I have times when I can say a word or a name (like ansewring a trivia question) then the second the words leave my mouth I have no idea what the word or name was. The rest of the sentance is still there but the one word or name is totally gone. It may come back an hour or so later. There are times when I am trying to say one thing but can't find the right word. I try to find another word to replace the one that is hiding and some times it works. Is this common?