Motor neurone disease Dr Rob Hicks Motor neurone disease (MND) is a progressive condition that damages the nervous system, leaving muscles wasted and weak.

In this article

Who's affected? What causes it?

What are the symptoms? What's the treatment?

Advice and support

MND tends to affect people over 40 and is most common between the ages of 50 and 70. There are about 5,000 people with MND at any one time in the UK.

The condition affects twice as many men as women. One or two people in every 100,000 will be diagnosed each year.

The exact cause of MND remains a mystery. It can run in families and for this reason one of the causes is presumed to be genetic. Damage to the nerves occurs, but why remains unclear. One theory is that molecules called free radicals are responsible for this damage.

Some evidence has shown that an excess of glutamate (a major nervous system chemical messenger) may be responsible for nerve damage. Glutamate plays an important role in the fast transmission of nerve signals.

When too much is present it can become 'excitotoxic', which means it's overactive and overstimulating. This is thought to damage key areas of the brain and spinal cord, resulting in the symptoms of MND.

Over time the cells responsible for transmitting the chemical messages that enable muscle movements become injured and subsequently die. This causes muscle weakness and wasting to develop.

The muscles of the hands, arms and legs are usually affected first. Someone may notice they drop things accidentally or find actions such as turning on a tap difficult. They may feel unbalanced and wobbly, and find themselves falling as their legs go from under them.

The affected muscles may become twitchy and stiff, and painful cramps may occur from time to time. As the muscle weakness gets worse, climbing stairs or getting up from sitting becomes difficult without some help.

As the disease progresses, the muscles of the mouth and throat may be affected. Speech may become slurred and because swallowing may be difficult, food particles find their way into the lungs, causing recurrent chest infections.

Neck muscles become weakened, such that a person's head cannot be supported and falls forwards.

Eventually, the disease interferes with the muscles involved in breathing. Although treatments can be given to make breathing easier, respiratory failure is usually the cause of death in this always fatal illness.

Unlike other neurological conditions, in MND the bladder and bowel functions are not affected, and it doesn't affect hearing, vision or intellect.

Many people with MND say the fact they're aware of what's happening to their body is the worst part of the disease.

It isn't possible to prevent MND from developing. Treatment can slow down the progression of the disease for some people and occupational therapy can help to overcome difficulties.

Treatment involves a package of measures tailored to the individual. Several specialists are needed to provide this care. Physiotherapy helps improve the flexibility of muscles and joints, while aids such as walking sticks, wall rails and stair lifts can help to maintain independence.

When speech and swallowing become a problem, a speech therapist can advise how best to cope. It's important a doctor specialising in MND is involved to ensure the most up-to-date support is provided.

As and when secondary problems arise, then appropriate treatments can be given. For example, depression can be treated with antidepressant medication and emotional support.

A patient's family and carers also need support. Caring for someone with such a distressing, debilitating disease, which kills most of those affected within five years, puts a great strain on relationships. People with MND and those caring for them are encouraged to get involved with local support groups.

Motor Neurone Disease Association
Helpline: 0845 762 6262
Email: enquiries@mndassociation.org
Website: www.mndassociation.org

Scottish Motor Neurone Disease Association
Tel: 0141 945 1077
Email: info@scotmnd.co.uk
Website: www.scotmnd.org.uk

This article was last medically reviewed by Dr Rob Hicks in May 2008