"My brain used to be my best friend," says Greg O'Brien, a journalist with early onset Alzheimer's. But he can't trust it anymore, he says. Alzheimer's is, in some ways, changing who he is.
Amanda Kowalski and Samantha Broun for NPR
Engaging, mentally stimulating work is good for the brain, scientists say, whether you get paid to do it or not. Running a household can be as mentally demanding as running a company.