Posts tagged TBI
Articles and news from the latest research reports.
One gene influences recovery from traumatic brain injury
Researchers report that one tiny variation in the sequence of a gene may cause some people to be more impaired by traumatic brain injury (TBI) than others with comparable wounds.
The study, described in the journal PLOS ONE, measured general intelligence in a group of 156 Vietnam War veterans who suffered penetrating head injuries during the war. All of the study subjects had damage to the prefrontal cortex, a brain region behind the forehead that is important to cognitive tasks such as planning, problem-solving, self-restraint and complex thought.
The researchers controlled for the size and location of subjects’ brain injuries and other factors, such as intelligence prior to injury, which might have contributed to differences in cognitive function. (Prior to combat, the veterans had completed the Armed Forces Qualifications Test, which included measures of intelligence that provided a baseline for the new analysis.)
“We administered a large, cognitive battery of tests to investigate how they performed after their injury,” said study leader Aron Barbey, a professor of speech and hearing science, of psychology and of neuroscience at the University of Illinois. “And we had a team of neurologists who helped characterize the nature and scope of the patients’ brain injuries.”
The researchers also collected blood for a genetic analysis, focusing on a gene known as BDNF (brain-derived neurotrophic factor).
The team found that a single polymorphism (a difference in one “letter” of the sequence) in the BDNF gene accounted for significant differences in intelligence among those with similar injuries and comparable intelligence before being injured.
“BDNF is a basic growth factor and it’s related to neurogenesis, the production of new neurons,” Barbey said. “What we found is that if people have a specific polymorphism in the BDNF gene, they recovered to a greater extent than those with a different variant of the gene.”
The change in the gene alters the BDNF protein: The amino acid methionine (Met) is incorporated at a specific site in the protein instead of valine (Val). Since people inherit two versions of each gene, one from each parent, they have either Val/Val, Val/Met or Met/Met variants of the gene.
“The effects of this difference were large – very large,” Barbey said. “If an individual had the Val/Val combination, then their performance on a battery of cognitive tests (conducted long after the injury occurred) was remarkably lower than that of individuals who had the Val/Met or Met/Met combination.”
On average, those with the Val/Val polymorphism scored about eight IQ points lower on tests of general intelligence than those with the Val/Met or Met/Met variants, Barbey said. Those with the Val/Val variant also were significantly more impaired in “specific competencies for intelligence like verbal comprehension, perceptual organization, working memory and processing speed,” he said.
To test these results, the researchers did the analysis over again “in a subset of individuals who had very similar (brain injuries) to the other group,” Barbey said. “We found the same kind of effects, suggesting that lesion location isn’t a factor influencing the difference between the groups.”
The finding opens a new avenue of exploration for treatments to aid the process of recovery from TBI, Barbey said.
(Source: news.illinois.edu)
How Well Do Football Helmets Protect Players from Concussions?
A new study finds that football helmets currently used on the field may do little to protect against hits to the side of the head, or rotational force, an often dangerous source of brain injury and encephalopathy. The study released today will be presented at the American Academy of Neurology’s 66th Annual Meeting in Philadelphia, April 26 to May 3, 2014.
"Protection against concussion and complications of brain injury is especially important for young players, including elementary and middle school, high school and college athletes, whose still-developing brains are more susceptible to the lasting effects of trauma," said study co- author Frank Conidi, MD, DO, MS, director of the Florida Center for Headache and Sports Neurology and Assistant Clinical Professor of Neurology at Florida State University College of Medicine in Port Saint Lucie, Fla. Conidi is also the vice chair of the American Academy of Neurology’s Sports Neurology Section.
For the study, researchers modified the standard drop test system, approved by the National Operating Committee on Standards for Athletic Equipment, that tests impacts and helmet safety. The researchers used a crash test dummy head and neck to simulate impact. Sensors were also placed in the dummy’s head to measure linear and rotational responses to repeated 12 mile-per-hour impacts. The scientists conducted 330 tests to measure how well 10 popular football helmet designs protected against traumatic brain injury, including: Adams a2000, Rawlings Quantum, Riddell 360, Riddell Revolution, Riddell Revolution Speed, Riddell VSR4, Schutt Air Advantage, Schutt DNA Pro+, Xenith X1 and Xenith X2.
