Biomedical subjects
Publications and source records attributed to Hugh C Hendrie.
Dementia with Lewy bodies (DLB) is the second most common neuropathologically diagnosed cause of degenerating dementia after Alzheimer's disease. We report the first autopsy-confirmed case in sub-Saharan Africa in a Nigerian patient. The case presented highlights the varied clinical presentation of DLB, and is intended to raise awareness about another possible cause of dementia in Nigerian subjects.
OBJECTIVE: To design a brief cognitive screener with acceptable sensitivity and specificity for identifying subjects with cognitive impairment. DESIGN: Cohort one is assembled from a community-based survey coupled with a second-stage diagnostic evaluation using formal diagnostic criteria for dementia. Cohort two is assembled from referrals to a specialty clinic for dementing disorders that completed the same diagnostic evaluation. SETTING: Urban neighborhoods in Indianapolis, Indiana and the Indiana Alzheimer Disease Center. PATIENTS: Cohort one consists of 344 community-dwelling black persons identified from a random sample of 2212 black persons aged 65 and older residing in Indianapolis; cohort two consists of 651 subject referrals to the Alzheimer Disease Center. MEASUREMENTS: Formal diagnostic clinical assessments for dementia including scores on the Mini-mental state examination (MMSE), a six-item screener derived from the MMSE, the Blessed Dementia Rating Scale (BDRS), and the Word List Recall. Based on clinical evaluations, subjects were categorized as no cognitive impairment, cognitive impairment-not demented, or demented. RESULTS: The mean age of the community-based sample was 74.4 years, 59.4% of the sample were women, and the mean years of education was 10.1. The prevalence of dementia in this sample was 4.3% and the prevalence of cognitive impairment was 24.6%. Using a cut-off of three or more errors, the sensitivity and specificity of the six-item screener for a diagnosis of dementia was 88.7 and 88.0, respectively. In the same sample, the corresponding sensitivity and specificity for the MMSE using a cut-off score of 23 was 95.2 and 86.7. The performance of the two scales was comparable across the two populations studied and using either cognitive impairment or dementia as the gold standard. An increasing number of errors on the six-item screener is highly correlated with poorer scores on longer measures of cognitive impairment. CONCLUSIONS: The six-item screener is a brief and reliable instrument for identifying subjects with cognitive impairment and its diagnostic properties are comparable to the full MMSE. It can be administered by telephone or face-to-face interview and is easily scored by a simple summation of errors.
Epidemiologic studies on dementia generally have 2 major interacting objectives: descriptive, where rates of dementia and Alzheimer Disease (AD) are calculated for communities and selected populations, and analytic, which attempt to explain the observed phenotypic variations in communities and populations by identifying disease risk factors. The public health benefits derived from descriptive studies are exemplified by the recent published review of the global prevalence of dementia under the auspices of Alzheimer Disease International. This review emphasized the enormous and growing burden associated with dementia particularly for countries in the developing world and outlined strategies to influence policy making, planning, and healthcare allocation. One interesting feature of descriptive studies on dementia is that although the few epidemiologic studies conducted in Africa suggest that rates of dementia and AD are relatively low, rates of AD and dementia have been reported to be relatively high for African Americans. The Indianapolis-Ibadan Dementia Project has reported that the incidence rates for AD and dementia in Yoruba are less than half the incidence rates for AD and dementia in African Americans. Analytic studies are now underway to identify risk factors that may account for these rate differences. The risk factor model being applied, attempts to identify not only putative genetic and environmental factors but also their interactions. So far the major findings have included: apolipoprotein E e4, a major risk factor for AD in most populations, is also a risk factor for AD in African Americans but not for Yoruba; African Americans are at higher risk not only for AD, but also for diseases associated with increased cardiovascular risk such as hypertension, diabetes, and metabolic syndrome; African Americans have higher rates of hypercholesterolemia than Yoruba: there is an interaction between apolipoprotein E e4, cholesterol, and AD risk in both Yoruba and African Americans. We eventually hope to create a risk factor model that will not only account for the dementia rate differences between Yoruba and African Americans, but also help explain dementia rates in other developing and developed countries.
Considerable advances have been made over the past decade in developing and adapting instruments to measure cognitive functioning in individuals with a wide range of educational and racial/ethnic backgrounds in different countries. Similar approaches can be used to extend these assessments to groups that have not yet been studied. The critical issues are to ensure that methods are appropriately harmonized to the local context, that local norms are established, and that local expertise is brought to bear in instrument development/adaptation. Effective instruments are also available to screen for depression in the elderly but closer attention should be made to possible ethnic differences in item response on these scales. The ideal screening tool should be quick, inexpensive, painless, and socially/culturally acceptable to the population. It should also have desirable psychometric properties. Examples are provided from several international studies. The context, costs, and objectives of screening a given population should be considered when selecting a screening instrument and a threshold on the scale, whether for clinical or research purposes.
OBJECTIVE: The authors conducted a longitudinal, population-based survey of African Americans in Indianapolis, Indiana, and Yoruba in Ibadan, Nigeria, using the Community Screening Interview for Dementia to assess the predictive value of informant reports of changes in personality on incident dementia and Alzheimer disease. METHODS: In all, 3,021 subjects had informants' reports of changes in personality and dementia status (2,084 subjects residing in Ibadan and 937 subjects residing in Indianapolis). RESULTS: After adjusting for demographic, cognitive, and functional characteristics in two markedly different populations, socioeconomically and culturally, subjects with changes in personality had approximately twice the odds of having dementia as subjects with no change in personality. CONCLUSION: The finding that in two markedly different populations, personality change is a significant predictor of future dementia, independent of cognition and functional status, should make clinicians particularly sensitive to these reports when they occur in their elderly patients.