Dane, 52, who continues to act and most recently appeared in streaming hit Euphoria, spoke of his battle with the aggressive neurological disorder on Good Morning America.

“I have one functioning arm. My dominant side, my left side, is functioning,” he said on Tuesday, adding, “my right side has completely stopped working”.

Dane, who first revealed his diagnosis in April, said he expected that he had just “a few more months” before his left arm and hand ceased to respond.

He recalled first noticing symptoms of ALS – better known in Australia as motor neuron disease – when he felt weakness in his right hand.

“I didn’t really think anything of it at the time,” he said.

“[I] thought maybe I had been texting too much or my hand was fatigued, but a few weeks later I noticed it had gotten a little worse.”

Dane subsequently consulted multiple hand specialists and neurologists until he was diagnosed with ALS.

The clearly emotional Dane said he remained optimistic despite the rapid deterioration of his health.

“I don’t think this is the end of the story,” he tearfully said.

“I just don’t feel in my heart like this is the end of me. I’m fighting as much as I can.”

So what is ALS?

ALS, also known as motor neurone disease (MND) or Lou Gehrig’s disease in the US, is a neurodegenerative disease that affects nerve cells controlling voluntary muscle movement.

MND Australia, the peak body for MND/ALS care, advocacy and research, says the average survival time after diagnosis is 2½ years.

A minority of those diagnosed, about 5-10 per cent, will survive for more than 10 years.

There are two main types of MND – sporadic and familial.

Sporadic is the most common form of MND. It occurs randomly, without any known genetic cause or family history.

Familial is an inherited form of MND that was initially thought to affect a much smaller number of people. However, recent genetic discoveries suggest hereditary forms of MND are more common than previously thought.

MND causes progressive degeneration of motor neurons in the brain and spinal cord, leading to muscle weakness, twitching, and eventual paralysis. Eventually, patients with the condition may find it difficult to walk, talk, and even swallow and breathe. 

 How does it progress?

MND symptoms worsen over time as motor neurons degenerate and stop sending signals to muscles.

As a result the muscles weaken, twitch and are prone to waste away or atrophy.

Eventually the brain loses its ability to initiate and control voluntary movements.

How is it treated?

While there is no cure for MND, treatments can help manage symptoms and improve quality of life.

Treatments may include physical, occupational, speech, respiratory, and nutritional therapies.

Some medicines may help ease muscle cramping, along with and heat or whirlpool therapy.

Exercise in moderation may help maintain muscle strength and function.

John Hopkins University says medicines like riluzole, edavarone, and sodium phenylbutyrate/taurursodiol are shown to improve short-term survival or slow physical decline in some cases of MND.

How many cases in Australia

MND Australia estimates that on average two people die from the condition and two are diagnosed with it in this country every day.

A Deloitte Access Economics report commissioned by MND Australia in 2015 estimated that there were 2094 Australians living with MND. Of those, 60 per cent were male and 40 per cent were female.

The highest prevalence of cases was reported in males aged 75-84 years.

Notable cases

Former AFL player, coach and current Australian of the Year Neale Daniher was diagnosed with MND in 2013 after which he decided to dedicate the remainder of his life to educating Australians about the disease.

Daniher became co-founder and patron of the charity, FightMND, which raises money for research through major events, direct donations and the sale of clothing and merchandise.

He received a Member of the Order of Australia (AM) award in the 2016 Queen’s Birthday Honours list for his efforts in raising awareness of MND and was promoted to Officer of the Order of Australia (AO) in the 2021 Queen’s Birthday Honours for “distinguished service to people with Motor Neurone Disease and their families through advocacy, public education and fundraising initiatives”.

Daniher, a tireless campaigner for MND sufferers, named Australian of the Year. Photo: AAP

This year Daniher was named Australian of the Year in January in recognition of his fundraising and determination in fighting MND.

American Lou Gehrig dominated baseball with the New York Yankees from 1923-1939.

Gehrig noticed declining strength and coordination during the 1938 season. In 1940, on his 36th birthday, doctors at the Mayo Clinic diagnosed him with ALS.

He died less than two years later at the age of 37 after bringing unprecedented attention to the condition.

Theoretical physicist Stephen Hawking’s 55 years living with MND is the longest documented case in history.

Hawking was initially given just two years to live. Photo: Getty

Hawking was diagnosed with the condition at the age of 21 while pursuing his PhD at Cambridge. Doctors initially gave him just two years to live.

While his form of MND progressed more slowly than many cases, it gradually paralysed his body over decades. By the late 1970s he could move only a few fingers and required 24-hour care.

Despite complete paralysis except for a cheek muscle, Hawking continued his research using adaptive technologies and used a computerised speech system that became his trademark voice in lectures and media appearances.

The exceptional duration of his case helped researchers study long-term MND progression and adaptation, while demonstrating how assistive technologies could extend communication abilities for patients with advanced symptoms.

Hawking revolutionised our understanding of black holes and the universe’s origins. He continued to produce groundbreaking research on the nature of space, time until his death at the age of 76 in 2018.