The study found that football helmets on average reduced the risk of traumatic brain injury by only 20 percent compared to not wearing a helmet. Of the 10 helmet brands tested, the Adams a2000 provided the best protection against concussion and the Schutt Air Advantage the worst. Overall, the Riddell 360 provided the most protection against closed head injury and the Adams a2000 the least, despite rating the best against concussion.
"Alarmingly, those that offered the least protection are among the most popular on the field," said Conidi. "Biomechanics researchers have long understood that rotational forces, not linear forces, are responsible for serious brain damage including concussion, brain injury complications and brain bleeds. Yet generations of football and other sports participants have been under the assumption that their brains are protected by their investment in headwear protection."
The study found that football helmets provided protection from linear impacts, or those leading to bruising and skull fracture. Compared to tests using dummies with no helmets, leading football helmets reduced the risk of skull fracture by 60 to 70 percent and reduced the risk of focal brain tissue bruising by 70 to 80 percent.
The study was supported by BRAINS, Inc., a research and development company based in San Antonio, Fla., focused on biomechanics of traumatic brain injury.
How our brain networks: Research reveals white matter ‘scaffold’ of human brain
For the first time, neuroscientists have systematically identified the white matter “scaffold” of the human brain, the critical communications network that supports brain function.
Their work, published Feb. 11 in the open-source journal Frontiers in Human Neuroscience, has major implications for understanding brain injury and disease. By detailing the connections that have the greatest influence over all other connections, the researchers offer not only a landmark first map of core white matter pathways, but also show which connections may be most vulnerable to damage.
"We coined the term white matter ‘scaffold’ because this network defines the information architecture which supports brain function," said senior author John Darrell Van Horn of the USC Institute for Neuroimaging and Informatics and the Laboratory of Neuro Imaging at USC.
"While all connections in the brain have their importance, there are particular links which are the major players," Van Horn said.
Using MRI data from a large sample of 110 individuals, lead author Andrei Irimia, also of the USC Institute for Neuroimaging and Informatics, and Van Horn systematically simulated the effects of damaging each white matter pathway.
They found that the most important areas of white and gray matter don’t always overlap. Gray matter is the outermost portion of the brain containing the neurons where information is processed and stored. Past research has identified the areas of gray matter that are disproportionately affected by injury.
But the current study shows that the most vulnerable white matter pathways – the core “scaffolding” – are not necessarily just the connections among the most vulnerable areas of gray matter, helping explain why seemingly small brain injuries may have such devastating effects.
"Sometimes people experience a head injury which seems severe but from which they are able to recover. On the other hand, some people have a seemingly small injury which has very serious clinical effects," says Van Horn, associate professor of neurology at the Keck School of Medicine of USC. "This research helps us to better address clinical challenges such as traumatic brain injury and to determine what makes certain white matter pathways particularly vulnerable and important."
The researchers compare their brain imaging analysis to models used for understanding social networks. To get a sense of how the brain works, Irimia and Van Horn did not focus only on the most prominent gray matter nodes – which are akin to the individuals within a social network. Nor did they merely look at how connected those nodes are.
Rather, they also examined the strength of these white matter connections, i.e. which connections seemed to be particularly sensitive or to cause the greatest repercussions across the network when removed. Those connections which created the greatest changes form the network “scaffold.”
"Just as when you remove the internet connection to your computer you won’t get your email anymore, there are white matter pathways which result in large scale communication failures in the brain when damaged," Van Horn said.
When white matter pathways are damaged, brain areas served by those connections may wither or have their functions taken over by other brain regions, the researchers explain. Irimia and Van Horn’s research on core white matter connections is part of a worldwide scientific effort to map the 100 billion neurons and 1,000 trillion connections in the living human brain, led by the Human Connectome Project and the Laboratory of Neuro Imaging at USC.
Irimia notes that, “these new findings on the brain’s network scaffold help inform clinicians about the neurological impacts of brain diseases such as multiple sclerosis, Alzheimer’s disease, as well as major brain injury. Sports organizations, the military and the US government have considerable interest in understanding brain disorders, and our work contributes to that of other scientists in this exciting era for brain research.”
Head first: reshaping how traumatic brain injury is treated
Traumatic brain injury affects 10 million people a year worldwide and is the leading cause of death and disability in children and young adults. A new study will identify how to match treatments to patients, to achieve the best possible outcome for recovery.
