Chemotherapy brain fog (also called chemo-brain or post-chemo brain) often occurs after a person has undergone cancer treatment. It can affect people’s thinking, ability to remember information, finish tasks, learn new things, or concentrate. Some of the factors that can cause memory lapses and fogginess include the chemo itself, anxiety and depression about cancer, fatigue, anesthesia from surgery, hormonal therapy, and anemia. Cytokines, which are signaling molecules of the immune system, may also play a role in cognitive changes experienced after chemo treatment. Higher levels of certain pro-inflammatory cytokines have been linked to cognitive impairment during and after chemotherapy, but the relationship between cytokines and chemotherapy-induced cognitive dysfunction is complex and not yet fully understood, so more research is needed. 

Changes in the brain after chemotherapy aren’t structural; the brain will likely look normal on a regular MRI because the damage is subcellular.  Functional MRI (fMRI) can show the changes because it looks at blood flow patterns throughout the brain and sheds light on brain function (versus structure).

About 50 to 75% of people undergoing chemotherapy report a lack of concentration, short-term memory loss, slowed processing speed, difficulty with word recall, and/or an inability to organize daily tasks after their chemo has ended. For many people post-chemo brain is a short-term problem lasting up to a few months, but for others the symptoms last for years after completing treatment.  These changes can affect the entire family.

Most of the memory problems are with retrieval, not storage (as in Alzheimer’s disease). People tend to go blank when trying to recall names or words in conversation but usually can recall them later. Many show less working memory capacity; working memory involves holding information for a brief time while manipulating it (such as when doing a multiplication problem only in one’s mind versus on paper). It is like a mental “scratchpad” that holds information while we work with it. 

Below are some suggestions that may help to alleviate some of the cognitive impairment experienced after chemotherapy treatment. It is advisable to let others know what you are experiencing so they will understand why you are having difficulty remembering things.

• Exercise, practice yoga or tai chi, and/or engage in mindfulness meditation, or just meditation. These can help you relax, dissipate stress, and improve focus and attention.
• Create easy-to-follow daily routines, from taking medications and eating breakfast on through your evening. Use a daily planner, notebook, notes, or your smartphone for reminders.
• Keep a diary or log ofthe times of day or the activities when you feel confused, have trouble concentrating or are forgetful, and what’s going on at the time, so you can plan to cope better with them in the future. 
• Try to focus on one thing at a time and do your most difficult tasks when you have the most energy.
• Get enough rest and sleep; fatigue increases post-chemo brain symptoms.
• Eat a brain-healthy diet.
• Give your brain a daily workout, using phone apps or websites with brain-stimulating exercises such as puzzles and word games. Paint pictures, play an instrument, or learn a new hobby. Be careful not to challenge yourself too much so you don’t get discouraged or frustrated.
• Pick a certain place to keep items that often get lost, like your keys or the remote. Put each item in its place after you use it.
• Ask for help when you need it. Having friends and loved ones help with daily tasks can cut down on distractions and help you save mental energy.

Patients experiencing cognitive problems and other symptoms six months or longer after stopping chemotherapy may want to seek treatment, such as cognitive rehabilitation. This might involve a combination of cognitive therapy, occupational therapy, sensorimotor therapy, neuromuscular therapy and vestibular therapy.