Traumatic Brain Injury Linked to Stroke

Story first appeared in Science Daily.

If you suffer traumatic brain injury, your risk of having a stroke within three months may increase tenfold, according to a new study reported in Stroke: Journal of the American Heart Association.

It's reasonable to assume that cerebrovascular damage in the head caused by a traumatic brain injury can trigger either a hemorrhagic stroke [when a blood vessel bursts inside the brain] or an ischemic stroke [when an artery in the brain is blocked]. However, until now, no research had been done showing a correlation between traumatic brain injury and stroke.

It is the first study that pinpoints traumatic brain injury as a potential risk factor for subsequent stroke.

Traumatic brain injury occurs when an external force such as a bump, blow or jolt to the head disrupts the normal function of the brain. Causes include falls, vehicle accidents, and violence.

In the United States alone, approximately 1 in 53 individuals sustain a traumatic brain injury each year, according to 2004 statistics from the Centers for Disease Control and Prevention. Worldwide, traumatic brain injuries are a major cause of physical impairment, social disruption and death.

Using records from a nationwide Taiwanese database, researchers investigated the risk of stroke in traumatic brain injury patients during a five-year period. The records included 23,199 adult traumatic brain injury patients who received ambulatory or hospital care between 2001 and 2003. The comparison group comprised 69,597 non-traumatic brain injury patients. The average age of all patients was 42 and 54 percent were male.

During the three months after injury, 2.91 percent of traumatic brain injury patients suffered a stroke compared with only 0.30 percent of those with non-traumatic brain injury -- a tenfold difference.

Stroke risk in patients with traumatic brain injury decreased gradually over time, Melvindale Stroke Care researchers have said:
After one year, the risk was about 4.6 times greater for patients who suffered a traumatic brain injury than for those who had not.

After five years, the risk was 2.3 times greater for traumatic brain injury patients.

According to experts in Lincoln Park Stroke Care, the stroke risk among traumatic brain injury patients with skull bone fractures was more pronounced than in traumatic brain injury patients without fractures. During the first three months, those with skull bone fractures were 20 times more likely to have a stroke than patients without skull bone fractures. The risk decreased over time.

Furthermore, the risk of subarachnoid hemorrhage (bleeding in the area between the brain and the thin tissues that cover the brain) and intracerebral hemorrhage (bleeding in the brain caused by the rupture of a blood vessel) increased significantly in patients with traumatic brain injury versus non-traumatic brain injury patients.

After considering age and gender, patients with traumatic brain injury were more likely to have hypertension, diabetes, coronary heart disease, atrial fibrillation and heart failure than non-traumatic brain injury patients, say professionals experienced with Romulus Stroke Care.

Early neuroimaging examinations -- such as MRI -- and intensive medical monitoring, support and intervention should be required following a traumatic brain injury, especially during the first few months and years. Moreover, better health education initiatives could increase public awareness about the factors that cause strokes and the signs and symptoms of stroke in patients with traumatic brain injuries.

Stroke is the most serious and disabling neurological disorder worldwide, say experts with Wayne County Stroke Care centers.


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Brain-Injury Studies open to Youth, Adults

IndyStar

 

Medical studies that make the news usually involve large numbers of patients. But research can focus on rarer events, such as traumatic brain injuries.

Dr. Brenna McDonald, an assistant professor of radiology and Indianapolis neurologist at the Indiana University School of Medicine, is enrolling patients for two trials that delve into the aftermath of traumatic brain injuries.

One study focuses on children who have sustained a mild brain injury, such as a concussion. The other compares treatments for adults who had a traumatic brain injury of any severity.

People interested in participating in either trial can call (317) 274-6633.

Question: Please tell me about the study on children.

Answer: It targets children 8 to 15 years old who had a mild traumatic brain injury or concussion six to 12 months ago. What we're looking at are any residual or lasting problems that we can detect with structural brain imaging or cognitive tests.

