I meant to mention this, but I forgot. 
Here we go.
It’s not so much about indexing as about getting a clue about the sound of the word. Like if I were to use the word in a sentence, I might recognize how my mouth would get ready to make a particular sound at the beginning of the word.
I don’t want to alarm you since I don’t know if your specific symptoms could be caused by this. It might be worth talking to your doctor about the possibility of having had TIA’s (transient ischemic attacks). These are mini-strokes that can go virtually unnoticed but which still have consequences.
The symptoms you describe however are so specific I don’t know if they could be caused by something like TIA’s. However I would definitely look into it.
I had encephalitis and spinal meningitis when I was a young child. I wasn’t supposed to survive and had the virgin mother of all headaches for about a month. There’s little doubt that there was significant brain damage and this has manifested itself in many ways over the years. One way is that I have an unbelievably selective memory. I need to hear a person’s name at least a dozen times before I can remember it but I can often pick up technical acronyms the first time out.
My mom never understood until she got older and had similar problems. At which point said something like welcome to my world. Now you know what I’ve always had to deal with. At least you know that I won’t give you any shit about it.
The point is, even if it is just part of aging, you need to get it checked out.
I have had the exact same problem for around 2 years (now 71 yo). I’m pressed for time but I’d like to post again on this matter. Usually I’ll get the whole word within a few minutes, but sometimes it takes many hours.
I was having memory problems and felt dull brained in general, as well as having aches and pains developing in the last few years. After a chance discussion I decided to cut wheat/gluten from my diet, and I feel young again. It took a few months to recover. I’m 40. I’m currently waiting to go back on wheat so I can have a celiac test done.
That is JUST me. What I am saying is that you could have a dietary issue. It doesnt have to be the same as mine.
This happens to me somewhat frequently and I just turned 24. I figure it’s because I’m very busy and have a lot of things to remember. It’s not always words but names of people, places, song titles, etc. that I sometimes have trouble remembering, but it usually comes to me without me having to look it up. Or sometimes I’ll accidentally write or say the wrong thing. The other day I was talking about Wal Mart and I called it “walnut.” I had been talking about walnuts earlier so I guess that wasn’t that weird.
What they are finding is that you can recover your abilities with practice,
its a bit like the index is out of order and its due to be rebuilt..