Understanding Brain Fog and How to Treat It

Chemo brain, also known as brain fog, can cause memory and attention problems during treatment. But for most people, these symptoms eventually go away. 

 

If you’ve felt forgetful or out of sorts since beginning breast cancer treatment, you’re not alone. Most people in treatment for cancer report problems with their focus, memory, and ability to make decisions — a batch of symptoms commonly called chemo brain, chemo fog, or brain fog. Doctors sometimes call this cancer-related cognitive impairment (CRCI).

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Cognitive impairment is a side effect of chemotherapy that affects up to 75% of people with breast cancer. You may also experience it when you receive a cancer diagnosis, following surgery, or during or after radiation, immunotherapy, or hormonal therapy. 

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Cognitive impairment affects how your brain functions and can vary from person to person. For some people there's a feeling of disassociation.

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People who experience cognitive impairment or brain fog also report:

• difficulty remembering dates or names

• taking longer than usual to finish tasks

• having problems concentrating

• having a hard time grasping new ideas

• difficulty finding the right words to say

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Does cognitive impairment ever go away?

“For the majority of breast cancer survivors, these issues don’t last long, gradually improve, and there are no long-term or permanent effects,” said Timothy Ahles, PhD, a behavioral psychologist and director of the Neurocognitive Research Lab at Memorial Sloan Kettering Cancer Center.  But chemo brain can last longer for some people: 20-30% of women experience prolonged cognitive deficits after treatment, according to one estimate. 

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What causes cognitive impairment?

While cognitive impairment is most often associated with chemotherapy or other treatments, just the mere experience of being diagnosed with cancer can cause brain fog and memory and concentration problems. Some people also develop anxiety or depression after being diagnosed or while going through treatment, which can also affect brain function. 

Other side effects of treatment can also affect how well the brain works, like anemia, pain (and medicines used to treat pain), fatigue, sleep problems, and appetite changes. 

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You may be at greater risk of getting cognitive impairment if you:

• have diabetes, hyperglycemia, or high blood pressure (high blood sugar levels and high blood pressure can damage blood vessels in the brain)

• have obesity or an autoimmune disorder like lupus or rheumatoid arthritis (these can lead to chronic inflammation, which causes structural changes in the brain) 

• are post-menopausal 

• don’t exercise 

• use substances like alcohol or cannabis that may cause thinking or memory problems

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The gut microbiome may play a role in cognitive impairment: Early research found that people who reported chemo brain symptoms also had a less diverse gut microbiome after chemo.  

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Treating cognitive impairment

While cognitive impairment brain has likely been around since the start of chemotherapy in the 1940s, it’s taken a while for healthcare professionals to take it seriously. That has started to change in recent years though, leading to more research on interventions. There’s still no FDA-approved medication for CRCI, but there are science-backed interventions. 

 

Cognitive Rehabilitation

Some cancer centres offer cognitive rehabilitation programs led by occupational therapists, neuropsychologists, or speech-language pathologists.

These programs teach practical strategies to compensate for memory and attention difficulties, such as:

• Memory training exercises

• Organizational strategies

• Attention-building activities

• Problem-solving techniques

• Planning and time-management skills

Research suggests cognitive rehabilitation can improve daily functioning and confidence in managing cognitive symptoms.

 

Cognitive Training

Computer-based brain training programs and mentally stimulating activities may also help strengthen cognitive skills.

Examples include:

• Word and number puzzles

• Strategy games

• Learning a new language or hobby

• Memory exercises

• Educational courses

While evidence is still developing, regular mental stimulation may support attention, memory, and executive functioning.

 

Acupuncture

Acupuncture has shown promise for managing several side effects of cancer treatment, including cognitive symptoms.

In one study, participants who received weekly acupuncture treatments for 10 weeks reported improvements in memory, concentration, and overall cognitive function. They also performed better on standardized cognitive tests compared with participants who did not receive acupuncture.

Although larger studies are still needed, acupuncture may be worth discussing with your healthcare provider if it is available and appropriate for you.

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Mindfulness, Meditation, and Music

Stress, anxiety, poor sleep, and fatigue can all worsen cognitive symptoms. Mind-body therapies may help improve both emotional well-being and cognitive function.