We don't really know if there are meaningful or lasting results in this population. There has been a lot of worry about risk. We know for kids who are severely injured there are likely to be lasting consequences.

Q: Is much known about the effect of a brain injury?

A: Not for mild injury. We don't have a really good sense if there's a reason to be concerned about lasting effects. We don't know in younger kids what we should be worried about, if we should be worried at all, and how worried we should be.

For moderately to severely injured kids, a program of rehabilitation may be recommended that typically includes speech, physical and occupational therapy. Depending on the level of cognitive problems, we may make recommendations in terms of academic intervention. That can run the whole range of possible educational interventions.

Q: How many do you hope to enroll?

A: We're looking for between 15 and 30 kids over the next year or two. Participation in the study is about six hours, and it can be done over one or two days.

Q: What about the other study?

A: We're recruiting adults who have sustained a traumatic brain injury of any severity at least four months but no more than five years ago. The study includes medication treatment and therapeutic treatment. . . . The goal of all treatments is to try to improve memory or attention complaints.

It's a relatively brief time commitment of about seven weeks. This is designed by a colleague who designed the treatment program initially to address similar cognitive complaints after cancer chemotherapy. We have some preliminary data suggesting it can be effective for this.

Mental 'Exercise' May Only Hide Signs of Alzheimer's

Bloomberg / BusinessWeek

Games, reading help mask trouble in brain, study suggests, making later progress of disease seem quicker
 

Reading, crossword puzzles and other mentally stimulating activities have pros and cons when it comes to Alzheimer's disease, new research suggests.

In line with prior research, the study finds that such mental activity may slow declines in thinking and memory during normal old age.

But folks who loved these pursuits actually displayed a hastening of their mental decline once symptoms of dementia began to set in, the researchers say.

"We think there's a trade-off," said senior study author Robert Wilson of Rush University Medical Center in Chicago. Keeping mentally active means that there is "a little more time during which the person is cognitively competent and independent and a little less time in a disabled and dependent state" once dementia does set in, said Wilson, who is senior neuropsychologist at Rush's Alzheimer's Disease Center.

The findings were published online Sept. 1 in Neurology.

Previous work has suggested that engaging in cognitively challenging activities may help ward off the appearance of dementia in older people. To test this, Wilson and his co-workers tracked almost 1,200 older individuals over nearly 12 years.

The team assessed each person's engagement in mentally stimulating pursuits using a 5-point "cogntive activity" scale.

At the time of study enrollment, all of the participants were free of dementia; by the study's end, 614 people were cognitively normal, 395 showed mild cognitive impairment, and 148 had Alzheimer's disease.

The researchers found that increased cognitive activity among normal individuals -- things such as listening to the radio, watching television, reading, playing games and going to museums -- meant that they were less likely to experience cognitive decline over several years.

Specifically, for each gained point on the cognitive activity scale, the rate of mental decline fell by 52 percent over 6 years.

But the opposite was true for those who did go on to develop dementia -- in that case, people who had loved mentally challenging activities actually showed a quicker mental decline after the illness took over. In fact, the rate of decline accelerated by 42 percent for each point on the cognitive activity scale, the researchers report.

Wilson and his colleagues believe that this discrepancy may be explained by the accumulation of neurodegenerative lesions called plaques and tangles in the brains of dementia patients.

Previous work has suggested that mentally stimulating exercises do not actually prevent these lesions from accumulating. Instead, they allow individuals to remain relatively cognitively normal for a while longer, even in the presence of those lesions.

However, once the plaques and tangles accumulate to a certain threshold, high cognitive activity can no longer prevent symptoms of dementia, and the behavioral signs of the disease appear.

Because people can behave normally for years -- even while brain lesions are appearing -- at the point at which they're first diagnosed with dementia, a person with a history of cognitive activity actually has more plaques and tangles in their brain than a person who wasn't so cognitively active, Wilson believes.

