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1.
J Geriatr Psychiatry Neurol ; 32(6): 336-343, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31480986

RESUMO

OBJECTIVE: This study investigated the association between small vessel disease (SVD) burden, a combination of multiple SVD markers and cognitive dysfunction after stroke. METHODS: The study sample comprised 451 patients with first-ever acute ischemic stroke. Cognitive functions were assessed with the Mini-Mental State Examination (MMSE) at 3, 9, and 15 months after the index stroke. Cognitive impairment was defined as an MMSE score of ≤26. A total SVD score, indicating SVD burden, was constructed by summing the scores of the 4 SVD markers (white matter hyperintensities [WMHs], lacunes, cerebral microbleeds, and perivascular spaces) ascertained by magnetic resonance imaging (range: 0-4). The association between SVD burden and cognitive dysfunction was assessed with linear mixed models or generalized estimating equation models, as appropriate. RESULTS: The majority of patients had mild-to-moderate stroke and at least one identifiable SVD marker. Cognitive impairment was found in about one-third of patients. After adjusting for confounding factors, the SVD burden was associated with MMSE scores (ß = -0.37, P = .003) and cognitive impairment (odds ratio [OR] = 1.20, 95% confidence interval [CI] = 1.02-1.42). SVD burden was specifically associated with the performance of MMSE subscores including orientation to place and time, calculation, and word recall. Of the SVD markers, WMHs was the most robust predictor of decrease in MMSE scores (ß = -0.25, P = .01) and cognitive impairment (OR = 1.14, 95% CI = 1.01-1.29). CONCLUSION: Cerebral SVD burden is associated with decreased MMSE scores, suggesting cognitive dysfunction during the first year after mild-to-moderate acute ischemic stroke.

2.
3.
Nat Commun ; 10(1): 3310, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31346172

RESUMO

Alzheimer's disease (AD) is a leading cause of mortality in the elderly. While the coding change of APOE-ε4 is a key risk factor for late-onset AD and has been believed to be the only risk factor in the APOE locus, it does not fully explain the risk effect conferred by the locus. Here, we report the identification of AD causal variants in PVRL2 and APOC1 regions in proximity to APOE and define common risk haplotypes independent of APOE-ε4 coding change. These risk haplotypes are associated with changes of AD-related endophenotypes including cognitive performance, and altered expression of APOE and its nearby genes in the human brain and blood. High-throughput genome-wide chromosome conformation capture analysis further supports the roles of these risk haplotypes in modulating chromatin states and gene expression in the brain. Our findings provide compelling evidence for additional risk factors in the APOE locus that contribute to AD pathogenesis.

4.
J Affect Disord ; 253: 218-223, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054447

RESUMO

BACKGROUND: Cerebral small vessel diseases (SVD) are associated with poststroke depressive symptoms (PDS). The mechanisms underlying the association between SVD burden and PDS are unclear. This study investigated the clinical pathways linking SVD burden to PDS. METHOD: A cohort of 563 patients with acute ischemic stroke were examined at three and fifteen months after stroke. PDS was measured with the 15-item Geriatric Depression Scale (GDS). Cognitive and physical functions were assessed with the Mini-Mental State Examination and the modified Rankin Scale, respectively. All patients received MRI scans at baseline. Infarct volumes and the four SVD markers (lacunae, white matter hyperintensities, cerebral microbleeds, and perivascular spaces) were assessed on magnetic resonance imaging. SVD burden was defined as a latent variable encompassing the information about all four SVD markers in structural equation modeling (SEM). SEM was further employed to examine the direct and indirect linking pathways between SVD burden, infarct volumes, stroke severity, poststroke cognitive and physical dysfunctions, and PDS. RESULTS: The latent SVD burden was directly associated with more severe PDS at the 3-month follow-up (path coefficient=0.11), while SVD burden and PDS at the 15-month were mainly linked through PDS at the 3-month follow-up (path coefficient=0.48). The volume of acute infarcts and impaired physical functions predominantly mediated the association between SVD burden and PDS at 3-month follow-up. Physical and cognitive functions 15 months after stroke mainly bridged the link between SVD burden and the PDS at the 15-month follow-up. LIMITATIONS: The study included patients with mild stroke, which reduced the generalizability of the findings. CONCLUSIONS: SVD burden not only directly determines poststroke depressive symptoms, but also worsens acute stroke lesions, stroke severity, and poststroke neurological deficits, thereby contributing further to the development of PDS over the first 15 months after stroke.

