Blood test detects concussion and subconcussive injuries in children and adults
Traumatic brain injury with no symptoms can cause wear and tear over time
August 26, 2019
Science Daily/Orlando Health
In one of the largest studies of its kind, researchers at Orlando Health are making new progress in finding ways to detect a traumatic yet sinister brain injury -- and getting closer to preventing further damage.
Subconcussive injuries often show no symptoms or immediate effects, but can cause wear and tear on the brain over time with repeated injuries. The latest study, published in the journal BMJ Paediatrics Open, includes more than 700 emergency room patients -- children and adults. The study gets us closer to developing a standard blood test to spot these injuries as early as possible.
"A unique feature of this study is that it includes patients who hit their heads but have no symptoms," said Linda Papa, MD, lead author of the study and emergency medicine doctor at Orlando Health. "This group is rarely -- if ever -- included in biomarker studies."
The blood test looks for two proteins (GFAP and UCH-L1) found in our brains and released into blood after an injury -- higher levels of which could indicate a concussion or subconcussive injury. Dr. Papa has been studying these biomarkers for more than a decade. Some of her previous studies have focused on athletes, but now she's expanding her research on subconcussive injuries to the general population and all age groups.
Historically, people who suffer head trauma without concussion symptoms may have been classified as having "no injury." Plus, there are very few studies addressing the impact of subconcussive injuries following head trauma in the civilian population, as opposed to military members or athletes.
"It is estimated that up to 3.8 million concussions occur in the U.S. annually from organized and recreational sports -- and there are more than 2 million ER visits for traumatic brain injuries and concussions," said Papa. "It is a significant health problem in both athletes and non-athletes."
The study looked at patients with concussions, those with head trauma without overt signs of concussion and those with body trauma without head trauma or concussion. Elevated levels of both biomarkers were found in patients with nonconcussive head trauma, potentially signaling a subconcussive brain injury.
Furthermore, this blood test goes even deeper than a routine CT scan. Previous studies using the two biomarkers have focused on detecting brain lesions, but subconcussive injuries don't necessarily result in lesions -- and even the vast majority of patients with concussions tend to have a normal CT scan.
"The study includes an array of patients with different injury mechanisms, including car crashes, falls and bicycle accidents in addition to recreational and sports injuries," said Papa. "It is not limited to just one group of injury types."
A number of companies are now working on developing a bench-top device for the hospital lab -- along with a point-of-care handheld device that can be used to detect subconcussive injuries in a variety of settings -- including sporting events, in the ambulance, at the scene of car crashes, in military settings or even after a simple bump to the head.
"The technology is only a year or two away," said Papa.
https://www.sciencedaily.com/releases/2019/08/190826092315.htm
Meaningful PTSD symptom decrease may lower type 2 diabetes risk
August 21, 2019
Science Daily/Saint Louis University
Research from Saint Louis University finds treatment for Post-Traumatic Stress Disorder (PTSD) that leads to an improvement in symptoms was associated with a 49 percent lower risk of incident type 2 diabetes.
The study, "Clinically Meaningful PTSD Improvement and Risk for Type 2 Diabetes," by Jeffrey Scherrer, Ph.D., professor in Family and Community Medicine at SLU, was published online Aug. 21 in JAMA Psychiatry.
"Some long-term chronic health conditions associated with PTSD may be less likely to occur among patients who experience clinically meaningful symptom reduction either through treatment or spontaneous improvement," Scherrer said.
PTSD affects up to 12 percent of civilians and nearly 30 percent of the veteran population. Those with PTSD are at risk for other health issues and improvement in PTSD symptoms is associated with parallel improvements in depression, emotional well-being, sleep, blood pressure and general physical health.
PTSD is associated with an increased risk of type 2 diabetes, which may be explained by the high prevalence of obesity, glucose dysregulation, inflammation, metabolic syndrome and depression among those diagnosed with PTSD versus those without PTSD.
This retrospective cohort study reviewed Veterans Health Affairs medical record data from 2008 to 2015. The researchers randomly selected 5,916 cases from among a veteran patient population aged 18 to 70 who had more than two visits to PTSD specialty care between 2008 and 2012. The patients were followed through until 2015.
After applying eligibility criteria, 1,598 patients with PTSD and free of diabetes risk were available for analysis.
