About Motor Neurone Disease

MND research 3

What is Motor Neurone Disease (MND)?

Motor neurone disease (MND) is a neurological condition caused by the damage and death of specific nerve cells called motor neurones in the brain and spinal cord.

Electrical signals travel from the brain to the muscles via the motor neurones. Damage and destruction of motor neurones results in a failure of signals to the muscles. This causes progressive weakness and wasting of muscles. Motor neurones of any part of the body can be affected resulting in a wide variety of symptoms.

Upper and lower motor neurones

  • Upper motor neurones: These begin in the brain and travel down into the spinal cord where they communicate with the lower motor neurones.
  • Lower motor neurones: These begin at the spinal cord. They receive information from upper motor neurones. They extend out of the spinal cord and travel to the muscles of the body.

Upper and lower motor neurones work together to control voluntary movements and reflexes. 

For example, when our hand touches a hot object, the painful sensation is carried by the sensory nerves to the brain. The brain then decides that the hand should be moved away to avoid pain. It then sends a signal to the spinal cord in the neck. This signal will then pass from the upper motor neurones to lower motor neurones down the right arm to the muscles involved in moving the hand. The signal ultimately results in a muscle contraction which causes the hand to move away from the painful stimulus.

Different types of MND

There are different types of motor neurone disease. Doctors and patients often use the term motor neurone disease as an umbrella term to describe the condition rather than the actual sub-type of motor neurone disease, which can make things confusing. Additionally, there can be an overlap between the various subtypes.

ALS is the most common form of MND and accounts for about 60 to 70% of the total MND cases. Men are more commonly affected than women. In this type of MND, both the upper motor neurones and lower motor neurones degenerate at the same time. Symptoms and signs depend upon the area of the body where the muscles are affected first (e.g. arm or leg) and can include muscle wasting, weakness, stiffness, cramps and rippling of the muscles, known as fasciculations. Over time, as ALS progresses, different areas of the body become involved. Involvement of the muscles controlling speech, swallowing and breathing can also occur.

Progressive muscular atrophy accounts for perhaps 10% of cases of MND. In this type of MND, only the lower motor neurones degenerate and life expectancy is longer than that in ALS. Sometimes MND can initially present as progressive muscular atrophy but over time the upper motor neurones can be involved and the diagnosis then changes to ALS. Men are more likely to be affected than women.
Primary lateral sclerosis

This is an uncommon form of MND accounting for approximately 1 to 2% of cases. In this type of MND, only the upper motor neurones degenerate. Sometimes MND can initially look like primary lateral sclerosis but over time the lower motor neurones can become involved and the diagnosis changes to ALS. After 5 years it is rare for PLS to convert to ALS, however this may still occur.


In true cases of primary lateral sclerosis the condition progresses slowly and life span may not be reduced although disability levels can be high. Common symptoms and signs include muscle weakness, stiffness and increased reflexes response.

About 20% of all cases of MND can present as progressive bulbar palsy. The term “bulbar” refers to an area at the base of the brainstem, called the medulla oblongata. Progressive bulbar palsy is a type of MND that involves degeneration of upper and lower motor neurones from that area. These motor neurones are responsible for innervating the muscles of the tongue, pharynx and larynx (called the bulbar muscles) and so the symptoms of progressive bulbar palsy include wasting, weakness or stiffness of the tongue, difficulty with speaking and swallowing and problems with the thickness or amount of saliva.

Progressive bulbar palsy is a term reserved for involvement only of the bulbar muscles in MND. Some people can develop problems with the bulbar muscles first and then go on to develop problems in the arms or legs – this is a form of ALS rather than progressive bulbar palsy. Likewise, the majority of people with ALS develop involvement of the bulbar muscles at some stage during the condition.

About 5 to 10% of all cases of MND can present with predominant lower motor weakness in both arms (Flail arm / man in a barrel syndrome) or in both legs (Flail leg). This is slowly progressive.

Causes of MND

The cause of MND is unknown and is the focus of ongoing research. In the vast majority of cases, MND occurs randomly and is called ‘sporadic MND’. In a much smaller number of cases, MND can be inherited and is called ‘familial’.

MND can present at any age. The only established risk factors for developing MND are age (the condition is more common as age increases), being male and having a family history of MND.

At present, there is no cure for MND and it remains a progressive condition. Management is therefore based around controlling symptoms and maintaining quality of life.

The prognosis in MND is varied and depends upon many different factors. Every person who develops MND is different and therefore the length of survival with MND is different too.

Additional support and information:

A video including helpful tips for MND patients can be found on YouTube.

Contact us

The Rob Burrow Centre for Motor Neurone Disease
Seacroft Hospital
York Road, Leeds, LS14 6UH

For all care centre queries, please contact Claire Lang, specialist nurse, on 0113 392 6755.

For questions about visiting the Hospital, please visit Seacroft Hospital Webpage.

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