Support Provided ByLearn More
Body + BrainBody & Brain

Brain Trauma: Expert Q&A

On August 5, 2008, neurosurgeon Jam Ghajar answered wide-ranging questions about traumatic brain injury (TBI) and techniques for diagnosing brain damage.


Receive emails about upcoming NOVA programs and related content, as well as featured reporting about current events through a science lens.

Q: Do you think it's possible that a brain injury could be inadvertently ignored for several years, yet still be accurately diagnosed and treated? Alan, Winston-Salem, North Carolina

Support Provided ByLearn More
Jam Ghajar: Dear Alan,
Yes, one of the symptoms of traumatic brain injury is a lack of awareness of deficits in attention and short-term memory. Usually close friends and family pick up on it and also notice that the person is somewhat different.

Your awareness of self is produced by accurate prediction of an expectation. When there is a disparity between what you expect and what happens, then "I" or awareness of self is reduced. This has been highlighted in self-tickling experiments where there is an interposed, unexpected delay in the tickle. (The person self-tickling might say, "I don't feel a tickle when I do it and expect it correctly.")

The sense of self is very much tied with a person's expectation synchronizing with what actually happens. That's why in unpredictable (expectation not met) environments, there is a feeling of de-personalization. This is a frequent feeling in war or disasters. It is also the reason why, especially as we get older, we tend toward a predictable, routine life-I predict (correctly), therefore I am.

Q: As a neuropsychologist specializing in mild traumatic brain injury, I see great promise in DTI [Diffusion Tensor Imaging] as a way to diagnose brain injury. Is DTI currently accepted as a clinical diagnostic tool? Has DTI been accepted in the legal community as a diagnostic test? Anonymous

Ghajar: Not yet. Imaging white matter integrity is key to assessing brain functions that rely on brain networking, such as attention and working memory for instance. DTI is the latest, but the physics and the method of measuring white matter integrity are evolving. DTI will be commercially available, but the issue remains of what is considered "normal."

Q: Is your eye-tracking device available for research? We work with multicultural populations with various levels of severity of TBI. Please advise where and how a portable eye tracker can be obtained for diagnostic/research use.

Regards, Marcel Ponton, Los Angeles, California

Ghajar: Dear Marcel,
There are many commercially available eye-tracking systems readily available for research. Our research has focused on the analysis of eye-target synchronization in predictable smooth eye pursuit. We have recently been awarded a Department of Defense grant to develop it for the military to diagnose concussion. Go to for further information.

Q: This year I was diagnosed with breast cancer. I recently completed my chemotherapy treatment. Prior to and since chemo treatment I have been reading about "chemobrain"-a phenomenon I have personally experienced. I have a much harder time concentrating; words, correct spelling, and names will escape me. My understanding is that this is only a recently acknowledged side effect of chemotherapy. I saw your program on PBS and the symptoms described by brain trauma patients and "chemobrain" seem very similar. Has your research been expanded to include other types of brain dysfunctions, including "chemobrain" or even Alzheimer's? Additionally, has your research shown any way to treat this gap in brain function? Sheen Arnold, Springfield, Missouri

Ghajar: Dear Sheen,
We have not used the EYE-SYNC with patients who have had chemotherapy.

Q: Our 10-year-old son has been diagnosed this year with ADHD without the hyper piece. After watching NOVA scienceNow on July 30th, we thought about three falls he had when he was four, five, and eight. All the falls happened at school, and all resulted in pain and a lump of some size to the head. There were no outward signs of concussion like confusion or vomiting, but we thought there might be a connection with these events and his diagnosis. Is there a place in the Down East area of Maine where we might have this looked at? Anonymous

Ghajar: Q: I am 35 years old and was diagnosed with Attention Deficit Disorder. While watching the Brain Trauma segment and how it affected attention, my mother made a connection. When I was two or three years old, I fell down the stairs and had a gash in my forehead. I could have suffered a concussion as a little girl, but there was not an MRI in existence during the mid 1970s. I would like to know if a fall during my early childhood contributed to my Attention Deficit Disorder.

