Prospective Memory Impairment in Mild Cognitive Impairment: An Analytical Review

Mild cognitive impairment (MCI) is a heterogeneous condition characterized by the presence in an otherwise healthy elderly individual of cognitive deficits involving specific domains in the absence of significant functional impairments. Reports indicate that prospective memory (PM), that is, the ability to remember to execute delayed intentions, is impaired in individuals with MCI. The present review discusses the current debate in the literature on PM functioning in MCI by focusing on the relationship between prospective retrieval and retrospective memory functioning. Analysis of the reported evidence revealed that both the prospective component and the retrospective component of PM can be impaired in MCI. Declarative memory dysfunction may account for the retrospective memory impairment, while either reduced executive abilities or a deficit of reflexive mechanisms could explain the prospective component impairment.     

轻度认知损伤的语义记忆研究述评

轻度认知损伤（Mild cognitive impairment,MCI）是介于正常老化与痴呆之间的过渡阶段,表现为与年龄和教育程度不相称的认知功能减退。本文回顾了近期有关MCI语义记忆的研究,分析比较了各研究的实验任务及结果,得出MCI患者存在一定程度的由多种原因造成的语义记忆损伤,语义记忆测验对MCI的早期筛查和转归预测有重要作用。最后指出将来的研究需要将包括语义记忆成分在内的多种认知测验相结合,以便及早发现有可能发展为痴呆的危险个体并开展相应干预。     

The selective impairment of semantic memory

The selective impairment of semantic memory is described in three patients with diffuse cerebrallesions. These patients, selected on the basis of a failure to recognize or identify common objects (agnosia for objects), were investigated in detail. In particular, their perceptual, language and memory functions were assessed, and the limits and properties of their recognition difficulties explored.

It was found that knowledge of pictorial representations of objects, and of words, was impaired or impoverished, and in both instances knowledge of subordinate categories was more vulnerable than superordinate categories. Evidence is presented that this impairment of semantic memory cannot be accounted for by intellectual impairment, sensory or perceptual deficits, or expressive language disorder. The implications of damage to the semantic memory system for the operation of other cognitive systems, in particular short and long-term memory functions, are considered. Some tentative evidence for the structural basis for a hierarchically organized modality-specific semantic memory system is discussed.     

Heterogeneity of Neuropsychological Impairment in HIV Infection: Contributions from Mild Cognitive Impairment

Despite longstanding acknowledgement of the heterogeneity of HIV-associated neurocognitive disorders (HAND), existing HAND diagnostic methods classify according to the degree of impairment, without regard to the pattern of neuropsychological strengths and weaknesses. Research in mild cognitive impairment (MCI) has demonstrated that classifying individuals into subtypes by both their level and pattern of impairment, using either conventional or statistical methods, has etiologic and prognostic utility. Methods for characterizing the heterogeneity of MCI provide a framework that can be applied to other disorders and may be useful in clarifying some of the current challenges in the study of HAND. A small number of studies have applied these methods to examine the heterogeneity of neurocognitive function among individuals with HIV. Most have supported the existence of multiple subtypes of neurocognitive impairment, with some evidence for distinct clinicodemographic features of these subtypes, but a number of gaps exist. Following a review of diagnostic methods and challenges in the study of HAND, we summarize the literature regarding conventional and empirical subtypes of MCI and HAND and identify directions for future research regarding neurocognitive heterogeneity in HIV infection.     

