Conversion of mild cognitive impairment to dementia: predictive role of mild cognitive impairment subtypes and vascular risk factors

Mild cognitive impairment (MCI) is regarded as a precursor to dementia, but not all patients with MCI develop dementia. We followed up 165 elderly outpatients with MCI for a mean of 3 years. The aims were (1) to investigate the risk of conversion to dementia for different MCI subtypes diagnosed according to standardized criteria (amnestic; impairment of memory plus other cognitive domains; nonamnestic); (2) to assess whether the risk of conversion was affected by several established and emerging vascular risk factors. Forty-eight subjects (29%) converted to dementia, and the risk of conversion was doubled for amnestic MCI with respect to the other subtypes. Independently of MCI subtype, risk of conversion was associated with atrial fibrillation and low serum folate levels. Our results show that current diagnostic criteria for MCI define heterogeneous populations, but some potentially treatable vascular risk factors may be of help in predicting conversion to dementia.     

Disability and mild cognitive impairment: a longitudinal population-based study.

OBJECTIVE: To determine whether mild cognitive deficit is associated with parallel changes in ability to perform activities of daily living. BACKGROUND: While considerable research has been conducted on the effect of senile dementia and other neurodegenerative disorders on ability to perform everyday activities, little is known about the much larger group of elderly persons suffering from mild cognitive deficits. METHODS: Disability prevalence was estimated in 368 persons over the age of 65 years recruited from the general population via a general practitioner network. Subjects were followed over a 3-year period using computerized cognitive assessment and observations of everyday functioning. Standardized neurological assessment in the third year permitted the identification of subjects who have evolved towards dementia. RESULTS: An overall disability prevalence was found in the general population of 26.3%, with 30.8% in subjects with sub-clinical cognitive impairment. Longitudinal follow-up showed cognitive decline over time without dementia to be paralleled by changes in activity performance, with visuospatial deficits having the most marked effect on overall functioning. High intelligence quotient (IQ) and education are seen to reduce the degree of activity loss, but only when senile dementia is not present. CONCLUSIONS: Difficulties in the performance of everyday activities were found more frequently in non-demented subjects with mild cognitive deficits than in the general population. High pre-morbid levels of ability are seen to have a protective effect. A diagnosis of dementia should not therefore be required by persons with cognitive impairment applying for home help.     

腔隙性梗死患者轻度血管性认知损害危险因素分析

目的探讨腔隙性梗死后血管性认知损害的相关危险因素。方法共138例腔隙性梗死患者根据蒙特利尔认知评价量表分为认知功能正常55例、轻度认知功能障碍73例和重度认知功能障碍10例,采用单因素和多因素后退法Logistic回归分析筛查腔隙性梗死后血管性认知损害相关危险因素。结果关键部位梗死灶(OR=1.179,95%CI:0.870~2.472;P=0.012)和脑白质高信号3~4级(OR=2.005,95%CI:0.910~4.502;P=0.024)是腔隙性梗死患者出现血管性认知损害的独立危险因素。结论腔隙性梗死后血管性认知损害是多因素共同作用的结果,其中关键部位梗死灶和脑白质高信号3~4级是独立危险因素。     

Midlife rheumatoid arthritis increases the risk of cognitive impairment two decades later: a population-based study

Inflammation has been associated with Alzheimer's disease (AD) and dementia. The association between rheumatoid arthritis (RA) or arthritis and dementia/AD has been investigated in several case-control or hospital- and register-based studies with mixed results. This long-term population-based study investigates the association between presence of joint disorders (RA and other joint disorders) in midlife and cognitive status later in life. 1,449 participants were first evaluated in 1972, 1977, 1982, and 1987 and follow-up was performed after 21 years. A self-administered questionnaire including questions on joint disorders was used at both evaluations. Cognitive status (control, mild cognitive impairment, dementia/AD) was assessed at follow-up. The presence of any joint disorder in midlife was significantly associated with a worse cognitive status later in life: OR (95% CI) in an ordinal logistic regression analysis adjusted for age, gender, follow-up time, education, APOEε4, body mass index, smoking, drug treatment, and diabetes was 1.96 (1.17-3.28). For RA only, OR (95% CI) was 2.77 (1.26-6.10). The correlation remained significant for RA when AD was considered instead of dementia OR (95% CI) 2.49 (1.09-5.67). The presence of joint disorders, especially RA, at midlife seems to be associated with a worse cognitive status later in life. Given the chronic inflammatory component of RA, this study suggests that inflammatory mechanisms may have an important role in increasing the risk of cognitive impairment and dementia/AD.     

