Motor neurone disease (MND or hemonga iaia) occurs when the nerve cells that control the muscles you use for moving, speaking, breathing and swallowing get damaged. Over time you get weaker and it’s harder and harder to do these things, until eventually you are no longer able to do them.
- Motor neurones are the nerves in your brain and spinal cord that carry messages to your muscles to get them to move, and when these get damaged, MND occurs.
- This means your muscles gradually weaken and waste away and you lose mobility in your limbs, and develop difficulties speaking, swallowing and breathing.
- MND occurs in 1 in 15,000 people, which means that in New Zealand more than 300 people are living with MND.
- There are several types of MND, with amyotrophic lateral sclerosis (ALS) being the most common form. Well-known people with ALS include the former American baseball player Lou Gehrig and physicist Stephen Hawking.
- Unfortunately, there is no cure for MND, but there are things you can do to live more comfortably with this condition.
Who is most likely to get motor neurone disease?
MND can affect adults at any age, but most people diagnosed with it are between the ages of 50 and 70. Men are more likely than women to get MND.
What are the causes of motor neurone disease?
In about 10% of cases, inherited gene mutations cause the condition. This is called familial MND. However, most cases of MND occur for no apparent reason in people without a family history of the disease. This is known as sporadic MND.
Research to understand what causes sporadic MND includes studies on:
- exposure to viruses
- exposure to certain toxins and chemicals
- genetic factors
- inflammation and damage to neurons caused by an immune system response
- nerve growth factors
- growth, repair and ageing of motor neurons.
What are the symptoms of motor neurone disease?
The early symptoms of MND are mild and develop gradually over time. The pattern of weakness is different for each person depending on which motor neurones are affected.
There are two types of motor neurones. Lower motor neurones control movement in your arms, legs, chest, face, throat and tongue. When signals from your lower motor neurons are disrupted, your muscles no longer work properly. They gradually weaken, and may begin wasting away and develop uncontrollable twitching and cramps.
Upper motor neurons direct your lower motor neurones to produce movements such as walking or chewing. When signals from the upper motor neurones are disrupted, your limb muscles develop stiffness and your movements become slow and require a lot of effort. Your tendon reflexes may become overactive, leading to strong knee and ankle jerks. Over time, you may lose the ability to control voluntary movement.
Common early symptoms include:
- a weak grip, which can make it hard for you to pick up or hold objects
- weakness in your shoulder that makes it hard to lift your arm
- a ‘foot drop’ caused by your ankle muscles getting weaker
- dragging your leg
- slurred speech.
As the nerve damage progresses, symptoms spread to other parts of your body and you increasingly find it hard to move, speak, swallow and even breathe. In up to 15% of cases, MND is also associated with a type of dementia that can affect your personality and behaviour.
How is motor neurone disease diagnosed?
If you suspect you have these symptoms, it’s important to see your doctor about them. Early diagnosis helps how your later symptoms can be managed.
There’s no one test, so diagnosis includes ruling out other conditions. If your doctor thinks you might have MND, they will refer you to a brain and nervous system specialist (neurologist). They will diagnose you based on your history, a physical examination and some specialised tests. These may include a needle test called electromyography (EMG), an electrical impulse test called a nerve conduction test, transcranial magnetic stimulation (TMS), MRI scans and blood tests.
How is motor neurone disease treated?
There is no cure for MND, so treatment is aimed mainly at relieving the symptoms and making you feel more comfortable. Medications can be used to help with symptoms such as muscle cramps, constipation, drooling and muscle twitching. There are also various aids to help you with breathing problems, communication difficulties and swallowing difficulties.
Recently, a medicine called riluzole (also called Rilutek) has become available in New Zealand for people with ALS. It is not suitable for everyone. Trials in people with this type of MND have shown an increase in survival of approximately 3 months. Riluzole does not stop the disease but slows its progress slightly.
MND is a complex disease, with people experiencing different symptoms, to a lesser or greater extent. To help you better manage your condition, it’s important to get advice from various health professionals such as your GP, specialists, physiotherapists, occupational therapists, speech and language therapists, nurse specialists and district nurses, dietitians and counsellors.
What is the prognosis for people with motor neurone disease?
Most people with MND live for 20 to 48 months after symptoms begin. About 5–10% of people with MND live for 10 years or more, while about 3 years is the mid-point of life expectancy from when you first get symptoms.
How can I care for myself with motor neurone disease?
You are likely to feel grief and need emotional support as you come to terms with your diagnosis. It’s important that you seek support from family and friends, as well as from experts in MND (see Support section below). Being informed about MND is also an important way to support yourself to live as well as possible with the condition (see Learn More below).
What support is available for people with motor neurone disease?
Motor Neurone Disease New Zealand will support you to manage your condition. They will assign you a support worker to help you access the appropriate care so that you can live your life as fully as possible. Because MND is a life-limiting condition, palliative care will also be available.
The following links provide further information about MND. Be aware that websites from other countries may have information that differs from New Zealand recommendations.
- Motor neurone disease: Bringing the New Zealand patient onto the world stage NZ Medical Journal, Vol 128 No 1409: 20 Feb 2015
- Motor neurone disease evidence-based treatments: An overview MND Australia, 2012
- Motor neurone disease Neurological Foundation, NZ
- What causes MND? MND, NZ
- Motor neurone disease Better Health, Australia, 2018