Table 5.
Distributional characteristics of cognitive scores by age groups
| Cognitive domains | Control (n=187) | LOAD (n=168) | P value1 | Difference between means1 |
|---|---|---|---|---|
| Digit Span Forward | ||||
| 50–59 years | 8.41 (2.53) (n=54) | 8.32 (2.48) (n= 56) | .23 | 1.67 (0.11–3.30) |
| 60–69 years | 8.21 (2.16) (n=92) | 7.23 (2.45) (n= 78) | .05 | 0.13 (–0.14–0.47) |
| 70–79 years | 8.34 (2.83) (n=28) | 5.91 (2.73) (n= 25) | <.0001 | 2.40 (1.20–6.70) |
| ≥80 years | 7.87 (2.52) (n=13) | 5.73 (2.54) (n= 9) | <.0001 | 2.12 (1.14–5.11) |
| p value2 | .1 | <.0001 | ||
| Difference between means2 | 1.39 (0.31–2.92) | 2.65 (1.17–7.13) | ||
| Digit Span Backward | 2.34 (0.98–4.21) | |||
| 50–59 years | 7.36 (2.35) | 7.32 (2.56) | .23 | 1.09 (0.12–3.34) |
| 60–69 years | 7.21 (2.12) | 6.73 (2.71) | .33 | 3.14 (1.57–5.21) |
| 70–79 years | 7.84 (2.43) | 5.91 (2.54) | .007 | 2.29 (0.98–4.02) |
| ≥80 years | 7.07 (2.13) | 5.38 (2.91) | .009 | |
| p value2 | .1 | .0009 | ||
| Difference between means2 | 143 (0.33–2.42) | 1.87 (0.73–2.98) | ||
| Trail Making Test A | ||||
| 50–59 years | 31.82 (1.21) | 34.72 (1.09) | .48 | 11.35 (7.23–14.32) |
| 60–69 years | 34.23 (1.09) | 38.32 (0.58) | .10 | 10.96 (8.31–13.46) |
| 70–79 years | 38.19 (1.02) | 64.02 (0.97) | <.0001 | 9.93 (6.54–14.48) |
| ≥80 years | 42.97 (0.97) | 73.89 (0.78) | <.0001 | 12.18 (9.73–15.93) |
| p value2 | .02 | <.0001 | ||
| Difference between means2 | 7.07 (4.13–9.12) | 8.33 (3.53–9.96) | ||
| Trail Making Test B | ||||
| 50–59 years | 78.82 (1.21) | 79.72 (1.09) | .48 | 21.89 (13.73–37.12) |
| 60–69 years | 84.23 (1.09) | 89.32 (0.58) | .30 | 20.23 (10.75–37.21) |
| 70–79 years | 93.19 (1.02) | 194.02 (0.97) | <.0001 | 24.08 (12.73–36.58) 28.13 (10.68–44.76) |
| ≥80 years | 97.17 (0.97) | 243.89 (0.78) | <.0001 | |
| p value2 | .008 | <.0001 | ||
| Difference between means2 | 31.65 (19.73–45.42) | 43.33 (20.28–55.15) | ||
| Logical Memory Ia | ||||
| 50–59 years | 11.72 (3.24) | 11.68 (3.09) | .18 | 5.12 (2.34–7.87) |
| 60–69 years | 10.32 (4.12) | 9.89 (3.12) | .07 | 3.73 (1.73–5.18) |
| 70–79 years | 10.01 (3.98) | 5.45 (3.56) | .001 | 3.02 (1.26–6.67) |
| ≥80 years | 9.92 (3.78) | 4.43 (3.29) | .0002 | 2.96 (1.05–6.43) |
| p value2 | .1 | .002 | ||
| Difference between means2 | 3.11 (1.13–6.12) | 4.62 (2.13–6.12) | ||
| Logical Memory IIa | ||||
| 50–59 years | 10.32 (3.56) | 10.18 (3.37) | .28 | 5.02 (2.79–9.34) |
| 60–69 years | 10.02 (4.23) | 9.26 (3.66) | .06 | 4.37 (2.04–8.75) |
| 70–79 years | 9.18 (4.12) | 4.81 (3.59) | .0009 | 3.05 (1.04–5.92) |
| ≥80 years | 8.95 (3.98) | 3.74 (4.02) | <.0001 | 3.39 (1.27–6.37) |
| p value2 | .08 | .0009 | ||
| Difference between means2 | 4.15 (2.13–6.82) | 3.32 (1.24–6.71) | ||
| Fluency (animals) | ||||
| 50–59 years | 19.28 (5.23) | 18.83 (5.23) | .10 | 6.35 (3.14–11.57) |
| 60–69 years | 18.29 (5.09) | 17.34 (5.32) | .09 | 4.37 (1.95–7.84) |
| 70–79 years | 16.76 (5.12) | 16.23 (4.87) | .32 | 4.06 (2.11–8.33) |
| ≥80 years | 16.23 (4.98) | 15.98 (5.49) | .20 | 6.45 (2.27–12.91) |