Incidence and risk factors for mild cognitive impairment: a population-based three-year follow-up study of cognitively healthy elderly subjects

BACKGROUND: Mild cognitive impairment (MCI) has attracted considerable interest as a potential predictor of Alzheimer's disease (AD). Both the apolipoprotein E (ApoE) epsilon4 allele and vascular factors have been associated with a higher risk for AD, recently they have also been linked to the risk of MCI. OBJECTIVES: To estimate the incidence of MCI among cognitively healthy elderly subjects during a 3-year follow-up, and to evaluate the impact of demographic and vascular factors as well as the ApoE epsilon4 allele on the conversion to MCI. METHODS: At baseline, the cognitive abilities of 806 out of 1,150 eligible subjects (aged 60-76 years) from a population-based sample were examined. Cognitively intact subjects (n = 747) were followed for an average of 3 years. RESULTS: 66 subjects (8.8%) had converted to MCI. The global incidence rate of MCI was 25.94/1,000 person-years. Persons with higher age (OR 1.08, 95% CI 1.01-1.16), ApoE epsilon4 allele carriers (OR 2.04, 95% CI 1.15-3.64) and persons with medicated hypertension (OR 1.86, 95% CI 1.05-3.29) were more likely to convert to MCI than those individuals of lower age and without an ApoE epsilon4 allele or medicated hypertension. Persons with high education (OR 0.79, 95% CI 0.70-0.89) were less likely to convert to MCI than persons with low or no education. In subjects with both the ApoE epsilon4 allele and medicated hypertension, the crude OR for conversion was 3.92 (95% CI 1.81-8.49). In subjects with cardiovascular disease, the crude OR for conversion was 2.13 (95% CI 1.26-3.60). Gender, elevated blood pressure, diabetes or cerebrovascular disease had no significant effect on the conversion to MCI. CONCLUSION: Higher age, the presence of at least one ApoE epsilon4 allele and medicated hypertension are independent risk factors, but high education is a protective factor for MCI. The results suggest that vascular factors may have an important role in the pathogenesis of MCI.     

轻度认知损害患者社会心理学危险因素的病例对照研究

目的 探讨老年人轻度认知损害可能的社会心理学危险因素.方法 采用成组比较的病例对照研究方法,调查轻度认知损害和认知功能正常受试者的社会人口学资料(性别、年龄等)、闲暇活动及个人爱好(书法、园艺、阅读书报等)、特殊经历(文革经历、精神创伤史)、参加社会活动情况.以及既往慢性病病史;通过χ2检验、Fisher精确概率法及t检验初步筛选危险因素,非条件Logistic逐步回归分析确定危险因素.结果 轻度认知损害组和认知功能正常组受试者的平均年龄分别为(77.07±0.59)岁和(76.91±0.58)岁,两组性别构成差异无统计学意义(P>0.05).单因素分析显示,两组受试者年龄,受教育程度,书法,写文章、自传或回忆录,锻炼或健身,参加社会活动等项因素比较,差异具有统计学意义(均P<0.05);而其他因素差异无统计学意义(均P>0.05).多因素分析进一步证实,年龄,受教育程度,写文章、自传或回忆录,锻炼或健身,参加社会活动等项因素与轻度认知损害呈显著正相关(均P<0.05),OR值(95%CI)分别为1.448(1.059～1.981)、0.513(0.346～0.761)、0.648(0.447～0.939)、0.570(0.357～0.911)和0.435(0.205～0.922).结论 老年性轻度认知损害与年龄,受教育程度,写文章、自传或回忆录,锻炼或健身,参加社会活动等5项影响因素显著相关.其中,年龄是轻度认知损害的独立危险因素;受教育程度高.写文章、自传或回忆录,参加锻炼或健身,参与社会活动为轻度认知损害的保护因素.针对上述因素早期采取适当的干预措施,可能成为预防和延缓老年人认知功能减退的重要途径.     

