Predictors for Favorable Cognitive Outcome Post-Stroke: A-Seven-Year Follow-Up Study

White matter integrity and functional connectivity of the default mode network in acute stroke are associated with cognitive outcome three months post-stroke

BACKGROUND

Knowledge about factors that are associated with post-stroke cognitive outcome is important to identify patients with high risk for impairment. We therefore investigated the associations of white matter integrity and functional connectivity (FC) within the brain's default-mode network (DMN) in acute stroke patients with cognitive outcome three months post-stroke.

METHODS

Patients aged between 18 and 85 years with an acute symptomatic MRI-proven unilateral ischemic middle cerebral artery infarction, who had received reperfusion therapy, were invited to participate in this longitudinal study. All patients underwent brain MRI within 24-72 h after symptom onset, and participated in a neuropsychological assessment three months post-stroke. We performed hierarchical regression analyses to explore the incremental value of baseline white matter integrity and FC beyond demographic, clinical, and macrostructural information for cognitive outcome.

RESULTS

The study cohort comprised 34 patients (mean age: 64 ± 12 years, 35% female). The initial median National Institutes of Health Stroke Scale (NIHSS) score was 10, and significantly improved three months post-stroke to a median NIHSS = 1 (p < .001). Nonetheless, 50% of patients showed cognitive impairment three months post-stroke. FC of the non-lesioned anterior cingulate cortex of the affected hemisphere explained 15% of incremental variance for processing speed (p = .007), and fractional anisotropy of the non-lesioned cingulum of the affected hemisphere explained 13% of incremental variance for cognitive flexibility (p = .033).

CONCLUSIONS

White matter integrity and functional MRI markers of the DMN in acute stroke explain incremental variance for post-stroke cognitive outcome beyond demographic, clinical, and macrostructural information.

Serum PAI-1/BDNF Ratio Is Increased in Alzheimer's Disease and Correlates with Disease Severity

We previously demonstrated that serum levels of plasminogen activator inhibitor-1 (PAI-1), which inhibits both the tissue plasminogen activator (tPA) and plasmin activity, are increased in patients with Alzheimer's disease. tPA/plasmin not only prevents the accumulation of β-amyloid in the brain but also is involved in the synthesis of the brain-derived neurotrophic factor (BDNF), a neurotrophin whose levels are reduced in Alzheimer. In the present study, we compared BDNF serum levels in Alzheimer patients with dementia to those in Alzheimer patients with amnestic mild cognitive impairment and to cognitively healthy controls. Moreover, we examined whether the PAI-1/BDNF ratio correlates with disease severity, as measured by Mini-Mental State Examination. Our results showed that BDNF serum levels are lower (13.7% less) and PAI-1 levels are higher in Alzheimer patients with dementia than in Alzheimer patients with amnestic mild cognitive impairment patients (23% more) or controls (36% more). Furthermore, the PAI-1/BDNF ratio was significantly increased in Alzheimer patients as compared to amnestic mild cognitive impairment (36.4% more) and controls (40% more). Lastly, the PAI-1/BDNF ratio negatively correlated with the Mini-Mental score. Our results suggest that increased PAI-1 levels in Alzheimer, by impairing the production of the BDNF, are implicated in disease progression. They also indicate that the PAI-1/BDNF ratio could be used as a marker of Alzheimer. In support of this hypothesis, a strong negative correlation between the PAI-1/BDNF ratio and the Mini-Mental score was observed.

White Matter Microstructural Alterations over the Year after Acute Ischemic Stroke in Patients with Baseline Impaired Cognitive Functions

Background

The disruption of white matter (WM) integrity is related to poststroke cognitive impairment (PSCI). The exploration of WM integrity alterations in the chronic stage of acute ischemic stroke (AIS) may help to improve the long-term outcomes of PSCI.

Methods

Sixty patients showing impaired cognitive functions within 3 days after AIS (baseline) and 25 healthy controls underwent diffusion kurtosis imaging scan and cognitive assessment at baseline and 1 year. Based on the tract-based spatial statistics (TBSS), kurtosis fractional anisotropy (KFA) and mean kurtosis (MK) were compared in WM tracts between the groups.

