Table 1: Octo-Twin participant characteristics. Year of testing Measure Baseline Year 2 Year 4 Year 6 Year 8 (
𝑛
=
5
7
2
) (
𝑛
=
4
7
0
) (
𝑛
=
3
6
1
) (
𝑛
=
2
7
4
) (
𝑛
=
1
9
4
) Retention from previous testing (%) 82.2 76.8 75.9 70.8 Age [M (SD)] 83.3 (3.0) 85.2 (2.8) 86.9 (2.5) 88.8 (2.5) 90.7 (2.4) Education [M (SD)] 7.2 (2.4) 7.3 (2.4) 7.3 (2.3) 7.2 (2.1) 7.2 (2.3) Sex, female [
𝑛
(%)] 369 (65) 304 (65) 235 (65) 195 (71) 144 (74) Reasoning [M (SD)] 11.5 (7.1) 11.4 (7.2) 11.4 (7.1) 10.8 (7.2) 10.3 (7.3) Memory [M (SD)] 9.6 (4.0) 9.4 (4.2) 9.2 (4.4) 9.2 (4.7) 9.0 (4.4) Semantic knowledge [M (SD)] 28.1 (11.1) 28.6 (11.2) 27.5 (12.4) 26.7 (13.0) 26.2 (11.4) Cognitive activity [M (SD)] 2.1 (1.7) 1.7 (1.6) 1.3 (1.4) 1.2 (1.4) 1.1 (1.3) Activity change [M (SD)] — −0.3 (1.3) −0.6 (1.3) −0.8 (1.5) −1.1 (1.6)
M: mean; SD: standard deviation. The theoretical ranges for each measure with a defined upper limit are as follows: reasoning = 0–42, Memory = 0–16, semantic knowledge = 0–44, and cognitive activity = 0–8.