Cognitive problems

Cognitive function refers to your thinking abilities. This includes communication, reasoning, perception, judgment, learning, attention, memory, organization and problem solving.

Cancer or its treatment, such as radiation therapy and chemotherapy, can affect cognitive function. Problems with cognitive function may be called cancer-related cognitive impairment, "brain fog" or "cancer fog." Problems with thinking and memory after having chemotherapy are commonly known as "chemo brain" or "chemo fog."

Cognitive problems can impact your emotional well-being and overall quality of life. You may have difficulty at school, at work or in carrying out your daily activities. Cognitive problems may also affect your ability to understand or make decisions. You may need help from others to do things you used to do on your own.

Because their brains are still developing, children have a higher risk for cognitive problems after cancer treatment than adults do. Having cognitive problems can affect a child's development in many ways and cause learning difficulties, such as problems with writing and math.

Cognitive problems can develop during or immediately after cancer treatment. They can also develop years later.

People with cancer can have cognitive problems for many reasons. These problems may have more than one cause.

Your brain controls your thoughts, emotions and actions. A brain tumour or another cancer that has spread ( metastasized) to the brain can cause cognitive problems, including trouble paying attention and memory loss. The severity of these problems depends on the age at diagnosis, where the tumour is in the brain, how quickly it is growing and its overall size. Brain tumours may also cause seizures and hydrocephalus, which can lead to cognitive issues.

Other types of cancer can also cause cognitive problems, such as tumours around an eye or ear, acute lymphoblastic leukemia and non-Hodgkin lymphoma (NHL) .

The type, dose and length of cancer treatment can affect cognitive function. Some cancer treatments are more likely to cause cognitive problems in children, such as radiation therapy to the head, neck or spinal cord, and chemotherapy given to the brain or spine. The healthcare team will develop a treatment plan that protects their cognitive function as much as possible.

Radiation therapy to the head and neck or to all of the body (called total body irradiation or TBI) can damage brain cells or make them form more slowly than normal. A high dose of radiation, receiving radiation when you are young, radiation to a large area of the brain or chemotherapy at the same time as radiation (called chemoradiation) increases the risk for cognitive problems. Cognitive problems usually show up 1 to 2 years or longer after radiation therapy to the head. Find out more about radiation therapy.

Chemotherapy may cause problems with attention, memory or problem solving. High doses of chemotherapy and chemotherapy given for a long time are more likely to cause cognitive problems. How chemotherapy drugs are given can also affect the risk of cognitive problems. For example, giving drugs directly into the cerebrospinal fluid (CSF) around the spinal cord (called intrathecal chemotherapy) is more likely to cause cognitive problems than giving drugs into a vein (called intravenous chemotherapy). Certain chemotherapy drugs can also cause hearing loss that may worsen cognitive problems. Find out more about chemotherapy.

Surgery to take a biopsy from or remove a tumour in the brain is done as carefully as possible. But there is a risk that this surgery may accidentally damage areas of the brain and cause cognitive problems. On the other hand, removing a tumour can sometimes improve cognitive function.

Hormone therapy controls the growth of cancer cells by changing the levels of certain hormones in the body. It's used to treat cancers that need hormones to grow, such as breast and prostrate cancers. But reducing the production of certain hormones can affect thinking. For example, estrogen protects nerve cells and cognitive function. So lower levels of estrogen in the body can cause cognitive problems. Find out more about hormone therapy.

Immunotherapy boosts the immune system or helps it find and destroy cancer cells. Some types of immunotherapy, including checkpoint inhibitors, may cause inflammation in the brain that can affect cognitive function. Find out more about immunotherapy.

Talk to your healthcare team to learn more about how cancer treatments may affect your cognitive function.

Cognitive problems can also be caused by conditions or symptoms related to cancer or cancer treatment, including:

• low red blood cell count( called anemia)
• sleep problems
• fatigue
• high blood calcium( called hypercalcemia)
• abnormally high or low levels of certain minerals in the body (called electrolyte imbalances)
• pain
• organ failure
• stress, anxiety, depression or other types of emotional distress caused by a cancer diagnosis

Sometimes medicines used to treat cancer or manage its side effects cause cognitive problems.