Midlife vascular risk factors and midlife cognitive status in relation to prevalence of mild cognitive impairment and dementia in later life: The Atherosclerosis Risk in Communities Study

Introduction

The interplay between midlife vascular risk factors and midlife cognitive function with later life mild cognitive impairment (MCI) and dementia (DEM) is not well understood.

Classification criteria for mild cognitive impairment: a population-based validation study

OBJECTIVE: To evaluate the predictive validity and temporal stability of diagnostic criteria for mild cognitive impairment (MCI). BACKGROUND: MCI has been proposed as a nosologic entity referring to elderly persons with subclinical cognitive deficits due to incipient dementia. Classification criteria, which have been derived from small, selected clinical groups, are currently disputed, and have not yet been assessed within the general population. METHODS: Subjects meeting current criteria for MCI and also age-associated cognitive decline (AACD-a similar concept that is assumed to be related to normal cognitive aging processes rather than incipient dementia) were identified within each of three waves of a longitudinal population study, which included a standardized neurologic examination. RESULTS: In the general population, the prevalence of MCI was estimated to be 3.2% and AACD 19.3%. MCI was a poor predictor of dementia within a 3-year period, with an 11.1% conversion rate. Subjects with MCI also constituted an unstable group, with almost all subjects changing category each year. Discriminant function analysis failed to isolate a homogeneous clinical group. Subjects classified as AACD, contrary to the theoretical assumptions underlying the disorder, represented a more stable group, with a 28.6% conversion rate to dementia over 3 years (relative risk = 21.2). CONCLUSION: MCI criteria perform poorly when applied to a representative population sample. The authors propose modifications to current diagnostic criteria to increase their capacity to detect incipient dementia.     

Mild cognitive impairment and risk of depression and anxiety: A population-based study

Introduction

Many people with mild cognitive impairment (MCI) suffer from concomitant depression or anxiety. Whether MCI increases the risk of future depression or anxiety is unknown.

Engaging in cognitive activities, aging, and mild cognitive impairment: a population-based study

The authors investigated whether engaging in cognitive activities is associated with aging and mild cognitive impairment (MCI) in a cross-sectional study derived from an ongoing population-based study of normal cognitive aging and MCI in Olmsted County, MN. A random sample of 1,321 study participants ages 70 to 89 (N=1,124 cognitively normal persons, and N=197 subjects with MCI) were interviewed about the frequency of cognitive activities carried out in late life (within 1 year of the date of interview). Computer activities; craft activities, such as knitting, quilting, etc.; playing games; and reading books were associated with decreased odds of having MCI. Social activities, such as traveling, were marginally significant. Even though the point-estimates for reading magazines, playing music, artistic activities, and group activities were associated with reduced odds of having MCI, none of these reached statistical significance. The equally high prevalence of reading newspapers in both groups yielded no significant between-group difference.     

