Nightly News | November 27, 2012
>>> now to health news tonight, and what they know about chemo brain , which will be familiar to you if you or someone you love has dealt with the frustration, fogginess and confusion among so many cancer patients. especially those in the fight against breast cancer . patients have talked about this since the dawn of chemotherapy. scientists say they can actually see it.
>> reporter: soon after she began her treatment for breast cancer , jodi, an author found herself in a mental fog. a condition known widely among cancer patients as chemo brain .
>> chemo brain was like having my brain constantly out of focus. it was as though i couldn't get the words in the proper alignment. as a writer, that was devastating.
>> reporter: the cloudiness continued. even after the chemo ended.
>> emotionally, i really wondered if i would ever be the same.
>> reporter: dr. rachel eggos has much of the understanding of the condition.
>> i have imaging evidence that shows chemo brain is real. part of being able to address a disease and help a patient through a disease is realizing the disease exists in the first place.
>> reporter: they performed brain scans on 128 breast cancer patients before, during and after chemotherapy. with knees images to measure how the brain is using energy. the researchers discovered chemo sets up very specific changes. in several key parts of the brain that control memory and decision making.
>> what am i going to get done today? what do i need to get at the grocery store? what am i going to have for dinner.
>> increasingly, hospitals and doctors are trying to make patients aware of the problem.
>> it's helpful for patients to understand they're not alone in this experience. that this does happen to a segment of the population. at present we can't predict who's at greatest risk for them.
>> fortunately the effect usually fades with time. better understanding of the impact on patients like jodi may lead to ways to treat or prevent the symptoms. robert bazell , nbc news, new york.