Stanford University School of Medicine researchers found evidence of a phenomenon called “chemo brain” in a study published Monday in the Archives of Neurology.

The neuroimaging study documented that when asked to perform certain tasks, women who had undergone chemotherapy for breast cancer had significantly less activation of a particular area of the brain known to play a key role in planning, attention and memory. Researchers compared the performance of the participants who had undergone chemotherapy to that of healthy women and breast cancer patients who had not undergone chemotherapy treatment.

The study provides evidence that “primary breast cancer may cause measurable brain injury,” according to its authors, and that women treated with chemotherapy may experience additional brain abnormalities and cognitive difficulties. The study also provides evidence of an association between breast cancer patients’ self-reported cognitive impairment and abnormalities in their brain function.

Lead author Shelli Kesler, assistant professor of psychiatry and behavioral sciences in the School of Medicine, described the study as validation for patients who complain of cognitive impairment following chemotherapy treatment.

The study used a questionnaire to record participants’ assessment of their own cognitive abilities and used functional magnetic resonance imaging (fMRI) to record which parts of the participant’s brains were activated when they performed a card-sorting task measuring problem-solving skills.

The study confirmed that cancer patients overall experience reduced activation of the prefrontal cortex, but those who had undergone chemotherapy treatment experienced significantly reduced activation of an additional region of the prefrontal cortex and had particular difficulty in completing the assigned task.

– Margaret Rawson