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Cognition and brain tumours

The physical presence of a brain tumour can impact your cognitive abilities, also known as "thinking skills", including difficulties learning, concentrating, problem solving, planning and decision making.

Thinking difficulties are a common side-effect experienced by people living with a brain tumour or receiving certain tumour treatments. 

This can be very mild and may not be immediately noticeable, only coming to light when you attempt complex tasks or if you return to work. You might simply feel that your memory or mental functioning has "slipped" but it won't generally impact your daily life.

If the impairment is more severe, however, it may make some aspects of daily life difficult and you may require support. 

Visit our coping with cognitive difficulties page to find strategies and tips for lessening the impact that thinking difficulties has on your life. 

What sort of thinking difficulties might I develop?

It’s important to remember that not everyone with a brain tumour will have thinking difficulties and, if you do, you’re unlikely to experience all of these effects.

Attention and concentration

You may become easily distracted and find it difficult to keep focused on a task over a long period of time. This can include losing the thread of conversations or starting tasks and not finishing them.

Another common symptom is not being able to concentrate when more than one thing is happening, for example, when you are in a crowd, or several people are speaking at once.

You might find the effort to overcome these difficulties can be extremely tiring as you try to focus and concentrate.

    Social cognition

    Social cognition refers to our ability to understand social situations and behave in an appropriate way - this can include knowing when to talk, when to listen and how to respond appropriately. It can also make it difficult for someone to understand humour.

    This type of thinking difficulty can cause people can lose their inhibitions. This can lead to them becoming inappropriately elated or depressed, acting uncharacteristically vulgar or being overly argumentative or passive. Unfortunately, those affected are often unaware they are behaving inappropriately or might show little regard for the consequences. 

    If your social cognition is impacted by a brain tumour it can be extremely isolating and it can affect your relationships and ability to work. Some people may find it difficult to understand these changes in behaviour or may think you are being unreasonable.

      Learning & memory

      Memory difficulties are usually with short-term memory, while long-term (old) memories are retained. This can mean that you may have trouble learning new things or remembering recent things, such as recent conversations.

      You may also have difficulty remembering to do things, such as keeping an appointment.

      Executive functions

      Executive functions are the high-level processes of the brain (cognitive functions) that include planning, organising, solving problems, making decisions and reasoning.

      Examples of how this could show itself include:

      • Not going to the supermarket to get more food without being reminded.
      • Impulsively buying things that you don't need or can't afford.
      • When shopping, not being able to decide on suitable substitutes, such as butter instead of margarine.
      • Being unable to cook ingredients to be ready at the same time.
      • Not being able to put the laundry out to dry whilst still remembering to attend to the cooking.
      • Difficulties in controlling your emotions, leading to rapid mood changes.

      For some people, these thinking difficulties can result in being fixated on one thing, having an inability to plan ahead or making it harder to learn from previous experiences. If you have difficulties with making decisions, you may also make decisions that appear spontaneous or out of character.

      Thinking speed

      You may feel that you’re not able to think as quickly as usual, making tasks longer to complete. This can make it more difficult to keep up with conversations and your reaction times may be slower than usual.

      Communication skills

      Their are many ways that a brain tumour can affect your ability to communicate with others and you can find detailed information about this on our communication difficulties page

      The following examples are a few ways cognitive difficulties might impact your communication skills or make it difficult to express your thoughts:

      • Misinterpreting body language.
      • Finding it harder to read or write.
      • Difficulty understanding numbers (written and spoken).
      • Forgetting, mispronouncing or using the wrong word, or putting words in the wrong order. 
      • Difficulty understanding words that you hear, particularly if the words are abstract, or if there’s noise or any other distraction.


      Perception is the process of taking in information from the world around you, organising that information and forming an understanding based on it - a brain tumour can cause difficulties forming that understanding.

      This can include difficulties recognising objects or understanding their function, judging distances or carrying out a movement or task, even if you understand what you need to do.

      Some terms you may hear in relation to brain tumours and perception are:


      A rare disorder that affects a person’s ability to recognise objects, people, words and sounds. 

      Although someone with agnosia will see or hear something, the sight or sound is stripped of its meaning. As a result, they may confuse the function of the object, e.g. they may use a comb as a fork or vice versa.


      A disorder of the brain and nervous system where a person has difficulty carrying out a movement or task, even if they understand what they need to do. Apraxia is also known as dyspraxia and can make tasks, such as pouring water from a kettle, very difficult - often making the person appear clumsy.

      In the UK, apraxia means the complete loss of the ability to co-ordinate movements, while dyspraxia refers to partial loss of this ability. However, other countries apply the terms in various ways.

      Some perception difficulties include visual problems, such as being unaware of objects around you because of reduced sight on one side of your field of vision. You can find detailed information about this on our sight difficulties page.

      What can cause thinking difficulties?

      There are various factors that affect how likely you are to experience thinking difficulties and what problems you might have, including the location of a tumour and the treatment you receive.

      Location of tumour in the brain

      Each section of the brain is responsible for different functions, some of which are complex and wide-ranging. As a result, the likelihood and type of thinking difficulty someone might experience will be affected by the physical location of the tumour.

