Effect of Illiteracy on Cognition and Cerebral Morphology in Later Life

ABSTRACT

BACKGROUND AND PURPOSE: A better developmental environment has positive effects on brain development. The acquisition of literacy during childhood may affect brain functional organization. The present study aimed to evaluate the effects of illiteracy on neuropsychological test results and cerebral morphology in later life. METHODS: We recruited 7 illiterate elderly farmers who had never attended school and had no reading or writing knowledge. These subjects were compared with 9 literate subjects in terms of neuropsychological performance and brain volume. All subjects were over 65-years-old and had the same regional and occupational background. RESULTS: Neuropsychological tests indicated that the performance of the illiterate subjects was worse than that of literate subjects in all cognitive domains except forward digit span, tool-use and tool-free gestures, verbal word recognition, and verbal generation of animals and grocery items. The illiterate group also showed significantly decreased cortical volume and surface area in both parietal lobes. However, the illiterate group showed increased cortical thickness in the left cuneus. CONCLUSIONS: Literacy acquired in childhood may increase the volume of the parietal lobe and improve neuropsychological performance through the process of brain plasticity. The effects can be lifelong.