Prevalence of mild cognitive impairment: a population-based study in elderly subjects

OBJECTIVES: Mild cognitive impairment (MCI) has been suggested as a term for a boundary area between normal aging and dementia, especially Alzheimer's disease (AD). In follow-up studies, more than 50% of MCI subjects have been converted to dementia in 3-4 years. However, the epidemiology of MCI is not well known. This study was designed to determine the prevalence of MCI in an elderly population. METHODS: A total of 806 subjects (60-76 years of age) from a population-based random sample of 1150 subjects living in the city of Kuopio in eastern Finland were evaluated. Neuropsychological tests and a structured interview including the modified Clinical Dementia Rating (CDR) were used to apply the diagnostic criteria of MCI as proposed by Mayo Clinic Alzheimer's Disease Research Centre. Thus, subjects having a test score more than 1.5 SDs below the age appropriate mean in memory tests and a CDR score of 0.5 but no dementia, were diagnosed as having MCI. RESULTS: A total of 43 subjects, 5.3%, met the MCI criteria. MCI was more prevalent in older and less-educated subjects, but no difference was found between men and women. The CDR appeared to be the most important part of the criteria. The memory tests had less impact on prevalence variables. CONCLUSIONS: The low prevalence of MCI indicate that in a population-based study design its criteria may identify a more homogeneous group of subjects at the lower end of the cognitive continuum as contrasted with various other criteria of cognitive impairment in the elderly population. This is compatible with follow-up studies showing a high probability of dementia in the MCI group. Thus, probable candidates for trials of preventive intervention for dementia can be screened from the elderly population using these diagnostic criteria.     

Incidence and risk factors for cognitive impairment no dementia and mild cognitive impairment in African Americans

The aim of this study was to estimate the age-specific incidence of cognitive impairment, no dementia and mild cognitive impairment (CIND/MCI) in a large, community-based sample of older African Americans in Indianapolis, IN. A longitudinal, prospective, 2-stage design was used with follow-up assessments 2 and 5 years after the baseline. A total of 1668 participants completed the 2-year follow-up and a total of 1255 participants completed the 5-year follow-up. The person-years method was used to calculate incidence rates. The age-standardized, annual incidence of CIND/MCI was 4.95% (CI=3.39-6.52) and the subtype of medically unexplained memory loss (single-domain and multidomain amnestic MCI) was 3.67% (CI 2.75-4.48). Rates increased with age (3.43% for participants aged 65 to 74 y, 6.44% from age 75 to 84 y, and 9.62% from age 85+ y), history of head injury [OR 2.37 (CI 1.31-4.29)], and history of depression [OR 2.22 (CI 1.16-4.25)] while increased years of schooling was protective [OR 0.91 (CI 0.85-0.97)]. Rates did not vary substantially by sex. Almost 1 in 20 elderly community-dwelling African Americans, and almost 1 in 10 of the oldest-old (85+ y) developed CIND/MCI each year in this cohort. Risk factors of age and education suggest exposures or mechanisms at both ends of the life span may be important variables in onset of CIND/MCI.     

Elderly-onset essential tremor and mild cognitive impairment: a population-based study (NEDICES)

Mild cognitive impairment (MCI) is often considered to be a transitional stage between normal aging and dementia. Frontal-executive dysfunction, memory impairments, and dementia have been associated with essential tremor (ET). Yet the association between MCI and ET has only been examined in one prior study. We determined whether ET is associated with MCI. We identified all persons with MCI and ET in a dementia-free, population-based study in central Spain (NEDICES). MCI was diagnosed using consensus criteria of the International Working Group on MCI. Forty-two (20.3%) of 207 ET cases had MCI versus 399 (16.1%) of 2,472 non-ET subjects (controls) (odds ratio [OR] = 1.32, 95% Confidence Interval [CI] = 0.93 to 1.89, p = 0.12). In a model that adjusted for age, gender, educational level, smoking, hearing impairment, depressive symptoms or antidepressant use, and use of a medication that could potentially affect cognitive function, the OR was 1.28, 95% CI = 0.88 to 1.84, p = 0.19. In an adjusted model, ET cases with tremor onset after age 65 were 57% more likely to have MCI than controls (OR = 1.57, 95% CI = 1.03 to 2.38, p = 0.03), whereas ET cases with tremor onset prior to age 65 and controls were equally likely to have MCI (OR = 0.73, 95% CI = 0.34 to 1.57, p = 0.43). In this study, older-onset ET was associated with MCI. This finding supports the hypothesis that cognitive disturbances are one of the core non-motor symptoms of ET.     