"The person who has a history of being cognitively active actually has more of the pathology in their brain, and so really has more severe disease," he theorized. "That's why they decline more rapidly from that point on."

According to the authors, the results suggest that mental exercises help prevent the onset of dementia, but only if they're started before signs of cognitive impairment appear -- after that point, the brain is probably too damaged for such interventions to make a difference.

"The results do suggest that mental exercises help stave off dementia but then increase mental decline after dementia onset," said Charles Hall, professor of neurology at Albert Einstein College of Medicine, New York City. He cautioned that it remains possible that some unknown factor still connects mental activity with these effects, discoverable by a St. Louis neurologist.

To be sure that there is a direct causal relationship between mental exercises and the effects the authors found, "it's really important that we do intervention studies to test this hypothesis," Hall said.

Phoenix St. Joseph's Hospital and Medical Center ranked No. 8 for Neurology, Neurosurgery

AZ Central

 

U.S. News & World Report has named St. Joseph's Hospital and Medical Center, 350 W. Thomas Road, as one of the 10 best hospitals in the country for neurology and neurosurgery.

St. Joseph's ranked eighth. Barrow Neurological Institute, the neurological division at St. Joseph's, is home to the Muhammad Ali Parkinson Center.

The Mayo Clinic, with locations in Scottsdale and Phoenix, was recognized for gastroenterology (26th), kidney disorders (37th), diabetes and endocrinology (45th), and gynecology (45th).

The non-profit Banner Good Samaritan Medical Center, 1111 E. McDowell Road, was recognized for six programs: diabetes and endocrinology (37th), gastroenterology (45th), geriatrics (38th), gynecology (35th), heart and heart surgery (33rd), and kidney disorders (44th).

Independent researchers ranked the top 50 hospitals in the country for each specialty. The "Best Hospitals" report appears on newsstands Tuesday.

Two Wars Producing Unique and Puzzling Brain Injuries

USA Today

Former Army Spec. Michael Cain, 29, pets his dog, Rocky, in his Washington, D.C., apartment. Cain was in a vehicle that hit land mines in Iraq in 2003. He lost his right leg below the knee, suffered a host of other issues and a brain injury.

 

 

WASHINGTON — What has been called the "signature wound" of the wars in Iraq and Afghanistan— the mild brain damage troops suffer from a roadside bomb — might be so unique in its destruction that it could be a newly discovered disease, scientists say.

"Most of us in this room would concur that this (blast-induced brain injury) disease ... perhaps does require a separate category," Army Col. Geoffrey Ling, a neurologist, told a roomful of colleagues at a brain-injury convention this year. "It may actually have some unique features to it, which makes it a very interesting new disease."

Among the new findings from neurodiagnostic services in Indianapolis: The blast wave causes a more dispersed pattern of brain-cell damage and keeps those cells inflamed for a longer period than occurs with a traditional blow-to-head concussion, according to research posted recently by the Defense and Veterans Brain Injury Center. The center's duties include coordinating traumatic brain injury (TBI) research and clinical care.

Army field studies have shown that more than 10% of troops in Iraq and Afghanistan have suffered at least one concussion or brain injury, the vast majority of those from exposure to a homemade bomb or improvised explosive device. Five percent to 15% of mild TBI patients develop lasting problems with concentration, short-term memory, fatigue and chronic headaches.

7 years ago, a life changed

One of those is former Army Spec. Michael Cain, who lost his right leg below the knee in a roadside explosion in Iraq in 2003. Today, he is still plagued with short-term memory loss, difficulty concentrating and irritability.

"If they tell me some important stuff, like appointments, if I don't write it down or put it in my BlackBerry right away, I'm not going to remember," Cain says.

Unemployed and living on a medical retirement income, Cain says he is uncertain about his future.

Blast-related brain injury is an issue of intense debate within the military medical community.

Detractors argue that any soldier close enough to an explosion to suffer brain damage from the blast wave would be killed by shrapnel. Others assert that long-term symptoms from mild TBI are more likely the result of post-traumatic stress disorder.