轻度认知功能障碍的防治决策

轻度认知功能障碍(mild cognitive i mpairment,MCI)被认为是阿尔茨海默病(alzhei mer disease,AD)的极早期。AD的防治需从MCI开始,早期发现,早期干预,以便延缓和阻止AD的发生。目前我国MCI具有就诊率低,诊断率低,治疗率低和漏诊率高的特点。临床研究要改变MCI三低一高的状况,医师及民众要提高对MCI的认识,应该采取重在预防,重视筛查,早期诊断,早期治疗的决策,可以延迟和阻止AD的发生。     

轻度认知功能障碍的防治决策

轻度认知功能障碍(mild cognitive impairment,MCI)被认为是阿尔茨海默病(alzheimer disease,AD)的极早期.AD的防治需从MCI开始,早期发现,早期干预,以便延缓和阻止AD的发生.目前我国MCI具有就诊率低,诊断率低,治疗率低和漏诊率高的特点.临床研究要改变MCI三低一高的状况,医师及民众要提高对MCI的认识,应该采取重在预防,重视筛查,早期诊断,早期治疗的决策,可以延迟和阻止AD的发生.     

轻度认知功能障碍与颈动脉狭窄的相关性研究

为了探讨颈动脉狭窄与轻度认知功能障碍(MCI)的关系,选取轻度认知功能障碍病例89例,健康对照组100例,全部行颈动脉彩超检查及简易智能状态量表(MMSE),蒙特利尔认知量表(MoCA),临床痴呆量表(CDR),日常生活能力量表(ADL),汉密尔顿抑郁量表(HAMD)测评.结果发现轻度认知功能障碍组颈动脉狭窄发生率明显高于对照组,左侧发生率明显高于右侧.其中随着狭窄的严重程度增加,患者在延迟回忆、视空间与执行功能、计算力与注意力、语言能力方面评分显著下降.从这一结果可以看出轻度认知功能障碍与颈动脉狭窄密切相关.     

Part-set cueing impairment & facilitation in semantic memory

The present study explored the influence of part-set cues in semantic memory using tests of “free” recall, reconstruction of order, and serial recall. Nine distinct categories of information were used (e.g., Zodiac signs, Harry Potter books, Star Wars films, planets). The results showed part-set cueing impairment for all three “free” recall sets, whereas part-set cueing facilitation was evident for five of the six ordered sets. Generally, the present results parallel those often observed across episodic tasks, which could indicate that similar mechanisms contribute to part-set cueing effects in both episodic and semantic memory. A novel anchoring explanation of part-set cueing facilitation in order and spatial tasks is provided.     

Development of a Brief Cognitive Screen for Mild Cognitive Impairment and Neurocognitive Disorder

Abstract

The purpose of this study was to develop and evaluate a brief cognitive screen for possible Mild Cognitive Impairment (MCI) and other neurocognitive impairment in a sample of general medical patients. Two hundred community-dwelling general medical patients aged 65 or older participated in this study. Age and education corrected scores from the Rey Auditory Verbal Learning Test and Mattis Dementia Rating Scale were used to classify participants into three groups: MCI, neurocognitive disorder, cognitively intact. Groups were then compared on an independent set of measures: the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) neuropsychological battery, Mini-Mental State Examination, and Clock Drawing Test. The MCI group constituted 9% of the sample, while 10.5% of the sample was classified into the neurocognitive disorder group. The CERAD Verbal Category Fluency and CERAD Word List Memory Test Delayed Recall measures were individually and collectively the most effective in differentiating cognitively intact elders from persons in both the MCI and neurocognitive disorder groups. We conclude that these two brief measures appear to be effective for detecting possible MCI or neurocognitive disorder, thereby facilitating identification of candidates who would benefit from more detailed neuropsychological assessment.     

Pattern of semantic memory impairment in dementia of Alzheimer's type

The specific pattern of semantic memory impairment in patients with dementia of Alzheimer's type (DAT) remains unclear. Specifically, the presence of a category-specific deficit for biological concepts (reflected in anomia for these concepts) has been questioned. We studied 9 DAT patients using a semantic association judgement test in which they had to decide which of the two given words was most like a target word (e.g., lamb: goat, sheep). The 150 target words were drawn from 6 categories: animals, clothing and furniture, fruits and vegetables, tools, action verbs, and abstract nouns. Age- and education-matched control subjects performed equivalently (between 86 and 90% correct) in all categories. Compared to control subjects, DAT patients made significantly more errors in abstract and biological nouns, but not in verbs and man-made artifacts. This pattern of semantic memory impairment--a sparing of verbs and a selective deficit of nouns in the biological category--has been documented in patients with temporal lobe damage, suggesting a critical dysfunction in the temporal lobes of DAT.     

