my 85 year old mom was diagnosed with vascular dementia this past year. She is just normal mom as I have always known her, but she repeats herself frequently and has trouble remembering regular day to day things. She can vividly recall her days as a child back in the 1930's and when I mentioned that to the doctor who is treating her, the doctor replied that long term memories are rehearsed memories and always the last to go.
She took one of those cognative tests that Trump took recently and was accused of cramming for by the DUmmies. My mom was in banking all her life and very good with math, but had difficulties with math on the test so that shows how ignorant the DUmmies are when they accuse Trump of being impared but helped by the doctors in passing the test.