‘Disorders of consciousness’: The million-dollar question and the mysteries of coma

One night, Fiona McKay didn’t show up for dinner with her friend Mandy Odlin. Mandy started to feel uneasy. It wasn’t like Fiona to miss a catch-up or even be five minutes late. Mandy asked her husband to check on Fiona at home while she waited in case her friend turned up.

When he arrived at Fiona’s, nothing seemed out of place at first. Then he peered through a window. Fiona was crumpled on the ground, covered in blood. “Help!” he yelled down the phone to Mandy. “Call an ambulance!” He broke through the door.

Fiona, 49, was at the bottom of a flight of stairs, dressed for an outing, her handbag still around her arm. Her breathing was raspy and gurgled. She couldn’t be woken. “It was horrendous,” Mandy recalls. “She was really far gone.” It turned out she had fallen down the stairs the night before, after getting home from a party. A brain injury had left her in a coma.

A helicopter flew her to Sydney’s Westmead Hospital, where surgeons raced to save her. The next time Mandy saw her friend, she was on life support. “The surgeon said, ‘If she does live, and she does regain consciousness, she has so much damage. All I can tell you is I’ve done the best I can.’”

A coma is, in many ways, a kind of twilight zone. Doctors don’t know for sure how long a patient will remain in that state, nor how much of them will ever be the same again. Loved ones are plunged into a complex and confronting world of protracted uncertainty.

But what is a coma? What do experts know about a patient’s level of consciousness? And how do doctors and families decide what to do next?

What’s a coma?

A coma is prolonged unconsciousness that can last hours, weeks or, in very rare cases, years. In 1941, Chicago girl Elaine Esposito went into a coma that lasted 37 years, one of the longest in recorded history. In popular culture, a coma is often portrayed as a liminal space between life and death: a protagonist reliving flashbacks of their past or meeting someone they know in a bright, empty space. They wake after months or years. “Where am I?”

In fact, comas rarely last longer than several weeks, says neurologist Professor Steven Laureys in Montreal, after which a patient either wakes or emerges into a different “disorder of consciousness”. “[The coma] will usually only be a temporary state because the deep centres in the brainstem that are critical for wakefulness are robust and resilient, and so most will recover.”

Coma takes its name from the Greek koma, or deep sleep. But “people don’t dream and wake up and feel normal and refreshed,” says John Myburgh, a professor of intensive care medicine at the George Institute in Sydney. “Coma is when people are unconscious and unable to speak, and unable to think. It’s probably best described as acute brain failure.”

“I honestly thought she was going to die. They let me just sit there with her after, but she was never conscious.”

Mandy Odlin, friend of patient Fiona McKay

Disorders of consciousness also include people being minimally conscious (able to respond to some commands) or being in a state of unresponsive wakefulness (where they may appear “awake” but don’t show any meaningful response). “It’s fair to say we are moving away from the term coma,” says Andrew Udy, an intensive care specialist at The Alfred in Melbourne. “It’s not overly helpful in some ways. What we’re describing is someone who has a disorder of consciousness. And, that in itself is a spectrum.”

A widely used scale for assessing coma was developed in 1974 by neurosurgeons in Glasgow, based on eye, verbal and motor responses, with a “one” for no response. A fully conscious person will score 15, while someone mildly concussed might be at 13. By a score of eight, a person is unconscious and tends to be at risk of breathing difficulty. Three is the deepest level – completely unresponsive, eyes closed, unable to squeeze another person’s hand, impervious to pain such as pressure to their fingernail bed.

This is all very different from an induced coma. When people arrive at a hospital unconscious, doctors often add sedatives, commonly with a drug called propofol, to induce a coma. An induced coma is much like a general anesthetic, except it’s not used to facilitate surgery and can last for days or weeks. This helps to let the brain recover and helps prevent secondary injury from swelling. It can reduce discomfort or agitation, too. “We get to a point where we feel it’s safe to reduce the sedation and allow them to emerge, and we see what we are left with and what we are dealing with,” Udy says.

The surgeons who first operated on Fiona put her into an induced coma and removed part of her skull to release pressure from bleeding. “I honestly thought she was going to die,” Mandy says. “They let me just sit there with her after, but she was never conscious.”

What is consciousness?

A coma is a symptom with many potential causes. These can be acute brain conditions such as trauma, strokes or tumours. The outcome in these cases, Myburgh says, “is dependent upon the capacity for the brain to recover itself”. Or the cause can come from elsewhere in the body: a heart attack starving the brain of oxygen, toxins from kidney and liver failure that can play havoc with brain functioning. Diabetics can be at particular risk if they have a build-up of chemicals called ketones, or a rapid drop or spike in blood sugar levels. But if doctors treat these problems, Myburgh says, the “coma generally gets better”.