Clinically meaningful symptom reduction is a decrease of 20 points on the PTSD Checklist score. The research found the results were independent of numerous demographic, psychiatric and physical comorbidities. The sample was 84.3 percent male, 66 percent Caucasian and 22 percent African-American. The mean age of the patients was 42.
The association was also independent of the number of PTSD psychotherapy sessions used.
"In patients with only PTSD, clinically meaningful PCL decrease is associated with lower risk for diabetes and in patients with PTSD and depression, we found improvement in PTSD was coupled with a decrease in depression," Scherrer said. "Thus decreased risk for type 2 diabetes appears to follow large PTSD symptom decrease and in patients with both PTSD and depression, improvement in both conditions may be necessary to reduce risk for type 2 diabetes."
"Surprisingly, clinically meaningful PTSD improvement was not associated with a change in BMI and A1C values." A prospective study is needed to advance research, Scherrer says, due in part to the limitations of medical record data. Such a study could determine if large decreases in PTSD checklist scores are associated with improved insulin resistance and reduced inflammation.
Take-aways
· The observational study examined whether veterans who experienced a greater reduction in symptoms of posttraumatic stress disorder (PTSD) had an associated lower risk of developing type 2 diabetes.
· The analysis included medical records from almost 1,600 veterans who received PTSD specialty care and had repeated completion of the PTSD Checklist as part of their treatment at the VA.
· Patients with versus patients without clinically meaningful improvement in PTSD symptoms had a 49 percent lower risk for type 2 diabetes over a 3-6-year follow-up period.
· In patients with PTSD and depression, improvement in both conditions was associated with lower risk for diabetes.
https://www.sciencedaily.com/releases/2019/08/190821142734.htm
More children suffer head injuries playing recreational sport than team sport
August 20, 2019
Science Daily/Murdoch Childrens Research Institute
An Australian/ New Zealand study examining childhood head injuries has found that children who do recreational sports like horse riding, skate boarding and bike riding are more likely to suffer serious head injuries than children who play contact sport like AFL or rugby.
Research, conducted by the PREDICT research network, Murdoch Children's Research Institute (MCRI), published on Wiley and soon to be published in the Australian Medical Journal, examined the data of 8,857 children presenting with head injuries to ten emergency departments in Australian and New Zealand hospitals.
A third of the children, who were aged between five and 18 years, injured themselves playing sport. Of these children four out of five were boys.
Lead research author, MCRI's Professor Franz Babl, says the team looked at 'íntracranial' injuries in children because while there is a lot of interest about sport and concussion, less is understood about the severity of head injuries children suffer while playing sport.
"The study found that in children who presented to the emergency departments after head injury and participated in recreational sports like horse riding, skate boarding and bike riding were more likely to sustain serious head injuries than children who played contact sport like AFL, rugby, soccer or basketball," he says.
"We found that 45 of the 3,177 sports-related head injuries were serious and classified as clinically important Traumatic Brain Injury (ciTBI), meaning the patient required either neuro-surgery, at least two nights in hospital and/or being placed on a breathing machine. One child died as a result of head injuries."
Prof Babl says that the sports which resulted in the most frequent reason for presentation to emergency departments included bike riding (16 per cent), rugby (13 per cent), AFL (10 per cent), other football (9 per cent), and soccer (8 per cent).
The most frequent causes of serious injury included bike riding (44 per cent), skateboarding (18 per cent), horse riding (16 per cent), with AFL and rugby resulting in one serious head injury each and soccer resulting none.
A total of 524 patients with sports-related head injuries (16 per cent) needed CT imaging, and 14 children required surgery.
https://www.sciencedaily.com/releases/2019/08/190820101527.htm
Anti-stress brain chemical is related to PTSD resilience after trauma
April 30, 2019
Science Daily/Elsevier
Fewer receptors for the anti-stress brain chemical nociceptin is associated with less severe posttraumatic stress disorder (PTSD) symptoms in college women who have experienced sexual violence, according to a study in Biological Psychiatry, published by Elsevier. The relationship between nociceptin receptor density and PTSD severity was present in women with recent PTSD symptoms but not those with past symptoms, suggesting a role for the receptors in recovery after sexual violence.
