NASCAR Concussions II: A Screening Test to Avoid Relying Entirely on the Driver

I was lucky enough to speak with Dr. Mark Lovell, an innovator in neurocognitive testing inbetween talks at a conference he was attending.  (Neurocognitive, incidentally, describes those thinking functions that are closely linked to particular areas of the brain.  We’re talking about things like attention, memory, speaking and understanding language, solving problems, and making decisions.)  Dr. Lovell was the founding director of the University of Pittsburgh’s Medical Center’s Sports Medicine Concussion Program and has published over a hundred journal articles and authored or co-authored nine textbooks about sports-related concussions.

Dr. Lovell came to my attention as the developer of the ImPACT (Immediate Post-Concussion Assessment Testing) test, which was one of the tools used to evaluate Dale Earnhardt, Jr.’s concussion.  Given that he is right up the road in Pittsburgh, I thought I’d spend a little time looking into exactly what the test is and whether it’s a viable alternative for NASCAR to use in screening drivers for concussion.

As I mentioned in my last post, physical damage to the brain can be detected by techniques like magnetic resonance imaging; however, even if the physical structure is intact, the brain works primarily on electrical and chemical signals – and we don’t have a way to simply look into a person’s head and verify that all the neurons are sending and receiving signals correctly.

Lovell wanted to make clear that concussions are a rapidly evolving field of research, noting that “90 percent of everything we know about concussion has been learned in the last ten years”.   Ten years ago, no one thought a concussion was a big deal.  Getting your “bell rung” was part of sports like football, hockey and boxing.  We’re learning now — especially from long-term studies of football and hockey players) that even a “mild” concussion in which you don’t lose consciousness can have short- and long-term results.

Here’s what the ImPACT test looks like:  You sit in front of a computer terminal for about twenty minutes and respond to a series of fast-moving activities.   For example, you’re given twelve target words to memorize – you get to see the words for 750 milliseconds each — and you get to see each word twice.  You are then presented with twenty four words, twelve of which are the ones you saw already and twelve of which are similar in some way to the words you saw.  For example, you might be shown the word “ice” as one of the ones to remember and “snow” as a non-target word.    A box comes up and asks “was pencil one of the words displayed?” and you click yes or no.  There are similar exercises using abstract designs, letters, colors, and symbols.  Each exercise tests one (or more) neurocognitive function.

It’s not easy.  In fact, when you’re done, you feel a little like someone has been throwing things at your brain.  The test requires you to multi-task and if you took the time to try to think about how to cheat, it would be obvious that you weren’t giving it your best try.

Lovell emphasizes that a complete evaluation for concussion requires many parts:  The process requires collecting demographic information and a health history survey, including any history of previous concussions.  If you’ve had mental health issues or are taking medications, that has to be factored in as well.  A full description of the injury also is usually included.  Assuming NASCAR adapted this as a standard test, this would all be on file or easily available.

The ImPACT test looks at six distinct elements:

  • Verbal memory (your ability to pay attention, learning and memory relating to verbal things like words, symbols and letters)
  • Visual memory (visual attention and scanning, learning and memory related to visual processes)
  • Visual motor speed (visual processing, learning and memory, and visual-motor response speed)
  • Reaction time (how fast you can respond to something)
  • Impulse control (this is actually a way of measuring the uncertainties inherent in the testing)
  • Symptom score (this measures the presence and severity of 22 symptoms, ranging from sleeping to balance to irritability to fogginess).  This is really the only area of the test in which a driver could try to hide evidence of a concussion.

Dr. Lovell recommends that athletes do a “baseline test” prior to engaging in their sport.  For NASCAR, that would be at the start of every season.  Although the test is still useful without a baseline, having the pre-test allows you to compare a driver’s current state with his previous state and reduces uncertainties that might be caused by things specific to an individual.   Over many years of testing athletes at all levels, the ImPACT people have collected scores for people in different age groups, genders and populations (i.e. athletes vs. us couch potatoes), so even without a baseline, a doctor would have some reference point for how well you ought to score by comparing your score with a typical score of someone similar to you.

