TABLE IV.

Comparison of sample size estimates (with 80% power) between TBM-derived measures and clinical measures

	AD	MCI
Loss rate %/year (1.5 T)	37	108
Loss rate %/year (3 T)	49	166
Change in CDR-SB	327	549
Change in ADAS-Cog	583	1183
Change in MMSE	3962	1531

These numbers are calculated based on the same sample of subjects. Both 1.5 and 3 T scans (using a TBM-derived loss rate in %/year) have a much lower n80 compared to the cognitive measures. These estimates may differ slightly from those in prior reports, as they depend to some degree on the specific cohort studied. Also, perhaps paradoxically, the change in MMSE has greater effect size in MCI than AD, so for that score, the sample size estimates are smaller for MCI than for AD.