Posts tagged concussions
Articles and news from the latest research reports.
From football to flies: lessons about traumatic brain injury
Faced with news of suicides and brain damage in former professional football players, geneticist Barry Ganetzky bemoaned the lack of model systems for studying the insidious and often delayed consequences linked to head injuries.
Then he remembered an unexplored observation from nearly 40 years ago: a sharp strike to a vial of fruit flies left them temporarily stunned, only to recover a short time later. At the time he had marked it only as a curiosity.
Now a professor of genetics at UW–Madison, Ganetzky is turning his accidental discovery into a way to study traumatic brain injury (TBI). He and David Wassarman, a UW professor of cell and regenerative biology, report this week (Oct. 14) in the Proceedings of the National Academy of Sciences on the first glimpses of the genetic underpinnings of susceptibility to brain injuries and links to human TBI.
TBIs occur when a force on the body jostles the brain inside the head, causing it to strike the inside of the skull. More than 1.7 million TBIs occur each year in the United States, about one-third due to falls and the rest mainly caused by car crashes, workplace accidents, and sports injuries. TBIs are also a growing issue in combat veterans exposed to explosions.
In many cases, the immediate effects of TBI are temporary and may seem mild — confusion, dizziness or loss of coordination, headaches, vision problems. But over time, impacts may lead to neurodegeneration and related symptoms, including memory loss, cognitive problems, severe depression, or Alzheimer’s-like dementia. Together TBIs cost tens of billions of dollars annually in medical expenses and indirect costs such as lost productivity.
Though TBIs can be classified from “mild” to “severe” based on symptoms, there is a poor understanding of the underlying medical causes.
“Unlike many important medical problems — high blood pressure, cancer, diabetes, heart disease — where we know something about the biology, we know almost nothing about TBI,” Ganetzky says. “Why does a blow to the head cause epilepsy? Or how does it lead down the road to neurodegeneration? Nobody has answers to those questions — in part, because it’s really hard to study in humans.”
Enter the fruit fly. The fly brain is encased in a hard cuticle analogous to the skull, and the basic mechanisms affecting nervous system function are the same in flies and mammals. In the new study, Ganetzky and Wassarman describe a way to reproducibly inflict traumas that seem to mimic the injuries and symptoms of human TBI.
“Now we have a system where we can look at the variables that are the inputs into TBI and determine the relative contributions of each to the pathological outcomes. That’s the real power of the flies,” says Wassarman.
As with humans, few flies die from the immediate impact. Afterward, though, the treated flies show many of the same physical consequences as humans who sustain concussions or other TBIs, including temporary incapacitation, loss of coordination and activation of the innate immune response in the short term, followed by neurodegeneration and sometimes an early death.
The researchers, led by Rebeccah Katzenberger, senior research specialist in the UW Department of Cell and Regnerative Biology, also found that age seems to play an important role. Older flies are more susceptible than younger ones to the effects of the impact and, Wassarman says, many of the outcomes of TBI are very similar to normal aging processes.
With this model, the researchers say, they can now draw on the vast collection of genetic tools and techniques available for fruit flies to probe the underlying drivers of damage.
“What we really want is to understand the immediate and long term consequences in cellular and molecular terms,” says Ganetzky. “From that understanding we can proceed in a more directed way to diagnostics and therapeutics.”
One of the key things they have already identified is the crucial role genetics plays in determining the outcome of an injury, revealed by the high degree of variability seen among different strains of flies. This finding may explain why all potential TBI drugs to date have failed in clinical trials despite showing promise in individual rodent models.
As Wassarman explains, “The heart of the problem of solving traumatic brain injury is that we’re all different.”
They are continuing to develop the model through large-scale genetic analysis and have already found that different sets of genes correlate with susceptibility in flies of different ages. With their system, they can also examine the effects of repeated injuries.
Ganetzky sees tremendous potential for developing applications from the fly-based approach and the Wisconsin Alumni Research Foundation (WARF) has filed for patent protection on the discovery.
“These exciting findings that we can study traumatic brain injury — a disorder of growing concern for athletes, the military, and parents — in the elegantly simple model of fruit flies is sure to interest those researchers and companies looking to address this concern,” says Jennifer Gottwald, WARF licensing manager. “The use of this model can accelerate the work of the medical research community in finding treatments and therapies to help patients.”
