Greetings, and thank you for your question. I see you are offline right now, so I will try to offer some information to get you started. Aricept, as you have noted, does not reverse Alzheimer's. It can slow the progress in many individuals. The average delay of symptoms is anywhere from 1 to 5 years, but this depends upon a lot of factors, such as how badly a person's symptoms are at the time of diagnosis, if other problems (especially neurological ones) are present, and if the doe is adjusted upwards and/or augmented with Namenda.
Generally, Aricept slows the deterioration during that several year period, but once it no longer works, the person's disease progresses rapidly to "catch up" where it should have been before the Aricept.
I hope this helps, please let me know if I may be of further assistance.