Source: The Conversation (Au and NZ)
Rugby league player Jai Arrow’s recently announced diagnosis of motor neurone disease has again brought this devastating disease to public attention. Motor neurone disease is relatively rare, with fewer than 1,000 Australians diagnosed each year.
Arrow’s diagnosis has shocked many because the disease is often associated with older adults, not elite athletes in the prime of life. So what is motor neurone disease? Why can it be difficult to diagnose?
And can it be treated? What is motor neurone disease? How does it progress? The disease affects the motor neurones, the specialised nerve cells that communicate signals from your brain to muscles throughout your body.
If these nerve cells are damaged or die you lose the ability to do some of the most basic things that require muscle function – moving, breathing, speaking or swallowing. Damaged or dead motor neurones cannot renew themselves.
So loss of muscle function is permanent. Motor neurone disease has life-changing symptoms that progressively worsen. The first symptoms can appear suddenly. In Arrow’s case he played the full 2025 NRL season, but recently reported changes in his speech.
The journey that each affected person faces after their diagnosis varies widely. This is due to a number of factors, including how progressed the disease is when it’s diagnosed and whether treatment starts early.
For instance, Arrow says he’s willing to be involved in clinical trials and use medication. AFL great Neale Daniher, 2025 Australian of the Year, has been living with his diagnosis since 2013. But most affected people can expect paralysis and death within two to five years.
Who’s at risk? What causes it? Most people diagnosed with motor neurone disease have the “sporadic” form, meaning the cause is unclear. And researchers don’t exactly know why it occurs in some people and not others.
As we see in Arrow’s case, being fit and 30 years old will not protect you. But 5–10% of cases are “familial”, meaning there is a recognised heritable genetic basis. For instance, the first discovered genetic cause were mutations affecting the enzyme SOD1.
Without this functioning enzyme, people cannot process harmful free radicals. There is also ongoing debate about whether repeated knocks to the head can increase the risk of motor neurone disease in some people. Several studies involving professional athletes and contact sports have suggested possible associations between repetitive head injury and motor neurone disease.
However proving one directly causes the other is difficult because many factors, including genetics and environmental exposures, are likely involved. Read more: I’ve seen the brain damage contact sports can cause – we all need to take concussion and CTE more seriously How is it diagnosed?
Why can that take so long? Early symptoms of motor neurone disease are often mild and dismissed. This could be slurred speech or tripping more often than usual on a lounge room rug. People can blame these on being tired or distracted.
But persistent or worsening symptoms may prompt someone to see a doctor. If a doctor suspects motor neurone disease, they need to exclude other potential causes first. Slurred speech could be a symptom of a stroke or Parkinson’s disease, for example.
There is no single test to diagnose motor neurone disease. So it is generally only through referral to a neurologist, then having nerve tests and imaging, that a definitive diagnosis can be made. As this process can take months, it often delays treatment.
This can have serious consequences as the patient’s symptoms worsen and their health deteriorates. Can motor neurone disease be treated? There is no cure. Instead, treatment focuses on managing symptoms, and trying to slow the progression of the disease.
For instance, this may include support to manage mobility, pain, work or eating well. The limited number of existing treatment options do little to change the trajectory of the disease. However, the drug tofersen, which has recently been provisionally approved by Australia’s drug regulator, seems to help people with the specific SOD1 mutation.
The drug meaningfully slows the progression of disease in this small sub-set of people with motor neurone disease. But it comes with side-effects, mainly related to the way the drug is delivered, via lumbar puncture.
How about the future? The more we learn about the underlying mechanisms of the disease, the better able we will be to prevent and treat it in the future. For example, we’re learning more about the involvement of other cells in the nervous system that are implicated in the disease.
These are the glial cells, microglia and astrocytes, which would normally support a healthy nervous system. In the sporadic form of motor neurone disease, these non-neuronal cells convert to a toxic state. So in the future, we may be able to prevent neurones from dying by targeting some of these other cells.
We are also learning more about how chronic (long-term) inflammation involving activation of the brain and spinal cord’s immune system drives how the disease progresses. For instance, our research and that of others is investigating how faulty mitochondria – the energy-producing structures in cells – may contribute to this inflammatory process.
So future treatments may target this pathway. However, for us to test whether any future treatments work, we need to measure how people respond in clinical trials. And experts don’t always agree on how best to do that.
So we have several challenges ahead. But with ongoing research and a focus on early diagnosis, our aim is to turn motor neurone disease from a fatal disease into a manageable one.
Peter J.
Crack receives funding from FightMND and the National Health and Medical Research Council.
Peter J. Crouch receives funding from FightMND and the National Health and Medical Research Council.
Original source: https://analysis1.mil-osi.com/2026/05/22/why-does-motor-neurone-disease-take-so-long-to-diagnose-and-can-it-be-treated/