A small study found that listening to 12 minutes of classical music each day improved cognition, fatigue, and stress levels in people receiving chemotherapy.

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Another group that practiced a 12-minute guided meditation (Kirtan Kriya) also experienced improvements in memory, focus, prioritization, and problem-solving abilities.

Other mindfulness practices—including deep breathing, yoga, and meditation—may also help reduce stress and improve concentration.

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Sleep Management

Poor sleep is strongly linked to memory and concentration problems.

Improving sleep quality may lessen cognitive symptoms by:

• Keeping a consistent sleep schedule

• Limiting caffeine late in the day

• Reducing screen time before bed

• Creating a comfortable sleep environment

• Discussing insomnia or sleep disorders with your healthcare provider

Treating sleep problems can often lead to noticeable improvements in daytime thinking and memory.

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Managing Fatigue, Anxiety, and Depression

Cancer-related fatigue and emotional distress can significantly affect cognitive function.

Managing these symptoms through:

• Counselling or psychotherapy

• Support groups

• Exercise

• Relaxation techniques

• Appropriate medications when needed

 

This may indirectly improve memory, attention, and mental clarity.

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Nutrition

No specific diet has been proven to cure chemo brain, but maintaining good nutrition supports overall brain health.

General recommendations include:

• Eating a balanced diet rich in fruits and vegetables

• Choosing whole grains

• Including healthy fats such as fish, nuts, and olive oil

• Staying well hydrated

• Limiting excessive alcohol

If appetite or nutrition is a concern, a registered dietitian can provide individualized guidance.

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Medications

There are currently no FDA- or Health Canada-approved medications specifically for cancer-related cognitive impairment (CRCI). Most clinical guidelines recommend starting with non-pharmacologic approaches, such as exercise, cognitive rehabilitation, sleep optimization, and managing fatigue, anxiety, or depression.

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In select patients with persistent, bothersome symptoms, a healthcare provider may consider an off-label medication after weighing the potential benefits and risks. These may include:

• Psychostimulants, such as methylphenidate or modafinil, which may help improve attention, alertness, and mental fatigue in some individuals. However, research findings have been mixed, and these medications are not routinely recommended.

• Donepezil, a medication used to treat Alzheimer's disease, has been studied in cancer survivors. While some small studies suggested possible benefits, larger clinical trials have not consistently shown meaningful improvements in cognitive function.

• Memantine has also been investigated, particularly in patients receiving radiation therapy to the brain, where it has been shown to help preserve cognitive function. Its role in chemotherapy-related cognitive impairment without brain radiation is less well established.

Before considering medication, healthcare providers should evaluate for other potentially reversible causes of cognitive symptoms, such as sleep disorders, depression, anxiety, anemia, thyroid disease, vitamin deficiencies, or medication side effects.

 

Talk to Your Healthcare Team

If brain fog is interfering with work, school, relationships, or daily activities, let your healthcare provider know. Cognitive changes can sometimes be related to other treatable conditions, such as thyroid disorders, vitamin deficiencies, medication side effects, depression, anxiety, or sleep problems.

Your healthcare team can help identify possible causes, recommend appropriate strategies, and refer you to specialists such as occupational therapists, neuropsychologists, or rehabilitation programs if needed.

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Cognitive Tips for Managing Brain Fog During Treatment

• Keep your brain engaged by learning something new.
  Challenge your mind with a new hobby, game, puzzle, or skill. Activities like card games, word puzzles, reading, or continuing to work (if you're able) may help keep your mind active.

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• Break complex tasks into smaller steps.
  Instead of trying to complete a complicated task all at once, tackle it in short, manageable sessions. Focus on one step at a time and take breaks as needed.

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• Use reminders and write things down.
  Keep notes, use checklists, set reminders on your phone, or say important information out loud to help reinforce your memory and stay organized.

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• Maintain a consistent routine.
  Following familiar daily routines can reduce mental effort and make it easier to stay focused and complete everyday tasks.

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• Switch to a hands-on activity when brain fog sets in.
  If you notice your concentration fading, take a break from mentally demanding tasks and do something physical or tactile, such as folding laundry, gardening, or tidying up. This can help give your mind a chance to reset.

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