What are they?
Four main forms of Motor Neurone Disease exist, each one of them affects those who suffer from it differently. There is often a lot of crossover between the different forms, so although it can be beneficial to categorise the various forms in which the disease manifests, in practice it isn’t necessarily that simple to delineate.
Amyotrophic lateral sclerosis (ALS)
ALS is by far the commonest type of MND, it involves both the lower and upper neurones. This type of the condition is primarily identified by loss of strength and muscle wastage in the patient’s limbs. You may notice that you trip when you walk or start to drop things more often. The normal life expectancy with this form of MND is between two and five years after the initial manifestation of its symptoms.
Progressive bulbar palsy (PBP)
This affects about twenty five percent of people who are diagnosed, again both the lower and upper motor neurones are involved. Its symptoms can include slurred speech and difficulty in swallowing. The average expected period of life is anywhere from six months to three years from the first symptoms occurring with this form of MND.
Progressive muscular atrophy (PMA)
This type is rarer, present in only a few MND sufferers, it mainly damages the lower motor neurones. The early symptoms of this form may first manifest themselves as a loss of strength or manual dexterity with your hands. Most sufferers of PMA live for upwards of five years.
Primary lateral sclerosis (PLS)
This is an extremely rare type of MND which involves only the upper motor neurones, causing primarily loss of strength in the patient’s lower limbs, though some sufferers also have a loss of manual dexterity in their hands and/or problems with their speech. Life expectancy with this form of the disease could generally be normal, although it may be shortened, this is dependent on if the PLS then progresses into ALS.
The rarer types of MND
As the rarer forms of MND, PMA and PLS only affect a few people (5% and 0.5% of MND sufferers respectively). This may mean that people with these types of MND can feel quite alone as it is unlikely they will have chance to come into contact with many more people with their condition.
Combined with the fact that these forms of MND behave quite differently in the beginning stages to the more common types, people can be left frustrated and bewildered as there is less information available and less chance to meet others who share their condition and may be able to offer suggestions or even just companionship as people who have the same experiences of living with these variants.
Both are rarer, slower progressive forms of MND, PMA affecting the lower motor neurones and PLS the upper. More information on each can be found in their relevant sections.