November 10, 2008
Roxanne Nelson

A new “brain-fitness” program might help breast cancer survivors deal with the cognitive dysfunction associated with chemotherapy. Often dubbed “chemobrain” by cancer patients, the term refers to a wide range of problems, including short-term memory loss, difficulty concentrating, reduced verbal memory, difficulty multitasking, and confusion, that have been linked to treatment with chemotherapeutic agents.

Although there is no standard therapy for chemobrain, researchers from Posit Science, in San Francisco, California, report that their brain-fitness program improved the auditory speed of processing in breast cancer survivors. In a randomized controlled trial, the results of which were presented at the 28th annual National Academy of Neuropsychology Conference, 41 breast cancer survivors were able to improve their auditory speed of processing, compared with pretraining levels. Their posttraining performance was also significantly faster than that of individuals in the age-matched control group.

However,”their speed increased after doing the program for 40 hours, so it may just be a practice effect, rather than a real improvement,” commented Lynne Taylor, MD, FAAN, a neuro-oncologist at Virginia Mason Medical Center, in Seattle, Washington. “That’s what happens when you play a video game, so we don’t know if there really was an improvement or they just got better at doing the program.” Dr. Taylor was not involved with the study.

The training program is a computer-based tool that uses adaptive exercises that target auditory/language systems. It is designed to drive generalized improvements in cognition by improving the speed and accuracy of information processing and engaging neuromodulatory systems of the brain. The participants trained for 1 hour per day, 5 days a week, for a total of 40 hours. Individuals were asked to identify a sequence of upward and downward frequency sweeps, which were presented at a faster rate as the person improved at the task.

“Some of the literature says that about 75% of women with breast cancer experience chemobrain after chemotherapy,” said coauthor Sarah-Jane Kim, MA, a researcher at Posit Science. “Participants say that they wish they had known beforehand about the mental side effects of their treatment. They’re told about the physical side effects, but not chemobrain.”

The participants were assessed before and after the training, and were compared with the control group. At baseline, the breast cancer survivors scored 85.50 (time in ms) for their auditory speed of processing task, compared with 95.89 for the controls. After completing 40 hours of training, that number decreased to 40.64 ms for the breast cancer patients.

“These results are from a 3 month follow-up,” said Ms. Kim. “After the participants completed the program, we asked them not to do any further training, and then we assessed them after 3 months.”

In a related study, explained Ms. Kim, breast cancer survivors reported an improved quality of life after completing the program. “We saw statistically significant improvements in the group’s perception of health-related quality of life, stress levels, and cognitive function.”

Although the study only included breast cancer survivors, Ms. Kim pointed out that they believe that the brain-fitness program would be helpful for other cancers as well.

Chemobrain Verified as a “Real” Condition
Several studies have consistently shown impairments in various cognitive domains among breast cancer survivors who were treated with adjuvant chemotherapy. Although research about chemobrain is still evolving, data show that this is a real condition and side effect of chemotherapy,” said Dr. Taylor.

A recent study used magnetic resonance imaging to compare regional brain-volume differences between breast cancer survivors who were exposed to adjuvant chemotherapy and unexposed controls (Cancer. 2007;109:146-156). “That study was very well done,” Dr. Taylor told Medscape Oncology, “and it showed that there were physical changes in the brains of breast cancer survivors. Parts of their brains were smaller.”

“What is interesting about this study is that they followed the patients for 3 years, and they found that it was a temporary problem that fixed itself,” said Dr. Taylor. “The study established that chemobrain is a real neuropathologic entity, but that it will eventually self-resolve, without the need for any type of training program. At 3 years, there were no differences in brain size between the cancer patients and the controls.”

Brain Fitness Needs More Rigorous Study
Although Dr. Taylor applauded the researchers for focusing on content and quality of life, she felt that there were a number of flaws in the study. “I think it needs to be studied in a much more rigorous fashion,” she said.

One major problem is that the breast cancer survivors had better auditory processing than the controls at baseline, so “the results are somewhat misleading,” she pointed out. “They say in their conclusion that, after completing the program, the breast cancer survivors significantly surpassed the performance of healthy age-matched controls,” said Dr. Taylor. “But they already had surpassed them at baseline.

“This means that auditory processing isn’t the variable they should have focused on. In terms of quality of life, auditory speed of processing is much less important than flexibility of thought or visual speed of processing, she said. ” We need to see better evidence and a wider scope of results before we can say that this works.”

The study authors are employees of Posit Science.

28th annual National Academy of Neuropsychology (NAN) Conference. Poster. Presented October 23, 2008.