[Citroënbender]

I know modestly well, half a dozen people with dementia; it’s a consequence of caring full-time for one of them. Their abilities range from living more or less independently through incontinent and incoherent. I’ll assert that through this level of “immersion” my insight may have some qualification.

I haven’t seen anything in news footage that suggests Mr Biden actually has dementia. His fine motor skills appear very consistent, you don’t see even fleeting frustration with a physical action. His gait and posture look pretty good for his age, too. Issues with speech (such as oft-cited “gaffes”) are more likely the result of cumulative brain injuries, but can be completely isolated from cognitive ability.