Although studies in animal models of PTSD have shown that nociceptin promotes resilience, the receptors had never been studied in people with the disorder. Using positron emission tomography brain imaging, researchers from University of Pittsburgh, Pennsylvania, showed that PTSD symptom severity is associated with fewer receptors in the midbrain and cerebellum -- regions involved in the brain's threat alarm system and that process subconscious triggers of PTSD related to the trauma.
"These results suggest that decreased nociceptin receptor density is a marker of resilience and recovery following trauma. If future studies confirm these results, nociceptin receptor density may become an important resilience biomarker in the evaluation of PTSD," said lead author Rajesh Narendran, MD.
The primary characteristics of PTSD include intrusive memories of the traumatic event and avoidance of anything that reminds one of the trauma. In women with recent PTSD, these primary symptoms were strongly associated with nociception receptor density.
"Alterations in nociceptin receptor regulation in PTSD could point to specific treatments that might target this receptor to treat symptoms of PTSD," said John Krystal, Editor of Biological Psychiatry.
This would be an important advance for the disorder, as currently available medications for PTSD treat secondary symptoms of the disorder, such as negative mood, but do not treat the primary symptoms associated with receptor measures in this study.
This means that the relationship between PTSD symptom severity and nociceptin receptors in the brain of women who have experienced sexual violence not only provides critical insight for understanding the biology of resilience and recovery after trauma, but also opens potential avenues for improving PTSD treatment and prevention.
https://www.sciencedaily.com/releases/2019/04/190430103505.htm
No link found between youth contact sports and cognitive, mental health problems
October 21, 2019
Science Daily/University of Colorado at Boulder
Adolescents who play contact sports, including football, are no more likely to experience cognitive impairment, depression or suicidal thoughts in early adulthood than their peers, suggests a new University of Colorado Boulder study of nearly 11,000 youth followed for 14 years.
The study, published this month in the Orthopaedic Journal of Sports Medicine, also found that those who play sports are less likely to suffer from mental health issues by their late 20s to early 30s.
"There is a common perception that there's a direct causal link between youth contact sports, head injuries and downstream adverse effects like impaired cognitive ability and mental health," said lead author Adam Bohr, PhD, a postdoctoral researcher in the Department of Integrative Physiology. "We did not find that."
The study comes on the heels of several highly-publicized papers linking sport-related concussion among former professional football players to chronic traumatic encephalopathy (CTE), cognitive decline and mental health issues later in life. Such reports have led many to question the safety of youth tackle football, and participation is declining nationally.
But few studies have looked specifically at adolescent participation in contact sports.
"When people talk about NFL players, they are talking about an elite subset of the population," said senior author Matthew McQueen, an associate professor of integrative physiology. "We wanted to look specifically at kids and determine if there are true harms that are showing up early in adulthood."
The study analyzed data from 10,951 participants in the National Longitudinal Study of Adolescent to Adult Health (Add Health), a representative sample of youth in seventh through 12th grades who have been interviewed and tested repeatedly since 1994.
Participants were categorized into groups: those who, in 1994, said they intended to participate in contact sports; those who intended to play non-contact sports; and those who did not intend to play sports. Among males, 26% said they intended to play football.
After controlling for socioeconomic status, education, race and other factors, the researchers analyzed scores through 2008 on word and number recall and questionnaires asking whether participants had been diagnosed with depression or attempted or thought about suicide.
"We were unable to find any meaningful difference between individuals who participated in contact sports and those who participated in non-contact sports. Across the board, across all measures, they looked more or less the same later in life," said Bohr.
Football players -- for reasons that are not clear -- actually had a lower incidence of depression in early adulthood than other groups.
Those who reported they did not intend to participate in sports at age 8 to 14 were 22% more likely to suffer depression in their late 20s and 30s.
"Right now, football is in many ways being compared to cigarette smoking -- no benefit and all harm," said McQueen, who is also director for the Pac-12 Concussion Coordinating Unit. "It is absolutely true that there is a subset of NFL players who have experienced horrible neurological decline, and we need to continue to research to improve our understanding of that important issue."
But, he said, "the idea that playing football in high school will lead to similar outcomes later in life as those who played in the NFL is not consistent with the evidence. In fact, we and others have found there is some benefit to playing youth sports."
