慢性不可预计温和应激大鼠microRNA差异表达谱分析

目的探讨慢性不可预计温和应激大鼠模型microRNA（miRNA）表达谱差异。方法采用慢性不可预计温和应激模型,将16只SD大鼠随机分为对照组和应激组,每组8只,对照组常规饲养,不予任何处理,应激组每天随机予1～2种温和刺激,共6周;造模结束后均采用旷场试验评价大鼠行为,安乐处死,取伏隔核低温保存。采用miRNA测序技术比较两组大鼠miRNA表达差异。结果与对照组比较,慢性不可预计温和应激大鼠有25个miRNA显著下调,2个miRNA显著上调。结论慢性不可预计温和应激可能使大鼠部分miRNA表达发生改变。     

遗忘型轻度认知损害的神经影像与神经心理特点

目的 了解aMCI脑结构改变和相关认知损害特点,探讨准确诊断aMCI的神经影像和神经心理生物指标。方法 3-DMRI采集35例aMCI患者和35名健康对照者脑结构信息,LEAP软件计算左右侧和均侧海马、杏仁核和颞角体积,MoCA测评认知功能。结果两组被试年龄、性别差异无统计学意义（P〉0．05）,受教育年限差异有统计学意义（P〈0．01）。aMCI的左、右侧及均侧海马萎缩和右侧颞角扩大（P〈0．05）,MoCA总评分和注意力、重复句子、抽象能力、延迟回忆、定向力等亚项得分减低（P〈0．05）,MoCA与右、均侧海马及右侧杏仁核呈正相关（P〈0．05）。ROC分析显示Mo—cA总评分、左、右及均侧海马、左、右及均侧杏仁核等指标诊断aMCI准确性高（P〈0．01）。单独认知指标MoCA总评分和重复句子（wilks’Lambda=0．299,X^2=80．905,df=2,P〈0．01）区分aMCI和NC的准确性为88．6％,单独脑结构指标均侧海马和杏仁核（wilks’Lambda=0．515,X^244．509,df=2,P〈0．01）的准确性为81．4％,认知和脑结构综合指标MoCA总评分、均侧海马和左侧杏仁核（Wilks’Lambda=0．261,X^2=89．228,df=3,P〈0．01）的准确性为95．7％。结论 aMCI期已出现特异的海马、杏仁核萎缩和弥漫性认知损害,在AD非痴呆期联合应用认知测试和神经影像指标更有助于AD早期准确诊断。     

The effects of a computer-based cognitive and physical training program in a healthy and mildly cognitive impaired aging sample

Objectives: The Long Lasting Memories (LLM) program concerns a newly integrated platform which combines cognitive exercises with physical activity within the context of advanced technologies. The main objective of this study was to present the preliminary results that determine the possible effectiveness of the LLM program in the improvement of cognitive functions and symptoms of depression in healthy elderly and subjects with mild cognitive impairment (MCI). Method: Fifty healthy and MCI subjects participated in the study. All of them received one hour's physical training and 35 minutes’ cognitive training, 3 times a week, during the 12 weeks of the program. Before and after the intervention all participants were assessed using a battery of neuropsychological tests.Results: The results showed a significant improvement after the LLM training in global cognitive function, in verbal memory, in attention, in episodic memory and symptoms of depression. Conclusion: This study indicates that LLM is a promising solution for older adults with and without cognitive impairment, maintaining their wellbeing with few professional and technical requirements.     

Perceived Cognitive Impairment among African American elders: health and functional impairments in daily life

Objectives: The Center for Disease Control began to assess Perceived Cognitive Impairment in 2009, yet there has been no in-depth study of how perceived decline in thinking or memory skills may be associated to the health and lifestyle of an independent community-dwelling older person. Among urban-dwelling older African Americans who are at elevated risk for cognitive impairment and dementia, we know even less regarding the interaction of these risk factors.Method: Five hundred and one African American elders (n = 501) between the ages of 55 and 95 with an average age of 70.73 years (SD = 8.6 years) participated in telephone interviews.Results: Approximately one-third of the elders reported that their memory, thinking skills, or ability to reason was worse than a year ago (n = 150; 29.9%) and 25% of this group (n = 38) reported that this Perceived Cognitive Impairment impacted their daily activities and/or warranted a consultation with their doctor. Bivariate analyses indicated that Perceived Cognitive Impairment was associated with increased health problems, mobility limitations, depressed mood, and lower social functioning.Conclusion: Elders who reported that cognitive problems impacted their daily functioning reported the greatest health and mental health problems. Perceived Cognitive Impairment is an important health variable with implications for an older adult's overall health, mobility, and mental health.     

Motor intentional disorders in vascular mild cognitive impairment and vascular dementia of subcortical type

Subcortical vascular mild cognitive impairment (svMCI), a prodromal stage of subcortical vascular dementia (SVaD), is primarily associated with frontal injuries, whereas amnestic MCI (aMCI) is associated with temporoparietal injuries. Twenty-seven patients with svMCI, 20 with aMCI, 14 with SVaD, and 10 normal controls underwent motor intentional tasks (force initiation, development, maintenance, and termination) using a force dynamometer. Of the four motor intentional tasks, the maintenance task proved sensitive in differentiating svMCI from aMCI. In most motor intentional tasks, performances of svMCI patients were intermediate between those of controls and SVaD patients (initiation and termination: NC=aMCI=svMCI>SVaD; development: NC>aMCI=svMCI>SVaD; maintenance: NC=aMCI>svMCI=SVaD).     

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.     

Neuroimaging in dementia

Over the last few years, advances in neuroimaging have generated biomarkers, which increase diagnostic certainty, provide valuable information about prognosis, and suggest a particular pathology underlying the clinical dementia syndrome. We aim to review the evidence for use of already established imaging modalities, along with selected techniques that have a great potential to guide clinical decisions in the future. We discuss structural, functional and molecular imaging, focusing on the most common dementias: Alzheimer's disease, fronto-temporal dementia, dementia with Lewy bodies and vascular dementia. Finally, we stress the importance of conducting research using representative cohorts and in a naturalistic set up, in order to build a strong evidence base for translating imaging methods for a National Health Service. If we assess a broad range of patients referred to memory clinic with a variety of imaging modalities, we will make a step towards accumulating robust evidence and ultimately closing the gap between the dramatic advances in neurosciences and meaningful clinical applications for the maximum benefit of our patients.