Prevalence of four subtypes of mild cognitive impairment and APOE in a Japanese community.
ABSTRACT The results of previous reports estimating the prevalence of mild cognitive impairment (MCI) have varied widely according to the criteria used to define MCI.
We assessed the cognitive function of Japanese community-dwelling individuals >or=65 years old and attempted to estimate the prevalence of four MCI subtypes (amnestic single, amnestic multiple, nonamnestic single, and nonamnestic multiple) using two cutoffs (1 and 1.5 SD) below normative standard. Presence of apolipoprotein E4 allele (APOE4), which is known as a strong risk factor for AD, is reportedly associated with high risk of conversion from MCI to AD. We therefore calculated the frequency of APOE4 carriers for each MCI subtype.
Initially 1888 (70%) of 2698 baseline samples participated, and 1433 (53%) subjects who had complete clinical data including APOE typing remained for the final analysis. The prevalence of MCI subtypes varied within the range of 1.7-16.6%, depending on the criteria applied. Prevalence of MCI was higher using a cutoff at -1.0 SD than at -1.5 SD, and prevalence of amnestic MCI single at -1.5 SD was lowest among all subtypes of MCI. Frequency of APOE4 was higher for amnestic MCI than for non-amnestic MCI or the cognitively normal group.
The prevalence of MCI was highly dependent on the diagnostic criteria applied. A higher frequency of APOE4 in participants with amnestic MCI subtype suggested a greater risk of future AD. For future interventions to delay the onset of dementia, targeting individuals with amnestic MCI multiple at -1 SD might be desirable.
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ABSTRACT: Mild cognitive impairment (MCI) is associated with an increased risk of developing dementia. Recently published results of the Current Concepts in MCI Conference suggested subclassifications for MCI (MCI-amnestic, MCI-multiple domains slightly impaired, MCI-single nonmemory domain) based on the recognized heterogeneity in the use of the term. These subclassifications have not been empirically validated to date. A community sample of 1045 dementia-free individuals aged 75 years and over was examined by neuropsychological testing in a three-wave longitudinal study. The prevalences and the predictive validities for the subclassifications of MCI and their modifications (original criteria except for the report of subjective decline in cognitive function) were determined. The prevalence was 1 to 15% depending on the subset employed. Subjects with a diagnosis of MCI progressed to dementia at a rate of 10 to 55% over 2.6 years, depending on the subset employed. MCI-amnestic achieved the highest positive predictive power (PPP). ROC curves of the subclassifications for MCI indicate that all but one subset for MCI failed to predict dementia (MCI-multiple domains slightly impaired-modified: AUC=0.585, P<0.01, 95% CI, 0.517-0.653). The use of modified criteria for MCI (original criteria except for the report of subjective decline in cognitive function) is associated with a higher diagnostic sensitivity but also with a reduction in diagnostic specificity and PPP. Modified criteria should be applied if a concept for MCI with a high sensitivity is required and the original criteria (including subjective cognitive complaint) if a concept with high specificity and high PPP is required.Psychological Medicine 08/2003; 33(6):1029-38. · 5.59 Impact Factor
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ABSTRACT: To compare the rates of conversion to Alzheimer dementia (AD) between subtypes of mild cognitive impairment (MCI) in a community-based birth cohort investigated at age 75 and followed up after 30 months. The Vienna Trans-Danube Aging Study investigated every inhabitant of the area on the left shore of the river Danube who was born between May 1925 and June 1926. With use of the official voting registry, 1505 subjects were contacted and 697 participated. Data refer to the cohort of 581 nondemented individuals who completed extensive neuropsychological examination at baseline. Follow-up after 30 months was possible in 476 probands (35 deceased). The 141 patients with MCI at baseline were classified into two subtypes. At follow-up, 41 of these patients with MCI were diagnosed with AD. Conversion rates to AD were 48.7% (CI: 32.4 to 65.2) for amnestic MCI and 26.8% (CI: 17.6 to 37.8) for nonamnestic MCI. Another 49 AD cases originated from cognitive health at baseline (12.6%; CI: 9.4 to 16.3). Patients with mild cognitive impairment (MCI) showed a high probability to be diagnosed with Alzheimer dementia (AD) after 30 months. Subtypes of MCI were not useful in defining early stages of various types of dementia: Not only amnestic MCI but also nonamnestic MCI converted frequently to AD, and conversion to vascular dementia and dementia with Lewy bodies was not restricted to nonamnestic MCI.Neurology 02/2007; 68(4):288-91. · 8.25 Impact Factor
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ABSTRACT: Mild cognitive impairment (MCI) is a condition referring to the persons with cognitive deficits measurable in some form or another, but not meeting criteria for dementia, and who have an increased risk of becoming demented. To establish the rate of progression to dementia in MCI, to investigate the risk of conversion for amnestic vs multiple-domains subtypes, and to identify the predictors of progression. MCI (n = 105) individuals enrolled in a longitudinal study received annual clinical and psychometric examinations for up to a mean of 3 years. The diagnosis of MCI according to Mayo Clinic Petersen's Criteria was conducted by a panel of specialists. After 3 years of follow-up, 23 of 105 subjects with MCI were diagnosed with dementia. 40 showed cognitive decline not dementia, 34 were stable and showed no cognitive decline or improvement, while eight showed cognitive improvement. We conclude that conversion rate from MCI to DSM-IIIR dementia was 21.9% over a period of 3 years. The occurrence of depressive symptoms may constitute a predictor for those who are more likely to progress to dementia. The risk of conversion to dementia was higher among the subjects with an evidence of impairment extending beyond memory than with those who suffered only from memory deficits, and the subjects who converted to dementia in this subtype had significantly higher baseline plasma total homocysteine levels than non-converters.International Journal of Geriatric Psychiatry 07/2007; 22(6):563-7. · 2.98 Impact Factor