Overview of cognitive and behavioural change and FTD
Some people with motor neurone disease (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.
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.
Cognitive changes can affect:
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.
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.
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.
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.
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.
Find out more
More information about cognitive change and FTD can be found in our booklet for health and social care professionals:
Contact MND Connect if you have any questions about MND and supporting people with the condition.
Other useful resources