Scorp... one thing jumped out at me... and shows how different each case is. Mom did well on other parts of the MMSE but there was no way she could count backwards from 100 by 7. She lost her ability to manipulate numbers very early in her disease even though she was an accountant/bookkeeper all of her life.
We also missed Mom's diagnosis for a number of years. Dad had Vascular Dementia and we all knew he could not remember. If something strange happened and Mom didn't remember it then Dad had to have done it. Made sense since he didn't remember
She also had her doctor's diagnosis of depression which mimics the dementia symptoms. Then it just all became too obvious. Even though her general physician assured us there was no problem (MMSE score of 27/30) I took her to a Memory Assessment Research Service that specializes in diagnosing dementia. We received back a diagnosis of Moderate to Sever Dementia consistent with Alzheimer's Disease. She was retested in 9 months to confirm the diagnosis. Over the last 6 years it has been validated by way of her decline.