Diffusion tensor imaging reveals subtle neuronal damage (red) in mild traumatic brain injury. Images courtesy Dr. Michael Lipton
Posted on 05/04/2009 9:30:32 AM PDT by neverdem
The consequences of mild traumatic brain injury are often anything but mild. Recent studies linking concussion to long-term neurologic deficits suggest that, for some individuals, the characteristic transient brain dysfunction and acute symptom resolution represent the beginning of potentially irreversible structural and functional brain alterations.
“Traumatic brain injury occurs as a spectrum disorder. The term 'mild' describes only the initial insult relative to the degree of neurological severity. There may be no correlation with the degree of short- or long-term impairment or functional disability,” said Dr. Nathan Zasler of the University of Virginia, Charlottesville, and medical director of the Concussion Care Centre of Virginia in Glen Allen.
By definition, mild traumatic brain injury (mTBI) results from direct trauma to the head or from an acceleration/deceleration stress to the brain. Such an injury poses a risk for short-term symptoms including headache and difficulty with balance, thinking, concentrating, and sleeping, and may lead to long-term symptoms categorized as postconcussive syndrome, according to the National Institute of Neurological Disorders and Stroke.
Investigators at the University of Illinois at Urbana-Champaign showed that college athletes with a history of sports-related concussion continue to have diminished brain function for a number of years after their injuries (J. Neurotrauma 2009 March [doi:10.1089/neu.2008–0766]). Specifically, “we were able to show that while our group of club and intercollegiate athletes performed normally on standard clinical neurocognitive assessment, they had suppressed brain functioning at an average 31/2 years post injury, including a decrease in attention allocation to things going on in their environment,” lead investigator Steven Broglio, Ph.D., said in an interview. The findings provide further evidence that concussion should not be considered a transient injury associated with short-lived neurologic impairment, he noted.
The authors of a widely reported Canadian case control study reached a similar conclusion. The study compared the neurocognitive status of currently healthy former university-level hockey and football players aged 50–65 years who had sustained a single concussion more than 30 years ago with that of former athletes with no concussion history. Electrophysiologic and neuropsychological tests indicated that individuals with a history of concussion had memory and attention problems along with slower reaction times relative to those of the controls (Brain 2009 Jan. 28 [doi: 10.1093/brain/awn347]).
At the more extreme end of the damage spectrum, biopsies of the brains of six former NFL players between the ages of 25 and 50 who had experienced multiple concussions during their careers revealed evidence of chronic traumatic encephalopathy, according to investigators at Boston University's Center for the Study of Traumatic Encephalopathy (CSTE). All six players had had emotional and behavioral problems such as drug abuse, and two committed suicide, said Dr. Ann C. McKee, lead investigator and CSTE codirector.
Mounting evidence of long-term effects of mTBI in athletes has led to growing concerns about the frequency of concussions among U.S. soldiers in Iraq and Afghanistan. An anonymous survey of more than 2,500 active duty and reserve soldiers conducted 3–4 months after a year-long tour of duty in Iraq showed that mTBI, when associated with a loss of consciousness, led to an increase in posttraumatic stress syndrome, relative to soldiers who had sustained other types of injuries or no injuries (N. Engl. J. Med. 2008;358:453–63).
Considering the large number of U.S. combat soldiers at risk for mTBI, the Department of Defense has mandated that all deploying troops undergo a cognitive functional assessment to serve as a baseline measure for comparison in case of later mTBI.
According to the Centers for Disease Control and Prevention, an estimated 5%–15% of individuals in the general population who sustain an mTBI have long-term deficits of some sort, although actual numbers are difficult to ascertain. “Not all people who sustain a mild brain injury recognize some of the later cognitive and behavioral impairments as related to the injury, and many don't seek medical treatment,” Dr. Zasler said. “This is why [mTBI] is sometimes called an invisible injury—people can look fine on the outside, but they may not be behaving fine, thinking fine, sleeping fine.”
Still, he added, most patients with single mTBIs recover relatively soon if they don't have comorbidities, or psychiatric or neurological histories that increase their vulnerability.
New evidence confirms suspicions that post mTBI problems are substantially underreported. Karen Hux, Ph.D., of the University of Nebraska-Lincoln and her colleagues evaluated a TBI screening procedure at vocational rehabilitation centers, domestic abuse and homeless shelters, and mental health centers. Of 1,999 screening protocols administered by professionals from four service agencies over a 6-month period, 531 were positive for a possible mTBI of sufficient severity to affect quality of life (Brain Inj. 2009;23:8–14).
