Reminisce therapy is very a very effective therapy for use with individuals with Alzheimer's disease. Everyone likes to talk about their past experiences, particularly the pleasant ones.
Individuals with Alzheimer's disease have flawed short term memory, but their long term memory remains in tact much longer.
In this video, a long term care facility employee is leading a male and female resident in a reminiscing session. The one thing that I would advise against is that the employee is addressing them as grandpa and grandma, which should not be done; unless they are one's actual grandpa or grandma. They need to hear their name once an hour.