Results

One year after AIS, 25 patients were diagnosed with PSCI and 35 patients with non-cognitive impairment (NCI). Compared with baseline, cognitive performance improved in 54 patients and remained unchanged in 6 patients at 1 year. TBSS analysis showed that there were no significant differences in WM tract integrity between the AIS and control groups at baseline (P > 0.05). Compared with the control group, the KFA and MK in multiple WM tracts in the AIS group decreased significantly at 1 year (P < 0.05). Longitudinal analysis showed that the KFA and MK of multiple WM tracts recorded at 1 year were significantly lower than those recorded at baseline in the AIS, PSCI, and NCI groups (P < 0.05), and PSCI group had a faster degeneration than NCI group (P < 0.05).

Conclusion

The finding suggests that the patients with baseline impaired cognitive functions still have WM microstructural damages at 1 year poststroke, even if their cognitive function has improved or returned to normal. Cautions should be taken against the possible negative impact of these changes on long-term cognition.

Multimodal individualised intervention to prevent functional decline after stroke: protocol of a randomised controlled trial on long-term follow-up after stroke (LAST-long)

INTRODUCTION

Multimodal interventions have emerged as new approaches to provide more targeted intervention to reduce functional decline after stroke. Still, the evidence is contradictory. The main objective of the Life After Stroke (LAST)-long trial is to investigate if monthly meetings with a stroke coordinator who offers a multimodal approach to long-term follow-up can prevent functional decline after stroke.

METHODS AND ANALYSIS

LAST-long is a pragmatic single-blinded, parallel-group randomised controlled trial recruiting participants living in six different municipalities, admitted to four hospitals in Norway. The patients are screened for inclusion and recruited into the trial 3 months after stroke. A total of 300 patients fulfilling the inclusion criteria will be randomised to an intervention group receiving monthly follow-up by a community-based stroke coordinator who identifies the participants' individual risk profile and sets up an action plan based on individual goals, or to a control group receiving standard care. All participants undergo blinded assessments at 6-month, 12-month and 18-month follow-up. Modified Rankin Scale at 18 months is primary outcome. Secondary outcomes are results of blood tests, blood pressure, adherence to secondary prophylaxis, measures of activities of daily living, cognitive function, physical function, physical activity, patient reported outcome measures, caregiver's burden, the use and costs of health services, safety measures and measures of adherence to the intervention. Mixed models will be used to evaluate differences between the intervention and control group for all endpoints across the four time points, with treatment group, time as categorical covariates and their interaction as fixed effects, and patient as random effect.

ETHICS AND DISSEMINATION

This trial was approved by the Regional Committee of Medical and Health Research Ethics, REC no. 2018/1809. The main results will be published in international peer-reviewed open access scientific journals and to policy-makers and end users in relevant channels.

TRIAL REGISTRATION NUMBER

ClincalTrials.gov Identifier: NCT03859063, registered on 1 March 2019.

Factors associated with cognitive impairment at 3, 6, and 12 months after the first stroke among Lebanese survivors

INTRODUCTION

This study aimed to calculate the rate of post-stroke cognitive impairment (PSCI) by evaluating the cognitive domains among Lebanese stroke survivors at 3, 6, and 12 months post-stroke, and to identify the contributing factors including pre- and post-stroke related factors.

METHODS

A multicenter longitudinal prospective study was conducted in 10 hospitals from Beirut and Mount Lebanon for a 15-month period. Mini-Mental State Examination (MMSE), modified Rankin Scale (mRS), Short Form Health Survey (SF12), National Institutes of Health Stroke Scale (NIHSS), and Hospital Anxiety and Depression Scale (HADS) were used to assess cognitive function, disability degree, Quality of Life (QoL), stroke severity, and levels of anxiety and depression, respectively. Then, univariate and multivariable analyses were performed to identify the predictors of PSCI.

