Table 3. Rate of decline in cognitive performance by baseline impairment status (full models shown).
| Intercept | Overall decline | Baseline effects | Longitudinal effects | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| NI | PI | CI | CPI | NI | PI | CI | CPI | |||
| CDR-SB | 0.06 (0.847) £ | 0.10 0.166) | Ref | -0.01 (0.864) | -0.18 (0.059) | -0.14 (0.138) | Ref | 0.15 (0.176) | 1.33 (<0.001) | 1.65 <0.001) |
| Word fluency | 3.03 (0.034) | 0.08 0.577) | Ref | -0.28 (0.439) | -0.89 (0.020) | -1.23 (0.001) | Ref | -0.25 (0.280) | -1.76 (<0.001) | -1.82 (<0.001) |
| BNT | 0.02 (0.985) | -0.22 (0.267) | Ref | 0.15 (0.569) | 0.31 (0.257) | -0.05 (0.867) | Ref | -0.35 (0.251) | -2.62 (<0.001) | -2.93 (<0.001) |
| TMA | -1.38 (0.784) | 0.52 (0.479) | Ref | 0.71 (0.563) | 0.32 (0.799) | 3.11 (0.020) | Ref | 1.47 (0.199) | 10.59 (<0.001) | 11.75 (<0.001) |
| TMB | -1.01 (0.872) | 1.79 (0.002) | Ref | 3.06 (0.047) | 6.30 (<0.001) | 8.97 (<0.001) | Ref | 0.08 (0.932) | 5.73 (<0.001) | 2.87 (0.008) |
| Composite cognition score | 0.14 (0.266) | -0.01 (0.645) | Ref | -0.01 (0.706) | -0.01 (0.836) | -0.05 (0.214) | Ref | -0.07 (0.080) | -0.45 (<0.001) | -0.45 (<0.001) |
| Frontal factor score | 0.10 (0.351) | 0.02 (0.054) | Ref | -0.02 (0.538) | -0.03 (0.356) | -0.09 (0.003) | Ref | -0.02 (0.261) | -0.14 (<0.001) | -0.14 (<0.001) |
| Temporal factor score | 0.15 (0.059) | -0.01 (0.646) | Ref | -0.04 (0.050) | -0.09 (<0.001) | -0.11 (<0.001) | Ref | -0.02 (0.209) | -0.15 (<0.001) | -0.15 (<0.001) |
| Parietal factor score | -0.02 (0.773) | 0.02 (0.067) | Ref | -0.01 (0.524) | 0.02 (0.337) | -0.04 (0.026) | Ref | -0.03 (0.107) | -0.15 (<0.001) | -0.17 (<0.001) |
£ Slope (p value); NI = not impaired, PI = physically impaired but cognitively normal, CI = cognitively impaired but physically normal, CPI = cognitively and physically impaired; PPT = Physical Performance Test; CDR-SB = CDR Sum of boxes; TMA = Trail making part A; TMB = Trail making part B; BNT = Boston Naming test; Baseline physical impairment status is based on baseline total PPT (<28). Baseline cognitive impairment was based on CDR score (≥0.5). Cognitive performance was assessed by several psychometric tests including CDR-SB, Animal testing, TMA, TMB, BNT and Factor scores.
Models are adjusted for age, gender, education, race, and baseline cognitive performance. Rates of decline in cognitive performance were higher in the CI and CPI groups than in the NI (reference) group. No significant differences were observed in the PI group compared to the NI group.