The human brain – despite being encased snugly within its protective skull – is terrifyingly vulnerable to traumatic injury. A severe blow to the head can set in train a series of events that continue to play out for months, years and even decades ahead. First, there is bleeding, clotting and bruising at the site of impact. If the blow is forceful enough, the brain is thrust against the far side of the skull, where bony ridges cause blood vessels to lacerate. Sliding of grey matter over white matter can irreparably shear nerve fibres, causing damage that has physical, cognitive and behavioural consequences. As response mechanisms activate, the brain then swells, increasing intracranial pressure, and closing down parts of the microcirculatory network, reducing the passage of oxygen from blood vessels into the tissues, and causing further tissue injury.
It is the global nature of the damage – involving many parts of the brain – that defines these types of traumatic brain injuries (TBIs), which might result from transport accidents, assaults, falls or sporting injuries. Unfortunately, both the pattern of damage and the eventual outcome are extremely variable from patient to patient.
“This variability has meant that TBI is often considered as the most complex disease in our most complex organ,” said Professor David Menon, Co-Chair of the Acute Brain Injury Programme at the University of Cambridge. “Despite advances in care, the sad truth is that we are no closer to knowing how to navigate past this variability to the point where we can link the particular characteristics of a TBI to the best treatment and outcome.”
Read moreGroundbreaking Research Explores Link Between Traumatic Brain Injury and Sleep
It has long been believed that a person with a concussion should stay awake or not sleep for more than a few hours at a time.
But there appears to be no medical evidence to support that idea, according to a study regarding the relationship between traumatic brain injury, also known as TBI, and sleepiness conducted by scientists at Barrow Neurological Institute at Phoenix Children’s Hospital and the University of Arizona College of Medicine – Phoenix.
"This translational research study lays the foundation for understanding the immediate impact of brain injury on a person’s physiology. In this case, substantial post-traumatic sleep occurred regardless of injury timing or severity," said Jonathan Lifshitz, director of the Translational Neurotrauma Program at Barrow Neurological Institute at Phoenix Children’s Hospital and an associate professor at the UA College of Medicine – Phoenix. "These studies explore sleep as an immediate response to TBI."
Traumatic brain injury is a major cause of death and disability throughout the world with little pharmacological treatment for the individuals who suffer from lifelong problems associated with TBI. Clinical studies have provided evidence to support the claim that brain injury contributes to chronic sleep disturbances as well as excessive daytime sleepiness. Clinical observations have reported excessive sleepiness immediately following traumatic brain injury. However; there is a lack of experimental evidence to support or refute the benefit of sleep following a brain injury.
"We know that some individuals after a traumatic brain injury become excessively sleepy and some cannot sleep at all. It is not well understood why this occurs as mechanisms of injury, and locations of injury are not always consistent between clinical phenotypes of normal sleep, hypersomnia and insomnia," said Matthew Troester, a neurologist and sleep specialist at Phoenix Children’s Hospital and a clinical assistant professor at the UA College of Medicine – Phoenix.
Lifshiz and his associates are breaking new ground with descriptions of sleep in the acute – or immediately after injury – state, where little is known clinically, Troester added.
"They demonstrate that the subjects slept immediately and similarly post-injury no matter the severity of the injury or time of day the injury occurred. This tells us that the brain is reacting to the injury in a very specific manner – not something we always see clinically – and, ultimately, this may help us better understand what the role of sleep is in brain injury" such as being restorative, protective or merely a consequence of the injury, he said. "It is an exciting beginning."
This initial study is phase one of the Post-Traumatic Sleep Study. Phase two is in the works. The research will look to provide medical evidence for sleeping after a concussion.
(Source: uanews.org)
Head injuries triple long-term risk of early death
Survivors of traumatic brain injuries (TBI) are three times more likely to die prematurely than the general population, often from suicide or fatal injuries, finds an Oxford University-led study.
A TBI is a blow to the head that leads to a skull fracture, internal bleeding, loss of consciousness for longer than an hour or a combination of these symptoms. Michael Schumacher’s recent skiing injury is an example of a TBI. Concussions, sometimes called mild TBIs, do not present with these symptoms and were analysed separately in this study.
