Executive functioning in healthy elderly Chinese people.

This study aimed to explore the executive function of healthy elderly Chinese people. A sample of 58 healthy Chinese aged 60 and over was recruited from Guangzhou in China. They were divided into two age groups, a younger age group (aged 60-70) and an older age group (aged over 70). Executive function was measured by a battery of seven tests which were assumed to capture specific components of executive function. The tests were initiation (Hayling Sentence Completion Test (HSC)), sustained attention (Monotone Counting Test), switching and flexibility (word fluency and modified Wisconsin Card Sorting Test (WCST)), disinhibition (Modified Six Element Task (SET), Stroop Test, and HSC), attention allocation and planning (SET and modified version of WCST), and updating (Chinese Letter-Number Span). When independent neurocognitive tests were analyzed, there were significant age differences in the WCST (perseverative errors and category completed, p=0.025, 0.023) and the SET (raw score, p=0.050). The older age group tended to do worse in the total profile score of the SET and correct responses of the HSC Part A. However, when these tests were grouped into specific executive function components, a significant difference was found between the two groups in attention allocation and planning (p=0.007) and total component score (p=0.026). Regression analyses also indicated that age accounted for only very little variance of executive function in this narrow band of the elderly, whereas educational level accounted for a large part of the variance in initiation (R(2)=0.252, p<0.001), switching and flexibility (R(2)=0.211, p<0.001), and updating (R(2)=0.236, p<0.001) components of executive function. Our findings suggest that a significant decline in general executive functioning with advancing age was only evident in some putative tests in this sample. In addition, executive functions were selectively affected by older age, with attention location and planning and initiation being the components that were most affected.