Dissociations in Visual Attention Deficits among Persons with Mild Cognitive Impairment

ABSTRACT

Impairments in visual attention and visual information processing have been identified as part of the neuropsychological features of Alzheimer's disease (AD), even in its earliest stages. There is increasing recognition that these deficits may be selective rather than global, with some attentional subtypes being more vulnerable than others. The few studies that have investigated attentional deficits in mild cognitive impairment (MCI), a putatively prodromal phase of AD, have not satisfactorily addressed the possible selectivity in attentional deficits in MCI. This study examined potential dissociations in visual attention deficits in MCI using a measure that assesses simple, divided, and selective attention. The results indicated a hierarchy of attentional impairments, with divided attention being the most affected and simple attention the least. Among participants with MCI, 53% showed evidence of impairment in divided attention compared to 19% of controls (OR = 4.81, p < .001). Poorer visual attention was also associated with poorer overall cognitive status. The implications of these findings for early identification of MCI, prevention of functional decline in MCI, and delay/reversal of cognitive degradation in MCI are discussed.     

Everyday Impact of Cognitive Interventions in Mild Cognitive Impairment: a Systematic Review and Meta-Analysis

Cognitive interventions in Mild Cognitive Impairment (MCI) seek to ameliorate cognitive symptoms in the condition. Cognitive interventions may or may not generalize beyond cognitive outcomes to everyday life. This systematic review and meta-analysis sought to assess the effect of cognitive interventions compared to a control group in MCI on generalizability outcome measures [activities of daily living (ADLs), mood, quality of life (QOL), and metacognition] rather than cognitive outcomes alone. PRISMA guidelines were followed. MEDLINE and PsychInfo were utilized as data sources to locate references related to cognitive interventions in individuals with MCI. The cognitive intervention study was required to have a control or alternative treatment comparison group to be included. Thirty articles met criteria, including six computerized cognitive interventions, 14 therapist-based interventions, and 10 multimodal (i.e., cognitive intervention plus an additional intervention) studies. Small, but significant overall median effects were seen for ADLs (d = 0.23), mood (d = 0.16), and metacognitive outcomes (d = 0.30), but not for QOL (d = 0.10). Computerized studies appeared to benefit mood (depression, anxiety, and apathy) compared to controls, while therapist-based interventions and multimodal interventions had more impact on ADLs and metacognitive outcomes than control conditions. The results are encouraging that cognitive interventions in MCI may impact everyday life, but considerably more research is needed. The current review and meta-analysis is limited by our use of only PsychInfo and MEDLINE databases, our inability to read full text non-English articles, and our reliance on only published data to complete effect sizes.     

认知和情绪冲突的监控与解决：来自轻度认知损伤的证据

轻度认知损伤(mild cognitive impairment, MCI)是介于正常老化和痴呆之间的过渡阶段。近年来, 执行控制的损伤被认为是MCI的核心特征之一。当前, 在MCI执行控制的领域内, 对冲突监控与解决的特征及其神经机制的研究较少。本研究拟通过认知及情绪冲突实验范式, 结合脑成像技术, 探讨遗忘型MCI (amnestic MCI, aMCI)认知和情绪冲突的监控与解决的特征及相应的脑激活模式; 通过对比aMCI和正常老年人在认知和情绪冲突任务中激活的神经环路, 考察aMCI是否在执行加工的神经网络上存在激活异常。在上述研究基础上, 研究者拟探讨aMCI在执行控制的冲突监控与解决上是否存在一般性的损伤机制, 同时试图寻找aMCI在执行控制的冲突监控与解决方面的认知及神经生物学标记。这对深入理解痴呆的发病进程并有针对性的开展痴呆的早期识别与干预具有重要的理论意义和实践意义。     

