Forgetfulness and thinking

MND rarely leads to any major changes in mental capacity though in the last few years new research has shown that more people than previously realised do experience some minor changes, including: 

• Forgetfulness and reduced concentration 
• Language problems, including remembering words and spelling
• Problems learning new things
• Difficulties with planning and decision-making
• Impulsive behaviour.

These changes may affect 20-30% of people, or possibly up to 50%, but they are likely to be mild, and the great majority of people living with MND do not need to worry that their mental capacity will be seriously affected. (A very small proportion, perhaps 2-3%, will experience a form of dementia).

Most people we talked to had not noticed any major changes in their mental capacity, although tiredness and difficulty in concentrating were common - tiredness is explored further in 'Tiredness, pain and discomfort'. Many valued the fact that even though their physical strength had been affected their mind seemed as clear as ever. Some even felt their mind was sharper. One man who was working full-time as well as doing a part-time PhD explained why this was important to him.

It is important to him that his mind is unaffected and he can continue to work in the same job.

However, a few people had noticed changes in themselves or a family member with MND. One man said during his interview, “There are words that I can't get and words that I can get….I can't find the words for when I'm talking to you.” He described a recent event when he had become confused, and how his concentration had been affected.

He recently had a 'funny turn' and became confused. He finds it harder to do crosswords or read a book now.

Often changes may be more obvious to a carer than to the person themselves. Some carers had noticed changes before diagnosis and thought at first it might be because of old age. It is important for carers to know of the possibility of minor changes, so they understand why their relative's behaviour has changed, and perhaps feel less frustrated or upset by it. 

Her husband's thinking has slowed down. He gets anxious and stressed when they try to plan arrangements too far ahead.

Even before diagnosis she noticed her husband had become forgetful and slow. The family described it as 'dithery'.

It is important to be aware that not all changes in behaviour are a sign of mental or cognitive impairment. They may also happen as a result of depression, or 'emotional lability' - this is a term used to describe a tendency to laugh or cry unexpectedly at what might seem the wrong moment, which affects some people living with MND. These are explored more fully in 'Emotional lability, depression and low mood'. Both depression and emotional lability can be treated.

Cognitive Change

Initially, it was thought that Motor Neurone Disease (MND) only affected the nerves used to control muscles. Research has given a better understanding of changes in the brain that affect thinking, emotion and behaviour. These changes are describe as cognitive change. For further information about cognitive change, see the MND Association's website 'Cognitive Impairment in MND: Information for Carers' information sheet 23.

Last reviewed March 2012.

Last updated March 2012.