Motor Neurone Disease

Understanding nerves

Nerves (neurones) are like wires that carry tiny electrical impulses ('messages') between the brain, spinal cord, and the rest of the body.

• Motor nerves carry messages from the brain and spinal cord to muscles, and make the muscles contract.
• Sensory nerves carry messages of touch, temperature, sound, smell, and taste from various parts of the body to the brain.

What is motor neurone disease?

In motor neurone disease (MND), motor nerves become damaged and eventually stop working. Therefore, the muscles that the damaged nerves supply gradually lose their strength.

There are various 'sub-types' of MND. In each type, symptoms tend to start in different ways. However, as the disease progresses, the symptoms of each type of MND tend to overlap. So, symptoms in the later stages of each type of MND become similar.

The main types of MND are:

• Amyotrophic lateral sclerosis (ALS). This is the 'classical' MND and the most common type. About 7 in 10 people with MND have this type. Symptoms tend to start in the hands and feet. The muscles tend to become stiff as well as weak at first.
• Progressive bulbar palsy. About 2 in 10 people with MND have this type. The muscles first affected are those used for talking, chewing, and swallowing (the bulbar muscles).
• Progressive muscular atrophy is an uncommon common form of MND. The small muscles of the hands and feet are usually first affected, but the muscles are not stiff.
• Primary lateral sclerosis is a rare type of MND. It mainly causes weakness in the leg muscles. Some people with this type may also develop clumsiness in the hands, or speech problems.

How common is ALS-MND?

In the UK about one or two people in 100,000 develop ALS-MND each year. So, it is an uncommon disorder. There are about 5000 people in the UK with ALS-MND.

Who gets ALS-MND?

ALS-MND can affect anyone. ALS-MND is rare under the age of 40. It usually develops between the ages of 50 and 80. It is more common in men, affecting about three men for every two women.

• In over 9 in 10 cases, it occurs 'out of the blue'. In these cases there is no family history of the disease, and you do not pass it on to your children (it is not hereditary).
• In less than 1 in 10 cases the condition is hereditary, and may be passed on to some of your children.

What causes ALS-MND?

The cause is not known. It is thought that certain chemicals or structures that only occur in motor nerves are damaged in some way. The reason why the nerves become damaged is not clear. (It is also not clear why sensory nerves, which have a similar structure, are not affected.) There may be one or more environmental factors that may trigger the damage in someone who is susceptible to the disease. Research continues to find the underlying cause of the damage to the nerves.

What are the symptoms of early ALS-MND?

The main feature of ALS-MND is muscle weakness which gradually becomes worse. The first symptoms commonly develop in the hands and arms, or feet and legs. Less commonly, the first symptoms are in the bulbar muscles (muscles around the face and throat).

• Hand and arm symptoms. At first you may notice that your grip is less strong. You may drop things, and find it difficult to open bottle tops, turn keys, etc. Symptoms first begin in a hand or arm in about 8 in 10 cases.
• Feet and leg symptoms. At first you may start to drag one leg, or tend to trip easily. You may become easily tired when climbing stairs, or when walking.
• Bulbar muscle symptoms. You may not be able to shout or sing. Your speech may become slurred. There may be a change in the quality of your voice.
• Other symptoms that may occur include: muscle cramps, tiredness, regular 'twitching' of weakened muscles (fasciculation), jerking of an arm or leg whilst you are resting.

How do symptoms progress?

Symptoms may affect just one arm or leg at first. They then gradually become worse, and spread to involve other limbs. Eventually, many muscles in the body become affected. Some muscle groups may be more badly affected than others. Muscles gradually become weaker and wasted. The problems that develop may eventually include the following.

• Mobility (walking) typically becomes worse.
• Doing tasks with your arms and hands becomes increasingly difficult.
• Eating and swallowing becomes difficult when the tongue and muscles around the mouth and throat become weak.
• Sneezing and coughing become weak.
• You become breathless on minimal exertion when the chest muscles become affected.

