Mild cognitive impairment: Disparity of incidence and prevalence estimates
The purpose of conducting this study was to identify areas of concordance and sources of variation for the published rates of prevalence and incidence associated with various definitions for mild cognitive impairment (MCI).
The study used systematic review of studies published in English since 1984. Studies were identified by searching MEDLINE and EMBASE databases. Population-based observational studies of incidence or prevalence of MCI and related terms were eligible for inclusion.
A total of 3,705 citations were identified, and 42 were accepted for inclusion; 35 included data on prevalence and 13 on incidence. The following four terms predominated: age-associated memory impairment (AAMI); cognitive impairment no dementia (CIND); MCI; and amnestic MCI (aMCI). Within each term, the operational definition varied. Substantial variation was observed for both incidence (MCI: 21.5-71.3; aMCI: 8.5-25.9 per 1,000 person-years) and prevalence of each definition of cognitive impairment (AAMI 3.6%-38.4%; CIND 5.1%-35.9%; MCI 3%-42%; aMCI 0.5%-31.9%). CIND and MCI showed increasing prevalence among older age groups, whereas age-specific rates of aMCI were lower and without any apparent age relationship.
Prevalence and incidence estimates associated with MCI vary greatly both between definitions and within a definition across the 42 publications. These wide differences pose a significant challenge to our understanding of the social burden of this disease. Enhancement and standardization of operational definitions of the subtypes of cognitive impairment could improve estimates of disease burden and provide a mechanism to assist in the identification of individuals at risk for future Alzheimer's disease and other dementias.
Available from: Baekhee Lee
- ", 10 participants for 20s ~ 40s and 20 participants for 50s ~ 70s were separately recruited and gender ratio was balanced. Considering that the prevalence of brain disorders under 50s is relatively small (< 5%) compared to that over 50s (< 45.7%) (Ward et al., 2012), the participant aged 50s ~ 70s was recruited by two times than that aged 20s ~ 40s in the present study. "
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ABSTRACT: A reduction of motor performance due to brain disorders can be screened by evaluating force tracking capabilities (FTCs). Existing studies have examined FTCs mainly using simple sinusoidal waves, of which repeated profiles have a critical limitation due to a learning effect in force tracking. The present study examined the effects of personal factors (age and gender) and sinusoidal wave factors (central force and complexity) on FTCs of healthy adults using composite sinusoidal wave profiles (CSWPs). FTCs were measured using Finger Touch for 30 seconds and quantified in terms of time within the target range (TWR, accuracy measure) and relative RMSE (RRMSE, variability measure). A total of 90 healthy adults in 20s to 70s with the equal gender ratio participated in the experiment consisting of combinations of 2 central force levels (6 N and 10 N) and 2 complexity levels (approximate entropy, ApEn = 0.03 and 0.06) of CSWPs. Significantly decreased FTCs (lower TWR and higher RRMSE) were found in aged adults, females, the low central force, and the high complexity. The detailed FTC decrements include a 43% reduced TWR and a 85% increased RRMSE of older adults in 70s as compared to those in 20s, a 17% reduced TWR and a 17% increased RRMSE of female as compared to those of male, a 30% reduced TWR and a 108% increased RRMSE at central force = 6 N when compared to those at central force = 10 N, and a 19% reduced TWR and a 30% increased RRMSE at ApEn = 0.06 as compared to those at ApEn = 0.03. The characteristics of FTCs for CSWPs can be of use in establishing an assessment protocol of motor performance for screening brain disorders.
Proceedings of the Human Factors and Ergonomics Society 59th Annual Meeting, Los Angeles, CA; 10/2015
- "It has been shown, for example, that HIV+ individuals showed a similar pattern and level of cognitive performance as much older seronegatives (Van Gorp et al. 1989). Indeed, the present sample of HIV+ individuals in their 60s had prevalence rates of MCI that were similar to those typically observed in seronegative adults aged 70 and over (Ward et al. 2012). These cognitive deficits in the cART era appear to be driven by a rise in the prevalence of impairment in memory and executive functions among HIV+ individuals who are medically asymptomatic (Heaton et al. 2011). "
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ABSTRACT: With the rising number of individuals in their 50s and 60s who are infected with HIV, concerns have emerged about possible increases in the rates of non-HIV-associated dementias. The current study examined the prevalence of mild cognitive impairment (MCI) in older HIV-infected adults, since MCI is an intermediate state between typical cognitive aging and dementia that emerges in this age range. Participants included 75 adults with HIV disease aged 50 years and older who were on combination antiretroviral therapy (cART) and had undetectable plasma viral loads and 80 demographically similar HIV-seronegative comparison subjects. Participants completed a research neuropsychological evaluation that was used to classify MCI according to the comprehensive diagnostic scheme described by Bondi et al. (J Alzheimers Dis 42:275-289, 2014). HIV-infected persons were over seven times more likely to have an MCI designation (16 %) than their seronegative counterparts (2.5 %). Within the HIV+ cohort, MCI had minimal overlap with diagnoses of asymptomatic neurocognitive impairment and was significantly associated with older age, lower Karnofsky Scale of Performance Scores, and mild difficulties performing instrumental activities of daily living (iADLs). HIV infection in older adults is associated with a notably elevated concurrent risk of MCI, which may increase the likelihood of developing non-HIV-associated dementias as this population ages further.
Journal of NeuroVirology 07/2015; 21(5). DOI:10.1007/s13365-015-0366-7 · 2.60 Impact Factor
Available from: Gayan Perera
- ". Though this work is specific to AD and not dementia, as AD is considered to be the most common type of dementia , similar age-specific trends and magnitude between the Europe and the United States is not unexpected. Sources of variability for prevalence of MCI and dementia have been previously described and potential causes include age and gender characteristics of study, diagnosis implementation, country, and year of study  . For MCI in particular, a lack of consensus in criteria choice and implementation remains an important factor of heterogeneity: overall prevalence was more than doubled using DSM-IV versus Petersen criteria in the same population sample . "
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ABSTRACT: Abstract: The prevalence of mild cognitive impairment (MCI) and dementia according to age remain uncertain. We systematically extracted age-stratified estimates of MCI and dementia prevalence reported in European studies since 1995, and performed meta-analyses for dementia. We identified 10 relevant studies on MCI and 26 studies on dementia. Studies on MCI presented visually substantial heterogeneity preventing a meta-analysis, a majority reporting an increase in prevalence at ≥75 years old. Prevalence of dementia rose continuously from 55 years of age, reaching 44.7% (39.8; 49.6) in those ≥95 years of age. Homogenization of MCI criteria, and additional studies in Northern European population would be warranted.
Journal of Alzheimer's disease: JAD 01/2015; 48(2). · 4.15 Impact Factor
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