Symptoms of the disease
Symptoms of the disease
MND is a progressive disease that can have an impact on an individual’s ability to walk, talk and limit their capacity to live independently. The disease varies enormously from person to person, and the symptoms described here are not always seen in everyone.
Initially, symptoms of MND may be subtle and can be mistaken for other unrelated conditions. The muscles first affected tend to be those in the hands, feet and mouth, although this is dependent on which type of the disease the person has. The first symptoms normally occur in the arm or leg, and this is true of around two-thirds of those with the disease. These initial symptoms are usually painless.
Symptoms can include:
- a weakened grip, which can cause difficulties picking up or holding objects
- weakness at the shoulder, making lifting the arm above the head difficult
- tripping up over a foot because of weakness at the ankle or hip
- widespread twitching of the muscles (fasciculations) or muscle cramps
- visible wasting of the muscles with significant weight loss.
For around a quarter of those with the disease, they may initially experience problems affecting muscles used for speech or swallowing. Symptoms can include:
- increasingly slurred speech (dysarthia)
- increasing difficulty swallowing (dysphagia).
MND can start by affecting the lungs, but this is very rare – only in around 3% of cases. The symptoms may include breathing difficulties and acute shortness of breath.
As the disease progresses, the limbs become weaker and the muscles may appear progressively wasted. The muscles may also become stiff – this is known as spasticity.
Speaking and swallowing difficulties
Around 80% of people with MND will at some point experience speech difficulties, and two thirds will experience problems with swallowing. They may also experience choking episodes.
Due to reduced swallowing, there may be excess saliva which can cause drooling. Alternatively saliva can be thicker than normal, making it difficult to clear from the chest or throat, as the muscles that control coughing have been weakened.
MND can cause episodes of uncontrollable, excessive yawning, even if the individual is not tired. This can sometimes cause jaw pain.
It can be quite common for a person to have episodes of sudden uncontrollable crying, or, more rarely, laughter. There is often no connection between these episodes and a person’s actual emotional state. It is an response caused by the effects of MND. Doctors may call this emotional lability or emotionality.
MND can also cause stress and anxiety, for those living with disease. These may include:
- insomnia, or
Changes to cognition and behaviour
Of those people living with MND:
- around 50% are unaffected by cognitive change
- around 35% experience mild cognitive change, with specific deficits in executive functions, language, behaviour and/or social cognition
- up to 15% develop frontotemporal dementia (FTD), either at the same time or after diagnosis of MND.
Cognitive change may manifest in many ways, such as problems with learning new tasks, short-term memory loss, lack of awareness or insight into their problems or their impact, poor concentration, inappropriate social behaviour. Not all of the above may be evident and they can vary in degree. Changes can be subtle and may be masked by movement and speech problems. Some may be part of the normal ageing process.
Behavioural changes may include egocentric or selfish behaviour, loss of interest, apathy, disinhibition, irritability, aggression and absence of insight into these changes. It is important to note that people with no cognitive changes can have profound behavioural abnormalities. And it is unlikely that someone experiencing these changes will know this is happening or can acknowledge the change.
FTD is a more severe form of cognitive and behavioural change manifesting as significant personality change and marked executive dysfunction. Changes in behaviour of the person living with MND can be distressing for people around them, including those who care for them. They may show a lack of empathy, emotional understanding or even lose their inhibitions which can make caring for them more difficult.
As the nerves and muscles that help control the lungs become weakened, breathing becomes harder. A simple activity such as walking can make the individual short of breath. Breathing can be particularly troublesome at night when people are lying down. Any interruption can cause the individual to wake up and lose sleep, resulting in increased drowsiness during the day.
As MND progresses to its final phase, a person may experience:
- increasing paralysis, which means they’ll need help with most daily activities
- significant shortness of breath
- Eventually, even with assistance, breathing may not be sufficient to keep the lungs functioning. Most people with MND become more and more drowsy before falling unconscious due to rises in carbon dioxide levels, causing the heart to stop and then they die.
MND does not affect the senses, so touch, taste, sight, smell and hearing remain intact. Bowel, bladder or sexual function are not directly affected by the disease, however lack of mobility may effect the person’s ability to maintain these functions independently. Some people with MND have additional symptoms that aren’t directly caused by the condition, and some that are related to the stress of living with it.