The only objective method for detecting or confirming mTBI is specialized medical imaging. “CT and MRI scans of patients suffering persistent cognitive impairment as a result of mild traumatic brain injury usually look totally normal. When you look at the raw images, you can't really see anything abnormal. What you need to do is look at the images quantitatively,” said Dr. Michael Lipton of the department of radiology at Albert Einstein College of Medicine in New York. He and his colleagues use MRI-based diffusion tensor imaging (DTI) to map the location, orientation, and anisotropy of the brain's white matter tracts. “We analyze each and every voxel of the brain looking for statistically significant differences between [mTBI] patients and healthy controls.”
The ability to detect subtle neuronal injury has important clinical implications for the management of mTBI, Dr. Lipton said. “Right now, there are a lot of candidate therapies, but if you look at the literature, all of the treatment trials are failures. This is because almost all of them are conducted in patients with moderate to severe brain injury. In those patients, it's too late.” Identifying individuals with mild injury would allow the use and evaluation of candidate therapies designed to arrest the progression of damage.
Although the clinical utility of DTI has been established and the technology is being used at many academic centers for clinical measurement, “with the current state of the art, it requires specialized expertise to be able to extract information from the images,” he said.
The early identification and management of mTBI should get a boost from evidence-based clinical guidelines by the American College of Emergency Physicians and the CDC. Although the 2008 guidelines are written primarily for emergency physicians, “many patients with mild traumatic brain injury seek care from other practitioners such as internists, family practitioners, geriatricians, pediatricians, and neurologists,” said Dr. Andy Jagoda of Mount Sinai School of Medicine in New York, and chair of the guideline writing panel. For that reason, all clinicians should be made aware of them.
Diffusion tensor imaging reveals subtle neuronal damage (red) in mild traumatic brain injury. Images courtesy Dr. Michael Lipton
PII: S0300-7073(09)70284-1
doi:10.1016/S0300-7073(09)70284-1
Everyone gets a knock on the head from time to time. For Democrats, the ill effects on rationality are lingering and permanent.
So, a brain injury can....what were we talking about???
It can lead to a lifetime of voting Democrat.
Cause more long term problems than previously believed. People who have had concussions apparently have a higher risk of problems with memory, attention, etc. than people who have not had concussions.
My own personal experience tends to agree with this. I fell ice skating almost a year ago and whacked my head really bad and broke my wrist. I am still having problems with memory and processing new information. It's better than it was but I might never be back the way I used to be.
I beg to differ. I had a severe TBI in 1984. While I still have some problems, I most definitely won’t vote D.
I remember seeing somewhere that a brain injury due to a plane wreck was suspected as the cause of Howard Hughes’ obsessive compulsive behavior.
Me, too. I think it’s cumulative ... thinking back to all the years I went horseback riding without a helmet and the times I landed on my head.
FWIW, at the time I had some days where I knew I was in a fog, but eventually recovered.
I thought all you sissy-boy hockey players wore helmets??? ;-) Figure skaters don’t. (Just teasing)
This was the worst fall I have ever had - I’m still skating but if I fall again, I will stop skating.
I think most people have trouble with names. I’ve always had trouble with that too. But it definitely takes me a lot more effort to absorb new information since last summer. Very frustrating.
Peer Review Needs Improvement ('peer review' is often equated with 'gold standard'. Far from it)
American Epidemics, a Brief History
Guidelines Spell Out Prophylactic Aspirin Use
FReepmail me if you want on or off my health and science ping list.
TBI is a real problem with returning Iraqi vets. Neurology diagnosed mine from having my chimes rung by too many close mortar detonations. Exaggerated startle respnonse, light sensitibity and balance problems went unchanged for two years until I was placed on high doses of vitamin D and after a month some of the problems did improve. Vitamin D is more than for strong bones and teeth, it is vital enzyme necessary for healthy central nervous system functions. When you are placed on high doses, serial blood tests have to be done to prevent toxic levels from being reached.
How high a dose of Vitamin D did they have you take?
I take it for other reasons but it would be nice if it helps my post-concussion issues.
I started off with 1000IU daily and have worked up to 5000 IU’s per day. After going for two years with no improvement, I started to get better after 4-6 weeks.
Very helpful. Thanks for posting.
I’m at about 1200 a day already. Perhaps it’s helped some.
Just kidding. Most of the time, we coaches never wore helmets....I was skating with the kids in warm-ups going backwards while facing the kids coming at me. A kid who was late, came off the bench behind me and lost his balance, took my legs out from under me and the rest was history. Blood was flowing from the cut on my head, I was out cold......after that, we all decided to wear helmets. Stuff happens. One guy lost a finger when he took off his glove to try to patch together a gouge in the ice and somebody skated over his hand. Stuff happens. Sorry to hear you are still struggling, hang in there.
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