Cognitive problems, also referred to as cognitive deficits or dysfunction, occur when a person has difficulties processing information, including mental tasks such as attention, thinking, and memory. Approximately 20% of people who undergo chemotherapy will experience some cognitive problem side effects, including children. The difficulties they face can vary in severity and can make it hard to complete daily activities. People who experience severe cognitive problems are encouraged to speak with their doctor and/or social worker about ways to manage the problems they face.

Symptoms

Cognitive problems include difficulties in many areas, such as:

• Difficulty concentrating or paying attention (short attention span)
  
  
• Memory loss or difficulty remembering things (especially problems with short-term memory)
  
  
• Problems with comprehension or understanding
  
  
• Difficulties with judgment and reasoning
  
  
• Impaired arithmetic, organizational, and language skills (such as not being able to organize thoughts, find the right word, or balance a checkbook)
  
  
• Problems performing multiple tasks (multitasking)
  
  
• Behavioral and emotional changes, such as irrational behavior, mood swings, inappropriate anger or crying, and socially inappropriate behavior (disinhibition)
  
  
• Confusion (delirium)

Of special note, "chemobrain,” sometimes called “chemofog,” is the term often used by cancer survivors to describe the cognitive problems experienced by some people after receiving chemotherapy. These people may experience long-term problems with mental skills such as memory, thinking, and concentration. People sometimes say that chemobrain feels like being in a mental fog.

Causes

Cognitive problems can be caused by many factors, including cancer, cancer treatments, medications, or other disorders:

• Brain cancer
  
  
• Other cancers that metastasize (spread) to the brain
  
  
• Chemotherapy, especially high-dose chemotherapy
  
  
• Radiation treatment to the head and neck, or total body irradiation
  
  
• Brain surgery, in which areas of the brain may be damaged or disrupted during a biopsy or the removal of a cancerous tumor
  
  
• Hormone therapy
  
  
• Immunotherapy (including interferon [Roferon-A, Intron A, Alferon N] and interleukin-2 [Proleukin])
  
  
• Medications, including some antinausea medications, antibiotics, pain medications, immunosuppressants, antidepressants, anti-anxiety medications, heart medications, and medications to treat sleep disorders
  
  
• Infections, especially those of the central nervous system (brain and spinal cord), and infections causing a high fever
  
  
• Other conditions or symptoms related to cancer or cancer treatments, including anemia, fatigue, stress, depression, insomnia, hypercalcemia (high blood calcium), and electrolyte (a mineral in your body, such as potassium and sodium) imbalances that can lead to dehydration or organ failure
  
  
• Not having enough of specific vitamins and minerals, such as iron, vitamin B, or folic acid
  
  
• Other brain or nervous system disorders unrelated to cancer

Management

Cognitive problems caused by a reversible condition, such as anemia or an electrolyte imbalance, usually resolve after the condition is treated. Likewise, problems caused by a medication should go away after the medication is stopped. Problems related to cancer in the brain usually improve with treatment, but some symptoms may continue. Unfortunately, cognitive problems related to chemotherapy (such as chemobrain), radiation therapy, or other cancer treatments can continue indefinitely. Management of these long-term cognitive problems may include:

• Medications, including stimulants (methylphenidate [multiple brand names]); cognition-enhancing drugs, commonly used to treat Alzheimer’s disease (donepezil [Aricept]); antidepressants; and opiate antagonists (naltrexone [ReVia])
  
  
• Occupational therapy and vocational rehabilitation, to help people with the activities of daily living and job-related skills
  
  
• Cognitive rehabilitation (also known as neuropsychological rehabilitation) and cognitive training, to help patients improve their cognitive skills and find ways to cope with cognitive problems

Suggestions for coping with cognitive problems

• Use a calendar or daily organizer to keep track of appointments, activities, and important dates.
  
  
• Ask people to repeat information and write down new information (names and phone numbers); use a tape recorder or take notes during conversations.
  
  
• Post reminders and make lists.
  
  
• Exercise your brain by doing brain-strengthening mental activities, such as solving crosswords or puzzles, painting, playing a musical instrument, or learning a new hobby.
  
  
• Physical activity can increase mental alertness. Try walking, swimming, doing yoga, or gardening.

Cognitive problems in children

Young children are especially susceptible to long-term cognitive set backs. These long-term deficits are most common in children who receive chemotherapy and/or radiation therapy that is directed to the central nervous system (CNS), such as head and neck radiation, total body radiation, and chemotherapy delivered directly into the spine (intrathecal chemotherapy) or the brain (intraventricular chemotherapy). CNS-directed chemotherapy and/or radiation therapy are most commonly used to treat CNS tumors, head and neck sarcomas, and acute lymphoblastic leukemia (ALL). Children who are treated before the age of five are most susceptible to cognitive deficits.

Long-term cognitive deficits can occur months or years after treatment ends and can continue into adulthood. Long-term cognitive deficits in childhood cancer survivors can include:

• Decreased overall intelligence (lower IQ)
  
  
• Learning disabilities
  
  
• Decreased attention span and attention deficit disorders
  
  
• Delayed development, including delayed social, emotional, and behavioral development
  
  
• Lower academic achievement (especially in reading, language, and mathematics)
  
  
• Decreased receptive and expressive language skills
  
  
• Decreased nonverbal and verbal memory skills

Children may be helped with occupational therapy, speech therapy, behavior therapy, social skills training, cognitive rehabilitation, and medications (such as methylphenidate for attention deficit disorders). Some children may need to learn new ways of learning in school or maintaining attention. Additional in-school options such as specialized reading and mathematics instruction, special education programs, and IEPs (individualized education programs) are also helpful. Because early intervention seems to offer the greatest benefit, it is important for parents to be aware of possible cognitive problems and to talk with their child’s pediatrician or oncologist as soon as they suspect a problem.

More Information

Rehabilitation

Late Effects of Childhood Cancer

Managing Side Effects

Additional resources

CancerCare: Chemotherapy Related Memory and Thinking Changes

Cancersymptoms.org: Cognitive Dysfunction

Lance Armstrong Foundation: Cognitive Changes