One of the challenges of concussion is that it’s a type of injury in which the patient may try to hide the symptoms from the doctor.  Dr. Lovell designed the ImPACT test to help diagnose concussion, even when the subject is reluctant to admit that he or she is exhibiting symptoms.  Trying to purposely score poorly on the test works against the athlete (a bad score makes it more likely you’ll be sat down), so the athlete is motivated to do their best.

Anyone developing a test (whether it be for education or medicine) has to worry about people who try to get around the test’s purpose.  What was most impressive to me in reading the research papers about the ImPACT test is that the developers have come up with ways to tell when people are trying to outwit the test.  Dr. Lovell laughed when he told me that some athletes “sandbag” during their baseline testing, thinking that if they have a lower baseline score, they can get hurt and it won’t be detected.  The test developers have found ways to measure whether someone was trying, for example, to be more accurate by taking the test more slowly, or to complete the test quickly without worrying about being correct.  The test is not only measuring neurocognitive function, it’s measuring whether you’re taking the test to the best of your ability.

Your score on the ImPACT test isn’t a yes/no measure of whether you have a concussion.  Concussion is a subtle enough injury that you still need evaluation by an experienced professional; however, Dr. Lovell believes that the ImPACT test is a good way to screen athletes to determine whether additional medical evaluation is necessary.

Your score on the ImPACT test also gives the diagnosing doctor some help in predicting time to recovery.  The team has developed a cut-off score that broadly predicts whether recovery time will be less than or more than two weeks.  It’s not exact, of course.  Dr. Lovell emphasizes that one of the challenges understanding and treating concussions is that every individual is different.  Most will fall into a “normal” range, but there are always exceptions at both ends of that range.  Repeat testing helps the doctor measure how well the patient is progressing because there can still be neurocognitive impairment well after the obvious symptoms have gone away.

ImPACT is a twenty-minute test administered on a computer.  A system for administering the test could be brought to any race (it’s much more portable than an engine dyno!) and, given that it takes just 20 minutes to complete, seems like a very easy to implement screening tool after any hard impact.  Again, Dr. Lovell would be the first to emphasize that you don’t just take the test and know that you do/don’t have a concussion; however, NASCAR could easily require any driver involved in a crash to do a quick assessment to determine whether they should be seen by a doctor for further followup.

Concussions – What Are They and Why Stop Racing?

We all know that concussions are caused by hits to the head, but what actually IS a concussion and why is one forcing Dale Earnhardt, Jr. to step out of the car and effectively take himself out of the running for a championship?

How Do You Know You’ve Got One?

A concussion is a type of traumatic brain injury (TBI).  The Centers for Disease Control estimate that 1.7 million people suffer a traumatic brain injury every year.  A concussion is a mild type of TBI, but it is not (as we used to think) negligible.  Symptoms of concussion generally fall into four categories:  problems thinking and/or remembering and concentrating; physical signs like headaches, nausea, or balance problems; emotional distress like irritability, sadness or nervousness, and sleep changes.  Symptoms don’t always appear right away after a concussion – it may take days to notice them.  The concept of ‘concussion’ isn’t really well agreed upon by the experts. Most limit concussion to a state in which there is no physical brain damage.  There is even disagreement as to whether you have to lose consciousness to have an official concussion.

Dale Jr.’s doctor mentioned that he had a ‘special’ MRI (magnetic resonance imaging) scan.  I suspect it was a functional MRI scan – you can read more about that and its utility in sports here.

What is a Concussion?

If you were to open up a head, the first thing you would notice is the cerebrospinal fluid.  Your brain is not rigidly held in place in your head.  The cerebrospinal fluid surrounds your brain and gives it a cushion so that it doesn’t bang against the skull when you move your head suddenly.  It’s sort of like an internal helmet for your brain.  In a concussion, the motion of the head is so sharp that the cerebrospinal fluid isn’t able to provide adequate cushioning.  Interestingly, some researchers believe that it’s the rotation of the brain and not the straight-line  motion that is responsible for the damage.  In fact – Dale, Jr. noted during his press conference this morning that the Talladega crash was “only” 20 g, but he also said that he was spinning at Talladega.  Once the damage happens, it can persist for days to weeks — or longer.  We’re still figuring that out.

