Cognitive Dysfunction ("Chemo Brain")

Last Modified: May 5, 2016

What is Chemo Brain?

Many survivors who have previously received or are currently undergoing chemotherapy report experiencing cognitive changes, often referred to as "chemo-brain." These changes include difficulty with short term memory, multi-tasking, new learning, reading comprehension, working with numbers and a decrease in concentration ability. For many years, this was attributed by physicians and researchers to depression or anxiety over the diagnosis and treatment of cancer. More recently, researchers have begun to study and document what survivors have been saying all along; cognitive changes after chemotherapy are real. Although we are not yet able to pinpoint whether only certain chemotherapy drugs are responsible, it seems certain that the effects are cumulative. That is, those who receive more chemotherapy tend to experience greater deficits. Studies have found that cognitive ability can improve over time in some survivors, but deficits are still present in many long-term survivors, even years after treatment. Each person's experience is unique, making it difficult to predict what deficits, if any, a person will experience, and whether or not they will persist after treatment.

In recent years, a number of studies have been reported, many showing some level of decline in brain function in cancer survivors post therapy, although some studies have not found any change. The effect can be a worsening of a pre-existing cognitive issue, or a new change in function. Some study participants worsen during therapy and gradually improve after, while others find their impairments are long-lasting, if not permanent.

What are these cognitive effects exactly? Survivors identify changes in attention / concentration, processing speed, verbal and visual memory, multitasking, word finding, and difficulty with organization. These effects can lead to an inability to perform one's job, difficulty managing family/home responsibilities and even social withdrawal for fear of embarrassment. Family, friends and co-workers often expect the survivor to be "back to normal", only adding to the stress of cognitive changes.

Rule Out Other Causes

It is important to remember that some very treatable problems can result in cognitive difficulties, such as thyroid dysfunction, depression and anxiety, so it is important to exclude or treat these diagnoses. Hypothyroidism (low thyroid hormone levels) is a common issue for survivors and can make you feel "fuzzy" or "out of it." This is easily treatable with supplemental thyroid hormone. Survivors who may be depressed or experiencing anxiety would benefit from consulting with a psychiatrist or psychologist experienced in working with cancer patients or survivors. Don't just assume your cognitive concerns are due to chemo-brain.

Treatments: Medications

Unfortunately, research into cognitive dysfunction is in its infancy.  We can take some lessons from research in dementia and Alzheimer disease in combination with common sense to develop some tips to regaining and/or optimizing your brainpower.

Researchers are studying some medications as potential treatments for cognitive changes, but there is not yet enough data to support their use. These include medications used to treat attention deficit hyperactivity disorder, Alzheimer disease, dementia, depression and narcolepsy. Many of these medications stimulate the brain and therefore may result in improved concentration, memory and attention, as well as fatigue. Along the same lines, caffeine is an over the counter stimulant that improves cognitive function for millions of people every day. It is a relatively safe way for many people to stimulate their brain function.

Ginkgo biloba is often promoted as a memory enhancer, but studies have not found this to be true. One large study of elderly patients found no decrease in Alzheimer's disease, and actually saw an increase in dementia and stroke in the group taking the supplement. Ginkgo biloba increases the risk of bleeding and should be used with caution. As with all herbal therapies, just because they are touted as "natural" does not mean they do not have side effects. Investigate the possible side effects of any supplement, as well as the reputation of the manufacturer and their products. Vitamin E, in safe doses, may be beneficial to brain health. However, Vitamin E can also interfere with medications such as blood thinners. Do not take any supplement without first checking with your provider. 

Treatments: "Brain Rehab"

Cognitive rehabilitation programs are structured programs utilizing exercise, tasks that use memory and puzzles to "rehabilitate" one's mind. These programs are typically used for people with brain injuries, but therapists have tailored programs for cancer survivors. A number of companies offer computer programs that aim to improve brain function. There are currently studies ongoing looking at the effectiveness of these programs in cancer survivors, so stay tuned.

Puzzles using numbers, like Sudoku, may help "exercise" your brain. It is likely that any brain stimulation may be helpful and certainly cannot hurt, whether through a game, taking a course at a local school, or joining a book discussion club.

Fatigue can enhance cognitive problems, so avoiding fatigue by getting enough sleep, incorporating exercise into your life and eating a healthy diet.

Tips for Managing Life with Chemo-Brain

There is no "quick fix" for chemo-brain.  It is important to be creative and incorporate things into your daily life that can help combat the symptoms.

  • Keep a detailed calendar or planner. Got a smartphone? Set alarms to remind you of important appointments.
  • The all-to-important sticky note – just be sure to put them in places you will see them!
  • In the evening, start a list for tomorrow- what needs to get done? who do I need to call? Create a notebook for this so you can flip ahead and add something to next week's list when it comes to mind.
  • Keep a pad in the kitchen for a shopping list- when you see something is running low; make it a habit to add it right away.
  • Put a basket near the front door for those items you need every day- cell phone, keys, etc.
  • Trouble remembering names? Think of a silly thing to jog that memory- I remember my neighbor Rena's name by thinking Xena Warrior Princess. Sounds silly, but I never forgot her name again!
  • Trouble remembering something is cooking? Get into the habit of setting a timer.  This is also a great use for your smart phone!
  • GPS / navigation systems/navigation apps can be lifesavers for getting places.
  • Most importantly, know your limitations. Don't take on tasks that require too much multi-tasking. Ask for help. Try to keep a positive outlook and find some humor in your "chemo-brain moments".

Further Reading

American Cancer Society: Chemo-Brain Attention, Thinking or Memory Problems

Coping with Chemobrain: Keeping your Memory Sharp


Argyriou AA, Assimakopoulos K, Iconomou G, Giannakopoulou F, Kalofonos HP. Either called "chemobrain" or "chemofog," the long-term chemotherapy-induced cognitive decline in cancer survivors is real. Journal of pain and symptom management. 2011;41(1):126-39.

Boykoff N, Moieni M, Subramanian SK. Confronting chemobrain: an in-depth look at survivors' reports of impact on work, social networks, and health care response. Journal of cancer survivorship : research and practice. 2009;3(4):223-32.

Ganz PA. "Doctor, will the treatment you are recommending cause chemobrain?". Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2012;30(3):229-31.

Holmes D. Trying to unravel the mysteries of chemobrain. The Lancet Neurology. 2013;12(6):533-4.

Kvale E, Urba SG. NCCN guidelines for survivorship expanded to address two common conditions. Journal of the National Comprehensive Cancer Network : JNCCN. 2014;12(5 Suppl):825-7.

Mayo Clinic. Chemo brain. 2016. Found at: C. Treating chemobrain: rehabilitation therapies emerge. Journal of the National Cancer Institute. 2012;104(22):1691-2.

Mitchell T, Turton P. 'Chemobrain': concentration and memory effects in people receiving chemotherapy - a descriptive phenomenological study. European journal of cancer care. 2011;20(4):539-48.

Silverman D & Davidson, I Your Brain After Chemo. 2009. Cambridge, MA: DaCapo Press.


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