What is motor neuron disease (MND)?
Motor neurons are specialised cells that carry messages about movement between the brain and the muscles. Loss of function, structure, or death of any kind of neuron is called neurodegeneration and if this continues to develop over time it is progressive. Motor neuron disease is the term for a group of related progressive neurodegenerative diseases that affect motor neurons. There are two kinds of motor neurons: upper and lower motor. They have different functions and are both taken into account when a diagnosis of MND is made.
Amyotrophic lateral sclerosis is the most common type of MND and is diagnosed based on upper and lower motor neuron degeneration being present in at least one region of the body. Primary lateral sclerosis is a rare type of motor neuron disease where only the upper motor neurons degenerate. Progressive muscular atrophy is a type of motor neuron disease where only the lower motor neurons degenerate. In rare cases motor neuron disease is associated with fronto-temporal dementia. In all cases the symptoms of the disease must progress over time.
For more information on MND please visit the Motor Neurone Disease Association website.