Cognitive Training Helps 'Chemo Brain' in Cancer Survivors

Kate Johnson

October 12, 2012

October 12, 2012 — "Chemo brain" — the cognitive impairment often reported in cancer survivors who have received chemotherapy — can be significantly improved with computerized brain-training exercises aimed at processing speed, according to a study of long-term breast cancer survivors.

The study appears in the October issue Breast Cancer Research and Treatment.

"This is the largest cognitive training study in long-term breast cancer survivors to date," write lead author Diane Von Ah, PhD, RN, assistant professor at the Indiana University School of Nursing and researcher at the Indiana University Melvin and Bren Simon Cancer Center in Indianapolis, and colleagues. "Findings from this study will ultimately lead to a full-scale efficacy trial and our overarching goal of identifying an effective treatment for cognitive impairment in breast cancer survivors."

The randomized controlled trial involved 88 breast cancer survivors (mean age, 56.5 years) who reported concerns about cognitive impairment and expressed an interest in treatment.

All women were recruited from January 1, 2009 to January 1, 2011, had received both chemotherapy and surgical treatment for early-stage breast cancer, and were disease-free (average time since last treatment, 5.5 years).

Numerous Outcomes Measured

Eligible participants underwent a baseline neuropsychologic assessment, completed a survey questionnaire, and were randomized to 1 of 3 groups: a memory-training intervention, a speed-of-processing training intervention, or a wait-list control group.

Primary outcomes were immediate objective memory (measured with composite immediate recall scores from the Rey Auditory Verbal Learning Test [AVLT] and the Rivermead Behavioral Paragraph Recall Test), delayed objective memory (measured with composite delay recall scores from the AVLT and Rivermead), and objective speed of processing (measured with the computerized Useful Field Of View test).

Secondary outcomes included perceived cognitive functioning, symptom distress, quality of life, and satisfaction/acceptability.

Each intervention involved ten 1-hour training sessions delivered by certified interventionists over 6 to 8 weeks and involving groups of 3 to 5 women. Memory training involved teaching participants strategies for remembering word lists, sequences, and text. Speed-of-processing training involved commercially available brain-fitness software (InSight, Posit Science), which reduces the stimulus duration during a series of progressively more difficult information-processing tasks.

Computerized Program Better?

Although both interventions improved cognitive function, the speed-of-processing intervention "resulted in immediate and durable improvements in objective measures of processing speed and verbal memory," the researchers report.

"Speed-of-processing training may have broader benefits in this clinical population," they note.

The speed-of-processing intervention, compared with the wait-list intervention, led to "reliable improvement" in immediate memory at postintervention (41% vs 10%; P =.007) and at 2-month follow-up (30% vs 18%; P = 0.004) and in delayed memory at 2-month follow-up (33% vs 11%; P = .010). It also led to a significant improvement in processing speed at postintervention (68% vs 43%; P =.040) and at 2-month follow-up (67% vs 61%; P =.016).

The memory intervention, compared with the wait-list intervention, led to reliable improvement in immediate memory at 2-month follow-up (39% vs 18%, P = 0.036) and in delayed memory at 2 months, (42% vs 11%; P = 0.013). It also led to a nonsignificant improvement in processing speed at postintervention (65% vs 43%) and at 2-month follow-up (73% vs 61%).

Asked by Medscape Medical News why speed-of-processing training appears to be superior to memory training, given that a larger percentage of the memory-training group showed improvement at 2 months, Dr. Von Ah said the study was not designed as a head-to-head comparison of the 2 interventions. "We were not powered adequately to make that comparison," she said in an email.

"You are correct that at the 2-month time point, a larger percent [of the memory-training group] had reliable improvement.... However, this was only seen at that 2-month time point on the primary outcomes, and not in the context of the totality of outcomes — symptom distress and quality of life," she explained.

The authors note that in terms of secondary outcomes, "significant improvements in perceived cognitive function, symptom distress (mood disturbance, anxiety, and fatigue), and quality of life" were seen in both intervention groups, compared with the control group.

Dr. Von Ah explained that when each intervention is compared with the control group, the results "truly depict the full story of the effects of the interventions on outcomes. This is what we used to make the statement that speed of processing may have 'broader' benefits."

Asked to comment on the findings, Michelle Janelsins, PhD, assistant professor in the Department of Radiation Oncology at the University of Rochester Medical Center School of Medicine and Dentistry in Rochester, New York, said the results are promising and support previous findings on the benefits of cognitive training in this population.

"Memory and processing-speed difficulties are among the most frequent complaints of breast cancer survivors," she told Medscape Medical News. "From this pilot study, it appears that both interventions are beneficial.... Further studies will be needed to determine which might be more beneficial...or whether the combination of both the training programs can maximize benefit," she said.

She noted that the training effects were sustained for 2 months and that, in addition to objective improvements in memory and processing speed, participants perceived significant cognitive improvements from the training.

"It would be interesting to see these promising results replicated in a larger efficacy study," she said. "Future research is needed to mechanistically understand how brain training helps to improve cognitive problems related to cancer treatments," she noted.

The study was supported by the Robert Wood Johnson Foundation Nurse Faculty Scholar Program (64194), American Cancer Society Institutional Research Grant (84-002-25), Indiana University School of Nursing Center for Enhancing Quality of Life in Chronic Illness, and the Mary Margaret Walther Program of the Walther Cancer Institute (0097.01). Posit Science Corporation, the developer of the speed-of-processing software (InSight) used in this study, provided the software. Coauthor Karlene Ball, PhD, from the University of Alabama at Birmingham, reports being on the board of directors of Posit Science, and owing stock in the company. Coauthor Fred Unverzagt, PhD, from the School of Medicine at Indiana University in Indianapolis, reports receiving training support from Posit Science. Dr. Janelsins has disclosed no relevant financial relationships.

Breast Cancer Res Treat.2012;135:799-809. Abstract