A recent University of Pennsylvania study of 3,000 men who had graduated high school in Wisconsin in 1957 found that those who played football were no more likely to suffer depression or cognitive impairment later. But some pointed out that the sport had changed radically since the 1950s.
The new study is among the largest to date and looks at those who played football in the 1990s.
The authors note that, due to the design of the dataset, they were only able to measure "intended" participation. (Due to the timing of the questionnaires, however, it is likely that those who reported participation in football actually did participate.)
They also could not tell how long an adolescent played, what position or whether a concussion or sub-concussive head injury was ever sustained. Further studies should be done exploring those factors, they said.
"Few current public health issues are as contentious and controversial as the safety and consequences of participation in football," they concluded. "Research on the risks of participation weighed with the risks of not participating in sports will enable parents and young athletes to make educated, informed decisions based on solid evidence."
A new CU Boulder study, looking at the long-term mental and physical health of CU student-athlete alumni, is already underway.
https://www.sciencedaily.com/releases/2019/10/191021082749.htm
Fundamental insight into how memory changes with age
October 17, 2019
Science Daily/King's College London
New research from King's College London and The Open University could help explain why memory in old age is much less flexible than in young adulthood.
Through experiments in mice the researchers discovered that there were dramatic differences in how memories were stored in old age, compared to young adulthood. These differences, at the cellular level, meant that it was much harder to modify the memories made in old age.
Memories are stored in the brain by strengthening the connections between nerve cells, called synapses. Recalling a memory can alter these connections, allowing memories to be updated to adapt to a new situation. Until now researchers did not know whether this memory updating process was affected by age.
The researchers trained young adult and aged mice in a memory task, finding that the animals' age did not affect their overall ability to make new memories. However, when analysing the synapses before and after the memory task, the researchers found fundamental differences between older and younger mice.
New memories were laid down via a completely different mechanism in older animals compared to younger ones. Further, in older mice the synaptic changes linked to new memories were much harder to modify than the changes seen in younger mice.
The basic biological processes for laying down memories is shared by mammals, so it is likely that memory formation in humans follows the same processes discovered in mice.
Lead researcher Professor Karl Peter Giese, from the Institute of Psychiatry, Psychology & Neuroscience at King's, said: 'Our results give a fundamental insight into how memory processes change with age. We found that, unlike in the younger mice, memories in the older mice were not modified when recalled. This 'fixed' nature of memories formed in old age was directly linked to the alternative way the memories were laid down, which our research revealed.'
'Until now it was thought that older people should be able to form memories in just the same way as younger people, so overcoming memory problems would simply involve restoring this ability,' added Professor Giese. 'However, our results suggest this is not true, and that there is an important biological difference in how memories are stored in old age compared to young adulthood.'
The results may have implications for conditions where memory recall is a problem, such as post-traumatic stress disorder (PTSD). Professor Giese suggests that ageing should be taken into consideration when treating patients with PTSD, since confronting and modifying traumatic memories is a core feature of some psychological treatments such as trauma-focused cognitive behavioural therapy.
https://www.sciencedaily.com/releases/2019/10/191017141112.htm
Childhood trauma has lasting effect on brain connectivity in patients with depression
April 8, 2019
Science Daily/University of Pennsylvania School of Medicine
A study lead by Penn Medicine researchers found that childhood trauma is linked to abnormal connectivity in the brain in adults with major depressive disorder (MDD). The paper, published this week in Proceedings of the National Academy of Sciences (PNAS), is the first data-driven study to show symptom-specific, system-level changes in brain network connectivity in MDD.
"With estimates of approximately 10 percent of all children in the United States having been subjected to child abuse, the significance of child maltreatment on brain development and function is an important consideration," said Yvette I. Sheline, MD, McLure professor of Psychiatry, Radiology, and Neurology, and director of the Center for Neuromodulation in Depression and Stress (CNDS) in the Perelman School of Medicine at the University of Pennsylvania. "This study not only confirms the important relationship between childhood trauma and major depression, but also links patients' experiences of childhood trauma with specific functional brain network abnormalities. This suggests a possible environmental contributor to neurobiological symptoms."