(Source: news.wisc.edu)
Age doesn’t impact concussion symptoms: study
Recent scientific findings have raised the fear that young athletes may fare worse after sustaining a sports-related concussion than older athletes.
Researchers in the Vanderbilt Sports Concussion Center compared symptoms associated with concussion in middle- and high-school aged athletes with those in college-age athletes and found no significant differences between the two age groups.
The study, “Does age affect symptom recovery after sports-related concussion? A study of high school and college athletes,” was published online Sept. 24 ahead of print in the Journal of Neurosurgery: Pediatrics.
Lead authors were Vanderbilt University School of Medicine students Young Lee and Mitchell Odom. Other researchers were Scott Zuckerman, M.D., Gary Solomon, Ph.D., and Allen Sills, M.D.
In this retrospective study, the researchers reviewed a database containing information on pre-concussion and post-concussion symptoms in two different age groups: younger (13-16 years old) and older (18-22 years old). Athletes (92 in each group) were evenly matched with respect to gender, number of previous concussions, and time to the first post-concussion test.
Each athlete completed individual pre- and post-concussion questionnaires that covered a variety of symptoms associated with concussion, some of which were headache, nausea, dizziness, fatigue, sleep problems, irritability and difficulties with concentration or memory. Each athlete’s post-concussion scores were compared to his or her own individual baseline scores.
The number or severity of symptoms cited at baseline and post-concussion showed no significant difference between the two age groups. Symptoms returned to baseline levels within 30 days after concussion in 95.7 percent of the younger athletes and in 96.7 percent of the older athletes.
“In the evaluation of sports-related concussion, it is imperative to parse out different ways of assessing outcomes: neurocognitive scores versus symptom endorsement versus balance issues, school performance, etc,” Zuckerman said.
“It appears that symptoms may not be a prominent driver when assessing outcomes of younger versus older athletes. We hope that our study can add insight into the evaluation of youth athletes after sports-related concussion.”
(Source: news.vanderbilt.edu)
Concussion Patients Show Alzheimer’s-like Brain Abnormalities
The distribution of white matter brain abnormalities in some patients after mild traumatic brain injury (MTBI) closely resembles that found in early Alzheimer’s dementia, according to a new study published online in the journal Radiology.
“Findings of MTBI bear a striking resemblance to those seen in early Alzheimer’s dementia,” said the study’s lead author, Saeed Fakhran, M.D., assistant professor of radiology in the Division of Neuroradiology at the University of Pittsburgh School of Medicine. “Additional research may help further elucidate a link between these two disease processes.”
MTBI, or concussion, affects more than 1.7 million people in the United States annually. Despite the name, these injuries are by no means mild, with approximately 15 percent of concussion patients suffering persistent neurological symptoms.
“Sleep-wake disturbances are among the earliest findings of Alzheimer’s patients, and are also seen in a subset of MTBI patients,” Dr. Fakhran said. “Furthermore, after concussion, many patients have difficulty filtering out white noise and concentrating on the important sounds, making it hard for them to understand the world around them. Hearing problems are not only an independent risk factor for developing Alzheimer’s disease, but the same type of hearing problem seen in MTBI patients has been found to predict which patients with memory problems will go on to develop Alzheimer’s disease.”
For the study, Dr. Fakhran and colleagues set out to determine if there was a relationship between white matter injury patterns and severity of post-concussion symptoms in MTBI patients with normal findings on conventional magnetic resonance imaging (MRI) exams. The researchers studied data from imaging exams performed on 64 MTBI patients and 15 control patients, using an advanced MRI technique called diffusion tensor imaging, which identifies microscopic changes in the brain’s white matter.
The brain’s white matter is composed of millions of nerve fibers called axons that act like communication cables connecting various regions of the brain. Diffusion tensor imaging produces a measurement, called fractional anisotropy, of the movement of water molecules along axons. In healthy white matter, the direction of water movement is fairly uniform and measures high in fractional anisotropy. When water movement is more random, fractional anisotropy values decrease.
Of the MTBI patients, 42 (65.6 percent) were men, and the mean age was 17. Sports injury was the reason for concussion in two-thirds of the patients. All patients underwent neurocognitive evaluation with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). The researchers analyzed correlation between fractional anisotropy values, the ImPACT total symptom score, and findings of sleep-wake disturbances.
Sleep-wake disturbances are among the most disabling post-concussive symptoms, directly decreasing quality of life and productivity and magnifying post-concussion memory and social dysfunction.
