Facts About MND

Download MND: Some Facts

Motor Neurone Disease (MND) is the name given to a group of closely related disorders which affect the motor neurones.  Motor neurones are nerve cells which control the voluntary movement of muscles.

Upper motor neurones run from the brain to the brainstem or spinal cord to connect with lower motor neurones.  Lower motor neurones then travel out to connect with the muscles for swallowing, chewing, tongue movement, facial expression, breathing, coughing and limb movement.

Degeneration of the motor neurones result in progressive muscle wasting and weakness because the nerve supply to the muscles is impaired.

• MND is an uncommon, but by no means rare disease.
• The number of people living with MND at any one time is approximately one in 15,000. In New Zealand over 300 people are living with MND.
• MND affects people from all communities.
• MND can affect adults at any age but most people diagnosed with MND are over the age of 40, with the highest incidence occurring between the ages of 50 and 70.
• Slightly more men than women get MND.
• A person’s lifetime risk of developing MND is up to 1 in 300.
• Most people with MND live for 20 to 48 months after symptoms begin. Five to ten percent of people with MND live for ten years or more.
• Each week MND will cause the death of 2 people in New Zealand.
• In approx. 90% of cases there is no known family history.
• In approx. 10% of cases the disease is known to be inherited.
• Around 15% of people with MND eventually show signs of frontotemporal dementia.

For more information, please download a PDF of our booklet, MND: Some Facts. If you or someone you care for has MND, you can request a print version of this booklet from your support team member.

For up-to-date information about what we currently know about the causes of MND, please see What Causes MND?

For current information about research towards a cure for MND, please see our Research Resources.

• In New Zealand an average of 144 people* are diagnosed with MND every year – about 3 in every 100,000 people. Internationally, the incidence of MND is much lower (approximately 2 in every 100,000 people).
• About 315 people* in New Zealand are living with MND.
• Worldwide, 4 to 5 million people now alive today will die from MND.
• The median age of onset of MND in New Zealand is 67 years old*.
• 35% of people with MND in New Zealand* are aged under 65.
• 58% of people with MND in New Zealand* are male. 42% are female.
• Each year MND causes the deaths of an average of 112 people* in New Zealand.
• In 2011, one in every 202 deaths in New Zealand was caused by MND.
• A person’s lifetime risk of developing MND is up to one in 300 (reference: Table 2, Johnston 2006).

We don't know why the rate of MND in New Zealand is higher than the international average. There could be genetic reasons, environmental factors, or our health system could be better at diagnosing people with MND – or some combination of these factors.

* Numbers are calculated from only those people with MND who register as clients of MND New Zealand during 2017-18. We estimate about 90% of people with MND in New Zealand register with MND New Zealand.

What are the symptoms of MND?

Early symptoms are mild and may include stumbling due to weakness of the leg muscles, difficulty holding objects due to weakness of the hand muscles, and slurring of speech or swallowing difficulties due to weakness of the tongue and throat muscles.

Cramps and muscle twitching are also common symptoms.

Emotional responses may be more easily triggered and the person with MND may be aware of laughing and crying more readily than previously.

For some people, the symptoms are widespread from the onset. However MND usually begins by affecting a single limb or aspect of motor function, becoming more generalised as the disease progresses.

There is no specific test for MND. Diagnosis requires eliminating other possible conditions.

Diagnosing MND is difficult because:

• the early symptoms can be hardly noticeable, eg clumsiness, stumbling or slightly slurred speech, and it may be some time before medical advice is sought,
• the disease affects everyone differently, and
• several other neurological conditions resemble MND, in the early stages especially, and need to be excluded.

How MND is diagnosed

If your general practitioner (GP) suspects a neurological problem, you will be referred to a neurologist who does the diagnosis. To improve timely referrals MND NZ has a Red Flag MND Diagnosis tool to help GPs.

If your neurologist believes there is cause for concern you may be sent for a series of diagnostic tests which may include the following:

Electromyography (EMG)

This test is sometimes called the needle test, because fine needles are used to record the naturally-occurring nerve impulses within certain muscles. Muscles that have lost their nerve supply can be detected because their electrical activity is different from normal healthy muscles. Recordings are usually taken from each limb and the bulbar (throat) muscles. The EMG can be shown as abnormal even if that particular muscle is as yet unaffected.

