Clinical Prediction of Alzheimer Disease Dementia Across the Spectrum of Mild Cognitive Impairment (original) (raw)
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Mild Cognitive Impairment Represents Early-Stage Alzheimer Disease
Archives of Neurology, 2001
Background: Mild cognitive impairment (MCI) is considered to be a transitional stage between aging and Alzheimer disease (AD). Objective: To determine whether MCI represents earlystage AD by examining its natural history and neuropathologic basis. Design: A prospective clinical and psychometric study of community-living elderly volunteers, both nondemented and minimally cognitively impaired, followed up for up to 9.5 years. Neuropathologic examinations were performed on participants who had undergone autopsy. Setting: An AD research center. Participants: All participants enrolled between July 1990 and June 1997 with Clinical Dementia Rating (CDR) scores of 0 (cognitively healthy; n = 177; mean age, 78.9 years) or 0.5 (equivalent to MCI; n=277; mean age, 76.9 years). Based on the degree of clinical confidence that MCI represented dementia of the Alzheimer type (DAT), 3 subgroups of individuals with CDR scores of 0.5 were identified: CDR 0.5/DAT, CDR 0.5/incipient DAT, and CDR 0.5/uncertain dementia. Main Outcome Measure: Progression to the stage of CDR 1, which characterizes mild definite DAT. Results: Survival analysis showed that 100% of CDR 0.5/ DAT participants progressed to greater dementia severity over a 9.5-year period. At 5 years, rates of progression to a score of CDR 1 (or greater) for DAT were 60.5% (95% confidence interval [CI], 50.2%-70.8%) for the CDR 0.5/DAT group, 35.7% (95% CI, 21.0%-50.3%) for the CDR 0.5/incipient DAT group, 19.9% (95% CI, 8.0%-31.8%) for the CDR 0.5/uncertain dementia group, and 6.8% (95% CI, 2.2%-11.3%) for CDR 0/controls. Progression to greater dementia severity correlated with degree of cognitive impairment at baseline. Twenty-four of the 25 participants with scores of CDR 0.5 had a neuropathologic dementing disorder, which was AD in 21 (84%). Conclusions: Individuals currently characterized as having MCI progress steadily to greater stages of dementia severity at rates dependent on the level of cognitive impairment at entry and they almost always have the neuropathologic features of AD. We conclude that MCI generally represents early-stage AD.
Journal of Neurology, Neurosurgery & Psychiatry, 2009
Objective-To compare rates of Mild Cognitive Impairment (MCI) and rates of progression to dementia, using different MCI diagnostic systems Methods-MCI was investigated at baseline in 3063 community-dwelling non-demented elderly in the Ginkgo Evaluation of Memory (GEM) study who were evaluated every six months to identify presence of dementia. Overall MCI frequency was determined using (1) Clinical Dementia Rating (CDR) score of 0.5 and (2) neuropsychological (NP) criteria, defined by impairment on standard cognitive tests.
The Fate of the 0.5s: Predictors of 2-Year Outcome in Mild Cognitive Impairment
Impairments in executive cognition (EC) may be predictive of incident dementia in patients with mild cognitive impairment (MCI). The present study examined whether specific EC tests could predict which MCI individuals progress from a Clinical Dementia Rating (CDR) score of 0.5 to a score Z1 over a 2-year period. Eighteen clinical and experimental EC measures were administered at baseline to 104 MCI patients (amnestic and non-amnestic, single-and multiple-domain) recruited from clinical and research settings. Demographic characteristics, screening cognitive measures and measures of everyday functioning at baseline were also considered as potential predictors. Over the 2-year period, 18% of the MCI individuals progressed to CDR Z 1, 73.1% remained stable (CDR 5 0.5), and 4.5% reverted to normal (CDR 5 0). Multiple-domain MCI participants had higher rates of progression to dementia than single-domain, but amnestic and non-amnestic MCIs had similar rates of conversion. Only three EC measures were predictive of subsequent cognitive and functional decline at the univariate level, but they failed to independently predict progression to dementia after adjusting for demographic, other cognitive characteristics, and measures of everyday functioning. Decline over 2 years was best predicted by informant ratings of subtle functional impairments and lower baseline scores on memory, category fluency, and constructional praxis. (JINS, 2011, 17, 277-288)
Neuropsychological measures predict decline to Alzheimer's dementia from mild cognitive impairment
Neuropsychology, 2012
Objective: Studies of Mild Cognitive Impairment (MCI) show elevated rates of conversion to dementia at the group level. However, previous studies of the trajectory of MCI identify great heterogeneity of outcomes, with a significant proportion of individuals with MCI remaining stable over time, changing MCI subtype classification, or reverting to a normal cognitive state at long-term follow-up. Method: The present study examined individual outcomes at 20 months in a group of older adults classified according to MCI subtypes. A total of 106 participants, 81 with different subtypes of MCI and 25 healthy controls, undertook longitudinal neuropsychological assessment of visual and verbal memory, attentional processing, executive functions, working memory capacity, and semantic memory. Results: At 20 months 12.3% of the MCI group progressed to dementia, 62.9% continued to meet MCI criteria, and 24.7% reverted to unimpaired levels of function. A discriminant function analysis predicted outcome at 20 months on the basis of baseline neuropsychological test performance with 86.3% accuracy. The analysis indicated that a pattern of impairments on visual episodic memory, verbal episodic memory, short-term memory, working memory, and attentional processing differentiated between participants who developed dementia, recovered from MCI, or remained in stable MCI. Conclusions: The results of the present study raise questions regarding the specificity of existing criteria for the subtypes of MCI, with these results indicating a high degree of instability in classification over time. In addition, the results suggest that multidomain MCI is the most reliable precursor stage to the development of AD.
