Age, walking time and cognitive test scores.

Values are expressed as the mean ± standard deviation in the whole study population and in the two subsets of subjects by age range. Percentages correspond to the ratio of low performers for each item. P values denote highly significant differences between the two age subsets.(1) Comparisons between subsets are performed by a Mann-Whitney U-test for the scores and walking time (non normal distributions) and by a chi-square test for the % of subjects with low scores.