[Executive functioning in normal aging]

Executive impairments seem to be an important characteristic of normal cognitive aging. This impairment can however affect elderly individuals in their daily living activities. Miyake et al.[Cogn Psychol 41 (2000) 49-100] showed that the executive system is made up of three particular components: the inhibition of irrelevant information, the updating of information in working memory and the mental shifting between tasks or mental sets. Although several studies showed specific trends with aging of one of these components, few have considered the functional links between the components. The present study examined the specific impairments of executive functions which occur in normal aging. We intend to characterize more precisely how the three components can evolve during the aging process.

The performances of 30 young adults and 29 older adults were evaluated on an executive battery of tests [Rev Neuropsychol 11 (2001) 383-433] and compared.

The descriptive analysis of the results showed that older participants were impaired in most of the tests compared to younger participants. In older participants, the executive functions evaluated revealed variable patterns of impairment. There was no set pattern and some tests gave the same results for younger and older subjects. Regarding the three executive components, inhibition and updating were impaired in older subjects, while flexibility was not.

This study provides elements useful for better understanding the mechanisms controlling executive function allowing a better comprehension of the normal pattern of cognitive aging.