The word “stroke” comes from the Greek apoplexia which implies being struck by a deadly blow, out of the blue. Strokes are often catastrophic, and terrifyingly common; first-time incidence of stroke occurs almost 17 million times a year worldwide – more than one every two seconds.

Dr Gary Lau, a clinical assistant professor of neurology at the University of Hong Kong, describes the two main types of strokes – ischemic stroke, which occurs when a blood vessel that supplies blood to the brain is blocked, and haemorrhagic stroke, caused by the rupture of a weakened blood vessel supplying the brain.

“The oxygen supply to the brain is impaired in both types of strokes, which results in a loss of function of brain cells. Ischemic strokes account for around 80 per cent of all strokes,” Lau says ahead of World Stroke Day on October 29.

Neurologist Dr Tsoi Tak-hong, vice-president of the Hong Kong Stroke Fund, adds that “by definition, every single stroke causes permanent damage” to some extent.

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Lau, who is also director of the university’s Stroke Research and Prevention Group, says there are about 13,000 new cases of stroke every year in Hong Kong – and that it is the fourth leading cause of death in the city.

Stroke is the second leading cause of death globally, and the leading cause of death in China. About 15 per cent of all stroke patients in Hong Kong are under 55 years old – and two per cent are under 40, like Sodderland.

After many MRI scans – including one while she was in an induced coma immediately after her stroke – doctors concluded Sodderland’s stroke was caused by a congenital malformation of blood vessels in her brain. But why did it take 34 years for it to bleed catastrophically? Sodderland believes it was stress.

“There is a rise in young people suffering strokes in different cultures around the world, and it’s thought to be due to a rise in stress and long working hours.

“Nobody knows why I had my AVM [arteriovenous malformation stroke] the day that I did, but it was during a very stressful period with relentless work, and my father had recently become ill.”

Lau lists top risk factors for ischemic stroke as undiagnosed or uncontrolled high blood pressure, diabetes and high cholesterol.

Knowing and managing your blood pressure is crucial, Tsoi says. “Hypertension is asymptomatic in most cases and is often only diagnosed after a catastrophic event such as a stroke,” he says.

In younger patients, there can be other causes, such as a tear affecting a blood vessel supplying the brain, which can occur after a neck injury from sports or even after a rigorous neck massage.

As in Sodderland’s case, it may be due to an underlying defect of the blood vessel, an aneurysm or a congenital vascular malformation.

Illicit drug use can also result in strokes in younger people.

We are all encouraged to be mindful of a “FAST” response to a stroke. The acronym urges us to watch out for Facial drooping, Arm weakness, Speech difficulties, and Time – as in don’t waste it in getting help.

Some clinics add an E and R (FASTER) for Eyes – often vision is affected – and React, move quickly to get help.

To limit the damage after a person has had a stroke, act quickly. The US Centres for Disease Control and Prevention suggests that patients who arrive at the emergency room within three hours of their first symptoms often have less disability three months after a stroke than those who received delayed care.

“A typical patient loses around 1.9 million brain cells for every minute in which stroke is untreated,” Lau explains. Patients with ischemic stroke who arrive in hospital early may be eligible for TPA – tissue plasminogen activator – a “clot busting” medication which significantly increases the chances of recovery, especially if administered soon after the stroke’s onset.

In recent years, a minimally invasive procedure in which the blood clot blocking a large artery is retrieved has increasingly been performed in suitable cases. The results are best if done as soon as possible, Lau says.

Our brains, says Tsoi, are “robust in self- repair and some lost functions can be regained” depending on the site and severity of the stroke.

Increasing research into how the brain adapts and changes functionally after stroke – its “neuroplasticity” – offers hope, Lau says.

“With such understanding, new treatments, which include stimulating different nerves, muscles of the body and parts of the brain, are being developed and tested to determine whether they enhance post-stroke recovery.

Sodderland’s stroke manifested in many ways – her memory was severely impacted in the immediate aftermath (she could not recall how to use her phone, for example, but knew it was a tool that could help her), as was her vision and her speech.

She had no peripheral vision on her right-hand side, and severe aphasia, a communication disorder affecting comprehension and expression. She couldn’t read – and she still struggles with reading a decade later.

According to the UK’s Stroke Association, one in eight strokes prove fatal within the first 30 days and one in four strokes within a year. That leaves a lot of stroke survivors, like Sodderland, and it’s estimated that half of them live with an enduring disability.

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Sodderland says: “The major challenge is how to help the survivor live in a new way after the brain trauma. Because it is so devastating and life-changing and affects the sense of self in such a core way, it’s really hard for therapists and doctors to know how to facilitate that person’s rebuilding.”

The burden of stroke on society, says Lau, is significant. He highlights a recent global study that estimated that there are about 100 million people living with stroke worldwide. Complete asymptomatic recovery, says Tsoi, with no residual impairment, occurs in only 20 per cent of stroke sufferers.

Of those, Lau says high blood pressure is the most important. “Monitor this regularly and ensure that it is well controlled,” he says – it should be kept below 130/80. Tsoi says stroke risk could be cut in half with good control of high blood pressure.

Those aged 65 and above should have regular heart rhythm monitoring for early diagnosis of atrial fibrillation, an abnormal heart rhythm, to protect against strokes.

In Hong Kong, Lau’s Stroke Research and Prevention Group has recently launched an app called WeRISE, a one-stop platform for stroke patients and their family members. It aims to help prevent stroke patients having another stroke, offering dietary advice, rehabilitation exercises and techniques for carers.

Sodderland, meanwhile, is recovering well, she says. She has made several films since My Beautiful Broken Brain, which still airs on Netflix, including Limbo, which is currently doing the festival rounds and has been commissioned for a feature-length script.

“I am working hard on that. I still can’t read properly, so it is very challenging, but also very exciting to know that the film industry is ready to create work with neurodivergent storytellers and prioritise inclusivity,” she says.