The results showed a significant correlation between high ImPACT total symptom score and reduced fractional anisotropy at the gray-white junction, most prominently in the auditory cortex. Significantly decreased fractional anisotropy was found in patients with sleep-wake disturbances in the parahippocampal gyri relative to patients without sleep-wake disturbances.
“When we sleep, the brain organizes our experiences into memories, storing them so that we can later find them,” Dr. Fakhran said. “The parahippocampus is important for this process, and involvement of the parahippocampus may, in part, explain the memory problems that occur in many patients after concussion.”
According to Dr. Fakhran, the results suggest that the true problem facing concussion patients may not be the injury itself, but rather the brain’s response to that injury.
“Traditionally, it has been believed that patients with MTBI have symptoms because of abnormalities secondary to direct injury,” he said. “Simply put, they hit their head, damaged their brain at the point of trauma and thus have symptoms from that direct damage. Our preliminary findings suggest that the initial traumatic event that caused the concussion acts as a trigger for a sequence of degenerative changes in the brain that results in patient symptoms and that may be potentially prevented. Furthermore, these neurodegenerative changes are very similar to those seen in early Alzheimer’s dementia.”
The researchers hope that these findings may lead to improved treatments in the future.
“The first step in developing a treatment for any disease is understanding what causes it,” Dr. Fakhran said. “If we can prove a link, or even a common pathway, between MTBI and Alzheimer’s, this could potentially lead to treatment strategies that would be potentially efficacious in treating both diseases.”
(Source: prweb.com)
Mild Blast Injury Causes Molecular Changes in Brain Akin to Alzheimer’s Disease
A multicenter study led by scientists at the University of Pittsburgh School of Medicine shows that mild traumatic brain injury after blast exposure produces inflammation, oxidative stress and gene activation patterns akin to disorders of memory processing such as Alzheimer’s disease. Their findings were recently reported in the online version of the Journal of Neurotrauma.
Blast-induced traumatic brain injury (TBI) has become an important issue in combat casualty care, said senior investigator Patrick Kochanek, M.D., professor and vice chair of critical care medicine and director of the Safar Center for Resuscitation Research at Pitt. In many cases of mild TBI, MRI scans and other conventional imaging technology do not show overt damage to the brain.
“Our research reveals that despite the lack of a lot of obvious neuronal death, there is a lot of molecular madness going on in the brain after a blast exposure,” Dr. Kochanek said. “Even subtle injuries resulted in significant alterations of brain chemistry.”
The research team developed a rat model to examine whether mild blast exposure in a device called a shock tube caused any changes in the brain even if there was no indication of direct cell death, such as bleeding. Brain tissues of rats exposed to blast and to a sham procedure were tested two and 24 hours after the injury.
Gene activity patterns, which shifted over time, resembled patterns seen in neurodegenerative diseases, particularly Alzheimer’s, Dr. Kochanek noted. Markers of inflammation and oxidative stress, which reflects disruptions of cell signaling, were elevated, but there was no indication of energy failure that would be seen with poor tissue oxygenation.
“It appears that although the neurons don’t die after a mild injury, they do sustain damage,” he said. “It remains to be seen what multiple exposures, meaning repeat concussions, do to the brain over the long term.”
(Source: upmc.com)
Engineer helping unravel mystery of traumatic brain injury
The American Academy of Neurology issued new guidelines last week for assessing school-aged athletes with head injuries on the field. The message: if in doubt, sit out.
With more than 3 million sports-related concussions occurring in the U.S. each year, from school children to professional athletes, the issue is a burgeoning health crisis.
While concussions may not be difficult to diagnose initially, the longer one waits, the more difficult treatment can be.
The efforts of a researcher and his colleagues at Washington University in St. Louis’ School of Engineering & Applied Science are helping to unravel the many mysteries of traumatic brain injury.
“There’s and urgent need to understand the problem of traumatic brain injuries, for the sake of athletes, military personnel and accident victims,” says Philip Bayly, PhD, the Lilyan and E. Lisle Hughes Professor of Mechanical Engineering.
“Anyone who has met someone who’s had a head injury knows how scary it is, and how frustrating it is that we know so little about the causal pathways, and thus the best therapeutic opportunities,” he says.