Researchers examined Swedish medical records going back 41 years covering 218,300 TBI survivors, 150,513 siblings of TBI survivors and over two million control cases matched by sex and age from the general population. The work was carried out by researchers at Oxford University and the Karolinska Institute in Stockholm.
'We found that people who survive six months after TBI remain three times more likely to die prematurely than the control population and 2.6 times more likely to die than unaffected siblings,' said study leader Dr Seena Fazel, a Wellcome Trust Senior Research Fellow in Oxford University's Department of Psychiatry. 'Looking at siblings who did not suffer TBIs allows us to control for genetic factors and early upbringing, so it is striking to see that the effect remains strong even after controlling for these.'
The results, published in the journal JAMA Psychiatry, show that TBI survivors who also have a history of substance abuse or psychiatric disorders are at highest risk of premature death. Premature deaths were defined as before age 56. The main causes of premature death in TBI survivors are suicide and fatal injuries such as car accidents and falls.
'TBI survivors are more than twice as likely to kill themselves as unaffected siblings, many of whom were diagnosed with psychiatric disorders after their TBI,' said Dr Fazel. 'Current guidelines do not recommend assessments of mental health or suicide risk in TBI patients, instead focusing on short-term survival. Looking at these findings, it may make more sense to treat some TBI patients as suffering from a chronic problem requiring longer term management just like epilepsy or diabetes. TBI survivors should be monitored carefully for signs of depression, substance abuse and other psychiatric disorders, which are all treatable conditions.'
The exact reasons for the increased risk of premature death are unknown but may involve damage to the parts of the brain responsible for judgement, decision making and risk taking. TBI survivors are three times more likely to die from fatal injuries which may be a result of impaired judgement or reactions.
'This study highlights the important and as yet unanswered question of why TBI survivors are more likely to die young, but it may be that serious brain trauma has lasting effects on people's judgement,' suggests Dr Fazel. 'People who have survived the acute effects of TBI should be more informed about these risks and how to reduce their impact.'
'When treating traumatic brain injuries focus is placed on immediate treatment and recovery of patients,' says Dr John Williams, Head of Neuroscience and Mental Health at the Wellcome Trust. 'This new finding offers important insight into the longer-term impact of TBIs on the brain and their effect on survival later in life. We hope that further research into understanding which parts of the brain are responsible will help improve future management programmes and reduce the potential for premature death.'
Even relatively minor brain injuries, concussions, had a significant impact on early mortality. People with concussion were found to be twice as likely to die prematurely as the control population, with suicide and fatal injuries as the main causes of death. This raises issues surrounding concussions in a wide range of sports, from American football, rugby and soccer to baseball and cricket.
(Source: ox.ac.uk)
Veterans’ Head Injury Examined
Roadside bombs and other blasts have made head injury the “signature wound” of the Iraq and Afghanistan conflicts. Most combat veterans recover from mild traumatic brain injury, also known as concussion, but a small minority experience significant and long-term side effects.
Now, researchers at Albert Einstein College of Medicine of Yeshiva University, in cooperation with Resurrecting Lives Foundation, are investigating the effect of repeated combat-related blast exposures on the brains of veterans with the goal of improving diagnostics and treatment.
Mild traumatic brain injury can cause problems with cognition, concentration, memory and emotional control as well as post-traumatic stress disorder (PTSD). Einstein scientists are using advanced MRI technology and psychological tests to investigate the structural and biological impact of repeated head injury on the brain and to assess how these injuries affect cognitive function.
"Right now, doctors diagnose concussion purely on the basis of someone’s symptoms," said Michael Lipton, M.D., Ph.D., associate director of Einstein’s Gruss Magnetic Resonance Research Center. "We hope that our research will lead to a more scientifically valid diagnostic technique—one that uses imaging to not only detect the underlying brain injury but reveal its severity. Such a technique could also objectively evaluate therapies aimed at healing the brain injuries responsible for concussions." Dr. Lipton is also associate professor of radiology, of psychiatry and behavioral sciences and of neuroscience at Einstein and medical director of MRI services at Montefiore Medical Center, the University Hospital for Einstein.