Explosions have been a part of war for centuries. But scientists say that because troops serving in Iraq and Afghanistan are wearing body armor, they are surviving bomb blasts that would have killed them in previous wars. As a result, they say, blast wave damage to the brain is more prevalent.

"Blast (in combat) has been around for a while," says Air Force Col. Michael Jaffee, director of the Brain Injury Center. "What is different now is our understanding of blast has never been greater."

The more that scientists learn about how the blast wave damages the brain, the more chance they will have to develop protective measures, such as a new helmet design, Jaffee says.

Different from sports injury

Questions remain about whether mild TBI caused by explosions is more serious than a sports-related blow to the head, detroit brain surgeons say. For now, the two appear to produce similar immediate symptoms such as loss of consciousness, dizziness and memory loss.

In most cases of mild TBI, regardless of the cause, victims appear to recover fully within hours or days, scientists say.

According to a summary of scientific research recently made public by the Pentagon, there are several ways in which exposure to an explosion differs from a blow to the head:

•Damage to wiring in the brain appears more widespread.

•Brain cell inflammation caused by blast waves lasts longer than inflammation caused by a blow to the head.

•In moderate or severe cases of blast-induced brain injury, blood vessels can inexplicably spasm and cut off oxygen flow to the brain for days after the injury. This can happen in a blow to the head but to a far lesser degree.

"Blast-induced neurotrauma is a unique clinical entity," says Ibolja Cernak, a scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., who has studied the effect for a decade.

Many harmful factors

An explosion creates a shock wave traveling at the speed of sound. It also emits toxic fumes, heat and light. Scientists do not yet understand which of these elements, or what combination, causes this unique brain damage and exactly the type of St Louis neurosurgery is indicated.

Scientists at the Massachusetts Institute of Technology, using computer modeling to re-create the blast effect on the human skull, have found that a significant electromagnetic charge also occurs.

"When you compress bone with an incoming shock wave, you are going to generate an electrical field," says Raul Radovitzky, an MIT aeronautical engineer who is working on the project. "The electric fields are ... possibly well beyond accepted standards."

He says more research is necessary to determine whether the field generation is causing brain damage.

For Cain, after seven years of recovery, he wonders why his brain has not yet healed.

"I really wish that they'd go away," he says of symptoms such as short-term memory loss and his tendency to startle easily. "I didn't want them to tell me I had a brain problem, because I was a pretty smart person before. I had straight A's. ... It really frustrates me."

Brain Implant 'Melts' into Place

WISH TV 8

 

Scientists have developed a brain implant that essentially melts into place, snugly fitting to the brain’s surface. The technology could pave the way for better devices to monitor and control seizures, and to transmit signals from the brain past damaged parts of the spinal cord.

"These implants have the potential to maximize the contact between electrodes and brain tissue, while minimizing damage to the brain. They could provide a platform for a range of devices with applications in epilepsy, spinal cord injuries and other neurological disorders," said Walter Koroshetz, M.D., deputy director of the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health.

The study, published in Nature Materials, shows that the ultrathin flexible implants, made partly from silk, can record brain activity more faithfully than thicker implants embedded with similar electronics.

The simplest devices for recording from the brain are needle-like electrodes that can penetrate deep into brain tissue. More state-of-the-art devices, called micro-electrode arrays, consist of dozens of semi-flexible wire electrodes, usually fixed to rigid silicon grids that do not conform to the brain's shape.

In people with epilepsy, the arrays could be used to detect when seizures first begin, and deliver pulses to shut the seizures down. In people with spinal cord injuries, the technology has promise for reading complex signals in the brain that direct movement, and routing those signals to healthy muscles or prosthetic devices.