5.
JAMA Neurol ; 76(7): 755-763, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30958514

RESUMO

Importance: Clinical practice guidelines support exercise for patients with Parkinson disease (PD), but to our knowledge, no randomized clinical trials have tested whether yoga is superior to conventional physical exercises for stress and symptom management. Objective: To compare the effects of a mindfulness yoga program vs stretching and resistance training exercise (SRTE) on psychological distress, physical health, spiritual well-being, and health-related quality of life (HRQOL) in patients with mild-to-moderate PD. Design, Setting, and Participants: An assessor-masked, randomized clinical trial using the intention-to-treat principle was conducted at 4 community rehabilitation centers in Hong Kong between December 1, 2016, and May 31, 2017. A total of 187 adults (aged ≥18 years) with a clinical diagnosis of idiopathic PD who were able to stand unaided and walk with or without an assistive device were enrolled via convenience sampling. Eligible participants were randomized 1:1 to mindfulness yoga or SRTE. Interventions: Mindfulness yoga was delivered in 90-minute groups and SRTE were delivered in 60-minute groups for 8 weeks. Main Outcomes and Measures: Primary outcomes included anxiety and depressive symptoms assessed using the Hospital Anxiety and Depression Scale. Secondary outcomes included severity of motor symptoms (Movement Disorder Society Unified Parkinson's Disease Rating Scale [MDS-UPDRS], Part III motor score), mobility, spiritual well-being in terms of perceived hardship and equanimity, and HRQOL. Assessments were done at baseline, 8 weeks (T1), and 20 weeks (T2). Results: The 138 participants included 65 men (47.1%) with a mean (SD) age of 63.7 (8.7) years and a mean (SD) MDS-UPDRS score of 33.3 (15.3). Generalized estimating equation analyses revealed that the yoga group had significantly better improvement in outcomes than the SRTE group, particularly for anxiety (time-by-group interaction, T1: ß, -1.79 [95% CI, -2.85 to -0.69; P = .001]; T2: ß, -2.05 [95% CI, -3.02 to -1.08; P < .001]), depression (T1: ß, -2.75 [95% CI, -3.17 to -1.35; P < .001]); T2: ß, -2.75 [95% CI, -3.71 to -1.79; P < .001]), perceived hardship (T1: ß, -0.92 [95% CI, -1.25 to -0.61; P < .001]; T2: ß, -0.76 [95% CI, -1.12 to -0.40; P < .001]), perceived equanimity (T1: ß, 1.11 [95% CI, 0.79-1.42; P < .001]; T2: ß, 1.19 [95% CI, 0.82-1.56; P < .001]), and disease-specific HRQOL (T1: ß, -7.77 [95% CI, -11.61 to -4.38; P < .001]; T2: ß, -7.99 [95% CI, -11.61 to -4.38; P < .001]). Conclusions and Relevance: Among patients with mild-to-moderate PD, the mindfulness yoga program was found to be as effective as SRTE in improving motor dysfunction and mobility, with the additional benefits of a reduction in anxiety and depressive symptoms and an increase in spiritual well-being and HRQOL. Trial Registration: Centre for Clinical Research and Biostatistics identifier: CUHK_CCRB00522.