Thank you for your response! Anonymous

Ghajar: Q: When my son was six to eight months old, he fell on the stairs with what I thought was a significant and serious "thud" to his forehead. No obvious serious damage at the time, although we were concerned enough to consult our pediatrician. No obvious loss of consciousness or broken bones. Please give us your thoughts as to the possible and probable ramifications. Apparent lessening of attention at school without ADD seems to be an issue for us. Thank you. Anonymous

Ghajar: Head injury very commonly causes increased variability and therefore distractibility. In children and adults with lots of energy and drive, this would have all the hallmarks of ADHD or ADD.

Unfortunately, we have a clinical label called ADHD or ADD defined by symptoms/behaviors but without a scientific basis of understanding. I will address "distractibility" and "hyperactivity":

One has to understand the nature of attention, broadly defined as selective awareness of one thing exclusive of other things (and related to potential for distractibility). Attention, by our working hypothesis, is a function that reduces variability in trying to achieve selective awareness of a thing. The inability to reduce variability causes awareness to shift easily to other things-distractibility.

An adult or child (who has more energy) with lots of intention to achieve goals (school, work, etc.) with an impaired ability to reduce variability will become more distractible and will task switch more often-leading to the appearance of hyperactivity. Switching rapidly from task to task is "hyper" active.

Q: Has this new technology (white matter imaging and eye-tracking device) been used in people diagnosed with autism? The symptoms seem somehow very familiar to my daughter's (forgetful, delay in response due to loss of quick word retrieval, etc.). Any insight would be very greatly appreciated. Angie Dirscherl, Spokane Valley, Washington

Ghajar: Dear Angie,
We have not used EYE-SYNC in autistic subjects yet.

I have been trying to find a way to approach the autism community using the predictive brain state scientific findings that could explain the age of diagnosis, the cause, the symptoms, and therapeutic interventions.

Autistics are known to have deficits in prediction that evolve at approximately 18 months. In my opinion, a lot of the confusion surrounding cause, diagnosis, and treatment could be quickly cleared up.

There are scientific studies that point to solving the puzzle-the problem is that they are in diverse scientific fields that don't communicate.

Q: When my daughter was 19 months old, she fell from a grocery cart onto the hard surface of a floor. The back of her head got the impact. At age 2.5, she was diagnosed with autism (lack of speech, eye contact, socialization). Could that impact have caused autism? Bahram, Seattle, Washington

Ghajar: Dear Bahram,
See the previous email response. At around the time of the fall is the time for diagnosing autism.

Q: Can minor brain trauma due to concussions trigger seizures? This happened to my daughter, who was hit by a car while riding her bicycle. X-rays, MRIs all came back negative for brain injury, yet the seizures went from petit mal to grand mal over a period of four years. Could the white matter of the brain have been damaged, causing these seizures? (She never had them before the accident.) Anonymous

Ghajar: Yes, even a minor head injury or concussion can cause a seizure. These are usually immediate and do not persist. Patients with more severe TBI can develop epilepsy. Consult with a neurologist who specializes in seizures.

Q: Dr. Ghajar,
I was fascinated by your segment on NOVA scienceNOW tonight. My interest runs in two directions-sports and 1st grade math!

As a high school coach, I was really excited by the notion that there may be a quick, accurate, field or court-side instrument to determine whether a young athlete has a concussion. When might the glasses be available?

And, second, I also teach 1st grade math, concentrating on children with focus problems (some of whom may have ADD or ADHD, but most of whom just seem to have an inability to focus-and maintain a mental image-for long enough to move to the next step of mathematical reasoning.)

I received a concussion in high school during a football practice when a much bigger teammate, whom I had out-maneuvered a couple of times, retaliated with a forearm shiver that landed squarely between my face mask and the lower edge of the front of my helmet. I now clearly remember feeling very similar to the young man in your segment, especially regarding the ability to do math. It was two-to-three weeks before I could keep a multi-step problem straight in my head. I would focus on step one, then step two, and when I got to step three, I couldn't remember what step one was. This is very similar to the difficulty many of my young students have. Have you given any thought to whether the white matter may be critical to academic "focus" issues? It seems to me that the similarities of response are quite remarkable.

Any thoughts? Hank Hankla (Beauvoir School), Washington, D.C.

