Memory issues, here. I didn’t think I would have bad memory issues until just a while ago, I had a thought on the tip of my nose, but forgot it in seconds and how it took me minutes to recall it. That’s a key sign right there.
Some people have better memory in old age, like it’s unreal sometimes with what some of them can remember. While the average person forgets thoughts in moments.
A bunch of studies have been run over the years. I’ve heard it every three or four years for probably the past decade or two.
A quick search will net a bunch of them. Search for scientific articles that show new learning decreases cognitive decline in old age.
You’ll get stuff like this:
https://www.health.harvard.edu/blog/learning-new-skill-can-slow-cognitive-aging-201604279502