6.
Ann Neurol ; 85(5): 752-764, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30840312

RESUMO

OBJECTIVE: To investigate whether hemodynamic features of symptomatic intracranial atherosclerotic stenosis (sICAS) might correlate with the risk of stroke relapse, using a computational fluid dynamics (CFD) model. METHODS: In a cohort study, we recruited patients with acute ischemic stroke attributed to 50 to 99% ICAS confirmed by computed tomographic angiography (CTA). With CTA-based CFD models, translesional pressure ratio (PR = pressurepoststenotic /pressureprestenotic ) and translesional wall shear stress ratio (WSSR = WSSstenotic - throat /WSSprestenotic ) were obtained in each sICAS lesion. Translesional PR ≤ median was defined as low PR and WSSR ≥4th quartile as high WSSR. All patients received standard medical treatment. The primary outcome was recurrent ischemic stroke in the same territory (SIT) within 1 year. RESULTS: Overall, 245 patients (median age = 61 years, 63.7% males) were analyzed. Median translesional PR was 0.94 (interquartile range [IQR] = 0.87-0.97); median translesional WSSR was 13.3 (IQR = 7.0-26.7). SIT occurred in 20 (8.2%) patients, mostly with multiple infarcts in the border zone and/or cortical regions. In multivariate Cox regression, low PR (adjusted hazard ratio [HR] = 3.16, p = 0.026) and high WSSR (adjusted HR = 3.05, p = 0.014) were independently associated with SIT. Patients with both low PR and high WSSR had significantly higher risk of SIT than those with normal PR and WSSR (risk = 17.5% vs 3.0%, adjusted HR = 7.52, p = 0.004). INTERPRETATION: This work represents a step forward in utilizing computational flow simulation techniques in studying intracranial atherosclerotic disease. It reveals a hemodynamic pattern of sICAS that is more prone to stroke relapse, and supports hypoperfusion and artery-to-artery embolism as common mechanisms of ischemic stroke in such patients. Ann Neurol 2019;85:752-764.

7.
Hum Brain Mapp ; 2018 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-30240493

RESUMO

Age-related changes in functional brain network have been well documented. However, recent studies have suggested the nonstationary properties of the functional connectivity of the brain, and little is known about the changes of functional connectivity dynamics during aging. In this study, a two-step singular value decomposition was introduced to capture the dynamic patterns of the time-varying functional connectivity in different frequency intervals, and the whole-brain and regional brain diversity were quantified by using Shannon entropy. The relationships between age and functional connectivity dynamics were investigated in a relatively large sample cohort of cognitively healthy elderly (N = 188, ages 65-80). The results showed an age-related decreased diversity in the whole brain as well as in the right inferior frontal gyrus, right amygdala, right hippocampus, left parahippocampal, and left inferior parietal gyrus in the frequency interval of 0.06-0.12 Hz. In addition, the whole-brain diversity during resting state could also reflect the general mental flexibility. This study provided the first evidence of frequency-specific age effects on the functional connectivity dynamics in cognitively healthy elderly, and may shed new light on the dynamic functional connectivity analysis of aging and neurodegenerative diseases.