Ghajar: Hi Hank,
You make some very interesting observations. Most of our thinking and learning relies on maintaining information over a few seconds, which is called working memory and is part of the attention process. People who are "variable" in maintaining the information over time are often called distractible or labeled as ADHD.

So the more "variable" you are in keeping information in your head (maintaining information), the more distractible and less aware you are-you can't concentrate and therefore can't learn. Here's an analogy: A train going from A to B relies on staying "on track," and if there is a lot of wobble (variability) in the wheels, then the train can come off the tracks and will not reach B. A student learning algebra needs to retain information when going (like the train on tracks) from one step to another.

Fatigue, age, head injury, distraction (concentrating on another task), and ADHD all produce a wobble and tendency to go "off track," leading to impairments in learning, short-term memory, and self-awareness.

The EYE-SYNC device measures how well you "stay on track," which is variability in scientific terms. It will be a very useful device to measure how well someone pays attention. Knowing this, one can prevent injury-because people who can't pay attention well (either due to a prior head injury or other cause) are likely to get future head injuries as well as other injuries.

Q: I work at a high school as a Certified Athletic Trainer (ATC) and have dealt with many sport concussions. The ones that are the hardest to deal with are where there are no obvious symptoms (balance, vision, or cognitive problems) that can be assessed, or that the athlete will admit to. There is a computer program (IMPACT) that several of the schools in the area have used, but the problem is that the post-test is not conclusive and is usually done 24-48 hours after a concussion is suspected. Your research is interesting in that it could lead to a "sidelines" test. Can you comment about your research and how it relates to the computer assessment programs on the market now.

Thank You, Anonymous

Ghajar: The standard neuropsychological tests for concussion are a battery of attention, working memory, and processing speed tests. However, to really understand what concussion is, one needs to know what the normal condition is-what is "attention"?

Attention is the main function that is disabled in concussion, because of anterior white matter rotational disruption. (We are currently examining the biology of this disruption.) This disrupted white matter subserves the attention neural network and produces increased vulnerability to another injury.

My colleagues and I have been scientifically studying concussion over the last six years and have developed a working hypothesis that explains concussion symptoms on the basis that attention is a process to reduce variability in interactions (Ghajar and Ivry, Neurorehabil Neural Repair. 2008 May-Jun;22(3):217-27).

Attention requires the brain to be a predictive state, and timing is critical to synchronize and interact with the external world. EYE-SYNC accurately and quickly measures attention using the predictive timing of eye movement.

The EYE-SYNC measurement can be performed in less than 30 seconds and concentrates on predictive timing. IMPACT and other neuropsychological battery tests take at least 20 minutes and are based on a variety of parameters.

Q: My husband received a concussion 3 1/2 years ago. He has had a continuous headache ever since. Doctors can find no "reason" for his continuing pain and disability, and have just told him it could last for years. Could damage to the white matter cause this, and what can be done about it? Thank you so much. We are at the end of our rope! Anonymous

Q: I continue to have mild headaches on a daily basis two years after a severe auto collision. Is it possible for a concussion to continue to cause headaches that long after an accident? Are there any treatments available? L. May, Strafford, Missouri

Ghajar: Headache is a common symptom after a concussion. In about 80 percent of concussion patients, the symptoms resolve after a few months, but 20 percent go on to have permanent symptoms.

According to our research and the work of others, the normal attention function of the brain when interacting with the outside world (conversation, work, social, etc.) is to be in a predictive state. That means you predict what is going to happen on a moment-to-moment basis, which normally leads to accurate synchronization of what you predict to what happens-for instance, when I'm having a conversation with someone, I expect to hear a word, and this happens.

The timing or synchronization is crucial to interactions-just think of a cell phone conversation where the caller's voice comes in at variable times (goes in and out). Guess what? You get a headache trying to have that conversation (error signals from your brain). Well this is what is going on in the head of someone after a concussion-they can't predict accurately when the next word is coming in, so their brain gets lots of error signals, leading to headaches.

Headaches can be reduced by a good night's sleep (which eludes many who have had a head injury), and by sticking to one easy task at a time in a quiet environment that has few distracters.

