White-matter changes in early and late stages of mild cognitive impairment

Mild Cognitive Impairment (MCI) is characterized by cognitive deficits that exceed age-related decline, but not interfering with daily living activities. Amnestic type of the disorder (aMCI) is known to have a high risk to progress to Alzheimer’s Disease (AD), the most common type of dementia. Identification of very early structural changes in the brain related to the cognitive decline in MCI patients would further contribute to the understanding of the dementias. In the current study, we target to investigate whether the white-matter changes are related to structural changes, as well as the cognitive performance of MCI patients. Forty-nine MCI patients were classified as Early MCI (E-MCI, n = 24) and Late MCI (L-MCI, n = 25) due to their performance on The Free and Cued Selective Reminding Test (FCSRT). Age-Related White-Matter Changes (ARWMC) scale was used to evaluate the white-matter changes in the brain. Volumes of specific brain regions were calculated with the FreeSurfer program. Both group and correlation analyses were conducted to show if there was any association between white-matter hyperintensities (WMHs) and structural changes and cognitive performance. Our results indicate that, L-MCI patients had significantly more WMHs not in all but only in the frontal regions compared to E-MCI patients. Besides, ARWMC scores were not correlated with total hippocampal and white-matter volumes. It can be concluded that WMHs play an important role in MCI and cognitive functions are affected by white-matter changes of MCI patients, especially in the frontal regions.     

弥散张量成像在轻度认知功能障碍中的应用

轻度认知功能障碍（MCI）目前已经成为严重影响老年人健康的疾病,早期具有可逆性。近年来弥散张量成像（DTI）以其定量显示脑白质纤维束的优势,越来越多的应用于临床,成为了研究的热点。目前研究表明,MCI患者海马、穹隆、扣带回和胼胝体的DTI指标变化明显,可用于MCI的早期识别和病情评估及预测,且多个指标联用可能增加其准确性。MCI患者DTI表现与认知功能的下降程度具有相关性,尤其与记忆功能的相关性较为确定。MCI亚型中,遗忘型MCI （aMCI）发展为阿尔茨海默病（AD）的风险更高,其部分各向异性（FA）值越低、平均弥散度（ADC）值越高预示着转化为AD的可能性越大;DTI技术对AD与MCI患者脑白质的差异较为灵敏,AD的脑白质病变范围更广、程度更重。但目前关于DTI在MCI中的应用尚存在诸多问题,尚需进一步研究。     

For the Sciences They Are A‐Changin’: A Response to Commentaries on Núñez et al.’s (2019) “What Happened to Cognitive Science?”

A recent issue of Topics in Cognitive Science featured 11 thoughtful commentaries responding to our article “What happened to cognitive science?” (Núñez et al., 2019). Here, we identify several themes that arose in those commentaries and respond to each. Crucial to understanding our original article is the fundamental distinction between multidisciplinary and interdisciplinary endeavors: Cognitive science began (and has stayed) as multidisciplinary but has failed to move on to form a cohesive interdisciplinary field. We clarify and elaborate our original argument and reiterate the importance of a data‐driven evaluation of the current status of the field, which exhibits a marked disciplinary imbalance, a lack of a coherent conceptual core, and a striking absence of a consistent curriculum in the institutions that grant degrees in this domain. Half a century after the creation of cognitive science, it may now be a good time to revisit goals and visions for how to best approach the ever‐fascinating scientific study of the mind(s).     

细胞因子白细胞介素-4对认知功能改善的研究进展

白细胞介素4(IL-4)是T辅助2(Th2)介导的免疫反应的基本免疫调节细胞因子,IL-4具有复杂的信号系统和多效的功能,但在脑组织中,诸多研究发现IL-4可在炎症中保护认知功能。该文总结了关于IL-4保护认知功能的证据及机制,以及在阿尔茨海默病、缺血性脑血管病以及手术后认知功能障碍中IL-4保护认知功能的途径及证据。     

Abnormalities of resting-state EEG in patients with prodromal and overt dementia with Lewy bodies: Relation to clinical symptoms

ObjectiveHere we tested if cortical sources of resting state electroencephalographic (rsEEG) rhythms may differ in sub-groups of patients with prodromal and overt dementia with Lewy bodies (DLB) as a function of relevant clinical symptoms.MethodsWe extracted clinical, demographic and rsEEG datasets in matched DLB patients (N = 60) and control Alzheimer’s disease (AD, N = 60) and healthy elderly (Nold, N = 60) seniors from our international database. The eLORETA freeware was used to estimate cortical rsEEG sources.ResultsAs compared to the Nold group, the DLB and AD groups generally exhibited greater spatially distributed delta source activities (DLB > AD) and lower alpha source activities posteriorly (AD > DLB). As compared to the DLB “controls”, the DLB patients with (1) rapid eye movement (REM) sleep behavior disorders showed lower central alpha source activities (p < 0.005); (2) greater cognitive deficits exhibited higher parietal and central theta source activities as well as higher central, parietal, and occipital alpha source activities (p < 0.01); (3) visual hallucinations pointed to greater parietal delta source activities (p < 0.005).ConclusionsRelevant clinical features were associated with abnormalities in spatial and frequency features of rsEEG source activities in DLB patients.SignificanceThose features may be used as neurophysiological surrogate endpoints of clinical symptoms in DLB patients in future cross-validation prospective studies.     

