, but the pathological mechanisms remain unclear. Previous studies have demonstrated that the CX3CR1 receptor plays a crucial role in maintaining an early protective microenvironment after stroke, but whether it persistently influences cognitive dysfunction in the chronic phase requires further investigation.

METHODS

Mouse was used to establish a middle cerebral artery occlusion (MCAO)/reperfusion model to study PSCI. Cognitive function was assessed by the Morris water maze (MWM) and the novel object recognition test. Neurogenesis was assessed by immunofluorescence staining with Nestin+ /Ki67+ and DCX+ /BrdU+ double-positive cells. The cerebral damage was monitored by [18 F]-DPA-714 positron emission tomography, Nissel, and TTC staining. The pyroptosis was histologically, biochemically, and electron microscopically examined.

RESULTS

Upon MCAO, at 28 to 35 days, CX3CR1 knockout (CX3CR1-/- ) mice had better cognitive behavioral performance both in MWM and novel object recognition test than their CX3CR1+/- counterparts. Upon MCAO, at 7 days, CX3CR1-/- mice increased the numbers of Nestin+ /Ki67+ and DCX+ /BrdU+ cells, and meanwhile it decreased the protein expression of GSDMD, NLRP3 inflammasome subunit, caspase-1, mature IL-1β/IL-18, and p-P65 in the hippocampus as compared with CX3CR1+/- mice. In addition, CX3CR1-/- mice could reverse infarct volume in the hippocampus region post-stroke.

CONCLUSION

Our study demonstrated that CX3CR1 gene deletion was beneficial to PSCI recovery. The mechanism might lie in inhibited pyroptosis and enhanced neurogenesis. CX3CR1 receptor may serve as a therapeutic target for improving the PSCI.

The Korean Version of the Oxford Cognitive Screen (K-OCS) Normative Study

OBJECTIVE

To generate a Korean version of the Oxford Cognitive Screen (K-OCS) and obtain cutoff scores that determine the impairment of each subdomain. Post-stroke cognitive impairment (PSCI) negatively impacts the rehabilitation process and independence in daily life. Its obscure manifestations require effective screening for appropriate rehabilitation. However, in most rehabilitation clinics, psychological evaluation tools for Alzheimer's dementia have been used without such considerations. The OCS is a screening assessment tool for PSCI and vascular dementia that can evaluate the cognitive domains most often affected by stroke, including language, attention, memory, praxis, and numerical cognition. It comprises 10 subtasks and enables quick and effective cognitive evaluation.

METHODS

The K-OCS, which considers Korea's unique cultural and linguistic characteristics, was developed with the approval and cooperation of the original author. Enrollment of participants without disabilities was announced at Duksung Women's University, Yongin Sevrance Hospital, CHA Bundang Medical Center. The study was conducted between September 2020 and March 2022 on 97 male and female participants aged ≥30 years.

RESULTS

All the 97 participants completed the task. In this study, the 5th percentile score was presumed to be the cutoff value for each score, and the values are provided here. The cutoff score for each OCS subtask was similar to that of the original British version.

CONCLUSION

We suggest the usability of the K-OCS as a screening tool for PSCI by providing the cutoff value of each subtask.

Dysfunction of the triple-network model is associated with cognitive impairment in patients with cerebral small vessel disease

Purpose

This study aimed to demonstrate the correlations between the altered functional connectivity patterns in the triple-network model and cognitive impairment in patients with cerebral small vascular disease (CSVD).

Methods

Resting-state functional magnetic resonance imaging data were obtained from 22 patients with CSVD and 20 healthy controls. The resting-state data were analyzed using independent component analysis and functional network connectivity (FNC) analysis to explore the functional alterations in the intrinsic triple-network model including the salience network (SN), default mode network (DMN), and central executive network (CEN), and their correlations with the cognitive deficits and clinical observations in the patients with CSVD.

Results

Compared to the healthy controls, the patients with CSVD exhibited increased connectivity patterns in the CEN-DMN and decreased connectivity patterns in the DMN-SN, CEN-SN, intra-SN, and intra-DMN. Significant negative correlations were detected between the intra-DMN connectivity pattern and the Montreal Cognitive Assessment (MoCA) total scores (r = -0.460, p = 0.048) and MoCA abstraction scores (r = -0.565, p = 0.012), and a positive correlation was determined between the intra-SN connectivity pattern and the MoCA abstraction scores (r = 0.491, p = 0.033).

Conclusions

Our study findings suggest that the functional alterations in the triple-network model are associated with the cognitive deficits in patients with CSVD and shed light on the importance of the triple-network model in the pathogenesis of CSVD.

