My daughter was 23-years old when we noticed the 'changes'. We took her to Johns Hopkins to the Kennedy Krieger Institute and were interviewed. At the time, we were told it was possibly dementia or possibly depression. Over the past few years we were told she was too young for it to be dementia and she must be depressed. Our daughter used to be very outgoing, read at a first or second grade level and would always get compliments about what a good dancer she was. Even though it is not unusual for someone who has Down Syndrome to have Alzheimer's in the forties, 23 was very unusual but a CT brain scan in June confirmed what we had known for five years. I'm very interested to hear if anyone else knows someone who has been diagnosed at such a young age. It has progressed considerably in the past eight months.