The nature of a coma is tied up with a question that humans have yet to unravel fully: what gives rise to consciousness? “That’s a million-dollar question,” says Jose Suarez, director of neurosciences critical care at Johns Hopkins in Baltimore. “You would think it would be a simple question to ask, but we haven’t been able to find the real answer. Consciousness and awareness mean different things to different people. It’s not the same when you’re talking about consciousness in religious terms or philosophical terms or medical terms.”

One question, sometimes referred to as “the hard problem of consciousness”, has perplexed philosophers and scientists for centuries. In the 1600s, French philosopher René Descartes used “I think, therefore I am” to express that consciousness was an undeniable fact because it can be observed from within oneself. Today’s scientists understand aspects of the brain’s workings – neurons fire, circuits carry messages and particular regions perform certain tasks – but they have not fathomed how the matter in our brains gives rise to our subjective experiences.

That’s a classic dinner party discussion for Matthew Kiernan, director of Neuroscience Research Australia, and his friends. “Some people have said, you know, consciousness leaves the body when you have a general anaesthetic, and it’s in some ether region and gets called back in. You can’t disagree with anyone because there aren’t answers.” Still, he says, “I suppose we’re getting closer to the core of what it all means.”

Steven Laureys, who founded the coma science group at Liege University Hospital in Belgium and is now a Canada Excellence Research Chair in Quebec, has studied consciousness in Buddhist monks and people under hypnosis to understand how brain activity influences subjectivity. “We studied the translator of the Dalai Lama, Thupten Jinpa, and many other monks to start with the extreme and see how that changes the structure and function of the brain. Meditation is training your attention, and we see a change in the networks,” he says. “Some philosophers consider it impossible for the mind to understand itself, but I think we should at least try.”

In coma patients, he has identified two networks that contribute to consciousness: one is involved in external awareness, the other in internal awareness. For humans to become aware of sensations and internal thoughts, messages from these networks pass through the deep centre of the brain, called the thalamus. “What is important is the interaction between millions of cortical neurons and the thalamus,” says Laureys. During a coma, he says, the networks disconnect, no longer engaging with the thalamus. “When we started, people said, ‘Well [the cause of coma] is global, it’s everywhere in the brain.’ And that is not true, you have these networks. Some parts of the brain are more important than others.”

Laureys has given medical opinions for patients all around the world, including Formula One driver Michael Schumacher, who was placed in an induced coma after a skiing accident in 2013. His family has not revealed what state he is in now. In 2021, his wife, Corinna, said in a television documentary that Schumacher is “different” and lives at home. “We do everything we can to make Michael better and to make sure he’s comfortable.”

In 2006, Laureys showed that some patients who were believed to be in a state of unresponsive wakefulness – then often called “vegetative” – were more conscious than assumed. Laureys put the patients in an MRI machine and asked them questions such as whether they were hearing their mother’s name correctly. If the answer was yes, he asked them to imagine playing tennis. If they wanted to say no, he asked them to imagine walking around their house. He saw different parts of the brain light up as the patients gave correct answers. “We were the first to actually communicate with patients through this ‘playing tennis’ paradigm.”

Up to two-thirds of the patients he sees himself with unresponsive wakefulness are, in fact, minimally conscious. But he adds this caveat: only difficult cases are referred to him, others might be more clear-cut. “Many of them – more than we thought – have more brain and cognitive activity going on.” (These patients are not to be confused with people with “locked-in syndrome”, a rare condition where someone is conscious but can move only their eyes; minimally conscious patients show some response with their eyes, respond to pain and might smile at someone they know.)

Minimally conscious patients generally have better outcomes than patients with unresponsive wakefulness, and Laureys’ findings had implications for patients’ comfort and rehabilitation efforts. But he cautions they don’t say much about what a minimally conscious state is really like. “Are they self-aware? These are tricky, tricky questions,” he says.

‘We’re trying to change the concept of this pessimism, this nihilistic approach to coma. We need better tools to assess those patients.’

Jose Suarez, Johns Hopkins in Baltimore

Treating doctors are well aware of the unknowns in their field. “At the moment, our measures of consciousness are fairly coarse: they come back to wakefulness and awareness,” Andrew Udy says. “It tells us nothing of what the patient is actually thinking at the time. That’s the best we can do at the moment.”

In Baltimore, Jose Suarez is hopeful higher-resolution brain imaging and better techniques for looking at brainwaves could one day make coma a “treatable medical entity”. “We’re trying to change the concept of this pessimism, this nihilistic approach to coma,” he says. “We need better tools to assess those patients so that we can determine who are the ones who are going to recover. At the moment, we are just learning how to do that.”

How are decisions made about someone in a coma?

