Table 2.
Executive function abilities: cross-sectional analysis between the young and older adults.
| Task | Young adults | Older adults | t | df | Young vs. old, p-value | ||||
|---|---|---|---|---|---|---|---|---|---|
| N | O | Mean (SD) | N | O | Mean (SD) | ||||
| Dual-tasking | |||||||||
| 1 TEA Auditory DT count accuracy (%) | 24 | 2 | 90.42 (13.34) | 20 | 4 | 92.50 (11.18) | −0.55 | 42 | 0.582 |
| 1 TEA Telephone code count DT accuracy (%) | 24 | 2 | 79.17 (15.12) | 20 | 4 | 75.88 (15.26) | 0.72 | 42 | 0.479 |
| 2 PRP Auditory RT1 (SOA 0 ms) DT (DT – ST) cost (ms) | 24 | 0 | 462.65 (323.27) | 22 | 3 | 439.85 (245.96) | 0.27 | 44 | 0.790 |
| 2 PRP Visual RT2 (SOA 0 ms) DT (DT – ST) cost (ms) | 24 | 0 | 809.45 (381.28) | 22 | 3 | 905.37 (292.60) | −0.95 | 44 | 0.347 |
| 2 PRP effect (DT SOA 0 ms – DT SOA 1000 ms), visual task, RT2 (ms) | 24 | 0 | 569.56 (254.83) | 22 | 3 | 732.51 (250.94) | −2.18 | 44 | 0.034 |
| 2 PRP Auditory R1 (SOA 0 ms) DT (DT – ST) cost (%) | 24 | 0 | 3.42 (6.92) | 22 | 3 | 0.09 (3.53) | 1.53 | 44 | 0.134 |
| 2 PRP Visual R2 (SOA 0 ms) DT (DT – ST) cost (%) | 24 | 0 | 4.33 (5.71) | 22 | 3 | 1.73 (2.41) | 1.98 | 44 | 0.054 |
| 2 PRP effect (DT SOA 0 ms – DT SOA 1000 ms), visual task, R2 (%) | 24 | 0 | −1.33 (9.60) | 22 | 3 | 1.09 (2.20) | −1.16 | 44 | 0.254 |
| Inhibition | |||||||||
| 3 HSCT inhibition RT cost (s) | 26 | 1 | 6.77 (17.80) | 23 | 1 | 28.30 (21.10) | −3.88 | 47 | <0.001 |
| Stroop interference score | 26 | 0 | 6.92 (10.48) | 25 | 0 | −5.60 (7.71) | 4.84 | 49 | <0.001 |
| Shifting | |||||||||
| 4 TS Local shift RT cost (ms) | 26 | 2 | 75.96 (84.29) | 21 | 2 | 206.20 (239.41) | −2.58 | 45 | 0.013 |
| 4 TS RT Mixing-cost (ms) | 26 | 2 | 286.67 (222.77) | 21 | 2 | 404.14 (314.73) | −1.50 | 45 | 0.142 |
| 4 TS Global shift RT cost (ms) | 26 | 2 | 363.06 (211.52) | 21 | 2 | 619.79 (457.52) | −2.55 | 45 | 0.014 |
| 4 TS Error-rate TS Local shift cost (%) | 26 | 2 | 4.77 (5.92) | 21 | 2 | 3.10 (4.58) | 1.06 | 45 | 0.293 |
| 4 TS Error-rate Mixing-cost (%) | 26 | 2 | 0.88 (3.71) | 21 | 2 | 4.81 (8.44) | −2.13 | 45 | 0.038 |
| 4 TS Error-rate Global shift cost | 26 | 2 | 5.54 (5.59) | 21 | 2 | 7.52 (9.14) | −0.92 | 45 | 0.364 |
| 5 TMT RT Shifting cost (s) | 19 | 2 | 31.00 (17.68) | 19 | 0 | 25.89 (11.99) | 1.04 | 36 | 0.305 |
| 5 TMT error-rate shifting cost (%) | 19 | 2 | 13.16 (36.67) | 19 | 0 | 18.42 (47.76) | −0.38 | 45 | 0.705 |
| Updating | |||||||||
| BDS score | 28 | 0 | 7.86 (2.16) | 25 | 0 | 7.68 (2.81) | 0.26 | 51 | 0.797 |
| N-back RT cost (ms) | 26 | 0 | 25.88 (186.22) | 23 | 1 | 6.34 (240.56) | 0.32 | 47 | 0.751 |
| N-back error-rate cost (%) | 26 | 0 | 50.43 (14.34) | 23 | 1 | 67.17 (14.52) | −4.06 | 47 | <0.001 |
The table contains the independent t-tests of selected measures for all four executive functions between the young and older adults.
N, number of participants (after removal of outliers); O, number of all outliers (i.e., N + O = original sample size); BDS, Backward digit span task; HSCT, Hayling sentence completion task; PRP, Psychological Refractory Period paradigm; NB, N-back task; Stroop, Stroop task; TEA, Test for Everyday Attention; TMT, Trail making task; TS, Task switching task; RT, Reaction time; R, Error-rate; SOA, Stimulus Onset Asynchrony. Please note RT1 corresponds with R1, and RT2 with R2. Please note in addition to performance outliers (i.e., participants with mean scores outside +/− 3 SD of the group mean) the following were also excluded from analysis, 1 two young adults and one older adult TEA participants who produced an error-rate of 60% or higher in any of the task conditions, 2two young adults PRP participants who produced an error-rate of 50% or greater, 3one young and one older adult HSCT participants due to audio recording issues, 4 two older adults TS participants due to data recovery issues, and 5 one young and two older adults from TMT part A, plus 5 young and 4 older adults from part B who produced three or more errors in either task part. Bold p-values indicate significant effects (p < 0.05). (Bonferroni corrected alphas for dual-tasking p < 0.003, inhibition p < 0.005, shifting p < 0.002, and updating p < 0.005.)