8.
Ophthalmology ; 2018 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-30114417

RESUMO

TOPIC: OCT is a noninvasive tool to measure specific retinal layers in the eye. The relationship of retinal spectral-domain (SD) OCT measurements with Alzheimer's disease (AD) and mild cognitive impairment (MCI) remains unclear. Hence, we conducted a systematic review and meta-analysis to examine the SD OCT measurements in AD and MCI. CLINICAL RELEVANCE: Current methods of diagnosing early AD are expensive and invasive. Retinal measurements of SD OCT, which are noninvasive, technically simple, and inexpensive, are potential biomarkers of AD. METHODS: We conducted a literature search in PubMed and Excerpta Medica Database to identify studies published before December 31, 2017, that assessed the associations between AD, MCI, and measurements of SD OCT: ganglion cell-inner plexiform layer (GC-IPL), ganglion cell complex (GCC), macular volume, and choroidal thickness, in addition to retinal nerve fiber layer (RNFL) and macular thickness. We used a random-effects model to examine these relationships. We also conducted meta-regression and assessed heterogeneity, publication bias, and study quality. RESULTS: We identified 30 eligible studies, involving 1257 AD patients, 305 MCI patients, and 1460 controls, all of which were cross-sectional studies. In terms of the macular structure, AD patients showed significant differences in GC-IPL thickness (standardized mean difference [SMD], -0.46; 95% confidence interval [CI], -0.80 to -0.11; I2 = 71%), GCC thickness (SMD, -0.84; 95% CI, -1.10 to -0.57; I2 = 0%), macular volume (SMD, -0.58; 95% CI, -1.03 to -0.14; I2 = 80%), and macular thickness of all inner and outer sectors (SMD range, -0.52 to -0.74; all P < 0.001) when compared with controls. Peripapillary RNFL thickness (SMD, -0.67; 95% CI, -0.95 to -0.38; I2 = 89%) and choroidal thickness (SMD range, -0.88 to -1.03; all P < 0.001) also were thinner in AD patients. CONCLUSIONS: Our results confirmed the associations between retinal measurements of SD OCT and AD, highlighting the potential usefulness of SD OCT measurements as biomarkers of AD.

9.
IEEE Trans Med Imaging ; 37(9): 2149-2160, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29994088

RESUMO

Acute ischemic stroke is recognized as a common cerebral vascular disease in aging people. Accurate diagnosis and timely treatment can effectively improve the blood supply of the ischemic area and reduce the risk of disability or even death. Understanding the location and size of infarcts plays a critical role in the diagnosis decision. However, manual localization and quantification of stroke lesions are laborious and time-consuming. In this paper, we propose a novel automatic method to segment acute ischemic stroke from diffusion weighted images (DWIs) using deep 3-D convolutional neural networks (CNNs). Our method can efficiently utilize 3-D contextual information and automatically learn very discriminative features in an end-to-end and data-driven way. To relieve the difficulty of training very deep 3-D CNN, we equip our network with dense connectivity to enable the unimpeded propagation of information and gradients throughout the network. We train our model with Dice objective function to combat the severe class imbalance problem in data. A DWI data set containing 242 subjects (90 for training, 62 for validation, and 90 for testing) with various types of acute ischemic stroke was constructed to evaluate our method. Our model achieved high performance on various metrics (Dice similarity coefficient: 79.13%, lesionwise precision: 92.67%, and lesionwise F1 score: 89.25%), outperforming the other state-of-the-art CNN methods by a large margin. We also evaluated the model on ISLES2015-SSIS data set and achieved very competitive performance, which further demonstrated its generalization capacity. The proposed method is fast and accurate, demonstrating a good potential in clinical routines.

10.
J Neurol Neurosurg Psychiatry ; 89(9): 918-926, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29666204

RESUMO

OBJECTIVES: Individual neuroimaging features of small vessel disease (SVD) have been reported to influence poststroke cognition. This study aimed to investigate the joint contribution and strategic distribution patterns of multiple types of SVD imaging features in poststroke cognitive impairment. METHODS: We studied 145 first-ever ischaemic stroke patients with MRI and Montreal Cognitive Assessment (MoCA) examined at baseline. The local burdens of acute ischaemic lesion (AIL), white matter hyperintensity, lacune, enlarged perivascular space and cross-sectional atrophy were quantified and entered into support vector regression (SVR) models to associate with the global and domain scores of MoCA. The SVR models were optimised with feature selection through 10-fold cross-validations. The contribution of SVD features to MoCA scores was measured by the prediction accuracy in the corresponding SVR model after optimisation. RESULTS: The combination of the neuroimaging features of SVD contributed much more to the MoCA deficits on top of AILs compared with individual SVD features, and the cognitive impact of different individual SVD features was generally similar. As identified by the optimal SVR models, the important SVD-affected regions were mainly located in the basal ganglia and white matter around it, although the specific regions varied for MoCA and its domains. CONCLUSIONS: Multiple types of SVD neuroimaging features jointly had a significant impact on global and domain cognitive functionings after stroke on top of AILs. The map of strategic cognitive-relevant regions of SVD features may help clinicians to understand their complementary impact on poststroke cognition.