MDD is a common mental disorder characterized by a variety of symptoms -- including persistently depressed mood, loss of interest, low energy, insomnia or hypersomnia, and more. These symptoms impair daily life and increase the risk of suicide. In addition, experiences of childhood trauma, including physical, sexual, or emotional abuse, as well as physical or emotional neglect, have been associated with the emergence and persistence of depressive and anxiety disorders. However, the neurobiological mechanisms underlying MDD are still largely unknown.
To address this challenge, a team led by Sheline utilized functional magnetic resonance imaging (fMRI) to investigate the brain networks and patterns that underlie the disorder. Researchers compared brain activity in 189 participants with MDD to activity of 39 healthy controls. First author Meichen Yu, a post-doctoral fellow in the CNDS, conducted statistical analyses to determine the associations between temporal correlations in connectivity within and between 10 well-established, large-scale resting state networks (RSNs) and clinical measures, including both past history of trauma and current clinical symptoms, such as depression, anxiety, suicidality. These symptoms were measured by 213 item-level survey questions.
The authors found that in patients with MDD, while the strongest correlations were with childhood trauma, abnormal network connectivity was also associated with current symptoms of depression. Even though participants in this study were not selected as participants based on a history of trauma, and the brain imaging took place decades after trauma occurred, prior trauma was evident in abnormal functional connectivity.
"These results suggest that resting-state network connectivity may point to some of the brain mechanisms underlying the symptoms of major depressive disorder," Sheline explains. "It may have the potential to serve as an effective biomarker, aiding in the development of depression biotypes and opening up the possibility of targeted diagnosis."
https://www.sciencedaily.com/releases/2019/04/190408161610.htm
Mindfulness may help decrease stress in caregivers of veterans
April 29, 2019
Science Daily/University of Illinois at Urbana-Champaign, News Bureau
Mindfulness therapy may be an effective way of mitigating the stress experienced by spouses and other informal caregivers for military veterans, a new study by researchers at the University of Illinois suggests.
Kinesiology and community health professor Sandraluz Lara-Cinisomo led a pilot study that taught caregivers of veterans in central Illinois mindfulness-based cognitive therapy skills. The caregivers in the treatment group -- mostly women caring for their spouses -- reported significant decreases in their perceived levels of stress, anxiety and worry.
By contrast, the researchers found no significant changes in any of these symptoms among the participants assigned to the waitlist control group.
"This not only shows the feasibility but also the promise that mindfulness has for improving mental health outcomes in this vulnerable, hard-to-reach population," Lara-Cinisomo said. "Although the study population was small, it shows that there's interest in this type of programming."
The researchers reported their findings in a paper published in the journal Mindfulness and examined the feasibility of the intervention in another paper published in the Journal of Holistic Nursing.
About 5.5 million informal caregivers, usually family members, provide daily care and support for U.S. military veterans. While recent federal legislation sought to bolster the financial support and assistance provided to these caregivers by offering programs such as mentoring, support groups, respite care and sometimes stipends, these services may be limited to those caring for veterans with specific diagnoses or types of injuries.
Moreover, some programs are designed primarily to serve the care needs of the veterans and only incidentally address the caregivers' needs, the researchers wrote.
"While the Veterans Administration, the Dole Foundation and other organizations are providing services, there's research to suggest that some services often don't match caregivers' needs," Lara-Cinisomo said. "Furthermore, there's been little research that has evaluated the effectiveness of current caregiver services."
Lara-Cinisomo said that compared with caregivers in the general population, those caring for veterans experience higher levels of psychological distress, poorer overall health and increased "caregiver burden" -- which refers to the overall emotional, physical and financial strain associated with providing multiple forms of care.
Additionally, caregivers of veterans engage in twice as much highly stressful or physically demanding care, compared with other caregivers, according to the study.
The majority of caregivers in the study had been providing care for more than nine years and spent 21-30 hours solely attending to the veterans' needs, in addition to other family obligations, Lara-Cinisomo said.
A large proportion of the veterans they were caring for had combat-related injuries along with a wide variety of other health issues, including mental illness and post-traumatic stress disorder, diabetes, cancer, traumatic brain injury and Parkinson's disease, Lara-Cinisomo said.
