Posted 08.26.2020 | by AMRA

Up to 78% of women undergoing chemotherapy for cancer report impairment in cognitive functioning, commonly referred to as “chemo fog.” These complaints are accompanied by functional connectivity changes in regions of the brain involved in attention and executive functioning. Functional connectivity is a measure of the degree to which different brain regions act in tandem. While the efficacy of mindfulness training for cancer-related emotional difficulties is supported, the effect on cognitive impairment remains unknown.

Gucht et al. [Cancer] tested mindfulness training against a wait-list control on cancer survivors’ subjective and objective cognitive impairment, psychological symptoms, and brain connectivity.

The researchers randomly assigned 33 Belgian female breast cancer survivors (average age = 45 years) with self-reported subjective cognitive impairment to either mindfulness training or a wait-list control. Mindfulness training was based on Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Cognitive Therapy (MBCT), and delivered in four group-based sessions, each lasting three hours. Home practice was encouraged and brief between-session telephone calls for encouragement and support were offered over an 8-week period.

Participants were assessed at baseline, one week after the intervention, and at 3 months after on a subjective measure of cognitive functioning and an objective battery of attention, concentration, memory, executive functioning, and processing speed. Other subjective measures were used to assess emotional distress, fatigue, and mindfulness (Comprehensive Inventory of Mindfulness Experiences).

Participants also underwent resting-state fMRI brain scans at all three assessment points. Six mindfulness participants and one control did not complete the study.

Results showed the mindfulness training group had significantly greater improvement in subjective cognitive impairment at post-treatment (Hedge’s g=0.99) and follow-up (g=0.95) than controls. The mindfulness group also had significantly greater decreases in emotional distress at post-treatment (g=0.55) and follow-up (g=0.81) as well as significantly greater decreases in fatigue at post-treatment (g=0.46) and follow-up (g=1.16) than controls. There were no significant group differences in the objective cognitive battery or mindfulness scores.

The brain imaging results showed that the mindfulness training group had significantly greater post-treatment increases in functional connectivity in regions controlling attention to sensory stimuli (anterior cingulate cortex and dorsal attention network) than controls. This increased functional connectivity was significantly correlated with decreases in emotional distress (r=-.57). There was a trend towards decreased default mode network connectivity in the mindfulness group.

The study findings support structured mindfulness training with telephone-based encouragement as a treatment for subjective cognitive impairment in cancer survivors who had been treated with chemotherapy.

The study is limited by the lack of an active control group and small sample size. The objective battery used may not have been sensitive enough to detect cognitive improvements as the sample performed within the normal range of scores at baseline, leaving little room for improvement.


Gucht, K. V. der, Ahmadoun, S., Melis, M., Cloe, E. de, Sleurs, C., Radwan, A., Blommaert, J., Takano, K., Vandenbulcke, M., Wildiers, H., Neven, P., Kuppens, P., Raes, F., Smeets, A., Sunaert, S., & Deprez, S. (2020). Effects of a mindfulness-based intervention on cancer-related cognitive impairment: Results of a randomized controlled functional magnetic resonance imaging pilot study. Cancer.

[Link to study]