| p value2 | .10 | .09 | ||
| Difference between means2 | 5.54 (2.74–9.65) | 7.32 (3.2–11.71) | ||
| Fluency (vegetables) | ||||
| 50–59 years | 17.31 (5.23) | 17.45 (5.23) | .32 | 8.68 (2.31–12.73) |
| 60–69 years | 16.14 (5.09) | 16.84 (5.32) | .23 | 7.45 (3.28–16.21) |
| 70–79 years | 15.45 (5.12) | 15.92 (4.87) | .21 | 5.78 (1.83–10.52) |
| ≥80 years | 15.27 (4.98) | 16.07 (5.49) | .10 | 5.73 (2.25–11.93) |
| p value2 | .07 | .10 | ||
| Difference between means2 | 6.05 (1.77–12.63) | 6.09 (1.28–12.92) | ||
| Clock Drawing Test | ||||
| 50–59 years | 8.38 (3.12) | 8.27(2.12) | .39 | 1.45 (0.07–5.91) |
| 60–69 years | 8.12 (2.77) | 7.66 (2.86) | .14 | 1.73 (0.33–6.24) |
| 70–79 years | 7.93 (3.09) | 7.43 (2.59) | .12 | 1.47 (0.07–4.36) |
| ≥80 years | 7.59 (2.72) | 7.27 (2.68) | .11 | 1.25 (0.02–4.98) |
| p value2 | .07 | .06 | ||
| Difference between means2 | 2.57 (0.27–4.94) | 2.46 (0.35–5.61) | ||
| Executive Function | ||||
| 50–59 years | 3.41 (3.32) | 3.44 (1.22) | .22 | 0.15 (−0.24–2.05) |
| 60–69 years | 3.39 (3.25) | 3.33 (1.35) | .10 | 0.16 (−0.2–2.93) |
| 70–79 years | 3.37 (2.87) | 1.34 (1.13) | .0002 | 0.17 (−0.17–2.07) |
| ≥80 years | 2.96 (2.66) | 1.27 (1.37) | <.0001 | 0.13 (−0.07–2.75) |
| p value2 | .06 | <.0001 | ||
| Difference between means2 | 0.05 (−0.01−2.97) | 0.11 (−0.31–2.28) | ||
| Episodic Memory | ||||
| 50–59 years | 3.53 (3.52) | 3.52 (3.35) | .16 | 0.12 (−0.29–2.93) |
| 60–69 years | 3.51 (3.45) | 3.51 (3.56) | .29 | 0.35 (−0.02–2.02) |
| 70–79 years | 3.49 (3.54) | 2.43 (2.13) | .001 | 0.29 (−0.34–3.13) |
| ≥80 years | 3.47 (3.48) | 1.36 (1.44) | <.0001 | 0.3 (−0.06–2.65) |
| p value2 | .07 | <.0001 | ||
| Difference between means2 | 0.05 (−0.27–2.55) | 0.04 (−0.11–3.31) | ||
| Attention | ||||
| 50–59 years | 11.55 (10.22) | 11.54 (10.42) | .30 | 0.18 (−0.02–2.81) |
| 60–69 years | 11.54 (10.24) | 11.52 (10.29) | .12 | 0.36 (−0.87–3.83) |
| 70–79 years | 1051 (10.46) | 5.52 (4.58) | .0001 | 0.07 (−0.01–2.55) |
| ≥80 years | 9.49 (9.45) | 3.49 (3.52) | .0001 | 0.12 (−0.04–2.63) |
| p value2 | .09 | .0001 | ||
| Difference between means2 | 0.25 (−0.07–1.96) | 0.04 (−0.27–2.87) | ||
| Semantic Memory | ||||
| 50–59 years | 0.55 (0.28) | 0.54 (0.42) | .30 | 0.15 (−0.07–2.01) |
| 60–69 years | 0.54 (0.98) | 0.52 (0.29) | .12 | 0.26 (−0.87–3.22) |
| 70–79 years | 0.51 (0.78) | 0.52 (0.58) | .20 | 0.25 (−0.03–2.55) |
| ≥80 years | 0.49 (0.32) | 0.49 (0.52) | .27 | 0.35 (−0.13–2.63) |
| p value2 | .09 | .10 | ||
| Difference between means2 | 0.25 (−0.07–1.96) | 0.14 (−0.57–2.88) |
Data are presented as mean and (standard deviation). The N for each age band is provided in the second row, and second and third column respectively. Difference in means is presented as means and (95% Confidence Intervals, CIs). Figures in parentheses are 95% CIs.
1
The p value indicates difference in means between LOAD group and control group.
2
The p value indicates difference in means between contrast age groups (50–59 vs. 70–79 years).
LOAD=Late Onset Alzheimer’s Disease.