To be eligible to participate in the eight-week intervention, caregivers had to be providing informal/unpaid care to a veteran, be at least 18 years old, able to walk or sit to perform the mindfulness activities and not have any mental health problems other than anxiety or depression.
Of the caregivers who met the screening criteria and enrolled in the study, 11 were randomly assigned to the mindfulness intervention and 12 to the waitlist control group. All of the participants completed the study, and those on the waitlist were offered the opportunity to go through the mindfulness training after the wait period.
Participants in the mindfulness intervention met weekly for two hours of instruction on the skills and how to apply them in stressful situations. These skills include focusing on body sensations to eliminate and reduce emotional activity, and concentrating on the present, as opposed to ruminating about their worries.
They were encouraged to practice these exercises at home for 30-40 minutes daily with the help of an audio CD. Participants reported that they spent an average of 19 minutes weekly engaging in the activities at home.
"Despite our small numbers, we were able to show that mindfulness helps and that it should be pursued not only by researchers, but by practitioners and those providing services to this population," said Lara-Cinisomo, who is currently working with colleagues at the RAND Corporation and Loyola University to build on these findings. "There also might be some additional benefits for the caregiver and the veteran, as well, that we should explore in future studies, such as improved sleep."
https://www.sciencedaily.com/releases/2019/04/190429154532.htm
Mindful body awareness training during treatment for drug addiction helps prevent relapse
April 16, 2019
Science Daily/University of Washington
A novel type of body awareness training helps women recover from drug addiction, according to new research from the University of Washington. People in the study made marked improvement, and many improvements lasted for a year.
It's the first time the mindfulness approach has been studied in a large randomized trial as an adjunct treatment. The training helps people better understand the physical and emotional signals in their body and how they can respond to these to help them better regulate and engage in self-care.
"We could teach this intervention successfully in eight weeks to a very distressed population, and participants not only really learned these skills, they maintained increases in body awareness and regulation over the yearlong study period," said Cynthia J. Price, a research associate professor in the UW School of Nursing and lead author of the study. "The majority of participants also reported consistent use of MABT skills, on a weekly basis, over the duration of the study."
And likely due to using the skills learned in the intervention, the women showed less relapse to drug and alcohol use compared to those who didn't receive the intervention, Price said. The findings were published in March in the journal Drug and Alcohol Dependence.
The training included one-on-one coaching in an outpatient setting, in addition to the substance use disorder treatment the women were already receiving. The intervention is called Mindful Awareness in Body-oriented Therapy (MABT) and combines manual, mindfulness and psycho-educational approaches to teach interoceptive awareness and related self-care skills. Interoceptive awareness is the ability to access and process sensory information from the body.
Researchers studied 187 women at three Seattle-area locations. The cohort, all women in treatment for substance use disorder (SUD), was split into three relatively equal groups. Every group continued with their regular SUD treatment. One group received SUD treatment only, another group was taught the mindfulness technique in addition to treatment, and the third group received a women's education curriculum in addition to treatment in order to test whether the additional time and attention explained any positive study outcomes.
Women were tested at the beginning, and at three, six and 12 months on a number of factors including substance use, distress craving, emotion regulation (self-report and psychophysiology), mindfulness skills and interoceptive awareness. There were lasting improvements in these areas for those who received the MABT intervention, but not for the other two study groups.
"Those who received MABT relapsed less," Price said. "By learning to attend to their bodies, they learned important skills for better self-care."
https://www.sciencedaily.com/releases/2019/04/190416141909.htm
Routine hits playing football cause damage to the brain
August 7, 2019
Science Daily/Carnegie Mellon University
New research led by Carnegie Mellon University and the University of Rochester Medical Center indicates that concussions aren't the sole cause of damage to the brain in contact sports. A study of college football players found that typical hits sustained from playing just one season cause structural changes to the brain.
The researchers studied 38 University of Rochester players, putting accelerometers -- devices that measures accelerative force -- in their helmets for every practice and game. The players' brains were scanned in an MRI machine before and after a season of play.
While only two players suffered clinically diagnosed concussions during the time they were followed in the study, the comparison of the post- and pre-season MRIs showed greater than two-thirds of the players experienced a decrease in the structural integrity of their brain. Specifically, the researchers found reduced white matter integrity in the midbrain after the season compared to before the season. Furthermore, and indicating the injury was specifically related to playing football, the researchers found the amount of white matter damage was correlated with the number of hits to the head players sustained.