Nerve Conduction Test

An electrical impulse is applied through a small pad on the skin, which measures the speed at which your nerves carry electrical signals. This test may be carried out at the same time as the EMG.

Transcranial Magnetic Stimulation (TMS)

This procedure is designed to measure the activity of the upper motor neurones; its findings can help in the diagnostic process. It may be carried out at the same time as a nerve conduction test.

Magnetic Resonance Imagery (MRI) scans

This involves lying flat in an MRI scanning machine. An MRI scan will not diagnose MND, because the damage caused by MND does not show up on this scan. It is a tool for eliminating other conditions that can mimic symptoms of MND.

Blood Tests

A blood test will be looking to see if there is a rise in levels of creatine kinase. This is produced when muscle breaks down and can occasionally be found in the blood of people with MND. It is not specific for MND and may also be an indicator of other medical conditions.

Other tests

There are several other tests your neurologist may request if the clinical findings indicate they could be useful.

Motor Neurone Disease can be classified into four main types depending on the pattern of motor neurone involvement and the part of the body where the symptoms begin. There can be an overlap between all of the different types so, while it is useful to classify the various types of the disease, in practice it is not always possible to be so specific.

Amyotrophic lateral sclerosis (ALS)

ALS is the most common type of MND, with both upper and lower motor neurone involvement. ALS is characterised by muscle weakness and stiffness, over-active reflexes and, in some cases, rapidly changing emotions. Initially the limbs cease to work properly. The muscles of speech, swallowing and breathing are usually also later affected.

Progressive bulbar palsy (PBP)

Mixed bulbar palsy and pseudo-bulbar palsy are forms of progressive bulbar palsy that involve the muscles of speech and swallowing. The nerves that control these functions are located in the bulb (the lower part of the brain), hence the term bulbar palsy (paralysis). The limb muscles may also later be affected. PBP affects about a quarter of people diagnosed, and involves both the upper and lower motor neurones.

Progressive muscular atrophy (PMA)

Progressive muscular atrophy affects only a small proportion of people, and has a slower rate of progression and longer survival compared to ALS and PBP types. It mainly causes damage to the lower motor neurones. Early symptoms may be noticed as weakness or clumsiness of the hand. Characterised by absent reflexes, muscle wasting and weakness.

Primary lateral sclerosis (PLS)

PLS is a rare form of MND involving the upper motor neurones only, causing mainly weakness in the lower limbs, although some people may experience clumsiness in the hands, or speech problems. Life span could essentially be normal, although in some cases PLS develops into ALS. Diagnosis is often provisional.

Upper vs lower motor neurons

Normally, messages from nerve cells in the brain (called upper motor neurons) are transmitted to nerve cells in the brain stem and spinal cord (called lower motor neurons) and from them to particular muscles.

Lower motor neurons control movement in the arms, legs, chest, face, throat, and tongue. When there are disruptions in the signals from the lower motor neurons, the muscles do not work properly. The muscles gradually weaken, and may begin wasting away and develop uncontrollable twitching (called fasciculations) and muscle cramps.

Upper motor neurons direct the lower motor neurons to produce movements such as walking or chewing. When there are disruptions in the signals from the upper motor neurons, the limb muscles develop stiffness (called spasticity), movements become slow and effortful, and tendon reflexes such as knee and ankle jerks become overactive. Over time, the ability to control voluntary movement can be lost.

Most motor neurone disease (MND) is sporadic. This means that it does not run in families. Only 10% of MND is estimated to be inherited.

In this small number of cases, there is a family history of MND and/or frontotemporal dementia. Where this occurs, the disease is caused by a mistake in the genetic code which can be passed down, although other triggers are still necessary for the disease to emerge.

If you are concerned about the possibility of a family history of MND and what that could mean for those close to you (in terms of inheriting the genetic code), you may wish to seek genetic counselling.

Genetic counselling in New Zealand

The Genetic Health Service NZ sees people where a mutation is already identified in their family, or to assess a family that has not had any testing. Testing needs to start in a family member with a clinical diagnosis of MND or dementia, as this gives the most information for a family.

A family has to have two or more first-degree (eg parent or sibling) or second-degree (eg grandparent, aunt, uncle) relatives with MND and/or early onset dementia to qualify for an assessment. All appointments are funded for New Zealand residents who meet referral criteria. A referral can come from a GP or specialist.

