轻度认知障碍

轻度认知障碍(MCI)是近年提出的新概念,是一种介于正常老化和痴呆的中间状态.前瞻性研究表明,MCI患者转化为痴呆的可能性显著高于正常老年人群.MCI的正确诊断,有助于筛查痴呆高危人群,为顶防痴呆、降低痴呆发病率提供了可能.     

轻度认知障碍

轻度认知障碍（MCI）是近年提出的新概念，是一种介于正常老化和痴呆的中间状态。前瞻性研究表明，MCI患者转化为痴呆的可能性显著高于正常老年人群。MCI的正确诊断，有助于筛查痴呆高危人群，为预防痴呆、降低痴呆发病率提供了可能。     

Physical Frailty Is Associated with Incident Mild Cognitive Impairment in Community‐Based Older Persons

OBJECTIVES: To test the hypothesis that physical frailty is associated with risk of mild cognitive impairment (MCI). DESIGN: Prospective, observational cohort study. SETTING: Approximately 40 retirement communities across the Chicago metropolitan area. PARTICIPANTS: More than 750 older persons without cognitive impairment at baseline. MEASUREMENTS: Physical frailty, based on four components (grip strength, timed walk, body composition, and fatigue), was assessed at baseline, and cognitive function was assessed annually. Proportional hazards models adjusted for age, sex, and education were used to examine the association between physical frailty and the risk of incident MCI, and mixed effect models were used to examine the association between frailty and the rate of change in cognition. RESULTS: During up to 12 years of annual follow‐up, 305 of 761 (40%) persons developed MCI. In a proportional hazards model adjusted for age, sex, and education, physical frailty was associated with a high risk of incident MCI, such that each one‐unit increase in physical frailty was associated with a 63% increase in the risk of MCI (hazard ratio=1.63; 95% confidence interval=1.27–2.08). This association persisted in analyses that required MCI to persist for at least 1 year and after controlling for depressive symptoms, disability, vascular risk factors, and vascular diseases. Furthermore, a higher level of physical frailty was associated with a faster rate of decline in global cognition and five cognitive systems (episodic memory, semantic memory, working memory, perceptual speed, and visuospatial abilities). CONCLUSION: Physical frailty is associated with risk of MCI and a rapid rate of cognitive decline in aging.     

MEMO+: Efficacy,Durability and Effect of Cognitive Training and Psychosocial Intervention in Individuals with Mild Cognitive Impairment

Background/Objectives

There is no consensus on the efficacy of cognitive training in persons with mild cognitive impairment (MCI) because of the paucity of well‐designed randomized controlled trials. The objective was to assess the effect of memory training on the cognitive functioning of persons with MCI and its durability and to evaluate whether this effect generalizes to daily life and whether positive effects could be obtained from psychosocial intervention.

Design

Single‐blind randomized controlled trial.

Setting

Research centers of the Institut Universitaire de Gériatrie de Montréal and Institut Universitaire en Santé Mentale de Québec.

Participants

Older adults meeting criteria for amnestic MCI (N = 145).

Intervention

Participants were randomized to cognitive training, a psychosocial intervention, or a no‐contact control condition. Interventions were provided in small groups in eight 2‐hour sessions.

Measurement

Outcome measures were immediate and delayed composite performance memory scores, psychological health (depression, anxiety, well‐being), and generalization effects of the intervention (strategy use in everyday life, difficulties in complex activities of daily living, memory complaints). Testing was administered before training and immediately, 3 months, and 6 months after training.

Results

Participants in the cognitive training condition improved on the delayed composite memory score and on strategy use in everyday life. Improvement was maintained at the 3‐ and 6‐month follow‐up assessments. Participants in the psychosocial and no‐contact conditions did not show any significant improvement.

Conclusion

Cognitive training improves the memory of persons with amnestic MCI. The effect persists over a 6‐month period, and learned strategies are used in everyday life. Cognitive training is a valid way to promote cognition in MCI.     

The Montreal Cognitive Assessment, MoCA: a brief screening tool for mild cognitive impairment

OBJECTIVES: To develop a 10-minute cognitive screening tool (Montreal Cognitive Assessment, MoCA) to assist first-line physicians in detection of mild cognitive impairment (MCI), a clinical state that often progresses to dementia. DESIGN: Validation study. SETTING: A community clinic and an academic center. PARTICIPANTS: Ninety-four patients meeting MCI clinical criteria supported by psychometric measures, 93 patients with mild Alzheimer's disease (AD) (Mini-Mental State Examination (MMSE) score > or =17), and 90 healthy elderly controls (NC). MEASUREMENTS: The MoCA and MMSE were administered to all participants, and sensitivity and specificity of both measures were assessed for detection of MCI and mild AD. RESULTS: Using a cutoff score 26, the MMSE had a sensitivity of 18% to detect MCI, whereas the MoCA detected 90% of MCI subjects. In the mild AD group, the MMSE had a sensitivity of 78%, whereas the MoCA detected 100%. Specificity was excellent for both MMSE and MoCA (100% and 87%, respectively). CONCLUSION: MCI as an entity is evolving and somewhat controversial. The MoCA is a brief cognitive screening tool with high sensitivity and specificity for detecting MCI as currently conceptualized in patients performing in the normal range on the MMSE.     

基于体素的形态学测量技术在轻度认知障碍和Alzheimer病中的应用

基于体素的形态学测量技术(VBM)是近年来发展起来的一种新型脑形态学测量技术,文章简要阐述了VBM的概念、基本原理和优缺点,同时对其在轻度认知障碍和Alzheimer病中的初步应用做了综述.     

基于体素的形态学测量技术在轻度认知障碍患者中的应用

轻度认知障碍(MCI)指认知功能降低超出其年龄和受教育水平,但尚未影响到日常生活状态.超过半数的MCI患者会在5年内进展为痴呆.因此,MCI被认为是痴呆的危险状态,早期诊断MCI可以预防患者进展为痴呆.基于体素的形态学测量技术(VBM)能定量计算全脑和局部灰质体素的大小和信号强度,是一种完全自动化的客观脑形态分析技术.文章就VBM技术在MCI患者中的应用做了综述.