Re: Question about diagnosis
Be glad if it isn't AD! Mostly it does move slowly, but noticeably. As far as I know there is no definitive test to diagnose it until after death, but MRI and CT Scans are used to rule out OTHER causes of dementia such a blood clots or bleeding or tumors in the brain.
If your Dad accepts that he has AD but does not show any worsening, he may not have it. In my experience people with this condition do not believe it! They think they are perfectly rational, and what is the matter with everyone esle out there? My Mom had an argument about which color traffic light means stop and which means go, and she was sure she was right . (she was not.)
Just be happy your Dad is OK. Maybe you could contact the doctor who orignally diagnosed it and tell him or her that your dad has not changed at all in all those years. Getting a second opinion is always a good idea.