Genetic testing identifies the cause in around 30% of familial MND. This means for many families the genetic cause remains unknown. When a mutation is known in a family, at-risk relatives can make an appointment for pre-symptomatic testing.

The first pre-symptomatic testing appointment with the Genetic Health Service will look at the family history, the inheritance pattern, the person’s motivation for testing, and the effects of testing on relationships. We later meet in person to review the results.

Some people stop the process after the first or second appointment as they decide they do not want to know, or want to delay knowing their result. As there is no cure for MND, many people do not wish to know their status. Others feel they need to know their result to properly plan for the future and make the most of their time.

Choosing to be tested or learn your status can be a very difficult decision, as it affects the wider family. The timing of the test can be very important. Two of most common times people seek genetic testing is before they have children, or before they have grandchildren.

The New Zealand government provides funding for family planning options such as testing during a pregnancy, or with IVF pregnancy, testing embryos known as Preimplantation Genetic Diagnosis (PGD). Both these testing options can only be done if a family’s genetic mutation is known. A separate appointment with the Genetic Health Service is required to thoroughly discuss family planning options and the PGD process. There is a substantial waitlist to access PGD at present. This will be discussed when the couple is seen by a fertility clinic.

Although sensitive to the emotional aspects of the situation, genetic counselling is not a form of psychotherapy. A genetic counsellor explains the facts as clearly as possible, and gives you accurate information on the implications for your family.

If you chose to undergo genetic testing, there may be an impact on your ability to obtain new insurance policies. You would have to declare genetic test results or family history if asked, and it may mean that you would not be covered for anything to do with MND and that your premiums become higher. This may not be an issue for you if you have insurance in place already. It may be advisable to speak to an independent financial or insurance advisor.

Genes that cause inherited MND

We know approximately 70% of the genes known to cause inherited MND. Currently, testing is only available for four of the genes that play a part in inherited MND:

• SOD1, discovered in 1993, accountable for 20% of cases of inherited MND
• TARDBP, discovered in 2008, accountable for 3-5% of cases of inherited MND
• FUS, discovered in 2009, accountable for 3-5% of cases of inherited MND
• C9ORF72, discovered in 2011, accountable for around 40% of cases of inherited MND

Other extremely rare causative genes have also been identified. These discoveries represent major breakthroughs because they can provide important clues as to how motor neurons are damaged in MND and may advance our understanding of all types of the disease

Further reading

• Latest genetic study on MND - on page 17 of our Autumn 2019 issue of MND News (PDF)
• Genetic testing for MND in New Zealand on page 4 of our Autumn 2017 issue of MND News (PDF).
• Introduction to inherited MND (MND Association of England, Wales and Northern Ireland fact sheet)
• Genetic testing and insurance  (MND Association of England, Wales and Northern Ireland fact sheet)
• Options when starting a family (MND Association of England, Wales and Northern Ireland fact sheet)
• Familial MND and Genetic Testing (MND Australia fact sheet)

Most people measure the progression of the disease in terms of the difficulties they encounter while going about their everyday life. There is help available with all of the following symptoms, in the form of medication, equipment aids and personal care.

Legs

Walking may become more difficult as the legs become weaker, some people may experience 'foot drop', the inability to lift the front part of the foot.

Arms and hands

Everyday tasks such as turning taps, brushing hair, dressing, and doing up buttons may become more difficult as the arms and hands begin to weaken.

Neck and shoulders

It may become difficult to keep the head upright as the muscles weaken.

Emotions

Emotional responses may be affected, leading to laughing or crying inappropriately or involuntarily. A physical response and not a mental one may be the cause of this.

Speech and swallowing

Difficulties may be experienced when eating, drinking and speaking.

Breathing

If the respiratory muscles become affected, there may be difficulties with breathing.

Cognitive function

Around 35% of people experience mild cognitive change, which can cause difficulties with memory, learning, language and concentration. About 15% of people show signs of frontotemporal dementia which causes more pronounced behavioural changes.

What remains unaffected by MND?

For most people with MND the intellect and memory are not affected, nor are the senses of sight, hearing, taste, smell and touch.

MND does not directly affect bowel and bladder functions, although immobility and changes to diet in later stages may lead to constipation and changes in bowel function. Speak to your Support Team Member for help with these challenges.

In most cases, sexual function will not be affected until the later stages of the disease.