Bayly, chair of the Department of Mechanical Engineering & Materials Science, researches the mechanics of brain injury. He recently received a $2.25 million grant from the National Institutes of Health to better understand traumatic brain injuries.
Head injuries, concussions and the resulting trauma have been in public discussion recently as the National Football League (NFL) deals with a lawsuit regarding head injuries by about one-third of living former NFL players. The league is accused of not providing information connecting football-related head injuries to brain damage, memory loss and other long-term health issues.
Bayly’s team is working on ways to measure 3-D relative motion between in the brain and skull and estimate strain during mild head acceleration. Bayly hopes computer simulation can teach researchers about the basic physics of brain injury and ways to develop new approaches to prevention and therapy.
“Our studies provide experimental data on how the brain actually responds mechanically in response to mild external loads,” Bayly says. “This is especially critical to developing useful computer simulations, to make sure they reflect reality.
These simulations will in turn be used to design new equipment, evaluate rule changes in sports and determine exposure thresholds or diagnostic tests.”
Computer simulation is important in creating animal models that can be used to develop diagnostic and therapeutic approaches, he says.
“Understanding mechanical deformation in traumatic brain injury is also essential to anyone studying brain trauma by exposing cultured brain cells to mechanical stress,” Bayly says. “We need to understand how much stress to apply and in what directions.”
How can athletes minimize their risks?
“From a mechanical standpoint, they should avoid repeated high head accelerations,” Bayly says. “Head-to-head collisions and collisions with head-to-ground are clearly to be avoided.”
Bayly says to truly protect athletes, new rules need to be instated.
“I would actually advocate for eliminating sports like boxing, in which injury-level accelerations are known to occur routinely. More research is needed on sports where the threshold is less clear.”
There is where Bayly and his colleagues come in.
“We need to do the research to find out what kinds of repeated accelerations are responsible for producing the degeneration seen in chronic traumatic encephalopathy,” he says.
(Image: Jupiterimages / Getty Images)
Researchers scoring a win-win with novel set of concussion diagnostic tools
From Junior Seau, former San Diego Chargers linebacker, to Dave Duerson, former Chicago Bears safety — who both committed suicide as a result of chronic traumatic encephalopathy (CTE) — traumatic brain injuries (TBIs) have been making disturbing headlines at an alarming rate. In the United States alone, TBIs account for an estimated 1.6 million to 3.8 million sports injuries every year, with approximately 300,000 of those being diagnosed among young, nonprofessional athletes. But TBIs are not confined to sports; they are also considered a signature wound among soldiers of the Iraq and Afghanistan wars.
The potential impact on the health and well-being of individuals with brain injuries are numerous. These individuals might display a range of symptoms — such as headaches, depression, loss of memory and loss of brain function — that may persist for weeks or months. The effects of brain injuries are most devastating when they remain unrecognized for long periods of time. This is where Christian Poellabauer, associate professor of computer science and engineering; Patrick Flynn, professor of computer science and engineering; Nikhil Yadav, graduate student of computer science and engineering; and a team of students and faculty are making their own impact.
Although baseline tests of athletes prior to an injury are trending up, these tests must still be compared to examinations after an injury has occurred. They require heavy medical equipment, such as a CT scanner, MRI equipment or X-ray machine, and are not always conclusive. The Notre Dame team has developed a tablet-based testing system that captures the voice of an individual and analyzes the speech for signs of a potential concussion anytime, anywhere, in real time.
“This project is a great example of how mobile computing and sensing technologies can transform health care,” Poellabauer said. “More important, because almost 90 percent of concussions go unrecognized, this technology offers tremendous potential to reduce the impact of concussive and subconcussive hits to the head.”
The system sounds simple enough: An individual speaks into a tablet equipped with the Notre Dame program before and after an event. The two samples are then compared for TBI indicators, which include distorted vowels, hyper nasality and imprecise consonants.
Notre Dame’s system offers a variety of advantages over traditional testing, such as portability, high accuracy, low cost and a low probability of manipulation (the results cannot be faked); it has also proven very successful. In testing that occurred during the Notre Dame Bengal Bouts and Baraka Bouts, annual student boxing tournaments, the researchers established baselines for boxers using tests such as the Axon Sports Computerized Cognitive Assessment Tool (CCAT), the Sport Concussion Assessment Tool 2 (SCAT2) and the Notre Dame iPad-based reading and voice recording test.