11.
J Alzheimers Dis ; 61(4): 1333-1341, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29376875

RESUMO

BACKGROUND: Unlike western countries, data on white matter hyperintensity (WMH) in community dwelling elderly in Asian population is very limited. OBJECTIVE: To examine the relation between baseline WMH burden and the risk of incident cognitive decline in a community-based cohort with Chinese-dwelling elderly. METHODS: We prospectively evaluated the incident cognitive decline for 226 participants in the Shanghai Aging Study. Baseline WMH severity was visually rated by the age-related white matter changes (ARWMC) scale based on MRI. Cox proportional hazards regression model was used to estimate the relative risk (RR) of total ARWMC scale, global ARWMC score, presence of lacune and microbleed, for incident cognitive decline by adjusting potential confounders. RESULTS: Forty subjects were identified with incident cognitive decline (new onset 34 mild cognitive impairment and 6 dementia) during a median duration of 6 years follow-up. The incidence of cognitive decline was 3.0 (95% confidence interval [CI] 2.2-4.1) per 100 person-years. Increasing total ARWMC scale [RR1.21 (95% CI 1.06-1.39), p = 0.004)], confluent WMH [RR3.16 (95% CI 1.50-6.64), p = 0.002), and presence of lacunes [RR 2.73 (95% CI 1.21-6.15)] at baseline were independent predictors of incident cognitive decline. CONCLUSION: Our study demonstrated that confluent WMH may increase the risk of incident cognitive decline by 3 folds in community dwelling subjects. Small vessel disease may cause heavy burden of cognitive impairment in the elderly in China.

12.
Int J Geriatr Psychiatry ; 33(5): 729-734, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29292529

RESUMO

BACKGROUND: The Montreal Cognitive Assessment (MoCA) is psychometrically superior over the Mini-mental State Examination (MMSE) for cognitive screening in stroke or transient ischemic attack (TIA). It is free for clinical and research use. The objective of this study is to convert scores from the MMSE to MoCA and MoCA-5-minute protocol (MoCA-5 min) and to examine the ability of the converted scores in detecting cognitive impairment after stroke or TIA. METHODS: A total of 904 patients were randomly divided into training (n = 623) and validation (n = 281) samples matched for demography and cognition. MMSE scores were converted to MoCA and MoCA-5 min using (1) equipercentile method with log-linear smoothing and (2) Poisson regression adjusting for age and education. Receiver operating characteristics curve analysis was used to examine the ability of the converted scores in differentiating patients with cognitive impairment. RESULTS: The mean education was 5.8 (SD = 4.6; ranged 0-20) years. The entire spectrum of MMSE scores was converted to MoCA and MoCA-5 min using equipercentile method. Relationship between MMSE and MoCA scores was confounded by age and education, and a conversion equation with adjustment for age and education was derived. In the validation sample, the converted scores differentiated cognitively impaired patients with area under receiver operating characteristics curve 0.826 to 0.859. CONCLUSION: We provided 2 methods to convert scores from the MMSE to MoCA and MoCA-5 min based on a large sample of patients with stroke or TIA having a wide range of education and cognitive levels. The converted scores differentiated patients with cognitive impairment after stroke or TIA with high accuracy.

