Table 1.
Exclusion of participants.
Table 2.
Demographics and outcome of home-based questionnaires in young and in older participants.
Fig 1.
Mean value of q-scores in each executive function test.
Data from young participants are shown in black, and those from older participants in gray. Error bars are standard deviations.
Table 3.
Outcome of stepwise multiple linear regression analyses*.
Table 4.
Outcome of confirmatory factor analyses for young and for older persons.
Note: Cell entries are the loadings of a given test (2nd column) on a given factor (1st column), as well as the pertinent standard errors, values of the asymptotic normal statistic and p-values. Bold p-values indicate statistical significance. The asymptotic normal statistic is the probability distribution for loading = 0.000.
Table 5.
Outcome of exploratory factor analyses for young and for older persons.
Fig 2.
Frequency distribution of bivariate correlations between test pairs.
Data are plotted separately for young (black) and for older participants (gray). For example, two correlations in older participants were in the range 0.5 to 0.6.
Fig 3.
Bivariate correlations between test pairs, plotted in ascending order.
Data from young participants are shown in black, and those from older participants in gray. Negative correlations imply that good performance on one test was associated with poor performance on the other test. Large squares denote test pairs which purportedly represent a common executive function. From bottom left to top right, the squares stand for updating, shifting, dual-tasking and inhibition in young persons, and for updating, shifting, inhibition and dual-tasking in older ones. Solid lines are predictions of piecewise linear regression with one breakpoint.
Table 6.
Outcome of piecewise linear regression of test pair correlations in young and older persons.
Fig 4.
Pattern of test pair correlations in the two age groups.
Each symbol represents the correlation for one test pair in older persons, plotted against the correlation for the same test pair in young persons. Dashed line is the regression line.