Table 4.
Sample size estimates (and 95% confidence intervals in parentheses) to power a one-year or two-year clinical trial to detect a 25%/year or 50%/year reduction (relative to A− NC) in the rate of disease progression of each patient group. See Section 2.5 for the sample size calculation. Measurements with a smaller sample size estimates (in absolute terms) are highlighted in bold. Abbreviations: ALOHA= Automatic Longitudinal Hippocampal Atrophy software/package; A+/A− = beta-amyloid positive/negative; NC = cognitively normal adults; eMCI = early mild cognitive impairment; lMCI = late mild cognitive impairment; 1M = 1,000,000.
| 1-year trial (180 to 400 days) | 2-year trial (400 to 800 days) | ||||
|---|---|---|---|---|---|
| 25% reduction | 50% reduction | 25% reduction | 50% reduction | ||
| A+ NC | DeepAtrophy | 3075 (574, 899,750) | 769 (146, 284,814) | 3597 (681, 764,563) | 900 (169, 90,163) |
| ALOHA | 3175 (778, 524,672) | 794 (190, 108,735) | 1657 (683, 13,580) | 415 (167, 3173) | |
| PACC | 1,658,058 (443,577, > 1M) | 414,515 (100,466, > 1M) | 21,758 (1998, > 1 M) | 5440 (495, > 1M) | |
| A+ eMCI | DeepAtrophy | 914 (422, 3400) | 229 (107, 828) | 485 (256, 1178) | 122 (64, 298) |
| ALOHA | 1575 (652, 7672) | 394 (169, 2288) | 1322 (555, 8372) | 331 (134, 1880) | |
| PACC | 38,395 (3781, > 1M) | 9599 (912, > 1M) | 5888 (1371, > 1M) | 1472 (329, 232,773) | |
| A+ lMCI | DeepAtrophy | 251 (156, 464) | 63 (38, 112) | 129 (80, 231) | 33 (21, 59) |
| ALOHA | 327 (192, 703) | 82 (48, 176) | 218 (129, 420) | 55 (32, 104) | |
| PACC | 988 (413, 4688) | 247 (102, 1140) | 267 (149, 631) | 67 (37, 158) | |