Brain scans may predict if patients will wake up
April 16th, 2014
03:47 PM ET

Brain scans may predict if patients will wake up

It can be one of the most difficult diagnoses for a doctor to make: whether a brain-damaged patient is in a permanent vegetative state and will never wake up, or if he is in a minimally conscious state and may one day recover.

In fact, for patients with significant swelling in the brain, a doctor's outcome prediction is currently "a little better than flipping a coin," researchers Jamie Sleigh and Catherine Warnaby write in The Lancet this week.

However, a new study published with their editorial suggests that some types of brain imaging could make an accurate diagnosis much more likely.

Some background

Patients who are in a minimally conscious state (MCS) may respond to stimuli; they may reach for a ball, say their name or look at someone as they enter the room, says Dr. Joseph Fins, an expert in neuroethics and brain injury at Weill Cornell Medical College. Minimally conscious patients have the potential to regain consciousness. Patients who are permanently vegetative do not.

Patients in a persistent vegetative state (VS) are unresponsive, even though their brain shows signs of some activity. The patient is essentially in a coma from which he or she is extremely unlikely to recover.

Both conditions are different from brain death, where the brain has stopped functioning altogether. Patients who are brain dead cannot recover.

Doctors have difficulty distinguishing between minimally conscious and vegetative states because the signs of responsiveness are subtle. "The challenge with MCS is that they only do these behavior intermittently, so it's very easy to miss," said Fins.

The study

The Lancet study authors looked at the potential of functional brain imaging to help doctors predict whether patients will regain consciousness. The study was conducted at a hospital in Belgium. Doctors tracked 81 patients who had been diagnosed as being in a minimally conscious state and 41 who'd been diagnosed as being in a vegetative state.

Up to 40% of patients are misdiagnosed in these situations, researchers wrote in the accompanying editorial. Four patients who were conscious but unresponsive were used as a control group. Doctors looked at functional MRI and PET scans for all patients.

The results

Researchers concluded that PET imaging was better than MRI at distinguishing how likely a patient was to recover. A PET scan was about 74% accurate in predicting whether a patient would recover during the study's one-year follow-up period, compared to the MRI's 56% accuracy rate. That's consistent with neurobiology research, says Fins.

The results did not surprise Fins, who explains that PET scans measure metabolic activity in the brain - the glucose, or energy, that the brain is actually using to function. By comparison, an MRI simply looks at the brain's structure.

A third of the patients whom doctors said were unresponsive showed brain activity similar to minimally conscious patients, according to the study. Nine of these patients eventually recovered consciousness.

"Just imagine," Fins said. "These patients are conscious ... To be segregated from the community because you've been misdiagnosed is a tragic thing. This is complicated stuff."


PET scans may eventually help doctors diagnose patients with serious brain injuries, lead study author Steven Laureys says, but it's not ready for widespread use yet. The study was done in a special unit with trained researchers. Using PET as a tool for diagnosis of brain-injured patients too soon could do more harm than good - leading to more misdiagnoses instead of less.

"Functional brain imaging is expensive and technically challenging, but it will almost certainly become cheaper and easier," Sleigh and Warnaby write.

"In the future, we will probably look back in amazement at how we were ever able to practice without it."

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soundoff (12 Responses)
  1. givemeglenn

    If there's even a 1% chance of recovery in this condition, then you have to err on the side that they'll recover, don't you?

    April 17, 2014 at 10:04 | Report abuse | Reply
    • sd

      Perhaps in a world of infinite resources.

      April 17, 2014 at 10:53 | Report abuse |
    • joe

      So if there is a 1% chance that a person may recover in the next 80 years we should keep them alive in a vegetable state? Imagine the 20 year old that is in a car accident and wakes up 90 years old. Did you really do anything nice for them?

      April 17, 2014 at 11:26 | Report abuse |
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      April 19, 2014 at 11:21 | Report abuse |
  2. Mike

    You have a big mistake in this article. They used functional MRI (fMRI) here, which is not a structural scan (that is regular MRI). Like PET, fMRI is used to detect activity in the brain, not make images of its structure. It is done by measuring the blood-oxygen-level dependent (BOLD) signal, which is a result of blood flowing into regions of the brain which were active, providing oxygen to these areas. PET works on a similar principle by measuring the glucose intake by activated areas.

    April 17, 2014 at 10:30 | Report abuse | Reply
    • neurogirl

      Can we up-vote Mike's comment to the top of the page!

      April 17, 2014 at 12:03 | Report abuse |
  3. reasonablebe

    speaking of which, what ever happened to that little girl who was declared brain dead following dental surgery? did her family finally deal with reality and ler her go or do they still have her on continual life support while her body goes through atrophy?

