I didn't make that comment. However, I would say that people in their fifties have started to experience age-related decline in numerous areas (memory included). Showing a memory improvement in people 50-80 should be more accurately described as "restoring" their memory rather than "boosting" it, which implies that they now have supranormal memory.
Am in my late 50s, can confirm. Memory, concentration, attention, and a bunch of other faculties, both mental and physical, are trending disgustingly downward.
I know there are things I could do to fight it, but motivation is another one of those things going down. f--- it, f--- everything.
Pushing 46, can confirm. Literally just got that thing that screams "maybe you need bifocals not contacts" where nothing close quite comes into focus... basic response is "fuck it, fuck everything" like you say.