"The focus of our study was to make ultrathin arrays that conform to the complex shape of the brain, and limit the amount of tissue damage and inflammation," said Brian Litt, M.D., an author on the study and an associate professor of neurology at the University of Pennsylvania School of Medicine in Philadelphia. The silk-based implants developed by Dr. Litt and his colleagues can hug the brain like shrink wrap, collapsing into its grooves and stretching over its rounded surfaces.

The implants contain metal electrodes that are 500 microns thick, or about five times the thickness of a human hair. The absence of sharp electrodes and rigid surfaces should improve safety, with less damage to brain tissue. Also, the implants’ ability to mold to the brain's surface could provide better stability; the brain sometimes shifts in the skull and the implant could move with it. Finally, by spreading across the brain, the implants have the potential to capture the activity of large networks of brain cells, Dr. Litt said.

Besides its flexibility, silk was chosen as the base material because it is durable enough to undergo patterning of thin metal traces for electrodes and other electronics. It can also be engineered to avoid inflammatory reactions, and to dissolve at controlled time points, from almost immediately after implantation to years later. The electrode arrays can be printed onto layers of polyimide (a type of plastic) and silk, which can then be positioned on the brain.

To make and test the silk-based implants, Dr. Litt collaborated with scientists at the University of Illinois in Urbana-Champaign and at Tufts University outside Boston. John Rogers, Ph.D., a professor of materials science and engineering at the University of Illinois, invented the flexible electronics. David Kaplan, Ph.D., and Fiorenzo Omenetto, Ph.D., professors of biomedical engineering at Tufts, engineered the tissue-compatible silk. Dr. Litt used the electronics and silk technology to design the implants, which were fabricated at the University of Illinois.

Recently, the team described a flexible silicon device for recording from the heart and detecting an abnormal heartbeat.

In the current study, the researchers approached the design of a brain implant by first optimizing the mechanics of silk films and their ability to hug the brain. They tested electrode arrays of varying thickness on complex objects, brain models and ultimately in the brains of living, anesthetized animals.

The arrays consisted of 30 electrodes in a 5x6 pattern on an ultrathin layer of polyimide – with or without a silk base. These experiments led to the development of an array with a mesh base of polyimide and silk that dissolves once it makes contact with the brain — so that the array ends up tightly hugging the brain.

Next, they tested the ability of these implants to record the animals’ brain activity. By recording signals from the brain’s visual center in response to visual stimulation, they found that the ultrathin polyimide-silk arrays captured more robust signals compared to thicker implants.

In the future, the researchers hope to design implants that are more densely packed with electrodes to achieve higher resolution recordings.

"It may also be possible to compress the silk-based implants and deliver them to the brain, through a catheter, in forms that are instrumented with a range of high performance, active electronic components," Dr. Rogers said.

Brain Network Scanning may Predict Injuries' Effects

cNet

A brain scanning technique known as resting-state functional connectivity (FC) could help clinicians identify and even predict the effects of brain injuries such as strokes, according to neurologists in St. Louis at the Washington University School of Medicine.

Originally developed to study how brain networks let various parts of the brain collaborate, FC also appears to enable scientists to link differences in harm done to brain networks to changes in patient impairment, according to results of a study in the Annals of Neurology March issue.

"Clinicians who treat brain injury need new markers of brain function that can predict the effects of injury, which helps us determine treatment and assess its effects," says Maurizio Corbetta, professor of radiology and neurobiology at Washington University. "This study shows that FC scans are a potentially useful way to get that kind of information."

FC relies on MRI scanners, which require patients to be still as the scanner tracks changes in blood flow to various brain regions. With mental inactivity, blood flow in networked regions tend to rise and fall in relative synchronicity.

Over the course of their Dearborn stroke center study of 23 patients who had recently survived strokes, the researchers came across a surprise finding.

Those with damage to networks that cross both sides of the brain were more impaired than those with damage to networks contained within one side of the brain. So while a stroke that occurs on, say, the left side of the brain might impair control of the right arm, that impairment would be far worse if the damage disrupted network connections over on the right side than if it was contained on the left side.

