For me my chemo brain has shown up as processing speed slow down. I've always been a super fast processor. Its noticeable in a classroom situation or when I watch/ play Jeopardy. Since my chemo (Cisplatin) I process slower. Its a side effect of Cisplatin and I knew that going in. Its pretty subtle as far as brain fog goes. During chemo I had fatigue and some word finding problems as well. I'm 2 years out from chemo now and all that remains is the speed thing.