RESULTS

Low MMSE scores were found among survivors during the first 3 months post-stroke (74.8%) of whom 53.7% presented with an MMSE ≤ 17, followed by 46.7% in the 6 months, and 37.6% at 12 months post-stroke. Follow-up comparisons showed a significant increase of MMSE scores over time (p < .001), indicating a 37% improvement of the cognitive function over time. The most affected cognitive domain was the attention and concentration at the three time points. Independent factors that were positively associated with low MMSE scores were as follows: sedentary behavior ≥ 12 h/day (AOR = 3.062, p = .033), involvement of the left hemisphere (AOR = 2.710, p = .006), HADS ≥ 11 (AOR = 2.536, p = .049), and high NIHSS scores (AOR = 3, p = .009). Age was the main predictor in the three time periods (AOR ≈ 3, p < .05). Inversely, female gender (AOR = 0.09, p = .027), high educational level (AOR = 0.2, p < .02), employment post-stroke (AOR = 0.3, p = .023), high Physical Component Summary (PCS) of Quality of Life (QoL) (AOR = 0.8, p < .001), and the use of anti-diabetic treatment post-stroke (AOR = 0.17, p = .016) improved MMSE scores to > 23.

CONCLUSION

The risk of PSCI among Lebanese stroke survivors was high especially in the acute phase, depending on various determinants. Health care providers are invited to implement an emergency rehabilitation program for an appropriate successful management of the risk factors in order to reduce stroke burden and to improve overall cognitive performance.

Carotid Atherosclerosis and Longitudinal Changes of MRI Visual Rating Measures in Stroke Survivors: A Seven-Year Follow-Up Study

OBJECTIVES

We aimed to assess longitudinal changes in MRI measures of brain atrophy and white matter lesions in stroke and transient ischemic attack (TIA) survivors, and explore whether carotid stenosis predicts progression of these changes, assessed by visual rating scales.

MATERIALS AND METHODS

All patients with a first-ever stroke or TIA admitted to Bærum Hospital, Norway, in 2007/2008, were invited in the acute phase and followed for seven years. Carotid ultrasound was performed during the hospital stay. Carotid stenosis was defined as ≥50% narrowing of lumen. MRI was performed one and seven years after the index event and analyzed according to the visual rating scales Fazekas scale (0-3), Medial Temporal Lobe Atrophy (MTLA) (0-4) score, and Global Cortical Atrophy (GCA) scale (0-3). Patients with MRI scans at both time points were included in this sub-study.

RESULTS

Of 227 patients recruited, 76 had both MRI examinations. Mean age 73.9±10.6, 41% women, and 9% had ≥50% carotid stenosis. Mean Fazekas scale was 1.7±0.9 and 1.8±1.0, mean MTLA score 1.0 ±1.0 and 1.7±1.0, and mean GCA scale score 1.4±0.7 and 1.4±0.6 after one and seven years, respectively. 71% retained the same Fazekas scale score, while 21% showed progression. Deterioration in GCA scale was seen in 20% and increasing MTLA score in 57%. Carotid stenosis was not associated with progression on Fazekas score, MTLA score or GCA scale.

CONCLUSIONS

Three out of five showed progression on the MTLA score. Carotid stenosis was not associated with longitudinal change of visual rating scales.

Association Between Small Vessel Disease Markers, Medial Temporal Lobe Atrophy and Cognitive Impairment After Stroke: A Systematic Review and Meta-Analysis

OBJECTIVES

Two-thirds of stroke survivors suffer from cognitive impairment, and up to one-third of them progress to dementia. However, the underlying pathogenesis is complex and controversial. Recent evidence has found that cerebral small vessel disease (SVD) markers and the Alzheimer's disease (AD) neuroimaging marker medial temporal lobe atrophy (MTLA), alone or in combination, contribute to the pathogenesis of poststroke cognitive impairment (PSCI). In the present systematic review and meta-analysis, we synthesized proof for these neuroimaging risk factors among stroke patients.

MATERIALS AND METHODS

PUBMED, MEDLINE, EMBASE and the Cochrane Library were searched for studies investigating imaging predictors of cognitive impairment or dementia following stroke. Meta-analysis was conducted to compute the odds ratios (ORs).

RESULTS

Thirteen studies were enrolled in the present study, and only ten of them, comprising 2713 stroke patients, were eligible for inclusion in the meta-analysis. MTLA was significantly correlated with PSCI (OR = 1.97, 95% CI: 1.48-2.62, I² = 0.0%). In addition, white matter hyperintensities (WMH), as a neuroimaging marker of SVD, were associated with PSCI (OR = 1.17, 95% CI: 1.12-1.22, I² = 0.0%). However, the presence of lacunar infarcts and enlarged perivascular spaces (EPVS) were not associated with the risk of PSCI.

