Different types of MND
There are four main types of MND, each affecting people in different ways. There can be a great deal of overlap between these types, which may make it difficult to provide an exact diagnosis.
We give brief definitions here, but further detail is provided under Information for download at the bottom of this page.
The following definitions talk about life expectancy, so you may not want to read any more at this stage.
Amyotrophic lateral sclerosis (ALS)
This is the most common form, with both upper and lower motor neurone involvement. This form of the disease is characterised by weakness and wasting in the limbs. Someone may notice they are tripping when walking or dropping things. Average life expectancy is from two to five years from onset of symptoms.
Progressive bulbar palsy (PBP)
PBP affects about a quarter of people diagnosed, and involves both the upper and lower motor neurones. Symptoms may include slurring of speech or difficulty swallowing. Life expectancy is between six months and three years from onset of symptoms.
Progressive muscular atrophy (PMA)
PMA affects only a small proportion of people, mainly causing damage to the lower motor neurones. Early symptoms may be noticed as weakness or clumsiness of the hand. Most people live for more than five years.
Primary lateral sclerosis (PLS)
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 is usually more than 10 years from onset of symptoms. As symptoms develop, some cases may be re-diagnosed as ALS.
Kennedy’s Disease and MND have similar traits, which can cause confusion during diagnosis. Kennedy’s Disease is a rare disorder of the motor neurones caused by a genetic mutation. It progresses slowly, leading to weakness, wasting of muscles and hormonal changes. Although it is not classed as a type of MND, it is included in the conditions supported by the MND Association.
It is possible through gene testing to determine an accurate diagnosis for Kennedy’s Disease. Most people with Kennedy’s disease start to show symptoms when they are 30-60 years old, but it can appear in older or younger people. There is currently no known cure, but symptoms can be managed to improve quality of life. Most people with Kennedy’s disease live an average life span.
Kennedy’s disease usually affects men. Most women who inherit the gene will not develop any symptoms, but will be carriers of it and may pass it on to their sons or daughters. In rare cases, women may develop symptoms, but these are usually milder than those experienced by men. The main symptoms of Kennedy’s disease in women are mild muscle cramps and fatigue. Little is known about Kennedy’s disease in women and research is currently underway.
Find out more about the Kennedy’s Disease Clinic in the following video:
Information for download
The following publications provide further detail on the types of MND
- Living with motor neurone disease (1188kb)
Our main guide for people with MND, providing an overview of the disease and how to manage its impact. This can be downloaded or ordered as a printed pack with additional items from our helpline, MND Connect. The guide has been developed to help people with MND achieve the best possible quality of life from diagnosis onwards. It includes top tips, directions to further information and details about accessing support services. (Code: LW002)
- Information sheet 2B – Kennedy’s Disease (133kb)
An explanation of Kennedy’s Disease (Code: IF002B)
- Information sheet 2C – Primary lateral sclerosis (PLS)
An explanation of PLS (Code: IF002C)
- Information sheet 2D – Progressive muscular atrophy (PMA)
An explanation of PMA (Code: IF002D)