14.
Stroke ; 49(1): 215-218, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29203690

RESUMO

BACKGROUND AND PURPOSE: Central autonomic dysfunction increases stroke morbidity and mortality. We aimed to investigate whether poststroke autonomic dysfunction graded by Ewing battery can predict clinical outcome. METHODS: In this prospective observational study, we assessed autonomic function of ischemic stroke patients within 7 days from symptom onset by Ewing battery. On the basis of the magnitude of autonomic dysfunction, we stratified patients into significant (definite, severe, or atypical) or minor (normal or early) autonomic function impairment groups and correlated the impairment with the 3-month modified Rankin Scale score (good outcome: modified Rankin Scale score 0≈2; poor outcome: modified Rankin Scale score 3≈6). RESULTS: Among the 150 patients enrolled (mean age, 66.4±9.9 years; 70.7% males), minor autonomic dysfunction was identified in 36 patients (24.0%), and significant autonomic dysfunction was identified in 114 patients (76.0%) based on Ewing battery. In 3 months, a poor functional outcome was found in 32.5% of significant group patients compared with 13.9% in the minor group (P=0.031). Crude odds ratios of the magnitude of autonomic dysfunction and 3-month unfavorable functional outcome after acute ischemic stroke were 2.979 (95% confidence interval, 1.071-8.284; P=0.036). After adjusting for confounding variables with statistical significance between the 2 functional outcome subgroups identified in univariate analysis (including sex and National Institutes of Health Stroke Scale score on admission), the magnitude of autonomic dysfunction still independently predicted an unfavorable outcome, with an odds ratio of 3.263 (95% confidence interval, 1.141-9.335; P=0.027). CONCLUSIONS: Autonomic dysfunction gauged by Ewing battery predicts poor functional outcome after acute ischemic stroke.


Assuntos
Doenças do Sistema Nervoso Autônomo , Sistema Nervoso Autônomo/fisiopatologia , Isquemia Encefálica , Acidente Vascular Cerebral , Idoso , Doenças do Sistema Nervoso Autônomo/etiologia , Doenças do Sistema Nervoso Autônomo/mortalidade , Doenças do Sistema Nervoso Autônomo/fisiopatologia , Isquemia Encefálica/complicações , Isquemia Encefálica/mortalidade , Isquemia Encefálica/fisiopatologia , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/mortalidade , Acidente Vascular Cerebral/fisiopatologia , Taxa de Sobrevida
15.
Front Aging Neurosci ; 9: 372, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29180960

RESUMO

Objective: Cerebral small vessel disease (SVD) is associated with increased mortality, disability and cognitive decline, depression in stroke survivors. This study examined the association between SVD burden, defined by a combination of SVD markers, and health-related quality of life (HRQoL) in acute ischemic stroke. Methods: Patients admitted with acute ischemic stroke of any etiology were prospectively screened between January 2010 to December 2014 and enrolled in the study if they met study entry criteria. HRQoL was evaluated with the 12-item Stroke Specific Quality of Life (SSQoL) at 3 months after the onset of acute ischemic stroke. SVD was ascertained by the presence of any of the SVD markers including lacune, white matter hyperintensities (WMH), cerebral microbleeds (CMB) and enlarged perivascular spaces (EPVS) in the basal ganglia or their combinations on brain magnetic resonance imaging (MRI). The presence of each individual marker scored 1 point and was summed up to generate an ordinal "SVD score" (0-4) capturing total SVD burden. Linear regression was used to determine the associations between SVD burden and HRQoL. Results: Of the743 acute ischemic stroke patients that formed he study sample (mean age: 66.3 ± 10.6 years; 41.7% women), 49.3%, 22.5%, 16.0%, 9.2% and 3.1% had SVD scores of 0, 1, 2, 3 and 4, respectively. After adjusting for demographic, clinical and imaging variables, the SVD score was independently associated with lower overall score of SSQoL (B = -1.39, SE = 0.56, p = 0.01), and its domains of mobility (B = -0.41, SE = 0.10, p < 0.001) and vision (B = -0.12, SE = 0.06, p = 0.03). Acute infract volume (B = -1.44, SE = 0.54, p = 0.01), functional independence (B = 5.69, SE = 0.34, p < 0.001) and anxious (B = -1.13, SE = 0.23, p < 0.001) and depressive symptoms (B = -3.41, SE = 0.22, p < 0.001) were also the significant predictors of the overall score of SSQoL. Conclusion: The brain's SVD burden predicts lower HRQoL, predominantly in domains of mobility and vision at 3 months after acute ischemic stroke. The evaluation of SVD burden could facilitate developing individual treatment strategies.

