I agree with what others have said. My thinking was MUCH worse before surgery, I think because of stress, dizziness, and the mind-space being taken up by all the research and decision-making (and stress again) that I was doing.
I work as an editor in a pretty demanding environment, so I was very concerned about temporal lobe (language area) retraction, but I came out fine. I do notice once in a blue moon I'll transpose letters or not be able to think of a word as quickly as I did before in speech (not in writing, when you have an extra second to think anyway, but during quick banter) -- but it has not negatively affected my work at all. I just check everything twice!
As for reasoning, remembering -- I haven't noticed any deficit there (except, again, there are thing I probably remember less well from the year before my surgery, when I was so stressed!). Then again, I've always had a bad memory anyway!
So, in all there may be very subtle changes, but I'm guessing comparable to what I'd be experiencing if I'd had *any* major health challenge over the last year.