Actually there needs to be an overhaul of the system, either age limit on senate, house and presidency which I agree with, or an independent medical examiner/s verifying they are mentally capable of carrying out duties (this wouldn't work and is too open to corruption).
Just don't let people serve after 60. It even works to reduce generational thinking that infects government policy.
News: A confused Dianne Feinstein tried to give a speech in the middle of a Senate hearing vote and was told to 'just say aye' instead ( www.businessinsider.com )
"Just say aye," Senate Appropriations Chairwoman Patty Murray repeatedly pleaded to Feinstein during the vote. Eventually, Feinstein did just that....