Common medicines that may cause cognitive problems include:

• drugs used to suppress the immune system (called immunosuppressants)
• corticosteroids
• pain relievers
• antidepressants
• heart medicine
• medicine to help you sleep

Other health problems and factors that can cause cognitive problems include:

• infections, especially of the brain and spinal cord
• abnormally high levels of certain proteins in the bloodstream
• diabetes
• high blood pressure
• not getting enough vitamins and minerals, such as iron, vitamin B and folic acid
• not having enough water in the body (dehydration)
• hormone changes due to menopause
• consuming alcohol or other substances that can affect thinking and coordination
• older age

Cognitive problems can be mild and may lessen or go away in the days or months following treatment. Some serious cognitive problems may be permanent or take a long time to improve. They sometimes get worse over time.

Cognitive problems are different for everyone. You may have difficulty with:

• language skills, including expressing yourself in words, remembering words or naming objects, understanding words or conversations, reading and writing
• doing math
• memory, including problems remembering names, dates and appointments
• learning new things
• doing different tasks at once (multi-tasking) or switching between tasks
• focusing, concentrating or organizing your thoughts
• judgment and reasoning
• fine motor skills, such as buttoning clothes or using a knife and fork
• thinking quickly

Cognitive problems can also include changes in your behaviour or emotions, such as:

• disorientation
• confusion
• mood swings
• inappropriate anger or crying
• irrational behaviour

Children with cognitive problems may have delayed social, emotional and behavioural development. They may also have difficulty learning. Some children with cancer may have difficulty speaking and expressing themselves. Find out more about speech-language problems in children.

Tell your doctor or healthcare team about any symptoms you have. The sooner you tell them of any symptoms, the sooner they can suggest ways to help manage them.

The early signs of cognitive problems may be subtle and easy to miss. Some of the changes that happen with cognitive problems can also be confused with or made worse by depression or fatigue.

Family members are often the first people to notice a change in a loved one’s cognitive function or personality. You can ask a family member or caregiver to keep track of changes in your thinking, communication and memory. If you or someone else notices changes in your cognitive function, tell your doctor. Your doctor may do a simple evaluation or refer you to a specialist for a more thorough assessment.

To assess cognitive function, your doctor may:

• do a physical exam
• talk to you about any cognitive changes you’ve noticed
• do cognitive testing to check your awareness of surroundings, judgment and reasoning, math and language skills and memory

Your doctor may order a CT scan or an MRI of the head to check for tumours, damage to the brain caused by radiation therapy or changes in the brain. If you are referred to a psychologist, you may have a neuropsychological evaluation to further assess your cognitive function.

Children who are at risk for cognitive problems and learning difficulties may be referred to a child psychologist for special testing. They can check the child's school-based skills, skills in processing and how they organize information. The evaluation can help you understand how your child thinks and behaves. Your child may redo these tests as part of their long-term follow-up.

Find out more about tests and procedures used to diagnose cognitive problems, including physical exam, CT scan and MRI.

Cognitive problems caused by cancer or its treatment may go away after treatment is finished. But sometimes they can continue for a long time or become permanent. The following may help you manage cognitive problems.

Medicines that may help with cognitive problems include:

• stimulants to improve concentration and memory
• antidepressants, if cognitive problems are due to or made worse by depression
• attention deficit hyperactivity disorder (ADHD) medicines
• antibiotics or other medicines to treat conditions that can cause cognitive problems, such as anemia or infection

Cognitive training and cognitive rehabilitation may be used to help you improve cognitive skills and cope with cognitive problems. Cognitive rehabilitation will re-teach thinking, reasoning or memory skills. These skills may not return to the way they were before cancer or its treatment, but cognitive rehabilitation can help improve your confidence and quality of life.

Occupational therapy and vocational rehabilitation may help you with everyday tasks and job-related abilities.

