Stress is enough to severely diminish memory and many other things. When I was worried daily about my continued employment I suffered in many ways, poor memory included. My back was a wreck as well. PT said they see that all the time. Stress manifests itself throughout the body.

Lucky thing it comes back once the stress is alleviated!

I'm now in my early 40's, and it's mostly the same as when I was younger... but it's like there's some memory corruption. I'll remember a concept but lose the word, or when interrupted it just take a moment for me to shake out of where I was, and then have to ask the person interrupting to repeat what they said.

>Old people might say it's just part of getting old.

This is true to an extent. Motor and cognitive skills may diminish slowly with age but memory impairment diseases like Alzheimer’s and Dementia are /never/ a normal part of aging.