UBC research shows that chemotherapy can lead to excessive mind wandering and an inability to concentrate. Dubbed ‘chemo-brain,’ the negative cognitive effects of the cancer treatment have long been suspected, but the UBC study is the first to explain why patients have difficulty paying attention.
Breast cancer survivors were asked to complete a set of tasks while researchers in the Departments of Psychology and Physical Therapy monitored their brain activity. What they found is that the minds of people with chemo-brain lack the ability for sustained focused thought.
“A healthy brain spends some time wandering and some time engaged,” said Todd Handy, a professor of psychology at UBC. “We found that chemo brain is a chronically wandering brain, they’re essentially stuck in a shut out mode.”
Handy explains that healthy brains function in a cyclic way. People can focus on a task and be completely engaged for a few seconds and then will let their mind wander a bit.
The research team that included former PhD student Julia Kam, the first author of the study, found that chemo brains tend to stay in that disengaged state. To make matters worse, even when women thought they were focusing on a task, the measurements indicated that a large part of their brain was turned off and their mind was wandering.
The researchers also found evidence that these women were more focused on their inner world. When the women were not performing a task and simply asked to relax, their brain was more active compared to healthy women.
Kristin Campbell, an associate professor in the Department of Physical Therapy and leader of the research team, says these findings could help health care providers measure the effects of chemotherapy on the brain.
“Physicians now recognize that the effects of cancer treatment persist long after its over and these effects can really impact a person’s life,” said Campbell.
Tests developed for other cognitive disorders like brain injury or Alzheimer’s have proven ineffective for measuring chemo brain. Cancer survivors tend to be able to complete these tests but then struggle to cope at work or in social situations because they find they are forgetful.
“These findings could offer a new way to test for chemo brain in patients and to monitor if they are getting better over time,” said Campbell, who also conducts research to measure how exercise can improve cognitive function for women experiencing chemo brain.
Funding: The study received funding from the Canadian Breast Cancer Foundation BC/Yukon.
Source: Heather Amos – University of British Columbia
Image Credit: The image is credited to Julia Kam
Original Research: Abstract for “Sustained attention abnormalities in breast cancer survivors with cognitive deficits post chemotherapy: An electrophysiological study” by J.W.Y. Kam, C.A. Brenner, T.C. Handy, L.A. Boyd, T. Liu-Ambrose, H.J. Lim, S. Hayden, and K.L. Campbell in Clinical Neurophysiology. Published online March 25 2015 doi:10.1016/j.clinph.2015.03.007
Sustained attention abnormalities in breast cancer survivors with cognitive deficits post chemotherapy: An electrophysiological study
•Our study examined if the ability to maintain sustained attention could be a feature of the cognitive difficulties reported by some breast cancer survivors (BCS).
•We found that BCS were less likely to maintain attention towards the task, and displayed reduced P3 amplitude to task relevant stimuli relative to healthy controls.
•This data underscores the utility of a new combination of laboratory-based measures for assessing self-reported attentional impairments in BCS.
Many breast cancer survivors (BCS) report cognitive problems following chemotherapy, yet controversy remains concerning which cognitive domains are affected. This study investigated a domain crucial to daily function: the ability to maintain attention over time.
We examined whether BCS who self-reported cognitive problems up to 3 years following cancer treatment (n = 19) performed differently from healthy controls (HC, n = 12) in a task that required sustained attention. Participants performed a target detection task while periodically being asked to report their attentional state. Electroencephalogram was recorded during this task and at rest.
BCS were less likely to maintain sustained attention during the task compared to HC. Further, the P3 event-related potential component elicited by visual targets during the task was smaller in BCS relative to HC. BCS also displayed greater neural activity at rest.
BCS demonstrated an abnormal pattern of sustained attention and resource allocation compared to HC, suggesting that attentional deficits can be objectively observed in breast cancer survivors who self-report concentration problems.
These data underscore the value of EEG combined with a less traditional measure of sustained attention, or attentional states, as objective laboratory tools that are sensitive to subjective complaints of chemotherapy-related attentional impairments.
“Sustained attention abnormalities in breast cancer survivors with cognitive deficits post chemotherapy: An electrophysiological study” by J.W.Y. Kam, C.A. Brenner, T.C. Handy, L.A. Boyd, T. Liu-Ambrose, H.J. Lim, S. Hayden, and K.L. Campbell in Clinical Neurophysiology. Published online March 25 2015 doi:10.1016/j.clinph.2015.03.007