@remlaps, I appreciate your informative and helpful publication.
I noticed the video where the guy was showing finger movements that help with memory training. That's very correct, and I know it.
After all, when kids are young, we teach them to use motor skills to develop brain and neural connections. After all, there are concentrated nerve endings at the fingertips.
Nerve endings are concentrated, and motor skills help children gain knowledge and skills in everyday life. I think many people lose their memory in old age because they do less with their hands because they think it is unnecessary.
I am sure that if many household chores are done by hand, such as sewing buttons with a needle, knitting, assembling puzzles from small parts, working in the garden, playing a musical instrument, learning a foreign language, reading books, then memory will stay with us until old age.