During the 2012 Bengal Bouts, nine concussions (out of 125 participants) were confirmed by this new speech-based test and the University’s medical team. Separate tests of 80 female boxers were also conducted during the 2012 Baraka Bouts. Outcomes of the 2013 Bengal Bouts are currently being compared to the findings of the University medical team on approximately 130 male boxers.
The testing was done in cooperation with James Moriarity, the University’s chief sports medicine physician, who has developed a series of innovative concussion testing studies.
With more than one million athletes now experiencing a concussion each year in the United States, the American Academy of Neurology (AAN) has released an evidence-based guideline for evaluating and managing athletes with concussion. This new guideline replaces the 1997 AAN guideline on the same topic. The new guideline is published in the March 18, 2013, online issue of Neurology®, the medical journal of the American Academy of Neurology, was developed through an objective evidence-based review of the literature by a multidisciplinary committee of experts and has been endorsed by a broad range of athletic, medical and patient groups.
“Among the most important recommendations the Academy is making is that any athlete suspected of experiencing a concussion immediately be removed from play,” said co-lead guideline author Christopher C. Giza, MD, with the David Geffen School of Medicine and Mattel Children’s Hospital at UCLA and a member of the AAN. “We’ve moved away from the concussion grading systems we first established in 1997 and are now recommending concussion and return to play be assessed in each athlete individually. There is no set timeline for safe return to play.”
The updated guideline recommends athletes with suspected concussion be immediately taken out of the game and not returned until assessed by a licensed health care professional trained in concussion, return to play slowly and only after all acute symptoms are gone. Athletes of high school age and younger with a concussion should be managed more conservatively in regard to return to play, as evidence shows that they take longer to recover than college athletes.
The guideline was developed reviewing all available evidence published through June 2012. These practice recommendations are based on an evaluation of the best available research. In recognition that scientific study and clinical care for sports concussions involves multiple specialties, a broad range of expertise was incorporated in the author panel. To develop this document, the authors spent thousands of work hours locating and analyzing scientific studies. The authors excluded studies that did not provide enough evidence to make recommendations, such as reports on individual patients or expert opinion. At least two authors independently analyzed and graded each study.
According to the guideline:
- Among the sports in the studies evaluated, risk of concussion is greatest in football and rugby, followed by hockey and soccer. The risk of concussion for young women and girls is greatest in soccer and basketball.
- An athlete who has a history of one or more concussions is at greater risk for being diagnosed with another concussion.
- The first 10 days after a concussion appears to be the period of greatest risk for being diagnosed with another concussion.
- There is no clear evidence that one type of football helmet can better protect against concussion over another kind of helmet. Helmets should fit properly and be well maintained.
- Licensed health professionals trained in treating concussion should look for ongoing symptoms (especially headache and fogginess), history of concussions and younger age in the athlete. Each of these factors has been linked to a longer recovery after a concussion.
- Risk factors linked to chronic neurobehavioral impairment in professional athletes include prior concussion, longer exposure to the sport and having the ApoE4 gene.
- Concussion is a clinical diagnosis. Symptom checklists, the Standardized Assessment of Concussion (SAC), neuropsychological testing (paper-and-pencil and computerized) and the Balance Error Scoring System may be helpful tools in diagnosing and managing concussions but should not be used alone for making a diagnosis.
Signs and symptoms of a concussion include:
Headache and sensitivity to light and sound Changes to reaction time, balance and coordination Changes in memory, judgment, speech and sleep Loss of consciousness or a “blackout” (happens in less than 10 percent of cases)
“If in doubt, sit it out,” said Jeffrey S. Kutcher, MD, with the University of Michigan Medical School in Ann Arbor and a member of the AAN. “Being seen by a trained professional is extremely important after a concussion. If headaches or other symptoms return with the start of exercise, stop the activity and consult a doctor. You only get one brain; treat it well.”
The guideline states that while an athlete should immediately be removed from play following a concussion, there is currently insufficient evidence to support absolute rest after concussion. Activities that do not worsen symptoms and do not pose a risk of repeat concussion may be part of concussion management.
The guideline is endorsed by the National Football League Players Association, the American Football Coaches Association, the Child Neurology Society, the National Association of Emergency Medical Service Physicians, the National Academy of Neuropsychology, the National Association of School Psychologists, the National Athletic Trainers Association and the Neurocritical Care Society.