CONCLUSIONS

The findings of the present study suggest that MTLA and WMH were associated with an increased risk of PSCI.

No evidence for amyloid pathology as a key mediator of neurodegeneration post-stroke - a seven-year follow-up study

Background

Cognitive impairment (CI) with mixed vascular and neurodegenerative pathologies after stroke is common. The role of amyloid pathology in post-stroke CI is unclear. We hypothesize that amyloid deposition, measured with Flutemetamol (¹⁸F-Flut) positron emission tomography (PET), is common in seven-year stroke survivors diagnosed with CI and, further, that quantitatively assessed ¹⁸F-Flut-PET uptake after 7 years correlates with amyloid-β peptide (Aβ₄₂) levels in cerebrospinal fluid (CSF) at 1 year, and with measures of neurodegeneration and cognition at 7 years post-stroke.

Methods

208 patients with first-ever stroke or transient Ischemic Attack (TIA) without pre-existing CI were included during 2007 and 2008. At one- and seven-years post-stroke, cognitive status was assessed, and categorized into dementia, mild cognitive impairment or normal. Etiologic sub-classification was based on magnetic resonance imaging (MRI) findings, CSF biomarkers and clinical cognitive profile. At 7 years, patients were offered ¹⁸F-Flut-PET, and amyloid-positivity was assessed visually and semi-quantitatively. The associations between ¹⁸F-Flut-PET standardized uptake value ratios (SUVr) and measures of neurodegeneration (medial temporal lobe atrophy (MTLA), global cortical atrophy (GCA)) and cognition (Mini-Mental State Exam (MMSE), Trail-making test A (TMT-A)) and CSF Aβ₄₂ levels were assessed using linear regression.

Results

In total, 111 patients completed 7-year follow-up, and 26 patients agreed to PET imaging, of whom 13 had CSF biomarkers from 1 year. Thirteen out of 26 patients were diagnosed with CI 7 years post-stroke, but only one had visually assessed amyloid positivity. CSF Aβ₄₂ levels at 1 year, MTA grade, GCA scale, MMSE score or TMT-A at 7 years did not correlate with ¹⁸F-Flut-PET SUVr in this cohort.

Conclusions

Amyloid binding was not common in 7-year stroke survivors diagnosed with CI. Quantitatively assessed, cortical amyloid deposition did not correlate with other measures related to neurodegeneration or cognition. Therefore, amyloid pathology may not be a key mediator of neurodegeneration 7 years post-stroke.

Trial registration

Clinicaltrials.gov (NCT00506818). July 23, 2007. Inclusion from February 2007, randomization and intervention from May 2007 and trial registration in July 2007.

Role of vinpocetine in ischemic stroke and poststroke outcomes: A critical review

Vinpocetine (VPN) is a synthetic ethyl-ester derivative of the alkaloid apovincamine from Vinca minor leaves. VPN is a selective inhibitor of phosphodiesterase type 1 (PDE1) that has potential neurological effects through inhibition of voltage-gated sodium channel and reduction of neuronal calcium influx. VPN has noteworthy antioxidant, anti-inflammatory, and anti-apoptotic effects with inhibitory effect on glial and astrocyte cells during and following ischemic stroke (IS). VPN is effective as adjuvant therapy in the management of epilepsy; it reduces seizure frequency by 50% in a dose of 2 mg/kg/day. VPN improves psychomotor performances through modulation of brain monoamine pathway mainly on dopamine and serotonin, which play an integral role in attenuation of depressive symptoms. VPN recover cognitive functions and spatial memory through inhibition of hippocampal and cortical PDE1 with augmentation of cyclic adenosin monophosphate and cyclic guanosin monophosphate ratio, enhancement of cholinergic neurotransmission, and inhibition of neuronal inflammatory mediators. Therefore, VPN is an effective agent in the management of IS and plays an integral role in the prevention and attenuation of poststroke epilepsy, depression, and cognitive deficit through direct cAMP/cGMP-dependent pathway or indirectly through anti-inflammatory and antioxidant effects.