Mean age, verbal intelligence, and SDS in each age group
| Age group (y) | 50–59 | 60–69 | 70–79 |
| Number (M:F) | 10 (4:6) | 12 (7:5) | 9 (5:4) |
| Mean age (y) | 55.2 ± 3.0 | 63.8 ± 2.9 | 73.2 ± 2.4 |
| Okabe’s Scale, total | 48.9 ± 3.0 | 47.0 ± 5.7 | 45.4 ± 6.9 |
| Information | 18.4 ± 1.6 | 17.5 ± 1.7 | 16.4 ± 1.9 |
| Mental control | 14.5 ± 1.6 | 12.4 ± 3.3 | 12.8 ± 2.9 |
| Digit span | 9.0 ± 1.6 | 8.9 ± 1.5 | 9.2 ± 0.7 |
| Associate learning | 7.0 ± 3.9 | 8.2 ± 3.6 | 7.0 ± 3.6 |
| SDS | 30.8 ± 5.9 | 28.9 ± 4.3 | 29.7 ± 5.7 |
Note.—Okabe Scale indicates Okabe’s Simplified Intelligence Scale (60-point scale); SDS, Zung Self-Rating Depression Scale (80-point scale).