TABLE 2.
Duration of follow‐up to observe cognitive decline in CC‐ACC versus PACC for cognitively normal Aβ+ individuals. Mean, standard deviation, and statistics of the t test against zero using either the CC‐ACC, PACC, or MMSE for varying follow up duration. n is the number of cognitively normal Aβ+ individuals from each sample used to calculate the test statistics. Sample size is number of individuals required to observe a hypothetical 25% decrease in cognitive decline using the CC‐ACC, PACC, or MMSE. Italicized cells represent rates of decline that are significantly less than zero (P < 0.05).
| ADNI MMSE | ADNI PACC | ADNI CC‐ACC | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Years of follow‐up | n | Mean (std) | T‐stat <0 (P) | Sample size | Mean (std) | T‐stat <0 (P) | Sample size | Mean (std) | T‐stat <0 (P) | Sample size |
| 1 | 127 | −0.091 (1.698) | −0.605 (0.546) | >2300 | 0.027 (0.983) | 0.311 (0.756) | NA | 0.015 (0.750) | 0.223 (0.824) | NA |
| 2 | 124 | –0.153(1.278) | –1.33(0.186) | >2300 | –0.081 (0.763) | –1.187 (0.237) | >2300 | −0.090 (0.764) | −1.309 (0.193) | >2300 |
| 3 | 49 | −0.242 (0.744) | −2.278 (0.027) | 1188 | −0.241 (0.465) | −3.636 (0.001) | 468 | −0.189 (0.400) | −3.308 (0.002) | 565 |
| 4 | 70 | −0.116(0.423) | −2.287(0.025) | 1683 | −0.120 (0.311) | −3.233(0.002) | 843 | −0.113, (0.235) | −4.027 (<0.001) | 545 |
| 5 | 41 | −0.211(0.588) | −2.298(0.027) | 978 | −0.208(0.403) | −3.304(0.002) | 474 | −0.201, (0.375) | −3.438 (0.001) | 438 |
| 6 | 41 | −0.139(0.427) | −2.079(0.044) | 1193 | −0.168(0.271) | −3.952(<0.001) | 332 | −0.177, (0.217) | −5.225, (<0.001) | 191 |
| 7 | 20 | −0.239(0.374) | −2.851(0.01) | 312 | −0.289(0.318) | −4.066(0.001) | 154 | −0.300, (0.255) | −5.257, (<0.001) | 93 |
| AIBL MMSE | AIBL PACC | AIBL CC−ACC | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 87 | −0.236 (1.603) | −1.389 (0.168) | >2300 | −0.154 (0.753) | −1.915 (0.059) | >2300 | −0.074 (0.708) | −0.981 (0.329) | >2300 |
| 2 | 115 | −0.052 (0.91) | −0.641 (0.523) | >2300 | −0.022 (0.363) | −0.654 (0.514) | >2300 | −0.051 (0.383) | −1.418 (0.159) | >2300 |
| 3 | 99 | −0.073 (0.472) | −1.537 (0.127) | >2300 | −0.087 (0.299) | −2.893 (0.005) | 1172 | −0.094(0.309) | −3.035 (0.003) | 1065 |
| 4 | 37 | −0.118 (0.446) | −1.666 (0.104) | 1812 | −0.086 (0.262) | −2.005 (0.053) | 913 | −0.115 (0.331) | −2.107 (0.042) | 827 |
| 5 | 45 | −0.23 (0.679) | −2.325 (0.025) | 1095 | −0.160 (0.350) | −3.059 (0.004) | 477 | −0.174 (0.338) | −3.447 (0.001) | 376 |
| 6 | 52 | −0.144 (0.355) | −3.058 (0.003) | 768 | −0.102 (0.232) | −3.162 (0.003) | 516 | −0.091 (0.264) | −2.478 (0.017) | 840 |
| 7 | 22 | −0.061 (0.249) | −1.146 (0.265) | 2105 | −0.064 (0.171) | −1.760 (0.093) | 704 | −0.076 (0.142) | −2.513 (0.020) | 347 |
Abbreviations: Aβ, amyloid beta; ADNI, Alzheimer's Disease Neuroimaging Initiative; AIBL, Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing; CC‐ACC, Cross‐Cohort Alzheimer Cognitive Composite; MCI, mild cognitive impairment; MMSE, Mini‐Mental State Examination; PACC, Preclinical Alzheimer Cognitive Composite.