Q: My neighbor's parents came to me to assess their daughter, who was hit in the head by a flying discus on a sports field during training practice. There was no obvious evidence of trauma or injury. This is one month later, and no sequale is evident. My question is: What can she do medically to follow up on a head trauma that has no obvious damage to her speech, coordination, memory? I am a retired intensive care nurse. Anonymous

Ghajar: Not all head injuries produce symptoms or brain injury. If there are no symptoms and a person's performance is the same as before, then usually no further tests are necessary.

Q: My son Ygnacio, 15 years old, had a severe TBI last August 2007. He had an almost full recovery-a 2.9 gpa, making new friends, joking, passing the math WASL as a 9th grader, etc. Since about June 18, 2008, he showed different signs-catatonia, seeing things, hearing voices, and not getting better. He has been on a low dose of risperidal (.5mg am & pm) since June 8. He is barely moving, saying random things, barely audible after not talking at all for 3-4 hours. Do you have any insight? We are going to Bremerton's ATU-Adolescent treatment unit tomorrow to have him observed. Are there some specialists in the area that can help us? Anne, Ygnacio's mom, Kingston, Washington

Ghajar: Dear Anne,
Head injury or Traumatic Brain Injury is the leading cause of disability and death in young people ( Due to the very high incidence of TBI, especially concussion, which accounts for 90 percent of TBI, it may seem to cause other problems that may not be connected. Schizophrenia, as an example, is diagnosed in the teenage years and early adulthood and could appear independent of a TBI.

In this case, there was almost full recovery then symptoms associated with schizophrenia appeared. On the other hand, severe TBI patients can improve and then deteriorate, usually after about nine months.

The symptoms of schizophrenia have been associated with decreased prediction. One example is if my thought comes to me when I don't expect it, I would attribute it to someone else, which could be classified as a hallucination.

The University of Washington in Seattle has excellent TBI and psychiatry services.

Q: How do you see the relationship between TBI [Traumatic Brain Injury] and PTSD [Post-Traumatic Stress Disorder]? Anonymous

Ghajar: I think that they are ill-defined clinical diagnoses that share common symptoms.

Brain imaging defines what we think is a biological injury. Imaging technologies are evolving, with MRI-Diffusion Tensor Imaging being the latest. The problem is that as the imaging gets better, it starts unraveling what we consider "normal." Some of our normal research subjects had abnormal DTI (perhaps suggesting that they had prior TBI?), and some TBI patients had normal DTI. In the normal population, there are studies now showing variations in DTI (e.g., between good vs. poor readers).

As imaging techniques imrove, we may see that some PTSD patients turn out to have TBI. More significantly, I think that PTSD patients will have an inherently or acquired deficiency in attention network connectivity. This would lead to higher variability in interactions, susceptibility to distraction, and anxiety.

I think that improving attention would reduce PTSD symptoms. When someone is fatigued (with subsequent lower attention), he or she is prone to anxiety.

Q: I had a severe concussion 30 years ago, when I was 38. I was unconscious for five days after a car accident. Before I was out of bed, I knew my memory was impaired. I have struggled with that ever since then. Is there anything I can do to help this condition now? I am 68 and am having increasing forgetfulness. My father had dementia, beginning in his 60s, so I thought perhaps it was just hereditary, but I know I have been struggling for 30 years now. Before that I was proud of an exceptional memory. That was also the case with my father though, too. Hereditary or trauma? Anonymous

Ghajar: Aging and concussion share many symptoms, mainly attention and short-term memory difficulty. The reason is that the underlying deficiency is the same, but from different causes. The leading cause of dementia is Traumatic Brain Injury, so it is difficult to say if your condition is 100 percent aging or TBI.

As we get older, or if we get a concussion, our reaction times get more variable and in general are longer. The problem is NOT longer reaction times, but the variability. We can't adjust ourselves because our reaction times are not predictably long or short (rather, they are short, long, long, long, short, etc).

Concussions produce variable reaction times because the brain circuit for reducing variability (attention circuit) is damaged. Aging also produces degeneration in this brain circuit causing variability.

Increased variability leads to poor attention and short-term memory. Ways to improve are #1 get a good night's sleep, #2 minimize distracters (noise, other tasks, phone, etc.), #3 be interested in what you are doing.