16.
Front Neurol ; 8: 593, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29170651

RESUMO

White matter hyperintensities (WMHs) have been reported to be correlated with functional brain changes, but the association of the specific WMHs distribution pattern with regional functional changes remains uncertain. The aim of this study is to explore the possible spatial correlation of WMH with changes in cerebral blood flow (CBF) and spontaneous brain activities in elderly using a novel approach. The WMHs, CBF, and spontaneous brain activities measured by intrinsic connectivity contrast (ICC), were quantified using multimodal magnetic resonance imaging for 69 elderly subjects. Such approach enables us to expand our search for newly identified correlated areas by drawing strengths of different modes and provides a means for triangulation as well as complementary insights. The results showed significant positive correlations between WMH volumes in the right superior corona radiata and CBF in the left supplementary motor area, as well as between WMH volumes in left anterior limb internal capsule and CBF in the right putamen. Significant correlations of regional WMH volumes and ICC were also detected between the right anterior corona radiata and the left cuneus, and the right superior occipital cortex, as well as between the right superior corona radiata and the left superior occipital cortex. These findings may suggest a regional compensatory functional enhancement accounting for the maintenance of cognitively normal status, which can be supported by the widely observed phenomenon that mild to moderate WMH load could have little effect on global cognitive performance.

17.
Sci Rep ; 7(1): 12441, 2017 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-28963553

RESUMO

Post-stroke cognitive impairment (PSCI) warrants early detection and management. We sought to develop a risk score for screening patients at bedside for risk of delayed PSCI. Ischemic stroke survivors with PSCI and no cognitive impairments (NCI) 3-6 months post-stroke were studied to identify candidate variables predictive of PSCI. These variables were used to develop a risk score using regression models. The score, and the best identified clinical cutoff point, underwent development, stability testing, and internal and external validation in three independent cohorts from Singapore and Hong Kong. Across 1,088 subjects, the risk score, dubbed CHANGE, had areas under the receiver operating characteristics curve (AUROC) from 0.74 to 0.82 in detecting significant risk for PSCI, and had predicted values following actual prevalence. In validation data 3-6 and 12-18 months post-stroke, subjects with low, medium, and high scores had PSCI prevalence of 7-23%, 25-58%, and 67-82%. CHANGE was effective in screening ischemic stroke survivors for significant risk of developing PSCI up to 18 months post-stroke. CHANGE used readily available and reliable clinical data, and may be useful in identifying at-risk patients for PSCI.

18.
Front Hum Neurosci ; 11: 414, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28860982

RESUMO

Given that the morphology of Chinese brains statistically differs from that of Caucasian, there is an urgent need to develop a Chinese brain template for neuroimaging studies in Chinese populations. Based on a multi-center dataset, we developed a statistical Chinese brain template, named as Chinese2020 (Liang et al., 2015). This new Chinese brain atlas has been validated in brain normalization and segmentation for anatomical Magnetic Resonance Imaging (MRI) studies, and is publicly available at http://www.chinese-brain-atlases.org/. In our previous study, we have demonstrated this Chinese atlas showed higher accuracy in segmentation and relatively smaller shape deformations during registration. Because the spatial normalization of functional images is mainly based on the segmentation and normalization of anatomical image, the population-specific brain atlas should also be more appropriate for functional studies involving Chinese populations. The aim of this technology report is to validate the performance of Chinsese2020 template in functional neuroimaging studies, and demonstrated that for Chinese population studies, the use of the Chinese2010 template produces more valid results. The steps of how to use the Chinese2020 template in SPM software were given in details in this technology report, and based on an example of finger tapping fMRI study, this technology report demonstrated the Chinese2020 template could improve the performance of the neuroimaging analysis of Chinese populations.