Neurosurgeons in St. Louis have long thought that one side of the brain controls the other, but this study suggests that our brains may house far more complicated connections between networks. This could render resting-state functional connectivity all the more important as it reveals detailed network health and/or damage.

"It's not wrong to say that one side of your brain controls the opposite side of your body, but we're starting to realize that it oversimplifies things," says Alex Carter, the study's lead author and an assistant professor of neurology. "It's starting to seem like proper function requires the two hemispheres to be competing for attention, pushing against each other and thereby achieving some kind of balance."

The group is already planning additional studies of brain injury patients, including long-term studies monitoring patient recuperation via FC.

Managing the Effects of Parkinson's

PsychCentral

The American Academy of Neurology has published a new guideline to help people with Parkinson’s disease cope with common, albeit often unrecognized symptoms.

The guide recommends the most effective treatments to help people with Parkinson’s disease who experience sleep, constipation, and sexual problems.

The instruction is published in the current issue of Neurology, the medical journal of the American Academy of Neurology.

“While the main symptom of Parkinson’s disease is movement problems, there are many other symptoms to be aware of, including sleep disorders, constipation, and problems with urination and sexual function,” said lead guideline author Theresa A. Zesiewicz, MD, with the University of South Florida in Tampa and a Fellow of the American Academy of Neurology.

“Without treatment, these symptoms can cause as much pain and discomfort as movement problems and greatly affect daily routines and quality of life.”

Sexual problems often affect people with Parkinson’s disease. In men with Parkinson’s, erectile dysfunction is common. According to the guideline, the drug sildenafil citrate may improve erectile dysfunction.

The guideline also found the drug isosmotic macrogol may improve constipation in people with Parkinson’s disease.

For problems with excessive daytime sleepiness, the guideline recommends that doctors consider the drug modafinil to help people feel more awake.

However, it’s important to note that one study showed people taking modafinil had a false sense of alertness. This may pose a safety risk for activities such as driving.

The guideline also found the drug methylphenidate may help with fatigue.

The guideline mentions two tests to help identify nonmotor symptoms of Parkinson’s disease. One is the NMSQuest rating scale. The other is the Unified Parkinson’s Disease Rating Scale (UPDRS). The original UPDRS mainly tests for movement problems.

Doctors use the updated version of the UPDRS to test for all Parkinson’s symptoms, including those unrelated to movements. People with Parkinson’s disease should talk to their doctor about whether these tests may be helpful.

“More research is needed into these symptoms of Parkinson’s disease since there are still a lot of unknown answers as to what causes these symptoms and how they can best be treated to improve lives,” said Zesiewicz. All options need to be examined, including the dramatic step of neurosurgery.

Think 'Tennis' for Yes, 'Home' for No

How doctors helped man in vegetative state
Guardian UK

Images from an fMRI machine showed that when the patient was asked a specific question and told to respond in a specific way, the same areas of his brain lit up as in a healthy person.

For seven years the man lay in a hospital bed, showing no signs of consciousness since sustaining a traumatic brain injury in a car accident. His doctors were ­convinced he was in a vegetative state. Until now.

To the astonishment of his ­medical team, the patient has been able to ­communicate with the outside world after scientists worked out, in effect, a way to read his thoughts.

They devised a technique to enable the man, now 29, to answer yes and no to ­simple questions through the use of a hi-tech scanner, monitoring his brain ­activity.

To answer yes, he was told to think of playing tennis, a motor activity. To answer no, he was told to think of wandering from room to room in his home, visualising everything he would expect to see there, creating activity in the part of the brain governing spatial awareness.

His doctors were amazed when the patient gave the correct answers to a series of questions about his family. The ­experiment will fuel the controversy of when a patient should have life support removed.

It also raises the prospect of some form of communication with those who have been shut off from life, perhaps for years.