The study is published in the journal Science Advances.
"Public perception is that the big hits are the only ones that matter. It's what people talk about and what we often see being replayed on TV," said senior study author Brad Mahon, an associate professor of psychology at Carnegie Mellon and scientific director of the Program for Translational Brain Mapping at the University of Rochester. "The big hits are definitely bad, but with the focus on the big hits, the public is missing what's likely causing the long-term damage in players' brains. It's not just the concussions. It's everyday hits, too."
The midbrain, located in the center of the head and just beneath the cerebral cortex, is part of a larger stalk-like rigid structure that includes the brain stem and the thalamus. The relative rigidity of the midbrain means it absorbs forces differently than surrounding softer tissues, making it biomechanically susceptible to the forces caused by head hits. The midbrain supports functions like eye movements, which are impacted by concussions and hits to the head. While head hits are known to affect many parts of the brain simultaneously, the researchers decided to focus the study on the midbrain, hypothesizing that this structure would be the "canary in the coal mine" for sub-concussive hits.
"We hypothesized and found that the midbrain is a key structure that can serve as an index of injury in both clinically defined concussions and repetitive head hits," said Adnan Hirad, an M.D./Ph.D. candidate at the University of Rochester's Medical Scientist Training Program and lead author of the study. "What we cataloged in our study are things that can't be observed simply by looking at or behaviorally testing a player, on or off the field. These are 'clinically silent' brain injuries."
Each player in the study received an MRI scan within two weeks of the start of each season and within one week at the end. The helmet accelerometers measured linear and rotational acceleration during all practices and games, recording all contact that produced forces of 10 gs or greater. Astronauts on the space shuttle experienced 3 gs during lift-off. Race car drivers feel the effects of 6 gs, and car crashes can produce brief forces of more than 100 gs.
The 38 NCAA Division III players experienced nearly 20,000 hits across all practices and games. Of those hits, the median force was around 25 gs, with half of the hits exceeding that amount. Only two of the nearly 20,000 hits resulted in concussions.
"We measured the linear acceleration, rotational acceleration and direction of impact of every hit the players sustained. This allowed us to create a three-dimensional map of all of the forces their brains sustained," Hirad said.
The MRI scans measured structural changes in the brain that took place over the course of each season. They found that rotational acceleration (impact causing the head to twist) more so than linear acceleration (head-on impact) is correlated with the observed changes in the structural integrity of white matter in the midbrain.
"This study suggests that midbrain imaging using diffusion MRI might be a way in the future to diagnose injury from a single concussive head hit and/or from repetitive sub-concussive head hits," said Dr. Jeffrey Bazarian, professor of Emergency Medicine, Neurology, Neurosurgery and Public Health Sciences at the University of Rochester Medical Center and a co-author of the study.
The second part of the study served as an independent means to validate the researchers' approach to the football cohort. This group included 29 athletes from various other contact sports who had a clinically defined concussion and 58 who didn't.
The concussed participants underwent MRI scans and offered blood samples within 72 hours of injury. Like the football cohort, those players exhibited reduced structural integrity in the midbrain. In addition, they exhibited increased tau, a protein, in their blood. As structural integrity in the brain decreases, tau increases.
"Tau is an important marker of acute changes in the brain and is thought to be, in the long term, implicated in neurodegenerative diseases like chronic traumatic encephalopathy, also known as CTE," Hirad said.
Given this new insight on repetitive head hits, what should we do?
"Our research, in the context of prior research over the past several years, is beginning to indicate that the accumulation of many sub-concussive hits is instrumental in driving long-term damage in football players' brains," Mahon said. "Future research will be required in order to translate our findings into concrete directives that are relevant to public health. An important direction for future research will be to carry out larger-scale longitudinal studies of contact sports athletes in various ages groups."
"We also need to re-evaluate how we make return-to-play decisions," Hirad said. "Right now, those decisions are made based on whether or not a player is exhibiting symptoms of a concussion like dizziness or loss of consciousness. Even without a concussion, the hits players are taking in practice and games appear to cause brain damage over time."
https://www.sciencedaily.com/releases/2019/08/190807142249.htm