19.
J Am Med Dir Assoc ; 18(9): 807.e17-807.e29, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28754516

RESUMO

BACKGROUND: Mild cognitive impairment (MCI) is a prevalent symptom associated with the increased risk of dementia. There are many cognitive tests available for detection of MCI, and investigation of the diagnostic performance of the tests is deemed necessary. OBJECTIVE: This study aims to evaluate the diagnostic performance of different cognitive tests used for MCI detection. DATA SOURCES: A list of cognitive tests was identified in previous reviews and from online search engines. Literature searches were performed on each of the cognitive tests in MEDLINE, Embase, and PsycINFO from the earliest available dates of individual databases to December 31, 2016. Google Scholar was used as a supplementary search tool. STUDY SELECTION: Studies that were used to assess the diagnostic performance of the cognitive tests were extracted with inclusion and exclusion criteria. Each test's performance was compared with the standard diagnostic criteria. Bivariate random effects models were used to summarize the test performance as a point estimate for sensitivity and specificity, and presented in a summary receiver operating characteristic curve. Reporting quality and risk of bias were evaluated. RESULTS: A total of 108 studies with 23,546 participants were selected to evaluate 9 cognitive tests for MCI detection. Most of the studies used the Mini-Mental State Examination (MMSE) (n = 58) and the Montreal Cognitive Assessment (MoCA) (n = 35). The combined diagnostic performance of the MMSE in MCI detection was 0.71 sensitivity [95% confidence interval (CI): 0.66-0.75] and 0.74 specificity (95% CI: 0.70-0.78), and of the MoCA in MCI detection was 0.83 sensitivity (95% CI: 0.80-0.86) and 0.75 specificity (95% CI: 0.69-0.80). Among the 9 cognitive tests, recall tests showed the best diagnostic performance with 0.89 sensitivity (95% CI: 0.86-0.92) and 0.84 specificity (95% CI, 0.79-0.89). In subgroup analyses, long- or short-delay recall tests have shown better performance than immediate recall tests. CONCLUSIONS: Recall tests were shown to be the most effective test in MCI detection, especially for the population with symptoms of memory deterioration. They can be potentially used as the triage screening test for MCI in primary care setting. But when a patient shows cognitive impairments beyond memory deterioration, a more comprehensive test such as the MoCA should be used.


Assuntos
Disfunção Cognitiva/diagnóstico , Rememoração Mental , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
20.
Nat Rev Neurol ; 13(3): 148-159, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28211452

RESUMO

Incident stroke has long been recognized to cause dementia shortly after the event. Patients who survive stroke without early-onset poststroke dementia (PSD) are at a high risk of developing dementia months to years after the initial stroke incident, which has generated enthusiasm for exploring treatments to prevent delayed-onset PSD in survivors of stroke. However, results from clinical trials completed in the past 10-15 years have been disappointing. In light of these results, the present Review revisits the mechanisms of both early-onset and delayed-onset PSD and proposes preventive strategies and directions for future clinical trials. Early-onset PSD results from a complex interplay between stroke lesion features and brain resilience, whereas delayed-onset PSD is associated mainly with the presence of severe sporadic small vessel disease (SVD), and to a lesser extent with Alzheimer disease pathology or recurrent stroke. As well as preventing stroke and delivering acute stroke treatments to reduce initial brain damage, measures to increase brain resilience could also reduce the risk of developing dementia if an incident stroke occurs. Future efforts to prevent delayed-onset PSD should focus on the study of sporadic SVD and on evaluating whether other strategies, in addition to conventional secondary stroke prevention, are effective in dementia prevention in this high-risk group.

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