2010
clinical diagnosis of probable Alzheimer's disease (AD), fi rst established over 25 years ago, was the requirement of a dementia syndrome. Th e clinician then proceeded to systematically rule out and exclude other neurological and/or medical conditions that might have accounted for the observed cognitive decline. Th is set of criteria as well as the Diagnostic and Statistical Manual of Mental Disorders (fourth edition) criteria for a dementia syndrome and probable AD [1] were designed to be conservative so that a neurodegenerative condition could not be established unless cognitive function was sufficiently compromised to interfere with an individual's social and/or occupational function.
Psychology and Aging, 2018
Mild Cognitive Impairment (MCI) is a heterogeneous condition between normal aging and dementia. Upon neuropsychological testing, MCI can be divided into four groups: singledomain amnestic MCI (sd-aMCI), multiple-domain amnestic MCI (md-aMCI), single-and multiple-domain non-amnestic MCI (sd-naMCI, md-naMCI). Some controversy exists about whether the risk of progression to Alzheimer's disease (risk-AD) is increased in all MCI subtypes. We meta-analyzed the risk-AD for four MCI groups using random-effects metaregression with the Hierarchical Robust Variance Estimator and sample size, criterion for objective cognitive impairment, length of follow-up and source of recruitment as covariates. From a pool of 134 available studies, 81 groups from 33 studies (N = 4,907) were metaanalyzed. All the studies were rated as having a high risk of bias. aMCI is overrepresented in studies from memory clinics. Multivariate analyses showed that md-aMCI had a similar risk-AD relative to sd-aMCI, whereas both sd-naMCI and md-naMCI showed a lower risk-AD compared to sd-aMCI. The risk-AD was significantly associated with differences in sample sizes across studies and between groups within studies. md-aMCI had a similar risk-AD relative to sd-aMCI in studies from memory clinics and in studies in the community. Several potential sources of bias such as blindness of AD diagnosis, the MCI diagnosis approach and the reporting of demographics were associated with the risk-AD. This work provides important data for use in both clinical and research scenarios.
In the present study we investigated the efficacy of the differential outcomes procedure (DOP) to improve visuospatial working memory in patients with Alzheimer's disease and mild cognitive impairment (MCI). The DOP associates correct responses to the to-beremember stimulus with unique outcomes. Eleven patients diagnosed with Alzheimer's disease, 11 participants with MCI, and 17 healthy matched controls performed a spatial delayed memory task under the DOP and a control condition (non-differential outcomes -NOP-). We found that performance (terminal accuracy) was significantly better in the DOP condition relative to the NOP condition in all three groups of participants. AD patients performed worse, and took longer to benefit from the DOP. In line with previous animal and human research, we propose that the DOP activates brain structures and cognitive mechanisms that are less affected by healthy and pathological aging, optimizing in this way the function of the cognitive system.
Journal of Neuropsychology, 2015
In the field of neuropsychology, it is essential to determine which neuropsychological tests predict Alzheimer's disease (AD) in people with mild cognitive impairment (MCI) and which cut-off points should be used to identify people at greater risk for converting to dementia. The aim of the present study was to analyse the predictive value of the cognitive tests included in a neuropsychological battery for conversion to AD among MCI participants and to analyse the influence of some sociodemographic variables - sex, age, schooling - and others, such as follow-up time and emotional state. A total of 105 participants were assessed with a neuropsychological battery at baseline and during a 3-year follow-up period. For the present study, the data were analysed at baseline. During the follow-up period, 24 participants (22.85%) converted to dementia (2.79 ± 1.14 years) and 81 (77.14%) remained as MCI. The logistic regression analysis determined that the long delay cued recall and the performance time of the Rey figure test were the best predictive tests of conversion to dementia after an MCI diagnosis. Concerning the sociodemographic factors, sex had the highest predictive power. The results reveal the relevance of the neuropsychological data obtained in the first assessment. Specifically, the data obtained in the episodic verbal memory tests and tests that assess visuospatial and executive components may help to identify people with MCI who may develop AD in an interval not longer than 4 years, with the masculine gender being an added risk factor.