脑大动脉病变与脑白质高信号的相关性研究进展

脑大、小血管共同构成了脑的血管树,它们在结构和功能上有一定的相关性。近年来,脑 大血管病变与脑小血管病之间相关关系的研究逐渐受到重视。大动脉粥样硬化、动脉延长扩张及管 壁僵硬度增大从不同侧面反映了大血管病变的特点,脑白质高信号是脑小血管病重要的影像学表现。 本文对动脉粥样硬化、动脉延长扩张及僵硬度增大与脑白质高信号之间的相关性进行综述,以探讨 脑大血管病变与脑小血管病的关系。     

小血管病性脑白质病变与认知功能障碍关系研究

目的 评估小血管病患者脑白质病变程度与认知功能的相关性。 方法 通过对浙江大学医学院附属第一医院神经内科门诊患者进行老年人认知功能下降知情者问 卷（informant questionnaire on cognitive decline in the elderly,IQCODE）、简易智能状态检查量表（minimental state examination,MMSE）、临床痴呆评定量表（clinical dementia rating,CDR）评分以及相关认 知功能评估,结合头颅磁共振成像（magnatic resonance imaging,MRI）检查及临床资料,筛选小血管病 变患者,并通过相关统计分析计算不同部位脑白质病变的程度及其对认知功能的影响。 结果 本研究共纳入患者147例,其中小血管病变（cerebral small vessel disease,SVD）患者33例,SVD患 者记忆力（z =-3.36）、定向力（z＝-3.14）、处理判断力（z =-3.38）以及社会事物能力（z =-3.22）较 正常者都明显下降（P =0.00）。脑室周围病变与MMSE分数（r =0.82）、CDR总分（r =0.62）、CDR记忆分 （r =0.82）显著相关（P值均=0.00）,皮质下病变与MMSE分数（r =0.51,P =0.01）、CDR记忆分（r =0.49, P =0.02）中度相关。 结论 在脑小血管病患者,MMSE评分、CDR评分对于脑白质病变特别是脑室旁病变的进展可能具有 一定的预测价值。     

Cortical and Subcortical Grey Matter Abnormalities in White Matter Hyperintensities and Subsequent Cognitive Impairment

Grey matter (GM) alterations may contribute to cognitive decline in individuals with white matter hyperintensities (WMH) but no consensus has yet emerged. Here, we investigated cortical thickness and grey matter volume in 23 WMH patients with mild cognitive impairment (WMH-MCI), 43 WMH patients without cognitive impairment, and 55 healthy controls. Both WMH groups showed GM atrophy in the bilateral thalamus, fronto-insular cortices, and several parietal-temporal regions, and the WMH-MCI group showed more extensive and severe GM atrophy. The GM atrophy in the thalamus and fronto-insular cortices was associated with cognitive decline in the WMH-MCI patients and may mediate the relationship between WMH and cognition in WMH patients. Furthermore, the main results were well replicated in an independent dataset from the Alzheimer''s Disease Neuroimaging Initiative database and in other control analyses. These comprehensive results provide robust evidence of specific GM alterations underlying WMH and subsequent cognitive impairment.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12264-021-00657-0.     

Regional White Matter Anisotropy and Reading Ability in Patients Treated for Pediatric Embryonal Tumors

Children treated with cranial irradiation for brain tumors have reduced white matter volume and deficits in reading ability. This study prospectively examined the relationship between reading and white matter integrity within this patient group. Patients (n = 54) were treated with post-surgical radiation followed by 4 cycles of high-dose chemotherapy with stem cell support. At 12 months post-diagnosis, all patients completed a neuropsychology evaluation and a diffusion tensor imaging (DTI) exam. White matter integrity was determined through measures of fractional anisotropy (FA). Significant group differences in FA were found between above average readers and below average readers within the left and right posterior limb of the internal capsule, and right knee of the internal capsule with a trend within the left temporaloccipital region. The integrity of the white matter in these regions may affect communication among visual, auditory, and language cortical areas that are engaged during reading.     

Fiber-Specific White Matter Alterations in Parkinson's Disease Patients with GBA Gene Mutations

Background

Patients with Parkinson's disease (PD) carrying GBA gene mutations (GBA-PD) have a more aggressive disease course than those with idiopathic PD (iPD).