Diagnostic accuracy of the Phototest for cognitive impairment and dementia in Argentina

Phototest is a simple, easy and very brief test with theoretical advantages over available dementia screening tests in Spain. The objective of this study was to estimate the diagnostic accuracy of the Phototest for cognitive impairment and dementia and to compare it with that of the MMSE and the Clock Drawing Test (CDT) in an Argentine population. A phase II cross-sectional study of diagnostic tests evaluation was performed in a sample of 30 controls, 61 with amnestic mild cognitive impairment (a-MCI), and 56 with mild Alzheimer type dementia (DAT). The diagnostic accuracy (DA) was assessed in relation to the clinical diagnosis by calculating the area under the ROC curve (UAC), Sensitivity (Sn), and Specificity (Sp).The DA of the Phototest for a-MCI and DAT (0.93 and 0.97 [UAC]) was higher than that of the MMSE and the CDT. The cut-off points of 27/28 for DAT (Sn = 89.29 [78.1–96.0], Sp = 96.67 [82.8–99.9]) and 30/31 for a-MCI (Sn = 85.25 [73.8–93.0], Sp = 90.00 [73.5–97.9]) maximized the sum of Sn and Sp. Phototest correlates significantly with MMSE and CDT. The Phototest is an efficient instrument for the detection of mild dementia or MCI, with good accuracy and good correlation with tests measuring overall cognitive impairment.     

Cerebral blood flow is an earlier indicator of perfusion abnormalities than cerebral blood volume in Alzheimer's disease

The purpose of this study was to elucidate whether cerebral blood flow (CBF) can better characterize perfusion abnormalities in predementia stages of Alzheimer''s disease (AD) than cerebral blood volume (CBV) and whether cortical atrophy is more associated with decreased CBV or with decreased CBF. We compared measurements of CBV, CBF, and mean cortical thickness obtained from magnetic resonance images in a group of healthy controls, patients with mild cognitive impairment (MCI) who converted to AD after 2 years of clinical follow-up (MCI-c), and patients with mild AD. A significant decrease in perfusion was detected in the parietal lobes of the MCI-c patients with CBF parametric maps but not with CBV maps. In the MCI-c group, a negative correlation between CBF values and cortical thickness in the right parahippocampal gyrus suggests an increase in CBF that depends on cortical atrophy in predementia stages of AD. Our study also suggests that CBF deficits appear before CBV deficits in the progression of AD, as CBV abnormalities were only detected at the AD stage, whereas CBF changes were already detected in the MCI stage. These results confirm the hypothesis that CBF is a more sensitive parameter than CBV for perfusion abnormalities in MCI-c patients.     

帕金森病患者血清人软骨糖蛋白39水平的改变及其与病情和认知功能的相关性

目的探讨帕金森病(PD)患者血清人软骨糖蛋白39(YKL-40)水平的改变及其与病情和认知功能的相关性。方法用ELISA法给63例PD患者和60名正常对照者进行血清YKL-40水平检测,以及蒙特利尔认知评估(Mo CA)量表评分。并给PD患者进行统一PD评定量表(UPDRS)Ⅰ、Ⅱ、Ⅲ评分,评定病情。对PD患者的血清YKL-40水平与UPDRSⅠ、Ⅱ、Ⅲ评分、病程及Mo CA量表进行相关性分析。结果 PD组的血清YKL-40水平[(3.717±0.1015)ng/ml]明显高于正常对照组[(2.919±0.1827)ng/ml](P0.001)。PD患者的血清YKL-40水平与UPDRSⅠ无相关性(r=0.21,P0.05),与UPDRSⅡ、Ⅲ评分呈正相关(r=0.9251,r=0.7767;均P0.0001),与PD患者的病程亦呈正相关(r=0.4323,P0.01),与Mo CA量表评分呈负相关(r=-0.6985,P0.0001)。结论 PD患者的血清YKL-40水平显著增高,并与病情和认知功能密切相关。YKL-40可成为PD诊断和病情判断的生物学指标。     

Cognitive function and its relationship with brain structure in myotonic dystrophy type 1

Studies have shown relationships between white matter abnormalities and cognitive dysfunction in myotonic dystrophy type 1 (DM1), but comprehensive analysis of potential structure–function relationships are lacking. Fifty adult‐onset DM1 individuals (33 female) and 68 unaffected adults (45 female) completed the Wechsler Adult Intelligence Scale‐IV (WAIS‐IV) to determine the levels and patterns of intellectual functioning. Neuroimages were acquired with a 3T scanner and were processed with BrainsTools. Regional brain volumes (regions of interest, ROIs) were adjusted for inter‐scanner variation and intracranial volume. Linear regression models were conducted to assess if group by ROI interaction terms significantly predicted WAIS‐IV composite scores. Models were adjusted for age and sex. The DM1 group had lower Perceptual Reasoning Index (PRI), Working Memory Index (WMI), and Processing Speed Index (PSI) scores than the unaffected group (PRI t₍₁₁₃₎ = ?3.28, p = 0.0014; WMI t₍₁₁₄₎ = ?3.49, p = 0.0007; PSI t₍₁₁₄₎ = ?2.98, p = 0.0035). The group by hippocampus interaction term was significant for both PRI and PSI (PRI (t₍₁₁₁₎ = ?2.82, p = 0.0057; PSI (t₍₁₁₂₎ = ?2.87, p = 0.0049)). There was an inverse association between hippocampal volume and both PRI and PSI in the DM1 group (the higher the volume, the lower the intelligence quotient scores), but no such association was observed in the unaffected group. Enlarged hippocampal volume may underlie some aspects of cognitive dysfunction in adult‐onset DM1, suggesting that increased volume of the hippocampus may be pathological.