Single Concussion May Cause Lasting Brain Damage
A single concussion may cause lasting structural damage to the brain, according to a new study published online in the journal Radiology.
"This is the first study that shows brain areas undergo measureable volume loss after concussion," said Yvonne W. Lui, M.D., Neuroradiology section chief and assistant professor of radiology at NYU Langone School of Medicine. "In some patients, there are structural changes to the brain after a single concussive episode."
According to the Centers for Disease Control and Prevention, each year in the U.S., 1.7 million people sustain traumatic brain injuries, resulting from sudden trauma to the brain. Mild traumatic brain injury (MTBI), or concussion, accounts for at least 75 percent of all traumatic brain injuries.
Following a concussion, some patients experience a brief loss of consciousness. Other symptoms include headache, dizziness, memory loss, attention deficit, depression and anxiety. Some of these conditions may persist for months or even years.
Studies show that 10 to 20 percent of MTBI patients continue to experience neurological and psychological symptoms more than one year following trauma. Brain atrophy has long been known to occur after moderate and severe head trauma, but less is known about the lasting effects of a single concussion.
Dr. Lui and colleagues set out to investigate changes in global and regional brain volume in patients one year after MTBI. Twenty-eight MTBI patients (with 19 followed at one year) with post-traumatic symptoms after injury and 22 matched controls (with 12 followed at one year) were enrolled in the study. The researchers used three-dimensional magnetic resonance imaging (MRI) to determine regional gray matter and white matter volumes and correlated these findings with other clinical and cognitive measurements.
The researchers found that at one year after concussion, there was measurable global and regional brain atrophy in the MTBI patients. These findings show that brain atrophy is not exclusive to more severe brain injuries but can occur after a single concussion.
"This study confirms what we have long suspected," Dr. Lui said. "After MTBI, there is true structural injury to the brain, even though we don’t see much on routine clinical imaging. This means that patients who are symptomatic in the long-term after a concussion may have a biologic underpinning of their symptoms."
Certain brain regions showed a significant decrease in regional volume in patients with MTBI over the first year after injury, compared to controls. These volume changes correlated with cognitive changes in memory, attention and anxiety.
"Two of the brain regions affected were the anterior cingulate and the precuneal region," Dr. Lui said. "The anterior cingulate has been implicated in mood disorders including depression, and the precuneal region has a lot of different connections to areas of the brain responsible for executive function or higher order thinking."
According to Dr. Lui, researchers are still investigating the long-term effects of concussion, and she advises caution in generalizing the results of this study to any particular individual.
"It is important for patients who have had a concussion to be evaluated by a physician," she said. "If patients continue to have symptoms after concussion, they should follow-up with their physician before engaging in high-risk activities such as contact sports."
Computer Model May Help Athletes and Soldiers Avoid Brain Damage and Concussions
Concussions can occur in sports and in combat, but health experts do not know precisely which jolts, collisions and awkward head movements during these activities pose the greatest risks to the brain. To find out, Johns Hopkins engineers have developed a powerful new computer-based process that helps identify the dangerous conditions that lead to concussion-related brain injuries. This approach could lead to new medical treatment options and some sports rule changes to reduce brain trauma among players.
The research comes at a time when greater attention is being paid to assessing and preventing the head injuries sustained by both soldiers and athletes. Some kinds of head injuries are difficult to see with standard diagnostic imaging but can have serious long-term consequences. Concussions, once dismissed as a short-term nuisance, have more recently been linked to serious brain disorders.
“Concussion-related injuries can develop even when nothing has physically touched the head, and no damage is apparent on the skin,” said K. T. Ramesh, the Alonzo G. Decker Jr. Professor of Science and Engineering who led the research at Johns Hopkins. “Think about a soldier who is knocked down by the blast wave of an explosion, or a football player reeling after a major collision. The person may show some loss of cognitive function, but you may not immediately see anything in a CT-scan or MRI that tells you exactly where and how much damage has been done to the brain. You don’t know what happened to the brain, so how do you figure out how to treat the patient?”
To help doctors answer this question, Ramesh led a team that used a powerful technique called diffusion tensor imaging, together with a computer model of the head, to identify injured axons, which are tiny but important fibers that carry information from one brain cell to another. These axons are concentrated in a kind of brain tissue known as “white matter,” and they appear to be injured during the so-called mild traumatic brain injury associated with concussions. Ramesh’s team has shown that the axons are injured most easily by strong rotations of the head, and the researchers’ process can calculate which parts of the brain are most likely to be injured during a specific event.