Objective

The objective of this study was to investigate fiber-specific white matter (WM) differences in nonmedicated patients with early-stage GBA-PD and iPD using fixel-based analysis, a novel technique to assess tract-specific WM microstructural and macrostructural features comprehensively.

Methods

Fixel-based metrics, including microstructural fiber density (FD), macrostructural fiber-bundle cross section (FC), and a combination of FD and FC (FDC), were compared among 30 healthy control subjects, 16 patients with GBA-PD, and 35 patients with iPD. Associations between FDC and clinical evaluations were also explored using multiple linear regression analyses.

Results

Patients with GBA-PD showed significantly lower FD in the fornix and superior longitudinal fasciculus than healthy control subjects, and lower FC in the corticospinal tract (CST) and lower FDC in the CST, middle cerebellar peduncle, and striatal-thalamo-cortical pathways than patients with iPD. Contrarily, patients with iPD showed significantly higher FC and FDC in the CST and striatal-thalamo-cortical pathways than healthy control subjects. In addition, lower FDC in patients with GBA-PD was associated with reduced glucocerebrosidase enzyme activity, lower cerebrospinal fluid total α-synuclein levels, lower Montreal Cognitive Assessment scores, lower striatal binding ratio, and higher Unified Parkinson's Disease Rating Scale Part III scores.

Conclusions

We report reduced fiber-specific WM density and bundle cross-sectional size in patients with GBA-PD, suggesting neurodegeneration linked to glucocerebrosidase deficiency, α-synuclein accumulation, and poorer cognition and motor functions. Conversely, patients with iPD showed increased fiber bundle size, likely because of WM reorganization. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.     

缺血性卒中患者脑白质病变对认知功能的影响

目的 探讨不同程度的脑白质病变对缺血性卒中患者认知功能的影响。方法 连续收集缺血性卒中患者,记录卒中危险因素,进行蒙特利尔认知评估量表（Montrealcognitive assessment,MoCA）等神经心理学测试,进行神经影像学检查,运用与年龄相关的脑白质改变分级量表（age-related white matter changes rating scale,ARWMCRs）对脑白质病变半定量评分。根据ARWMCRs评分结果,将患者分为3组：轻度组、中度组和重度组。比较轻、中、重三组间认知功能的差异。结果 与脑白质病变轻度组比较,中、重度组患者MoCA评分下降（P均＜0.01)。相关性分析发现ARWMCRs评分与MoCA评分呈负相关（r =-0.677,P＜0.01）。结论 脑白质病变影响缺血性卒中患者的认知功能。脑白质病变程度越重,认知功能下降就越为显著。     

脑小血管病患者外周血同型半胱氨酸水平与认知功能的相关性研究

目的 HHcy是脑血管病和认知功能障碍的危险因素之一。本文拟明确脑小血管病（small vessel disease，SVD）患者外周血Hcy水平与早期认知功能损害的相关性及其机制。 方法 连续入组缺血性卒中后门诊随访的非痴呆SVD患者，登记人口社会学、血管危险因素等资 料，进行全面认知评估。入组1周内采集空腹静脉血检测Hcy，根据血浆Hcy水平将SVD患者分为HHcy组 （Hcy＞15 μmmol/L）和正常Hcy（normal Hcy，NHcy）组（Hcy≤15 μmmol/L）。2周内行多模式头颅MRI检 查。对2组患者的认知评分及影像特点进行比较，并与Hcy水平进行相关性分析。 结果 ①研究共纳入81例SVD患者，平均年龄（64.3±7.4）岁；男性65例，占80.2%；轻度认知障 碍50例，占61.7%。②HHcy组30例（37.0%），NHcy组51例（63.0%）。HHcy组吸烟比例高于NHcy组。 ③HHcy组执行功能中交替连线测验B（trail making test B，TMT-B）耗时数高于NHcy组（P =0.016），数 字符号转换测验（digital symbol substitution test，DSST）（P =0.013）、数字广度测验（digital span test， DS）顺背（P =0.029）得分低于NHcy组。④HHcy组较NHcy组中重度脑室旁白质病变（63.3% vs 39.2%， P =0.018）、深部白质病变（60.0% vs 37.3%，P =0.036）和多发微出血（36.7% vs 17.3%，P =0.047）的 比例更高，且Hcy水平与脑室旁白质病变评分显著相关（r =0.227，P =0.041）。⑤经脑室旁白质病变评 分校正后，Hcy水平与TMT-B耗时数（r =0.278，P =0.013）正相关，与DSST（r =-0.354，P =0.004）和DS 顺背（r =-0.366，P =0.001）得分负相关。 结论 SVD患者外周血Hcy水平与执行注意以及脑室旁白质病变严重程度显著相关，外周血Hcy水平 可能是SVD早期认知功能障碍的生物标志物之一。     