In one of Australia’s biggest intensive care units, at The Alfred in Melbourne, a teenage boy holds the hand of a man motionless in a bed. The man has been in a coma for eight days since an accident. His doctors have been reducing sedation to see if he will wake. “Unfortunately, the assessment is he is still very unconscious,” says Andrew Udy. “We will use time over another week and see how he emerges.”

Time is a common theme in this field of medicine. Awareness is not like a light switch that can simply be turned on; people rise to consciousness gradually, and the longer doctors wait, the clearer the picture. “Time is a really useful diagnostic tool and prognostic tool,” says Udy. In Fiona’s case, her siblings, Stuart and Kathy, and her father, Donald, flew from New Zealand to be with their sister at Westmead. No one knew when she would wake or what level of brain damage she would have. “That was the hard part,” Stuart says. “The doctors, no matter how good they are, they don’t know. It seems to be time; time is what they rely on.”

In the ICU at The Alfred, nurses adjust air mattresses and turn patients every four hours to prevent bedsores. Doctors perform tests to check for awareness. Brain scans help to paint a picture of what recovery could be like. “We just have to take it day by day,” says Udy. He aims to be open with families every step of the way. “We will take them on that journey. We will give bad news when we need to, and when we’re not sure, we will say so.”

About 60 per cent of the patients in the unit are in induced comas. Roughly a quarter have brain injuries that mean they might not regain consciousness. Clinical nurse Catherine Bell helps to wean patients off sedatives to see if they wake. “There’s a range of different reasons as to why someone might not wake up straight away. It depends on the degree of their brain injury, what the diagnosis of that is, and any confounding issues with their body,” she says.

Some circumstances are black and white, such as when the person is classified as brain-dead. In these cases, they have a heartbeat but there is irreversible loss of all brain function. Their pupils don’t respond to light, and they’re unable to breathe without a ventilator. “No one has ever recovered from brain death if it wasn’t a diagnostic error,” says Steven Laureys. Brain death meets the legal definition of death in Australia.

In other circumstances, as time passes and the person doesn’t regain consciousness, their longer-term quality of life becomes clearer. Doctors have discussions as early as possible with a substitute decision-maker, usually the patient’s next of kin. “We’re very keen on ensuring that the family has agency, they have involvement, they have a voice that represents the patient’s values, and we listen very much to that voice,” Udy says. Social workers and psychologists can help support families.

Says Laureys: “This can happen to any of us at any time – a traffic accident, a cardiac arrest – so we should make a living will, but we should also identify a person of trust so that when you can no longer communicate your wishes, they can share it with the doctors.”

“I would never want a family member to think, ‘Well, I turned off somebody; it was my decision to progress down a certain path’ – because that’s a really difficult burden to carry.”

Andrew Udy, intensive care specialist

Doctors aim to reach a consensus with the person’s loved ones on the best course of action. Still, it is ultimately up to the treating doctor to determine what to do. If it remains unclear what the person’s outcome will be after weeks in ICU, doctors can give the patient a tracheotomy, a procedure that allows them to breathe through a tube in the neck to bypass upper-airway complications. Sedatives are tapered off, and they’re moved on to a ward. In some scenarios, recovery could be uncertain for up to 12 months.

Udy says for doctors to advocate for this there has to be some hope of recovery to a level acceptable to the patient. Factors such as age, underlying medical conditions, the severity of the injury, and the acceptability of any long-term impairment, play a role. ”We use this to judge whether inserting a tracheostomy is the best pathway, not always having complete certainty about what the final outcome might be.“

However, if the patient is facing a poor prognosis where life support is merely staving off an inevitable death, the doctor can advise withdrawing life support and moving the person to palliative care. “It is the responsibility of the medical team, or the healthcare system, to make these decisions,” Udy says. “We would never want a family member to think, ‘Well, I turned off somebody; it was my decision to progress down a certain path’ because that’s a really difficult burden to carry. My clinical experience is that most families, when you spend time with them, when you discuss the information – and we often do get third, fourth, fifth opinions – they see the situation is not salvageable.”

In rare cases, a family or a relative will contest the medical advice through tribunals and courts. In Udy’s experience, he can count these cases on one hand. In 2000, the NSW Supreme Court granted a family’s request for a 37-year-old man believed to be in a “vegetative state” to continue to receive life support. The judge found this had been a “premature diagnosis”, and there had been inadequate consultation with the family. By the time of the decision, the man had been moved to a nursing home and was able to respond, write and do several body functions. In a different case in 2004, the NSW Supreme Court upheld the advice of doctors to withdraw life support for a 75-year-old man who had suffered a cardiac arrest and was in a deep coma, finding this was in the patient’s “best interests and welfare”.

