What is motor neurone disease?
The term motor neurone disease (MND) or Amyotrophic Lateral Sclerosis (ALS) describes a group of related diseases affecting the motor nerves or neurones in the brain and spinal cord, which pass messages to the muscles telling them what to do. This means messages gradually stop reaching the muscles, which leads to weakness and wasting. MND can affect how a person with the condition walks, talks, eats, drinks and breathes. However, not all symptoms necessarily happen to everyone and it is unlikely they will all develop at the same time, or in any specific order.
The French neurologist Jean-Martin Charcot first described motor neurone disease in 1874. MND is the commonly used term in the UK, but in other parts of the world, like America and parts of Europe, it is known as amyotrophic lateral sclerosis. Although there is currently no cure for MND, symptoms can be managed to help achieve the best possible quality of life for people living with the disease.
Types of MND
There are four main types of MND that we know about. It’s useful to know the different types, although it’s not always possible to determine which type an individual has.
Amyotrophic lateral sclerosis (ALS)
This is the most common form, with both upper and lower motor neurone involvement. This form of the disease is characterized by weakness and wasting in the limbs. An individual may notice they are dropping things, or tripping when they walk. Life expectancy is two to five years from when the first symptoms begin.
Progressive bulbar palsy (PBP)
Affecting about a quarter of people with MND, PBP involves both upper and lower motor neurones. Symptoms may include slurring of speech or difficulty swallowing. Life expectancy is between six months and three years from the onset of symptoms.
Progressive muscular atrophy (PMA)
PMA affects only a small proportion of people and causes damage to the lower motor neurones. Early symptoms may be noticed as weakness or clumsiness of the hands or feet. On average, people usually live for more than five years.
Primary lateral sclerosis (PLS)
This is a rare form of MND with people experiencing stiffness and clumsiness in the hands or legs, or speech problems. Average life expectancy may be more than 10 years although it may be life-limiting.
Kennedy’s Disease and MND are quite similar, and can cause confusion during diagnosis. It typically affects men, although women carry the defective gene. 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. Although not classed as MND, it is included in the conditions supported by the MND Association.