(Bloomberg) — “Chemo brain,” a term describing the forgetfulness and cognitive fog that breast-cancer patients undergoing chemotherapy experience, may have more to do with the stress and fatigue caused by the disease, a study suggests.

More women with breast cancer scored lower on cognitive function tests before getting chemotherapy than did those without the disease, according to research presented Friday at the San Antonio Breast Cancer Symposium in Texas. Women set to undergo radiation, rather than chemotherapy, for their disease also performed worse on memory and thinking tests before therapy.

The findings suggest that more can be done to help reduce stress and fatigue in breast cancer patients to alleviate their difficulties thinking clearly, remembering things and carrying out jobs and other responsibilities, said Bernadine Cimprich, the lead study author. Meditation, exercise and psychological support may help, she said.

“There is a need for increased clinical awareness that cognitive problems can begin before any treatment and might get worse over time,” Cimprich, an associate professor emerita at the University of Michigan School of Nursing in Ann Arbor, said Thursday in a telephone interview. “’Chemo brain may not be the right label for cancer-related cognitive dysfunction. That then opens an opportunity for various interventions that were not there before.”

While worry can lead to fatigue, the cancer itself may cause inflammation and affect cognitive function, she said.

Researchers in the study looked at 29 women who were scheduled to undergo chemotherapy, 37 scheduled to undergo radiation therapy and 32 healthy women. They performed a working memory task while undergoing magnetic resonance imaging before therapy and one month after.

They found the chemotherapy group performed the worst on the cognitive test before the treatment and one month after therapy. While the radiation group performed about as poorly on the test before getting treatment as those scheduled to receive chemotherapy, they did just as well as the women without breast cancer on the test one month later.

Cimprich said researchers are looking at data taken one year after the initial test to see if cognitive problems persist.

The research was funded by the U.S. National Institutes of Health.