Motor neurone disease is a rare condition that progressively damages parts of the nervous system. This leads to muscle weakness, often with visible wasting.

Motor neurone disease, also known as amyotrophic lateral sclerosis (ALS), occurs when specialist nerve cells in the brain and spinal cord called motor neurones stop working properly. This is known as neurodegeneration.

Motor neurones control important muscle activity, such as:

• gripping
• walking
• speaking
• swallowing
• breathing

As the condition progresses, people with motor neurone disease will find some or all of these activities increasingly difficult. Eventually, they may become impossible.

It's not clear what causes motor neurones to stop working properly. In about 5% of cases there's a family history of either motor neurone disease or a related condition called frontotemporal dementia. This is known as familial motor neurone disease. In most of these cases, faulty genes have been identified as making a major contribution to the development of the condition.

There's no single test to diagnose motor neurone disease and diagnosis is based mainly on the opinion of a brain and nervous system specialist (a neurologist). The diagnosis of motor neurone disease is usually clear to an experienced neurologist, but sometimes specialised tests are needed to rule out other conditions with similar features.

Read more about the causes of motor neurone disease and diagnosing motor neurone disease.

Progression of symptoms

The symptoms of motor neurone disease begin gradually over weeks and months, usually on one side of the body initially, and get progressively worse. Common early symptoms include:

• a weakened grip, which can cause difficulty picking up or holding objects
• weakness at the shoulder that makes lifting the arm difficult
• a "foot drop" caused by weak ankle muscles
• dragging of the leg
• slurred speech (dysarthria)

The condition isn't usually painful.

As damage progresses, symptoms spread to other parts of the body and the condition becomes more debilitating.

Eventually, a person with motor neurone disease may be unable to move. Communicating, swallowing and breathing may also become very difficult.

In up to 15% of cases, motor neurone disease is associated with a type of dementia that can affect personality and behaviour. This is called frontotemporal dementia, and is often an early feature when it occurs in motor neurone disease. The affected person may not realise that their personality or behaviour is different.

Who's affected by motor neurone disease?

Motor neurone disease is a rare condition that affects around two in every 100,000 people in the UK each year. There are about 5,000 people living with the condition in the UK at any one time.

The condition can affect adults of all ages, including teenagers, although this is extremely rare. It's usually diagnosed in people over 40, but most people with the condition first develop symptoms in their 60s. It affects slightly more men than women.

Treating motor neurone disease

There's currently no cure for motor neurone disease. Treatment aims to:

• make the person feel comfortable and have the best quality of life possible
• compensate for the progressive loss of bodily functions such as mobility, communication, swallowing and breathing

For example, a breathing mask can greatly help the symptoms of breathing and weakness, and a feeding tube (called a gastrostomy) helps maintain nutrition and overall comfort. If necessary, medication can be used to help control excessive drooling.

A medication called riluzole has shown a very small improvement in patients' overall survival, but it isn't a cure and doesn't stop the condition progressing.

Read more about treating motor neurone disease.

Survival rates

Motor neurone disease is a severely life-shortening condition for most people. Life expectancy for about half of those with the condition is three years from the start of symptoms. However, some people may live for up to 10 years, and in rarer circumstances even longer.

Living with motor neurone disease is extremely challenging and often a terrifying possibility before the diagnosis is made. However, it's not necessarily as bleak as people imagine.

With strong community and specialist support, many people can maintain some independence for a significant part of the condition's course, and experience a quality of life they may not have imagined was possible at the time of their diagnosis.

The end of life for someone with motor neurone disease isn't usually distressing and is most often in their own home. In most cases, a person with the condition will die in their sleep as the end stage of gradual weakness in their breathing muscles. Although some people with the condition will have swallowing problems, they won't choke to death.

Advice and support

The Motor Neurone Disease Association (MNDA) is the leading UK charity for people affected by the condition.

The MNDA can give you information, practical advice and support about living with motor neurone disease and coping with the emotional impact of being diagnosed. They've also produced a useful guide about living with motor neurone disease (PDF, 1.15Mb).

The MNDA also run a network of specialist hospital clinics across the UK, where a neurologist who's an expert in motor neurone disease can provide you with further information and advice.