Vocabulary Knowledge is Not a Predictor of General Cognitive Functioning in Elderly People with Very Low Educational Attainment

Abstract

INTRODUCTIONThe population is rapidly aging worldwide, which has made it important for clinicians to determine the characteristic changes in cognitive function that accompany normal aging, and distinguish it from pathological aging. Assessing cognitive decline involves an objective assessment of how much the individual' s cognitive performance falls below the average within the normative sample. Further, estimating an individual' s premorbid or baseline cognitive functioning and assessing how much change has occurred involves the need to consider individual differences within the normative sample. According to the revised diagnostic and statistical manual of mental disorder, 1 significant cognitive decline from premorbid cognitive performance is an important criterion for diagnosing neurocognitive disorders, which challenges the clinicians to effectively estimate premorbid functioning for the diagnosis of dementia and other neurocognitive disorders.Educational attainment is an important factor to consider in neuropsychological evaluation. Studies have shown that elderly people with very low educational attainment have distinctive neurocognitive characteristics from well-educated elderly individuals in both quantitative and qualitative aspects. Vocabulary Knowledge is Not a Predictor of GeneralCognitive Background and Purpose Vocabulary knowledge is used as a representative index of general intelligence, and is regarded as a marker for cognitive reserve in elderly people. However, vocabulary knowledge mainly depends on formal education, hence, it may not fully represent cognitive functioning in elderly people with poor educational backgrounds. Herein, we investigated whether vocabulary knowledge is a measure of general cognitive ability among normal elderly people with few years of formal education. Methods The association between vocabulary knowledge and general cognitive functioning was compared between 35 elderly females with very low educational attainment and 68 elderly females with higher education. Results The vocabulary knowledge was a significant predictor of general cognitive functioning in elderly individuals with more than primary education, even after controlling the effects of age and years of education. However, it was not a significant predictor of general cognitive functioning in elderly individuals with very low educational attainment. Conclusions Vocabulary assessment was effective in estimating general cognitive functioning in elderly individuals who received ≥6 years of education. Our findings suggested that vocabulary knowledge may not be an effective proxy of premorbid intelligence or cognitive reserve in people who have not completed elementary schooling.

Moderating effect of cognitive reserve on the association between grey matter atrophy and memory varies with age in older adults

“…One notable point in the study is that the completion of basic formal education may play a crucial role in resisting and adapting to accumulated neuropathology. Literacy and arithmetic as well as basic reasoning and conceptualisation capacity taught in elementary or middle school can profoundly affect the person's CR needed in older age . Considering that a significant proportion of the elderly population, especially women, received minimal education in South Korea, our findings have important implications on the high prevalence of dementia in South Korea, and how these people may be vulnerable to late‐life neuropathological accumulation …”