The Einstein researchers are studying 20 veterans from Ohio and Michigan who were deployed in Iraq and Afghanistan and have exhibited symptoms of repeated concussion. Twenty of the veterans’ siblings or cousins without concussion are acting as controls. The researchers are using an advanced MRI-based imaging technique called diffusion tensor imaging (DTI) to identify injured brain areas.
DTI “sees” the movement of water molecules within and along axons, the nerve fibers that constitute the brain’s white matter. This imaging technique allows researchers to measure the uniformity of water movement (called fractional anisotropy, or FA) throughout the brain. Abnormally low FA within white matter indicates axon damage and has previously been associated with cognitive impairment in patients with traumatic brain injury. (The researchers also use DTI in an ongoing study of amateur soccer players to assess possible brain injury from repeatedly heading soccer balls.)
The final group of veterans is scheduled to visit Einstein for testing in February 2014. Preliminary results should be available later this year.
Dietary Amino Acids Relieve Sleep Problems after Traumatic Brain Injury in Animals
Scientists who fed a cocktail of key amino acids to mice improved sleep disturbances caused by brain injuries in the animals. These new findings suggest a potential dietary treatment for millions of people affected by traumatic brain injury (TBI)—a condition that is currently untreatable.
“If this type of dietary treatment is proved to help patients recover function after traumatic brain injury, it could become an important public health benefit,” said study co-leader Akiva S. Cohen, Ph.D., a neuroscientist at The Children’s Hospital of Philadelphia (CHOP).
Cohen is the co-senior author of the animal TBI study appearing today in Science Translational Medicine. He collaborated with two experts in sleep medicine: co-senior author Allan I. Pack, M.D., Ph.D., director of the Center for Sleep and Circadian Neurobiology in the Perelman School of Medicine at the University of Pennsylvania; and first author Miranda M. Lim, M.D., Ph.D., formerly at the Penn Sleep Center, and now on faculty at the Portland VA Medical Center and Oregon Health and Science University.
Every year in the U.S., an estimated 2 million people suffer a TBI, accounting for a major cause of disability across all age groups. Although 75 percent of reported TBI cases are milder forms such as concussion, even concussion may cause chronic neurological impairments, including cognitive, motor and sleep problems.
“Sleep disturbances, such as excessive daytime sleepiness and nighttime insomnia, disrupt quality of life and can delay cognitive recovery in patients with TBI,” said Lim, a neurologist and sleep medicine specialist. Although physicians can relieve the dangerous swelling that occurs after a severe TBI, there are no existing treatments to address the underlying brain damage associated with neurobehavioral problems such as impaired memory, learning and sleep patterns.
Cohen and team investigate the use of selected branched chain amino acids (BCAA)—precursors of the neurotransmitters glutamate and GABA, which are involved in communication among neurons and help to maintain a normal balance in brain activity. His research team previously showed that a BCAA diet restored cognitive ability in brain-injured mice. The current study was the first to analyze sleep-wake patterns in an animal model.
Comparing mice with experimentally induced mild TBI to uninjured mice, the scientists found the injured mice were unable to stay awake for long periods of time. The injured mice had lower activity among orexin neurons, which help to maintain the animals’ wakefulness. This is similar to results in human studies showing decreased orexin levels in the spinal fluid after TBI.
In the current study, the dietary therapy restored the orexin neurons to a normal activity level and improved wakefulness in the brain-injured mice. EEG recordings also showed improved brain wave patterns among the mice that consumed the BCAA diet.
“These results in an animal model provide a proof-of-principle for investigating this dietary intervention as a treatment for TBI patients,” said Cohen. “If a dietary supplement can improve sleeping and waking patterns as well as cognitive problems, it could help brain-injured patients regain crucial functions.” Cohen cautioned that current evidence does not support TBI patients medicating themselves with commercially available amino acids.
(Source: chop.edu)
Neural prosthesis restores behavior after brain injury
Scientists from Case Western Reserve University and University of Kansas Medical Center have restored behavior—in this case, the ability to reach through a narrow opening and grasp food—using a neural prosthesis in a rat model of brain injury.
Ultimately, the team hopes to develop a device that rapidly and substantially improves function after brain injury in humans. There is no such commercial treatment for the 1.5 million Americans, including soldiers in Afghanistan and Iraq, who suffer traumatic brain injuries (TBI), or the nearly 800,000 stroke victims who suffer weakness or paralysis in the United States, annually.