Six-month course of mild cognitive impairment and affective symptoms in late-life depression

Mild cognitive impairment (MCI) is frequent in patients with late-life depression. Previous studies indicate that cognitive performance in these patients is not or only marginally improved when they recover from depression. However, recovery from cognitive impairments due to depression may have a longer time course than recovery from affective symptoms. In a group of 34 elderly depressed patients (mean age: 73.4 years) admitted to a gerontopsychiatric day-clinic, severity of depression and cognitive performance were assessed before the initiation of treatment and were reassessed 6 months later. At admission, 18 of 34 patients (53%) fulfilled the criteria for MCI, with a preponderance of impairments in short-term memory and visuospatial capabilities. At the 6-month follow-up, cognitive performance had not significantly improved for the entire group; 12 of 27 patients (44%) still were fulfilling the criteria for MCI. No relationships could be ascertained between cognitive impairment or functional level and severity or course of depression. Patients with diurnal variations of the depressive symptomatology were less likely to fully recover from depression.     

Heterogeneity in risk factors for cognitive impairment, no dementia: population-based longitudinal study from the Kungsholmen Project.

OBJECTIVES: The objectives of this study were to investigate the relation of vascular, neuropsychiatric, social, and frailty-related factors with "Cognitive impairment, no dementia" (CIND) and to verify their effect independently of future progression to Alzheimer disease (AD). METHODS: Seven hundred eighteen subjects aged 75+ years who attended baseline, 3- and 6-year follow-up examinations of the Kungsholmen Project, a Swedish prospective cohort study, were studied. CIND was defined according to the performance on the Mini-Mental State Examination. Potential risk factors were collected at baseline and clustered according to four research hypotheses (frailty, vascular, neuropsychiatric, and social hypothesis), each representing a possible pathophysiological mechanism of CIND independently of subsequent development of AD. RESULTS: Over a mean 3.4 years of follow up, 82 participants (11.4%) developed CIND. When the population was subsequently followed for a mean of 2.7 years, subjects with CIND had a threefold increased risk to progress to AD. After multiple adjustments, including adjustment for the development of AD at the 6-year follow up, risk factors for CIND were hip fracture, polypharmacy, and psychoses. CONCLUSIONS: The results suggest that not only the AD-type neurodegenerative process, but also neuropsychiatric- and frailty-related factors may induce cognitive impairment in nondemented elderly. These findings may have relevant preventive and therapeutic implications.     

运用磁共振动脉自旋标记技术鉴别轻度认知功能障碍和血管性轻度认知功能障碍

目的研究轻度认知功能障碍(MCI)和血管性轻度认知功能障碍(VaMCI)患者各认知功能脑区域脑血流量(CBF)的特点,为早期诊断提供科学依据。方法选择2016年1月-2018年1月昆明市延安医院神经内科门诊及住院部确诊的24例MCI患者(MCI组)和24例VaMCI(VaMCI组)患者及24名老年健康志愿者(正常对照组)作为研究对象,运用动脉自旋标记(ASL)技术采集3组受试者认知功能脑区域的CBF数据。结果与正常对照组相比,MCI组双侧额叶、双侧海马脑血流灌注增加,双侧颞叶、楔前叶等部位脑血流灌注降低(P 0. 05);与正常对照组相比,VaMCI组双侧额叶、双侧海马脑血流灌注增加,双侧楔前叶、角回等部位脑血流灌注降低(P 0. 05);与MCI组相比,VaMCI组左侧颞叶、双侧扣带回、左侧杏仁核脑血流灌注增加,右侧颞叶、右侧扣带回等部位脑血流灌注降低(P 0. 05)。结论 MCI患者和VaMCI患者认知功能脑区域脑血流灌注具有不同的特点,磁共振ASL技术能够为两者的鉴别提供影像学帮助。