Hey, wanna learn about chemobrain? I thought so. It seems I may have it, but what exactly is it? I spent some time researching it today. It turns out that "chemobrain" was coined in about the 90's (at least in the literature) to refer to the mid to long term cognitive impairment that patients who got chemo (mostly for breast cancer) subjectively reported. It is a separate entity from what I have which has not lasted long enough and is not far enough out from chemo to be officially chemobrain.
The fancy names for the fuzzy headedness that goes with chemo are "chemo related (or induced) cognitive impairment" (CICI or CRCI). The milder short term stuff that I have seems to be called "a side effect." Not all types of chemo seem to cause the long term effects and it seems that what I have gotten (daunarubicin, cytarabine) is not on the lists that I have found. The worst agents seem to be those that cross the blood brain barrier and those that are associated with ablating hormones (anti-estrogens, treatment for reproductive cancers). All of this is good news for me.
The symptoms typically associated with chemobrain are: difficulties with hind/fore sight and judgement, problems following conversations, concentration problems, word finding, retaining things one read. I find following conversations and general processing speed to be my biggest problems. I think I can concentrate and retain new material OK. I think my judgement is not impaired. I have noticed some word finding problems, but can still do NYT Thursday crosswords so it can't be too bad (I never could do the Friday ones).
There is no real agreement on what causes it, how common it is, how to measure it or identify if a particular person has it or how to treat it. People do studies where they have people who identify with chemobrain take various batteries of cognitive tests. Sometimes they find impairment objectively, sometimes they don't. This could be because we're not having people take the right tests, it's too subtle to show up on tests, we're not testing the right people, etc. Interestingly, despite not really having a good idea of what it is or how to measure it, many sources of information state that the prognosis is good and most cases resolve spontaneously within five years. This would be an example of pre-mature reassurance in my book. It could be that they are saying that the people who will tell you one year out that they have CRCI will tell you five years out that they don't any longer. That seems like it would be an OK thing to say although not really very intellectually rigorous.
I was very worried that this new, slower version of my brain was going to be permanent. I imagined that I would not be able to go back to being a doctor and that something would have gone wrong with my disability insurance and I would have to work at a job or two just to keep food on the table--maybe I'd have to work cleaning my old office or stocking the shelves in the local pharmacy. The whole not thinking well experience is quite scary. My brain feels like the most vulnerable part of my body. I found it extremely reassuring to know that my brain function is likely to return to its pre-morbid levels given the agents I got and the disease I have. Here's hoping it's true.