The prosthesis, called a brain-machine-brain interface, is a closed-loop microelectronic system. It records signals from one part of the brain, processes them in real time, and then bridges the injury by stimulating a second part of the brain that had lost connectivity.
Their work is published online this week in the science journal Proceedings of the National Academy of Sciences.
“If you use the device to couple activity from one part of the brain to another, is it possible to induce recovery from TBI? That’s the core of this investigation,” said Pedram Mohseni, professor of electrical engineering and computer science at Case Western Reserve, who built the brain prosthesis.
“We found that, yes, it is possible to use a closed-loop neural prosthesis to facilitate repair of a brain injury,” he said.
The researchers tested the prosthesis in a rat model of brain injury in the laboratory of Randolph J. Nudo, professor of molecular and integrative physiology at the University of Kansas. Nudo mapped the rat’s brain and developed the model in which anterior and posterior parts of the brain that control the rat’s forelimbs are disconnected.
Atop each animal’s head, the brain-machine-brain interface is a microchip on a circuit board smaller than a quarter connected to microelectrodes implanted in the two brain regions.
The device amplifies signals, which are called neural action potentials and produced by the neurons in the anterior of the brain. An algorithm separates these signals, recorded as brain spike activity, from noise and other artifacts. With each spike detected, the microchip sends a pulse of electric current to stimulate neurons in the posterior part of the brain, artificially connecting the two brain regions.
Two weeks after the prosthesis had been implanted and run continuously, the rat models using the full closed-loop system had recovered nearly all function lost due to injury, successfully retrieving a food pellet close to 70 percent of the time, or as well as normal, uninjured rats. Rat models that received random stimuli from the device retrieved less than half the pellets and those that received no stimuli retrieved about a quarter of them.
“A question still to be answered is must the implant be left in place for life?” Mohseni said. “Or can it be removed after two months or six months, if and when new connections have been formed in the brain?”
Brain studies have shown that, during periods of growth, neurons that regularly communicate with each other develop and solidify connections.
Mohseni and Nudo said they need more systematic studies to determine what happens in the brain that leads to restoration of function. They also want to determine if there is an optimal time window after injury in which they must implant the device in order to restore function.
(Source: blog.case.edu)
Music brings memories back to the brain injured
In the first study of its kind, two researchers have used popular music to help severely brain-injured patients recall personal memories. Amee Baird and Séverine Samson outline the results and conclusions of their pioneering research in the recent issue of the journal Neuropsychological Rehabilitation.
Although their study covered a small number of cases, it’s the very first to examine ‘music-evoked autobiographical memories’ (MEAMs) in patients with acquired brain injuries (ABIs), rather than those who are healthy or suffer from Alzheimer’s Disease.
In their study, Baird and Samson played extracts from ‘Billboard Hot 100’ number-one songs in random order to five patients. The songs, taken from the whole of the patient’s lifespan from age five, were also played to five control subjects with no brain injury. All were asked to record how familiar they were with a given song, whether they liked it, and what memories it invoked.
Doctors Baird and Samson found that the frequency of recorded MEAMs was similar for patients (38%–71%) and controls (48%–71%). Only one of the four ABI patients recorded no MEAMs. In fact, the highest number of MEAMs in the whole group was recorded by one of the ABI patients. In all those studied, the majority of MEAMs were of a person, people or a life period and were typically positive. Songs that evoked a memory were noted as more familiar and more liked than those that did not.
As a potential tool for helping patients regain their memories, Baird and Samson conclude that: “Music was more efficient at evoking autobiographical memories than verbal prompts of the Autobiographical Memory Interview (AMI) across each life period, with a higher percentage of MEAMs for each life period compared with AMI scores.”
“The findings suggest that music is an effective stimulus for eliciting autobiographical memories and may be beneficial in the rehabilitation of autobiographical amnesia, but only in patients without a fundamental deficit in autobiographical recall memory and intact pitch perception.”
The authors hope that their ground-breaking work will encourage others to carry out further studies on MEAMs in larger ABI populations. They also call for further studies of both healthy people and those with other neurological conditions to learn more about the clear relationship between memory, music and emotion; they hope that one day we might truly “understand the mechanisms underlying the unique memory enhancing effect of music”.