Speech therapy, behavioural therapy and social skills training may be helpful for children with cognitive problems and related learning difficulties.

Counselling and support provided during cognitive rehabilitation can help you as your needs change over time. A counsellor can support both you and your family.

Having cognitive problems can affect a child's ability to learn. Some children may develop learning difficulties after cancer treatment is finished (called a late effect) .

Children with learning difficulties may have problems with:

• writing, such as finding it difficult to write neatly, quickly or accurately
• spelling
• understanding math concepts
• staying alert and concentrating
• completing tasks on time
• completing assignments that require multiple steps (processing)
• planning and organization
• problem solving
• reading and understanding (comprehension)
• learning new vocabulary
• using calculators or computers
• hearing
• fatigue, such as falling asleep during class

Missing school, spending a lot of time in the hospital and side effects from cancer treatments can also affect a child's ability to learn. Some of these difficulties are temporary. Others can be long-term or permanent problems.

If your child has difficulty learning, you can get help to be sure they are supported at school. Sharing the results of your child's psychological testing with the school can help them meet your child's needs. Talking with your child's teacher regularly can help you understand how your child is doing at school and what support they might need. As your child gets older, encourage them to speak up so they can get what they need to help them learn.

Your child may be able to get support at school and manage learning difficulties by:

• sitting closer to the front of the classroom
• reducing the amount of written work in the classroom
• using digitally recorded textbooks and lessons
• using a computer to take notes instead of writing by hand
• using a calculator for math
• asking for extra time for tests or having an oral exam instead of a written exam
• getting a classroom aide
• getting extra help with math, spelling, reading, organizational skills or any other problem areas
• having help or extra time to get to classes
• using an elevator to help reduce fatigue
• having a second set of textbooks at home
• joining specialized school programs to support their reading and math skills

Cancer and its treatment may affect learning skills, but they usually don't affect a child's creativity. There is also always more than one way to learn. By focusing on your child's strengths and supporting them in their weaker areas of learning, you and your child's teachers can help your child's progress in school.

You might react to cognitive problems in different ways. Some people may feel frustrated, defensive and embarrassed that they can't think about or remember things as they used to. Other people may not even know that they have cognitive problems, which can make caregivers feel frustrated and helpless.

Everyone copes with cognitive problems differently. The following strategies may help you cope with cognitive problems.

Keep a record of your symptoms. This record can help you figure out when you become more distracted. It can also show you if your memory is worse when you are tired, hungry or at other times. Knowing when your thinking is at its best or worst can help you plan your day so that you do harder tasks when you feel the best.

Use a paper or electronic calendar or a daily organizer to record appointments, activities, notes and important dates. You can also set alarms on your smartphone or tablet as reminders. Keep the calendar or organizer with you to help you keep track of the tasks you need to do and to reschedule them if needed. It can be helpful to try to do only one task at a time.

Make a habit of checking your schedule in the morning, at noon, and then again in the evening to stay on top of your tasks.

Physical activity, such as walking, swimming or gardening, can help make you mentally alert. It's also important to get plenty of rest and try to reduce your stress. Yoga or meditation can help you relax and think more clearly.

You can exercise your brain with jigsaw or crossword puzzles, painting, playing a musical instrument or learning a new hobby. Wordplay, such as rhyming, can also help you remember things.

Talk to your family and friends about how you feel and how changes to your cognitive function affect you. They can better support you if they understand how you feel. They may also have some suggestions about how they can help.

Talk to your employer about getting support if you have problems at work, such as managing your workload or meeting deadlines.

All people who are treated for cancer need regular follow-up. Your healthcare team will develop a follow-up plan based on the type of cancer, how it was treated and your needs.

Make sure you tell your doctor about all the treatments you've had If you are at risk for cognitive problems, your doctor will ask you about your symptoms and how you are coping. You may have a physical exam and cognitive testing.

Ask your healthcare team questions at your appointments. You can also take a friend or family member with you to take notes so that you can read what was said after the appointment.