Influence of education on aspects of cognitive functions in non-demented elderly Nigerians

Cognitive function was assessed in 930 elderly Nigerians living in an urban community by trained medical students who were blinded to the educational status of the subjects. They used a pretested and validated questionnaire. The subjects were later evaluated for the presence of dementia according to DSM-IIIR criteria by neurologists who then determined the educational status of the subjects. There were 361 males and 569 females with a mean age of 58.5 years (SD = 14.8). One hundred and sixty-one subjects (17%) with at least 6 years of education performed better on all aspects of cognition assessed (p less than 0.001). The differences in performance were statistically significant on assessment of general knowledge, intelligence, abstract thinking, depth of information and immediate recall (p less than 0.001) but not for calculation, orientation, attention and language comprehension. Our findings confirm the confounding effect of education on cognitive assessment and suggest the possibility of developing a short culture-free and educationally unbiased instrument for assessing cognitive functions in Nigerians.