Incidence of mild cognitive impairment in the Pittsburgh Cardiovascular Health Study-Cognition Study

and Department of Neurology (O.T.C.), University of California Davis, Davis.
Neurology (Impact Factor: 8.29). 10/2012; 79(15). DOI: 10.1212/WNL.0b013e31826e25f0


Objectives and methods:
The purpose of this study was to examine the incidence of mild cognitive impairment (MCI) and patterns of progression from incident MCI to dementia in 285 cognitively normal subjects (mean age, 78.9 years) in the Cardiovascular Health Study-Cognition Study from 1998-1999 to 2010-2011.

Two hundred (70%) of the participants progressed to MCI; the age-adjusted incidence of MCI was 111.09 (95% confidence interval, 88.13-142.95) per 1,000 person-years. A total of 107 (53.5%) of the incident MCI subjects progressed to dementia. The mean time from MCI to dementia was 2.8 ± 1.8 years. Forty (20%) of the incident MCI cases had an "unstable" course: 19 (9.5%) converted to MCI and later returned to normal; 10 (5%) converted to MCI, to normal, and later back to MCI; 7 (3.5%) converted to MCI, to normal, to MCI, and later to dementia; and 4 (2%) converted to MCI, to normal, and later to dementia. There was an increased mortality rate among the cognitively normal group (110.10 per 1,000 person-years) compared to those with incident MCI who converted to dementia (41.32 per 1,000 person-years).

The majority of the subjects aged >80 years developed an MCI syndrome, and half of them progressed to dementia. Once the MCI syndrome was present, the symptoms of dementia appeared within 2 to 3 years. Progression from normal to MCI or from normal to MCI to dementia is not always linear; subjects who developed MCI and later returned to normal can subsequently progress to dementia. Competing mortality and morbidity influence the study of incident MCI and dementia in population cohorts.

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    • "These studies have confirmed that some people with MCI are stable over time, whereas others develop AD, some revert to cognitive normality, and still other people who had reverted to normality revert back to an MCI diagnosis, and finally develop dementia. The prevalence of MCI is very variable; it has been reported that between 30% and 50% of the cases return to a normal cognitive state during follow-up (Garc ıa-Herranz, D ıaz- Mardomingo, & Peraita, 2014; Lopez et al., 2012; Peraita et al., 2011), although the percentage of people with MCI who develop dementia, especially AD, between 2 and 5 years after diagnosis is between 10% and 20% (D ıaz-Mardomingo et al., 2010; Lonie et al., 2010; Petersen et al., 1999). The possibility of identifying people at high risk of incipient dementia long before their cognitive deficits become clinically evident, through their performance in certain cognitive tests, represents a great advance in the research of dementias. "
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    ABSTRACT: 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. © 2015 The British Psychological Society.
    No preview · Article · Mar 2015 · Journal of Neuropsychology
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    • "Others have noted that impairments in executive functions (i.e., Trail Making B [6] [32]), language (i.e., Semantic Fluency [6] [26] [34]), or even a summary measure of mental state (i.e., Mini-Mental State Examination (MMSE) [6] [35], Clock test [26]) are better predictors of dementia than memory function alone. However, it should be noted that even among the longitudinal studies, follow-up is generally limited to two years or fewer and most of the conversions from MCI to dementia occur relatively early in the longitudinal follow-up suggesting that these patients were on the cusp of clinical dementia (for discussion, see [36]). Brain functional imaging studies with SPECT have found that those patients who develop dementia from MCI showed reduced cerebral blood flow in a variety of brain regions including the medial temporal lobe, the temporal/parietal cortex, the posterior cingulate gyrus, the precuneus, and the prefrontal cortex [35, 37–43]. "
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    ABSTRACT: Background: There is a range of factors that predict the development of Alzheimer's disease (AD) dementia among patients with amnestic mild cognitive impairment (MCI). Objectives: To identify the neuropsychological, genetic, and functional brain imaging data that best predict conversion to AD dementia in patients with amnestic MCI. Methods: From an initial group of 42 amnestic MCI patients assessed with neurological, neuropsychological, and brain SPECT, 39 (25 converters, 14 non-converters) were followed for 4 years, and 36 had APOE ε4 genotyping. Baseline neuropsychological data and brain SPECT data were used to predict which of the MCI patients would develop dementia by the end of the 4 years of observation. Results: The MCI patients who had converted to AD dementia had poorer performance on long-term visual memory and Semantic Fluency tests. The MCI subjects who developed dementia were more likely to carry at least one copy of the APOE ε4 allele (Hazard Risk = 4.22). There was lower brain perfusion in converters than non-converters, mainly in postcentral gyrus. An additional analysis of the SPECT data found differences between the MCI subjects and controls in the posterior cingulate gyrus and the basal forebrain. When the brain imaging and neuropsychological test data were combined in the same Cox regression model, only the neuropsychological test data were significantly associated with time to dementia. Conclusion: Although the presence of reduced brain perfusion in postcentral gyrus and basal forebrain indicated an at-risk condition, it was the extent of memory impairment that was linked to the speed of decline from MCI to AD.
    Full-text · Article · Mar 2014 · Journal of Alzheimer's disease: JAD
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    ABSTRACT: Persons with mild cognitive impairment (MCI) have overt changes in thinking and memory, but they are still largely independent in daily affairs. They have a far higher rate of developing dementia (progressing to a more debilitating state of cognitive impairment) than cognitively normal persons, but at the individual patient level, prognosis is variable. Sometimes persons with MCI do not worsen and a few even revert back to cognitive normality.(1,2) The variable prognosis in MCI is one reason why the term "MCI" has caught on: not only does it denote a sense of severity at the mildest level, it also conveys uncertainty of prognosis. Identification of the subset of patients with MCI at highest risk to progress to more severe cognitive impairment is a very important goal for research and future clinical care. Quantitating the degree of cognitive impairment by traditional history-taking, brief mental status testing, and more detailed neuropsychological assessment are necessary and informative first steps. However, knowledge of cognitive and functional status in MCI still leaves much uncertainty regarding the ability to predict worsening.
    No preview · Article · Feb 2013 · Neurology
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