Decisions about life support weigh heavily on doctors and nurses. Laureys has spent decades thinking about disorders of consciousness. He has come to the personal conclusion that if he was ever in a minimally conscious state, he “would not want to be kept alive in that condition”. But he doesn’t allow this to influence his view as a practitioner. “This is my personal opinion and I have the utmost respect for the patients I see where it is different. It is not for me to judge.”

What happens when someone does wake?

Nearly three weeks passed, and Fiona was still in a coma. Her family visited at Christmas and took turns holding her hand. “We told her that everyone was waiting for her, and we’re here for you,” says Stuart. “Some people say they can hear what you’re saying. Whether they can or not, I don’t know. But we felt, at least if we talk, perhaps she can.”

The turning point came one day when doctors took Fiona off a ventilator, and she was able to breathe. She opened her eyes, and it was clear to Stuart she recognised her family. At that point, “we knew she was going to come out of this,” he says. She was moved to the hospital’s brain injury unit to start recovery. “That was a pretty good step.”

When patients first wake, it’s unlikely they will say anything coherent. “There’s a lot of reorientation that’s needed,” says Udy. Doctors will tell the person they’re in hospital, what day it is. Questions from the patient tend to come later: What happened to me? I need to go home. What about my pets? What about my partner?

Overwhelmingly, people have no memory of being in a coma. “There’s no reliable scientific study telling us what’s going on,” says Laureys. Sometimes, people have vivid memories that can’t be disentangled from the sedation wearing off as they’ve emerged.

When Melburnian Tim Boyle was rushed to hospital with a rare bowel condition in 2003, he was in an induced coma for about 20 days. “I didn’t know what the hell was going on,” he recalls. “You have all these weird dreams, you don’t know what reality is any more. I was on the seventh floor of St Vincent’s and thought there were people looking in my window all night.” In 2015, he was the first in Australia to have a bowel and kidney transplant, which was done at the Austin Hospital, where he spent weeks in an induced coma as he recovered.

Fiona has no recollection of her fall or the coma, just scattered memories of the months that followed during her rehabilitation. “I remember I didn’t like it. I wanted to be at home, and I didn’t realise the extent of my injury at the time.”

“You just never know what is around the corner, you could be hit by a bus, you could be involved in some sort of accident. We see a significant proportion of people who just seem very unlucky.”

Andrew Udy, intensive care specialist

People who have suffered a brain injury often have their memories wiped for a period after the event, called post-traumatic amnesia. “It means they are not laying down any new memories,” says Natasha Lannin, a neuroscience professor and chair of research and occupational therapy at Alfred Health. The person might not be able to process that they are in hospital or have a head injury.

Recovery relies on the brain’s capacity for neuroplasticity, where it finds new pathways to replace those lost due to cell damage. Specialists will work on the person’s strengths as they emerge from the coma. If they can respond well to commands with eye movement, for example, they could start with therapists holding up coloured cards. “We work with them where they’re at but push them to the next level,” says Lannin. “What we’re teaching is other untapped areas of the brain that are aligned but have never been used for that job before to start taking over that responsibility.”

Research shows hearing someone else speak up to eight times a day can improve a patient’s outcome. “If you can’t be there all the time to talk to them, we recommend just retelling stories and having a headset with that recorded for them,” says Lannin. Smells and images can help, too. “We suggest really large blown-up photographs and familiar items like a doona cover that’s washed with Mum’s washing powder, so it smells not like a hospital but a familiar smell.”

Patients can spend many months in hospitals or rehabilitation facilities. It’s a slow process of rebuilding. “I haven’t met anyone with a very severe brain injury who has got a life that’s consistent with the life they were living before their brain injury,” says Lannin.

Fiona learned to walk again and did therapy for her slurred speech. It was hard work, for five days a week. Her biggest incentive was her daughters, 12 and 9 at the time. Today, she lives a relatively normal, independent life. But it’s taken years for her to come to terms with her injury and the brakes it put on her career, which, as it happens, was as an occupational therapist. “The fact of the matter is I have a severe injury, but people can’t see it, so they don’t know,” she says.

She doesn’t dwell on the time she lost. “You don’t have a lot of insight.” But she does think about how lucky she was. “I’m grateful my friends did come. Very grateful. But, you see, you don’t know what’s going to happen in life, you’ve got to roll with the punches.”

It’s something Andrew Udy has come to understand while working in intensive care, too. “You just never know what is around the corner, you could be hit by a bus, you could be involved in some sort of accident,” he says. “We see a significant proportion of people who just seem very unlucky.”

Mandy has one distinct memory from the day she saw her friend awake again: “She just looked at me and said, ‘Mandy, I’m not dead.’ Those were her first words to me. I just looked at her and giggled and said, ‘No, you’re not Fiona. You made it.’”

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