Two professionals examining a brain scan

This information is for health and social care professionals.

Some people with MND will experience changes in thinking, reasoning and behaviour. For many people the changes will be subtle and have little or no effect on daily life, but a small number of people will develop frontotemporal dementia (FTD) and need additional support.

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Cognitive change and frontotemporal dementia


People with MND appear to fall into four groups:

  • around 50% are unaffected by cognitive change
  • around 35% experience mild cognitive change, with specific deficits in executive functions, language and/or social cognition
  • up to 15% develop frontotemporal dementia (FTD), either at the same time or after diagnosis of MND
  • up to 15% of people diagnosed with FTD go on to develop MND. Symptoms of dementia may lead to FTD being diagnosed before movement is affected and MND is diagnosed.

There is a wide spectrum of changes in cognition in MND. Some people experience very mild changes, barely noticeable, whereas for others the changes can be more pronounced and obvious.

Other possible causes

Other causes of problems with thinking, memory and behaviour

It is important to rule out other potential causes of temporary confusion or problems with thinking, memory and behaviour, including infections, a build-up of carbon dioxide in the body caused by respiratory muscle weakness, mood and emotional lability.


Executive function

In those with MND affected by cognitive change, the most prominent impairment is in executive functions. This may lead to problems with:

  • setting and achieving goals
  • planning and problem solving
  • responding to new situations
  • shifting attention or dividing attention between different tasks
  • initiating and inhibiting responses.

Some people also show changes in their ability to understand and produce spoken or written language. Some researchers have questioned whether language changes may be at least as common as executive function changes.


Behavioural impairment is a recognised feature of MND and problems may include socially inappropriate behaviour, disinhibited comments, impulsivity, apathy and inertia, loss of sympathy and empathy for others, and perseverative, rigid, stereotyped or compulsive behaviour. People who are cognitively normal can have profound behavioural abnormalities.

Social cognition

Understanding and interpreting other people’s thoughts/beliefs/feelings. Changes in social cognition can be challenging for carers/family of people with MND, as well as for health and social care professionals.

Unaffected aspects of cognition

Memory (acquiring, retaining and retrieving new information) is not usually affected, although some people may experience problems with their memory as a secondary consequence of executive dysfunction, along with problems with attention.

Problems with perception (dealing with the information gathered by the five senses) are rarely seen.

Frontotemporal dementia (FTD)

A small but significant minority of people experience severe changes that will be diagnosed as frontotemporal dementia (FTD). These changes are most often in behaviour and executive skills, but sometimes they are in language or conceptual understanding.

There will be some people who first present with symptoms of FTD and then go on to display symptoms of MND. In this group, the dementia may mask physical symptoms, because of the person’s difficulty recognising and verbalising that something is wrong; hence the importance of physical examination.

Understanding the level of cognition of the person with MND is crucial to help them and their family to cope with what may lie ahead, including being able to make timely decisions about treatment and care.

The family may experience relief when cognitive and behavioural changes are professionally acknowledged, and the relationship to MND is properly attributed and explained.

Assessments can lead to suggestions of how to help minimise any confusion and frustration that the changes are presenting. Any management of changes in cognition and/or behaviour should always involve the person with MND, together with their family and carers.

Assessment methods

Methods commonly used by professionals include:

  • interview
  • functional assessment
  • standardised screening measure of cognition and behaviour
  • informant-based behavioural questionnaires
  • assessment according to current criteria for MNDbi (behavioural impairment), MNDci (cognitive impairment) and MND-FTD.

A formal, detailed assessment should be undertaken by a clinical neuropsychologist where available.

Assessment tools include:

  • The Edinburgh Cognitive and Behavioural ALS Screen (ECAS) tool has been designed specifically as a first step in assessing the presence of cognitive change in MND. The tool is designed to take 20 minutes to complete by any health or social care professional, including non-neuropsychologists. It can be used to screen people to see whether they would benefit from a full neuropsychological assessment.
  • The MiND-B is a simple tool for the identification and quantification of behavioural symptoms in ALS. It measures three behavioural domains: apathy, disinhibition and stereotypical behaviour.
  • The M-ACE is a brief and sensitive cognitive screening tool for dementia. Unlike the ECAS tool, it is not specific to MND.

Supporting people affected by cognitive change and FTD

Some people with MND will experience changes in thinking, reasoning and behaviour. For many people the changes will be subtle and have little or no effect on daily life, but a small number of people will develop frontotemporal dementia and need additional support.

Being alert to the possibility of cognitive and/or behavioural change at any stage of MND can be valuable, as these changes may have an impact on service use and decision making.

Management of people who show signs of cognitive impairment should focus on forward planning and organising appropriate support strategies for them and their families/carers.

Professionals who can support

If cognitive change has been identified, it is important to alert all members of the multidisciplinary team, allowing them to react and implement any changes needed in care planning.

If the person is not already in contact with them, it may be useful to refer to occupational therapy (for strategies and equipment to manage activities of daily living) or speech and language therapy (for strategies and equipment for communication).

The following services may be referred to for home support:

  • GP
  • palliative care team
  • community mental health team
  • old-age psychiatry services
  • young-onset dementia services
  • local multidisciplinary team.
Advance care planning

Many people living with progressive illnesses such as MND fear losing control and not being able to make their own care decisions. Discussion of advance care planning is recommended, particularly if cognitive change is identified.

Supporting carers and family members

Supporting carers is vital. Their individual needs may be complex depending on the severity of cognitive and/or behavioural change in the person with MND.

Cognitive and behavioural change is a symptom for which many carers feel unprepared, especially as many people will not have been told that this can occur as part of MND. Clear explanations and instruction can help. The needs of carers and family members should be assessed and support strategies advised.

A clear and detailed care plan is essential, so the carer feels supported and reassured that they have been listened to and that instructions are consistent and sensitively understood.

Aggressive behaviour

Professionals must be aware of the risks to carers and family where behavioural changes include aggression.

A combination of lack of empathy and self-seeking behaviour may lead to carers and family or the person themselves being in danger, especially if the person has retained mobility. Situations such as these will be challenging for professionals, as well as carers, and day-to-day management must be considered.

Page last updated: July 2021
Next review: July 2023