What is MND?

Motor neurone disease (MND) is the name given to a group of diseases in which the nerve cells - neurones - controlling the muscles that enable us to move, speak, breathe and swallow; undergo degeneration and die.

Neurones are nerve cells. Motor neurones take messages from the brain to the voluntary muscles and to some glands. There are two types of motor neurones. Upper motor neurones (UMN) take the messages from the brain through the spinal cord. Lower motor neurones (LMN) take the message from the spinal cord to the muscles.

MND leads to the degeneration of these motor neurones. It can affect:

• just the upper motor neurones in the brain that descend to the spinal cord or,
• just the lower motor neurones that exit the spinal cord to activate muscles or,
• both upper and lower motor neurones.

With no nerves to activate them, muscles gradually weaken and waste. The patterns of weakness vary from person to person.

MND does not affect the sensory neurones – the nerves that receive messages from things we see, touch, smell, hear and taste.

MND occurs at similar rates in most countries of the world. It is estimated that there are presently more than 2,000 people with MND in Australia. Slightly more men than women are diagnosed with MND, most commonly in the 50 to 60 year age group. However, MND may be diagnosed in adults at any age.

Early symptoms of motor neurone disease are often mild. They may include:

• stumbling due to weakness of the leg muscles
• difficulty holding objects due to weakness of the hand muscles
• slurring of speech or swallowing difficulties due to weakness of the tongue and throat muscles
• cramps and muscle twitching (fasciculation).

Diagnosing motor neurone disease can be difficult, and so sometimes a diagnosis may take time as the neurologist would like to observe a person over a period of time to see how the symptoms may change or respond to tests. If your doctor/GP thinks your symptoms may be due to a neurological problem, they should organise a referral to a neurologist.

MND takes several forms. 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 cure for MND, but a medication has been approved in Australia for people with amyotrophic lateral sclerosis (ALS) - the most common form of MND. This medication may extend a person’s survival time by a median of six to nineteen months.

The neurones carrying sensory messages of pain, touch, heat, cold and pressure from the skin and deeper tissues back to the spinal cord and brain are unaffected.

However, while most people experience little or no pain at any stage of the illness, others may experience some pain or discomfort such as:

The causes of motor neurone disease are not yet known, but ongoing research throughout the world is looking for causes.

About 10% of people diagnosed with MND have a ‘familial’ form of the condition; that is, there is or has been more than one affected person in a family. The remaining 90% of people with MND are the only affected person in their family and are said to have ‘sporadic’ MND. Most people with MND have the sporadic form and so it is not a genetic or inherited form of the condition and so will not be passed on in families.

In the past, it was thought that motor neurone disease (MND) only affected the nerve cells (neurones) controlling the muscles that enable us to move, speak, breathe and swallow. However, it is now known that up to 50% of people with MND can experience changes in cognition, language, behaviour and personality.