As most longitudinal studies administer cognitive tests annually, there is a paucity of data with tests of episodic memory to plan ≤6 month-duration proof-of-concept clinical studies with novel therapeutics that would be expected to impact episodic memory function. ADNI-GO and ADNI2 provided an opportunity to generate such information, as they administered the Rey's Auditory Verbal Learning Test (AVLT) six months after enrollment and obtained baseline PET scans. Permission was obtained from LONI and ADNI2/ADNI-GO cognitive test and florbetapir PET scan results were downloaded. An early AD cohort was created by including subjects from these two datasets that had baseline MMSE scores between 21 and 26 (inclusive), baseline PET results, and baseline and six-month AVLT5 (total of 5 immediate recall trials) results. 67 subjects were identified; 23 of whom had baseline florbetapir global SUVR < 1.1 (PET- subjects) and 43 of whom had baseline SUVR ≥1.1(PET+ subjects). At baseline, mean MMSE was 25.3(SD=1.3) in PET- and 24.6(1.5) in PET+ (p=0.02 vs. PET-). Mean AVLT5 was 32.4(8.5) in PET- and 28.2(9.7) in PET+ (p=0.04 vs. PET-). At six months, the change in z-score of AVLT5 was -0.22(95% CI: +0.07 to -0.51) in PET- and −0.19 (95% CI: +0.05 to -0.43) in PET+ subjects. Sample size calculations indicated that assuming a z-score decline at six-months of −0.2 in a control arm, there would be 90% power to show a treatment effect if a therapeutic would be expected to improve AVLT performance by a z-score of 0.3. Practice/learning effects appear to be minimal at six months with a word list-based verbal learning test to evaluate episodic memory, thereby providing an opportunity to show a treatment effect if the therapeutic showed at least a modest effect of improving episodic memory function. A six-month trial would be of insufficient duration if the expected treatment effect were limited to slowing of decline in episodic memory function. Amyloid PET status had limited impact on level of decline in verbal learning performance. However, selecting PET+ subjects could potentially limit ceiling effects for improvement, as it would select subjects with worse performance at baseline.