Table 1.
Octo-Twin participant characteristics.
| Year of testing | |||||
|---|---|---|---|---|---|
| Measure | Baseline | Year 2 | Year 4 | Year 6 | Year 8 |
| (n = 572) | (n = 470) | (n = 361) | (n = 274) | (n = 194) | |
| 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.