The team described its new technique in the Jan. 8 edition of the Journal of Neurotrauma. The lead author, Rika M. Wright, played a major role in the research while completing her doctoral studies in Johns Hopkins’ Whiting School of Engineering, supervised by Ramesh. Wright is now a postdoctoral research fellow at Carnegie Mellon University. Ramesh is continuing to conduct research using the technique at Johns Hopkins with support from the National Institutes of Health.
Beyond its use in evaluating combat and sports-related injuries, the work could have wider applications, such as detecting axonal damage among patients who have received head injuries in vehicle accidents or serious falls. “This is the kind of injury that may take weeks to manifest,” Ramesh said. “By the time you assess the symptoms, it may be too late for some kinds of treatment to be helpful. But if you can tell right away what happened to the brain and where the injury is likely to have occurred, you may be able to get a crucial head-start on the treatment.”
Concussions and head impacts may accelerate brain aging
Jul 31, 2012 by Laura Bailey
Concussions and even lesser head impacts may speed up the brain’s natural aging process by causing signaling pathways in the brain to break down more quickly than they would in someone who has never suffered a brain injury or concussion.
The photos compare images of two brains, one with and without head injury. The red areas indicates electrical activity in response to the task researchers asked study participants to perform, and non-injured brains show more red, thus more electrical activity during the task. Image courtesy of Steven Broglio
Researchers from the University of Michigan School of Kinesiology and the U-M Health System looked at college students with and without a history of concussion and found changes in gait, balance and in the brain’s electrical activity, specifically attention and impulse control, said Steven Broglio, assistant professor of kinesiology and director of the Neurotrauma Research Laboratory.
The declines were present in the brain injury group up to six years after injury, though the differences between the study groups were very subtle, and outwardly all of the participants looked and acted the same.
Broglio, who is also affiliated with Michigan NeuroSport, stressed that the studies lay out a hypothesis where concussions and head impacts accelerate the brain’s natural aging process.
The study, “Cognitive decline and aging: The role of concussive and subconcussive impacts,” appears in the July issue of journal Exercise and Sport Sciences Reviews.
"The last thing we want is for people to panic. Just because you’ve had a concussion does not mean your brain will age more quickly or you’ll get Alzheimer’s," Broglio said. "We are only proposing how being hit in the head may lead to these other conditions, but we don’t know how it all goes together just yet."
Broglio stressed that other factors, such as lifestyle choices, smoking, alcohol consumption, physical exercise, family history and whether or not you “exercise” your brain also impact the brain’s aging process. Concussion may only be one small factor.
To begin to understand how concussions might impact brain activity and its signaling pathways, researchers asked the participants to perform certain tasks in front of a computer, and took images of their brains. The brains of the nonconcussed group showed a greater area of electrical activation than the participants with a history of brain injury.
The signaling pathways in our brains are analogous to a five-lane highway. On a new highway, traffic runs smoothly and quickly as all lanes are in top shape. However, during normal aging, the asphalt deteriorates and lanes might become bumpy or even unusable. Traffic slows.
Similarly, our brains start with all pathways clear to transfer electrical signals rapidly. As we age, the brain’s pathways break down and can’t transfer the information as quickly. Concussive and other impacts to the head may result in a ‘pothole’ on the brain’s highway, causing varying degrees of damage and speeding the pathway’s natural deterioration.
"What we don’t know is if you had a single concussion in high school, does that mean you will get dementia at age 50?" Broglio said. "Clinically, we don’t see that. What we think is it will be a dose response.
"So, if you played soccer and sustained some head impacts and maybe one concussion, then you may have a little risk. If you went on and played in college and took more head balls and sustained two more concussions, you’re probably at a little bigger risk. Then if you play professionally for a few years, and take more hits to the head, you increase the risk even more. We believe it’s a cumulative effect."
In the next phase of study, researchers will look at people in their 20s, 40s and 60s who did and did not sustain concussions during high school sports. They hope to learn if there is an increasing effect of concussion as the study subjects age. If interested in participating in the study, email neurotraumalab.umich@gmail.com.
Researchers from the departments of Physical Medicine and Rehabilitation, and Neurology, and the Michigan Alzheimer’s Disease Center also participated in the study.
Source: University of Michigan