Impact of White Matter Lesions on Depression in the Patients with Alzheimer's Disease

Objective

Comorbid depression is common in patients with Alzheimer''s disease (AD). An increase in white matter lesions (WMLs) has been associated with depression in both elderly individuals with normal cognition and patients with Alzheimer''s disease. We investigated whether the severity and location of WMLs influence the association between WMLs and comorbid depression in AD.

Methods

We enrolled 93 AD patients from Seoul National University Bundang Hospital. We administered both the Mini International Neuropsychiatric Inventory (MINI) and the Korean version of the Consortium to Establish a Registry for Alzheimer''s Disease Assessment Packet (CERAD-K) clinical and neuropsychological battery. Subjects also underwent brain magnetic resonance imaging (MRI). We diagnosed AD according to the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer''s Disease and Related Disorders Association. We diagnosed depressive disorders according to the DSM-IV diagnostic criteria, and evaluated the severity of depressive symptoms using the Korean version of the Geriatric Depression Scale (GDS-K). We quantified the WML volumes from the brain MRI using a fully automated segmentation algorithm.

Results

The log of the WML volume in the frontal lobe was significantly associated with depressive disorders (odds ratio=1.905, 95% CI=1.027-3.533, p=0.041), but not with the severity of depressive symptoms as measured by the GDS-K.

Conclusion

The WML volume in the frontal lobe conferred a risk of comorbid depressive disorders in AD, which implies that comorbid depression in AD may be attributed to vascular causes.     

Transient Cognitive Impairment and White Matter Hyperintensities in Severely Depressed Older Patients Treated With Electroconvulsive Therapy

BackgroundAlthough electroconvulsive therapy (ECT) is a safe and effective treatment for patients with severe late life depression (LLD), transient cognitive impairment can be a reason to discontinue the treatment. The aim of the current study was to evaluate the association between structural brain characteristics and general cognitive function during and after ECT.MethodsA total of 80 patients with LLD from the prospective naturalistic follow-up Mood Disorders in Elderly treated with Electroconvulsive Therapy study were examined. Magnetic resonance imaging scans were acquired before ECT. Overall brain morphology (white and grey matter) was evaluated using visual rating scales. Cognitive functioning before, during, and after ECT was measured using the Mini Mental State Examination (MMSE). A linear mixed-model analysis was performed to analyze the association between structural brain alterations and cognitive functioning over time.ResultsPatients with moderate to severe white matter hyperintensities (WMH) showed significantly lower MMSE scores than patients without severe WMH (F(1,75.54) = 5.42, p = 0.02) before, during, and post-ECT, however their trajectory of cognitive functioning was similar as no time × WMH interaction effect was observed (F(4,65.85) = 1.9, p = 0.25). Transient cognitive impairment was not associated with medial temporal or global cortical atrophy (MTA, GCA).ConclusionAll patients showed a significant drop in cognitive functioning during ECT, which however recovered above baseline levels post-ECT and remained stable until at least 6 months post-ECT, independently of severity of WMH, GCA, or MTA. Therefore, clinicians should not be reluctant to start or continue ECT in patients with severe structural brain alterations.     

认知储备对不同认知阶段脑白质高信号人群脑白质纤维束完整性的影响

目的 探讨认知储备（cognitive reserve,CR）对不同认知阶段脑白质高信号（white matter hyperintensity, WMH）患者白质纤维束完整性的影响。