Ischemia-Reperfusion Programming of Alzheimer's Disease-Related Genes-A New Perspective on Brain Neurodegeneration after Cardiac Arrest

The article presents the latest data on pathological changes after cerebral ischemia caused by cardiac arrest. The data include amyloid accumulation, tau protein modification, neurodegenerative and cognitive changes, and gene and protein changes associated with Alzheimer's disease. We present the latest data on the dysregulation of genes related to the metabolism of the amyloid protein precursor, tau protein, autophagy, mitophagy, apoptosis, and amyloid and tau protein transport genes. We report that neuronal death after cerebral ischemia due to cardiac arrest may be dependent and independent of caspase. Moreover, neuronal death dependent on amyloid and modified tau protein has been demonstrated. Finally, the results clearly indicate that changes in the expression of the presented genes play an important role in acute and secondary brain damage and the development of post-ischemic brain neurodegeneration with the Alzheimer's disease phenotype. The data indicate that the above genes may be a potential therapeutic target for brain therapy after ischemia due to cardiac arrest. Overall, the studies show that the genes studied represent attractive targets for the development of new therapies to minimize ischemic brain injury and neurological dysfunction. Additionally, amyloid-related genes expression and tau protein gene modification after cerebral ischemia due to cardiac arrest are useful in identifying ischemic mechanisms associated with Alzheimer's disease. Cardiac arrest illustrates the progressive, time- and area-specific development of neuropathology in the brain with the expression of genes responsible for the processing of amyloid protein precursor and the occurrence of tau protein and symptoms of dementia such as those occurring in patients with Alzheimer's disease. By carefully examining the common genetic processes involved in these two diseases, these data may help unravel phenomena associated with the development of Alzheimer's disease and neurodegeneration after cerebral ischemia and may lead future research on Alzheimer's disease or cerebral ischemia in new directions.

Evaluation of the functional outcome and mobility of patients after stroke depending on their cognitive state

The study aimed to analyze the functional outcome and mobility in stroke patients depending on their cognitive state. 180 patients after first stroke were divided into four groups: 48 patients without symptoms of cognitive impairment (G1); 38 with mild cognitive impairment without dementia (G2); 47 with mild dementia (G3); 47 with moderate dementia (G4). The Mini Mental State Examination (MMSE), Barthel Index (BI), Sitting Assessment Scale (SAS), Berg Balance Scale, Trunk Control Test and Test Up & Go were used. The tests were carried out at the time of admission to the ward (T1) and at the time of discharge (T2). A statistically significant improvement was demonstrated in all parameters in almost all groups. No significant difference was observed only in groups G1 and G4 in SAS head. Statistically significant differences in BI results in T2 between groups G1 and G4 were noted. The lowest change in BI was observed in the G4. Regression analysis showed that MMSE and BI at T1 and MMSE score at T2 explained the functional status at T2. Cognitive dysfunction at the time of admission to the ward and discharge may determining the patient's functional status at the time of discharge from the ward.

Causality between cognitive performance and cardiovascular disease: A bidirectional Mendelian randomization study

BACKGROUND

Growing evidence points to a connection between cardiovascular disease and cognitive impairment. These observational study findings, however, were not all uniform, and some did not discover a link like this. Investigating the causal link between cognitive impairment and cardiovascular disease is vital.

METHOD

Using publicly available genome-wide association study (GWAS) summary datasets and stringent screening instrumental variables, we carried out a bidirectional Mendelian randomization study. To investigate the causality between cardiovascular disease and cognitive impairment, three different MR techniques-inverse variance weighted (IVW), MR-Egger, and weighted median-as well as various sensitivity analyses-Cochran's Q, ivw_radial, leave-one-out (LOO), MR-Egger intercept, and MR-PRESSO-were used.

RESULTS

The causal impact of genetically predicted cognitive performance on hypertension, atrial fibrillation, heart failure, coronary atherosclerosis, coronary artery disease, and myocardial infarction was detected in the forward MR analysis, but not stroke or any subtypes. We only discover the causal effects of hypertension, any stroke, and its subtypes (ischemic and small vessel stroke) on cognitive performance in the reverse MR analysis.

CONCLUSION

This MR analysis offers proof of a causal link between cognitive impairment and elevated cardiovascular disease risk. Our research emphasizes the value of cognitively impaired patients being screened for cardiovascular disease, which may offer fresh perspectives on cardiovascular disease prevention.

MoCA Domain-Specific Pattern of Cognitive Impairment in Stroke Patients Attending Intensive Inpatient Rehabilitation: A Prospective Study

A domain-specific perspective to cognitive functioning in stroke patients may predict their cognitive recovery over time and target stroke rehabilitation intervention. However, data about domain-specific cognitive impairment after stroke are still scarce. This study prospectively investigated the domain-specific pattern of cognitive impairments, using the classification proposed by the Montreal Cognitive Assessment (MoCA), in a cohort of 49 stroke patients at admission (T0), discharge (T1), and six-month follow-up (T2) from subacute intensive rehabilitation. The predictive value of T0 cognitive domains cognitive impairment at T1 and T2 was also investigated. Patients' cognitive functioning at T0, T1, and T2 was assessed through the MoCA domains for executive functioning, attention, language, visuospatial, orientation, and memory. Different evolutionary trends of cognitive domain impairments emerged across time-points. Patients' impairments in all domains decreased from T0 to T1. Attention and executive impairments decreased from T0 to T2 (42.9% and 26.5% to 10.2% and 18.4%, respectively). Conversely, altered visuospatial, language, and orientation increased between T1 and T2 (16.3%, 36.7%, and 40.8%, respectively). Additionally, patients' global cognitive functioning at T1 was predicted by the language and executive domains in a subacute phase (p = 0.031 and p = 0.001, respectively), while in the long term, only attention (p = 0.043) and executive (p = 0.019) domains intervened. Overall, these results confirm the importance of a domain-specific approach to target cognitive recovery across time in stroke patients.