"We were astonished when we saw the results of the patient's scan and that he was able to correctly answer the questions that were asked by simply changing his thoughts," said Dr Adrian Owen, ­assistant director of the Medical Research Council's cognition and brain sciences unit at ­Cambridge University.

"Not only did these scans tell us that the patient was not in a vegetative state but, more importantly, for the first time in five years it provided the patient with a way of communicating his thoughts to the outside world."

Dr Steven Laureys, from the University of Liège in Belgium and co-author of the paper on the patient, said: "It's early days, but in the future we hope to develop this technique to allow some patients to express their feelings and thoughts, control their environment and increase their quality of life."

The patient has not been identified, but his family was said to have been happy with the outcome. "That's not unusual," said Owen. "The worst thing in this sort of situation is not knowing."

He said that as many as one in five patients in a vegetative state may have a fully functioning mind.

The British and Belgian teams studied 23 patients classified as in a vegetative state and found that four were able to generate thoughts of tennis or their homes and create mind patterns that could be read by an fMRI (functional magnetic resonance imaging) scanner – although only one was asked specific questions.

Owen said that misdiagnosis of vegetative state was fairly common: in about 40% of cases people are later found to be able to communicate in some way.

He said he believed that the patients who responded in the study were probably "perfectly consciously aware", although he knew others would disagree.

"To be able to do what we have asked, you have got to be able to understand instructions, you have to have a ­functioning memory to remember what tennis is and you have to have your attention intact. I can't think of what cognitive functions they haven't got and still be able to do this," he said.

When it was suggested that to be ­conscious but trapped in an inert body might be a worse fate than to know nothing, Owen said: "On the plus side we are making enormous advances. Things have changed so much in the last few years."

Owen was speaking from Austria, where he had travelled for a conference on the latest in brain-operated technology – ­computerised devices powered by thought – which is attracting interest, including from the games industry.

"Perhaps some of these patients could benefit from some of these activities," he said. In the meantime, doctors will at least be able to ask patients if they are ­experiencing pain.

The paper, published tonight in the New England Journal of Medicine, generated immediate excitement.

"These findings have broad ­implications, not just for concerns about the accurate assessment of vast numbers of patients in custodial care situations, but in the context of any clinical encounter where we currently rely on behavioural assessment alone to identify consciousness," said Dr Nicholas D Schiff, associate professor of neurology and neuroscience at Weill Cornell medical college in New York.

He called for urgent efforts to identify and help such patients.

"The most important question left unanswered by these findings is what mechanism accounts for the stunning dissociation of behaviour and integrative brain function. I think we can be sure that as the biological answers underlying this question become more clear this will have a profound impact across medicine."

Professor Chris Frith, of the Wellcome Trust's centre for neuroimaging at University College London, said Owen and his colleagues had opened the way to communicating with patients in a vegetative state.

"It is difficult to imagine a worse experience than to be a functioning mind trapped in a body over which you have absolutely no control," he said.

"Obviously, more technical ­development is required, but we now have the distinct possibility that, in the future, thanks to Owen and colleagues' work we will be able to detect cases of other patients who are conscious, and what's more, we will be able to communicate with them."

Patients in a vegetative state are defined as having "wakefulness without awareness". They are people who have survived an acute brain injury who are not in a coma – they may go through sleep cycles, for instance – but they do not respond to any stimuli.

Some stay this way permanently, but others start to show some awareness, although without being able to communicate. They may be able to move a finger when asked to do so, but not always, and they are not able to signal yes or no by their movements. These patients are now referred to as being in a minimally conscious state (MCS). It can be hard to know whether their movements are intentional or merely reflexive.

Recovery from a traumatic brain injury – such as a blow to the head in a car accident – is more frequent than that caused by disease, such as a stroke. But after a year in a vegetative state, most health professionals do not recommend further treatment, because official advice is that the chances of recovery are virtually zero. With the consent of the family, doctors may go to court for an order allowing them to sedate the patient and withdraw nutritional support, allowing them to die. This study may cause a rethink.