Functional Disability in Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

Accumulating evidence suggests that the pre-dementia syndrome mild cognitive impairment (MCI) is characterized by decrements in instrumental activities of daily living (IADL). The current review was a quantitative synthesis of the available literature to objectively characterize IADL disability in MCI while clarifying inconsistencies in findings across studies. It was hypothesized that individuals with MCI would display significantly greater functional impairment relative to cognitively intact controls. Candidate moderators specified a priori included functional assessment approach, MCI subtype, depressive symptoms, and language conducted. Online databases (PubMed/MEDLINE and PsycINFO) and reference lists were searched to identify peer-reviewed publications assessing IADL in MCI compared to normal aging. A total of 151 effect sizes derived from 106 studies met inclusionary criteria (N?=?62,260). Random effects models yielded a large overall summary effect size (Hedges’ g?=?0.76, 95 % confidence interval: 0.68???0.83, p?<?.001) confirmed in multi-level analyses adjusted for nesting of effect sizes within studies (g?=?0.78, 95 % confidence interval: 0.69???0.87). Functional assessment strategy and MCI subtype were significant moderators of effect size, whereas depressive symptoms and language were not. Results convincingly demonstrate that MCI is associated with significant difficulties in the performance of complex everyday tasks. It appears that functional decline, like cognitive decline, exists on a continuum from healthy aging to dementia onset. Implications for clinical practice and research priorities are discussed.     

轻度认知损伤重复效应脑电研究：范式及应用

“语义一致性加重复”范式（congruity-plus-repetition paradigm）在早前重复范式的基础上增加了早期语义情境用以控制重复效应的前期成份N400和后期成份P600之间的相互干扰。作者回顾了这种范式在轻度认知损伤（mild cognitive impairment,MCI）的事件相关电位研究领域的应用,并分析了该范式在MCI的识别及预测其向痴呆转归方面的优越性。提示效应的组合更能标记正常认知老化向痴呆的动态过渡;能产生两个或多个效应组合的实验范式将是该领域未来研究方向之一。     

Cognitive integration of language and memory in bilinguals: semantic representation

Understanding cognitive research on the integration of 2 languages in bilingual memory is difficult because of the different terminology, methodology, analysis, and interpretation strategies that scholars with different backgrounds bring to the research. These studies can be usefully categorized on 2 dimensions: memory for verbal experience versus linguistic knowledge, and systemwise versus pairwise issues. Experimental findings in this area converge on the conclusion that at the word meaning/conceptual level, both episodic and linguistic memory can be characterized as shared at the systems level and at least partly shared at the pairwise translation-equivalent level. Interpretation problems that stem from weak hypothesis testing structure and from covert translation can be minimized by using appropriate design and analysis techniques.     

Inhibitory Control Deficits in Individuals with Amnestic Mild Cognitive Impairment: a Meta-Analysis

Neuropsychology Review - Amnestic mild cognitive impairment (aMCI) is a prodromal stage of Alzheimer’s disease that is characterized by impairments in episodic memory. Recent evidence has...     

Mild memory impairment in healthy older adults is distinct from normal aging

Mild memory impairment was detected in 28% of a sample of healthy community-dwelling older adults using the delayed recall trial of a word list learning task. Statistical analysis revealed that individuals with memory impairment also demonstrated relative deficits on other measures of memory, and tests of executive function, processing speed and global cognition, as measured by the CERAD and CogState batteries and CANTAB paired associate learning task. These relative deficits cannot be explained by age-related changes, education, intelligence, mood, health-related factors, or the individuals' ApoEepsilon4 status. Memory-impaired individuals (n = 30) did not recognize the extent of their memory and cognitive difficulties beyond the general complaints expressed by normal elderly (n = 77) within the study and their apparent difficulties did not appear to impact on their participation in life activities. These findings suggest it is unlikely that the memory and cognitive difficulties demonstrated by individuals with mild memory impairment reflect normal aging. Rather it is possible that such impairment may signal early neurodegenerative processes worthy of further investigation.