Key Observations
Scope and Sensitivity: ADAS-Cog13 is an extension of ADAS-Cog11, adding delayed word recall and number cancellation to better capture early AD changes and executive function. This makes ADAS-Cog13 more suitable for trials in early or prodromal AD (e.g., blarcamesine), while ADAS-Cog11 remains effective for mild-to-moderate AD (e.g., zervimesine, buntanetap).
Scoring and Interpretation: ADAS-Cog13’s higher scoring range (0–85) provides greater resolution for tracking subtle cognitive changes, but its complexity can complicate administration. ADAS-Cog11 (0–70) is simpler but may miss nuanced effects in early stages.
Trial Context: In the trials discussed, ADAS-Cog13 (blarcamesine) detected significant slowing of decline in early AD, while ADAS-Cog11 (zervimesine, buntanetap) showed benefits in mild-to-moderate AD, with buntanetap uniquely reporting cognitive improvement rather than just slowing decline.