The rate that the disease progresses can vary from person to person. Muscles weakened by ALS-MND do not recover. However, weeks or months may go by where the disease does not seem to progress. Eventually, severe disability develops. As the disease becomes severe, people with ALS-MND are unable to walk, talk or eat, and need a lot of care.

About 7 in 10 people with ALS-MND die within 3-5 years of the onset of symptoms. About 2 in 10 survive 5 years, and about 1 in 10 survive 10 years or more.

The cause of death is usually respiratory failure, combined with a chest infection (pneumonia) when the muscles used to breathe become very weak.

What is not affected in ALS-MND?

• Intellect does not usually change as the 'thinking' part or the brain is not usually affected. However, a rare sub-type of MND (about 3 in 100 cases) is associated with early dementia.
• Sensory parts of the nervous system are not affected so you can feel, see, smell, taste, and hear as before.
• Bladder and bowel function usually remains normal, so incontinence is not usually a feature. However, poor mobility may cause continence problems in the later stages of the illness.
• Emotional feelings and sexual desire are not directly changed by ALS-MND. However, some people with ALS-MND suddenly cry or laugh in inappropriate moments. (This is not a sign of mental illness, but a feature of ALS-MND and cannot be helped, although may be embarrassing when it occurs.) Also, depression and anxiety may develop as a reaction to the illness.

Are any tests needed?

There is no test that confirms ALS-MND. People with suspected ALS-MND are normally referred to a specialist (neurologist) for assessment. At first it may be difficult for a specialist to be sure that you have ALS-MND when early minor symptoms first develop. However, the diagnosis usually becomes clear as the typical symptoms and signs of the disease gradually become worse. Tests such as a brain scan or muscle tests may be done to rule out other causes of the symptoms if there is doubt about the diagnosis.

What are the treatments for ALS-MND?

There is no cure for ALS-MND, but treatments can help.

Riluzole - can modify the disease process a little

This medicine prolongs survival in some cases by a modest amount (on average, by 3-4 months). It works by blocking the release of certain chemicals involved with passing electrical impulses between nerves. This has some protective effect on the nerves, and slows down the disease progression.

Many people with ALS-MND also take vitamin E which may have a modest effect on disease progression. Research continues to find better medicines to treat ALS-MND.

Treatments to help ease symptoms and problems that develop with ALS-MND

Many different problems can develop in ALS-MND. It is beyond the scope of this leaflet to list all possible situations. Most people with ALS-MND are cared for by a professional team which include neurologists, specialist nurses, physiotherapists, speech and language therapists, occupational therapists, dieticians, counsellors, etc. Each problem that arises needs to be assessed, and dealt with as far as possible by the relevant members of the team. For example, some of the problems that may arise, and their treatments include the following.

• Medicines can ease some of the symptoms that may develop. For example:
  • Painful cramps can be eased by quinine.
  • Excessive fatigue may be eased by pyridostigmine.
  • Stiff muscles may be eased by muscle relaxants.
  • Excessive saliva that is difficult to swallow can be reduced by medicines.
  • Constipation is a common problem that can be eased with diet and laxatives.
• Physiotherapy can help to maximise mobility. This includes: providing splints, collars, and other supports to help with posture. Also, to help prevent joints from becoming stiff, and to advise on mobility aids when then become necessary.
• Occupational therapy can provide advice and aids to cope with activities of daily living that become difficult.
• Speech therapy and various communication aids can help you to communicate when speech becomes difficult.
• Dietary advice is often needed when feeding and swallowing become difficult.

Further help and information

This leaflet is only a brief introduction to ALS-MND. For further help and information contact:

Motor Neurone Disease Association
PO Box 246, Northampton, NN1 2PR
Helpline: 08457 626262 Web: www.mndassociation.org

Scottish Motor Neurone Disease Association
76 Firhill Road, Glasgow, G20 7BA
Tel: 0141 945 1077 Web: www.scotmnd.org.uk