Motor neurone disease (MND or hemonga iaia) is a progressive neurological disease. It causes increasing muscle weakness and eventually paralysis. In MND the motor neurones (nerve cells) in your brain and spinal cord die. This leads to difficulties with moving, speaking, breathing and swallowing. It also causes muscle cramps, muscle twitches (fasciculations) and for some people it can affect their behaviour.
It's not known why or how MND develops. There's no cure or treatment but with medication it may be possible to slow the progress of MND.
MND can affect adults (rarely children) of any age, but most people are between 50 and 70 years of age when diagnosed. Men are more likely to get MND than women.
Video: What is motor neurone disease (MND)?
How common is MND?
How common a condition is can be measured as a person's lifetime risk of developing it, or as the number of people who have it at any one time (prevalence).
A person's lifetime risk of developing MND, if they live to 100 years of age, is about 1 in 300 (0.33%). The prevalence, or number of people living with MND at any one time, is about 1 in 15,000. In Aotearoa New Zealand there are currently about 400 people with MND.