    April 17, 2014 at 12:08 | Report abuse | Reply
  4. d4drd



    you may be watched
    do usa&israel use the internet(facebook,youtube,twitter, chat rooms ..ect)to collect informations,can we call that spying??
    they ask for ur name,age,gender,occupation,location&sometimes political point of veiw?!?!
    do they record&analyse everything we do on the internet,,can they harm you using these informations??
    تحذير قد تكون مراقب
    هل تستخدم امريكا و اسرائيل الانترنت بمواقعه (فيس بوك,يوتيوب,تويتر,غرف الشات....الخ) للتجسس؟
    warning you may be watched
    do usa&israel use the internet(facebook,youtube,twitter, chat rooms ..ect)to collect informations,can we call that spying??
    they ask for ur name,age,gender,occupation,location&sometimes political point of veiw?!?!
    do they record&analyse everything we do on the internet,,can they harm you using these informations??
    تحذير قد تكون مراقب
    هل تستخدم امريكا و اسرائيل الانترنت بمواقعه (فيس بوك,يوتيوب,تويتر,غرف الشات....الخ) للتجسس؟
    warning you may be watched
    do usa&israel use the internet(facebook,youtube,twitter, chat rooms ..ect)to spy??
    do usa&israel use the internet 2 collect informations,,can we call that spying??
    they ask for ur name,age,gender,occupation,location&sometimes political point of veiw?!?!
    do they record&analyse everything we do on the internet,,can they harm you using these informations??

    April 17, 2014 at 12:13 | Report abuse | Reply
  5. helicohunter

    Whether to "pull the plug" is a complicated decision based not only on likelihood of regaining consciousness, but also on what wishes the person had expressed before the accident. Having a complete picture of the damage and brain activity present will be very useful. For example, if someone shows no evidence of consciousness for 6 months or a year, the family may decide that there is little hope of meaningful recovery and the person wouldn't want to live that way. If there's evidence of consciousness, more aggressive treatment and environmental stimulation (music, talking) would be reasonable. Some people with locked-in syndrome manage to be happy, while others want to die. PET scans may be one tool for determining what the patient wants if eye blink communication doesn't work.

    April 17, 2014 at 12:16 | Report abuse | Reply
  6. Geo

    Not sure I believe an of this... In 2006 my husband was a victim of crime, was hit on the head with a BB gun riffle. I was told that on contact he fell flat forward. By the time I got to the hospital he was on life support. He had surgery for the swelling around his brain. I was asked to make a decision after the surgery because he was still unresponsive and as the surgeons put it in a "vegetative state". For 3 days they kept insisting to take him off life support....on the 4th day he comes out his coma and removes everything that was hooked on him. Stayed in the hospital for 3 weeks to monitor hos brain and have surgery for his broken jaw. Other than that he only suffers from occasional vertigo and short term memory loss.....

    April 17, 2014 at 12:20 | Report abuse | Reply
  7. Social Psychologist

    Well put Timmy. Lately I've been designing studies to address the question "Why do people often not act in their own best interest?" If you are correct, it is due to powerful structural forces (e.g. PAC money controlling politicians) that produce cognitive distortion among individuals (e.g., a single payer system will lead to "death panels" and I will lose my free choice). Maybe there is also fear of the unknown; that is, the current system may not be great but I am fairly certain how it works and prefer that to a more unpredictable system.

    April 17, 2014 at 08:58 | Report abuse | Reply
  8. Timmy Suckle

    I kissed my way up to CEO at a health insurance company. Now I take over $1,000,000 of your health care dollars for NO VALUE ADDED to your health care. And that’s just me. Now think about how many other CEOs, VPs, Directors, Managers, etc. are at my company alone. Now multiply that by thousands of others at hundreds of other health insurance companies. From 10 to 25% of your health care dollars go towards administration that adds NO VALUE to your health care. But my company’s PAC dollars will continue to fool you little people into thinking that a single payer system will be bad. Little people like you are so easy to fool. Little people also don’t realize that a single payer system is the ONLY system that would allow little people (as an entire country) to negotiate better health care prices. Little people don’t realize that the Medical Cartels already know that. And that is the reason why the Medical Cartels spend so much PAC money from the hospitals and doctors lobbying against a single payer system. Some little people say that a single payer system would cost you little people more. But if that were true, then wouldn’t the hospitals and doctors WANT that extra money? Yes they would. So why do the Medical Cartels lobby against a single payer system? It’s because the Medical Cartels know it would allow little people to negotiate better health care prices. And that’s what the Medical Cartels are afraid of. Period.
    But us big wigs at insurance companies, hospitals, and pharmacy companies don’t ever need to worry about health care no matter what it costs. We get our health care paid for one way or another by you little people. And we get the little people that work at our companies to contribute to our PACs. And us big wigs say it’s to protect the little peoples’ jobs. But in reality it would be in the little peoples’ best interest to NOT contribute to the PAC. Again, little people are so easily fooled. I won’t ever have to worry about losing my job with so many little people being brain washed by the Medical Cartels’ PAC money. Not only that, the Medical Cartels’ PAC money is used to elect so many republicans that will never allow a single payer system. Republicans have always fought against any meaningful health care reform. But that’s what our Medical Cartels’ PACs pay them for. Politicians can be bought so easily.
    Pretty soon the only people that will be able to afford health care is us big wigs. And that’s the way it should be. We don’t want you little people using up the resources when we need them. And once again, I thank you little people for capping my SS tax at the $117,000 level. Now I only pay 1.17% SS tax and you little people pay 6.2%. Also, thank you for extending my tax breaks. I’m using the extra money on my vacation houses.

    April 17, 2014 at 13:52 | Report abuse | Reply

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