Yeah, I guess you need to have experience working with elders to really understand what they are saying and I am definitely reading between the lines as I have spent over a decade in elder care.

"This study challenges the prevailing narrative of inevitable cognitive decline, suggesting instead that brain health can be proactively cultivated at any age."

The human mind can be improved at any age. Therefore you can still relearn previous concepts and learn new things at any time. I don't think serious cognitive decline is a given, but some cognitive decline is natural when the mind isn't being exercised about a topic. Think learning a foreign language in high school but not remembering much because you didn't keep practicing.