Practical issues in cognitive screening of elderly illiterate populations in developing countries. The Indo-US Cross-National Dementia Epidemiology Study

The study of the epidemiology of dementia, specifically Alzheimer's disease, in developing countries requires specialized instruments and personnel. Cultural and sub-cultural differences among populations are highly relevant to the design of such instruments. Over and above the cultural issues, it is widely recognized that low education and illiteracy pose considerable challenges to reliable and valid cognitive screening. The overall objectives of the Indo-US Cross-National Dementia Epidemiology Study were: a) to determine the prevalence and incidence of, and risk factors for, Alzheimer's and other dementias in a defined Indian community; and b) to compare these results with those found in a defined American community. To achieve these epidemiological objectives, our first task was to develop, systematically and empirically, suitable cognitive and activities assessment screening instruments for use in India, which would 1) be culturally fair, psychometrically sound, and valid for a population with little or no education; 2) be optimally sensitive and specific for dementia; and 3) allow not only the identification but also the more detailed characterization of dementia, and of normal and abnormal cognitive aging. In this paper we address the practical issues involved in the development and administration of the modified cognitive screening battery in our rural Indian context.

Effect of education and gender adjustment on the sensitivity and specificity of a cognitive screening battery for dementia: results from the MoVIES Project. Monongahela Valley Independent Elders Survey

The Monongahela Valley Independent Elders Survey (MoVIES) used a multiphase process to identify demented persons among 1,366 randomly selected noninstitutionalized individuals 65 years and older. Raw test scores from a cognitive screening battery were used to identify cognitively impaired individuals who were referred for a clinical evaluation. Subsequently, test scores were adjusted for education and gender within age strata. Adjusting test scores affected sensitivity for dementia only among the most educated, increasing sensitivity among younger subjects and decreasing among the older subjects. Specificity increased among the least educated and the oldest subjects. Overall, the adjusted criteria did not perform as well as the unadjusted criteria in this sample. Adjustment for education will not necessarily improve the ability of a screening battery for cognitive function to identify demented persons, particularly if unadjusted scores perform well.