As the link below notes, we all suffer mild cognitive impairment (MCI) as we age but that can develop into Alzheimer's or other forms of dementia.
IMO, Biden is suffering from more than MCI. Trump is similar but also coupled with his other lifelong mental issues such as NPD.
Both are good examples of never voting for Presidents over 65 and/or requiring a third party mental and physical exam every six months of POTUS with implementation of the 25th Amendment if they become too handicapped .
Whenever a leftist hack bloviates BOTH sides, you know they are lying dumb fucks.