      You can find more detailed information about this on our symptoms based on tumour location page.

      However, it is important to remember that this division is not definitive and that tumours in one area can cause thinking difficulties listed under another area.

      Brain tumour treatments

      Surgery, radiotherapy and chemotherapy can all interfere with your memory or your thinking and reasoning abilities, at least temporarily.


      In some cases, the removal of the tumour and the pressure it was causing on the brain, can lead to an improvement of cognition.

      However, it can also lead temporary cognitive difficulties caused by swelling and increased pressure in the brain. Steriods may be given to help reduce the swelling quicker, lessening the impact of any thinking difficulties.

      It's important to remember that the purpose of surgery is to remover as much of the tumour as possible and any removal of brain tissue can affect the cognitive function controlled by that area of the brain.

      Learn more about brain surgery.


      Although radiation to healthy cells is kept to a minimum, radiotherapy can damage the blood supply to brain cells in the treated area. This can cause swelling or fluid retention and press on the brain, which is called 'radiation induced encephalopathy'.

      It can also cause a shortage of oxygen and nutrients to the brain cells, which, over time, can lead to the cells dying. You may hear this called 'radionecrosis'. As a result, thinking difficulties can develop months, or even years, after radiotherapy treatment. It can also cause any existing impairment to get worse over time.


      Regularly referred to as "chemo brain" or "chemo fog", people receiving chemotherapy often experience difficulties with memory and concentration, after having chemotherapy are common. The changes are usually mild, but can affect your quality of life.

      Find out more about chemotherapy.


      It's important to remember that you should never stop taking prescribed medication suddenly. 

      You should always speak to your healthcare team about any side-effect you are experiencing, including thinking difficulties, and they will work with you to develop a more suitable treatment plan.


      When steroids are prescribed they often reduce pressure on the brain caused by swelling or retention of fluid, thereby improving cognitive function. However, they can also cause mood disturbances, difficulty concentrating and memory problems.

      A small number of people may also experience steroid-induced psychosis if given high doses of steroids while in hospital.This can include periods of hypermania, where you may become prone to making impulsive or rash decisions, alternating with periods of depression. These effects are usually temporary but you should alert your healthcare team if you experience any of these symptoms.

      Anti-Epileptic Drugs

      Some older AEDs (Anti-Epileptic Drugs) have been known to cause thinking difficulties that affect someone's memory, ability to concentrate and executive functioning, such as slowness in thinking. Newer generation AEDs are less likely to cause cognitive difficulties and have fewer effects when they do.

      Over the counter medicines

      Although you can buy over the counter medicines without a prescription, they can still cause thinking difficulties. You should talk to your healthcare team about potential side-effects or reactions with other medication before taking over the counter medicines.

      Other factors that contribute to thinking difficulties

      The following are some of the more common factors that contribute to thinking difficulties if you're living with a brain tumour.


      As well as AEDs, seizures themselves are thought to have an effect on cognitive functioning. People with brain tumours and epilepsy have been found to have slower processing speeds and problems with attention and executive functioning.

      People with epilepsy seek help for memory problems more often than for any other thinking difficulty. This is possibly because the temporal lobe is often involved in seizures, as well as being important in memory functions.


      One of the most common side-effects of living with a brain tumour is fatigue, which is a well-known cause of thinking difficulties. Fatigue can have a significant impact on memory, concentration and ability to plan and organise, as it can deplete the energy required for these functions.

      Emotional or psychological factors

      A brain tumour diagnosis is a huge life event that can often impact on a person's mental health. Mental illnesses like depression or anxiety may negatively affect cognitive functions, such as motivation, concentration and memory.


      Brain tumours and many tumour treatments can affect your appetite, making you feel like you don't want to eat. However, not eating can actually make thinking difficulties worse and cause you to be more fatigued.

      Visit our diet page to find out more.


      Alcohol has a general depressive effect on the brain and can cause many thinking difficulties. This includes slower thinking or reaction times, reduced reasoning or inhibitions and memory problems. It's therefore advisable to avoid alcohol.

      Are there any treatments available for thinking difficulties?

      While there’s no simple cure for thinking difficulties, you can work with your healthcare team to help improve your cognitive functioning or develop coping strategies that will lessen the impact on your day-to-day life.

      For example, if you’re having seizures, your health team can work with you to find an anti-epileptic drug that best reduces the effect of the seizures. Similarly, they will select an AED that’s less likely to add to your cognitive burden.

      Dosages of medications, such as steroids, can also be altered if they’re believed to be causing additional cognitive effects or making existing effects worse.

      Your healthcare team can also identify whether your problems are made worse by other underlying factors, such as depression or anxiety, and help to address these.

      You can also find more information on our coping with cognitive difficulties page or join one of our closed Facebook groups and get some tips from other people affected by brain tumours.

      Get support

      If you need someone to talk to or advice on where to get help, our Support and Information team is available by phone, email or live-chat.

      Living with memory loss

      Jennifer's shares her experience of memory difficulties after being diagnosed with a brain tumour.

      If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:

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