What we know is that a concussion changes the biochemical functioning of the cells in the brain.  A brain relies on two types of cells:  glial cells (which are like the brain’s pit crew, providing structural and metabolic support) and neurons.  The neurons (shown at right) are responsible for transmitting information.  The axon sends out information and the soma and dendrites receive information.  The information starts as an electrical pulse and then is converted into a chemical signal at the junctions between neurons.  In order for this to work, everything has to function correctly:  encoding the signal by the axon, the chemical processes that move the signal from neuron to neuron, and the decoding process by the soma and dendrites.  If any of these is impaired, the message is compromised.  You can think of a concussion as being like a cell phone in an area of poor reception.  Your cell phone, the person to whom your talking’s cell phone, and the transmission towers all have to work.  If they don’t, some things get through, but other things are jumbled and you can’t understand the message.

Your brain is one giant chemistry set.  When the electrical signals in your brain aren’t converted to chemicals appropriately, you end up with an imbalance of chemicals within the brain.  This means that your brain slows down – the cells slow down the process of dividing and become less active.  There can be a reduction in blood flow to the brain, and less energy is sent to the cells than they expect.  It’s very much like what happens when you get a cold – everything slows down in your body so that the immune system can focus on fighting off the cold.  In this case, however, it’s your brain that slows down.

The primary treatment for a concussion is rest – physical and mental.  A concussion impacts the functioning of the brain, so someone suffering a concussion needs to go easy on the thinking and external stimulus, as well as physically rest. The most important factor, thought, is that the brain is much more susceptible to long-term damage while it is recuperating.  If Dale Earnhardt, Jr. were in another crash this week, he could suffer more damage and it could be more severe.  We know that repeated concussions, like those sustained by football players or boxers, have the potential to cause long-term debilitating neurological diseases like Parkinsons or Alzheimers.  That’s why it is important for him to step out of the car this week.  I can’t imagine it was an easy decision for him to make; however, it was the right decision for him to make.

Questions

Q:  Why wasn’t Dale Earnhardt, Jr. diagnosed until now?

A:  Symptoms sometimes don’t show up for days — or weeks.  Also, many symptoms are possible to have without having a concussion – it’s the combination of symptoms that makes it a concussion.

As Dale, Jr. mentioned in his press conference, he didn’t tell anyone he had symptoms.  A more serious concussion could produce noticeable dizziness, lack of balance and coordination, vomiting or other symptoms, but the list of symptoms includes things like persistent headaches that aren’t apparent to doctors unless the patient says something.

Q:  Why sitting out two weeks?

A:  We don’t know how long it takes for the brain to heal.  It’s still healing, even after the immediate symptoms disappear.  Given the increased danger of possibly permanent damage if he were in another crash, this seems like a good decision.  Having two concussions within a few weeks of each other makes the situation worse.

Q:  If Dale, Jr. feels better in time for Kansas, could he race?

A:  Probably not.  Even when the symptoms lessen, there is still the increased risk for injury.  The patient feeling better is not a reliable indication that he is able to race.  Since they announced two weeks already, I’d be surprised if he’s at Kansas.

Q:  What is the “impact” test?

A:  ImPACT stands for Immediate Post-Concussion Assessment and Cognitive Testing.  It is a computerized test that takes about 20 minutes to complete and provides doctors with a way of assessing if there has been damage to the brain.    It’s a neurocognitive test – meaning that it tests how your brain is working.  Things like X-Rays and standard MRIs look at the physical condition of the brain – this looks at the functionality.  The test measures verbal and visual memory, how long it takes you to process information, and reaction time.  It consists of things like a series of three letters that you are asked to remember and reproduce, matching colors and shapes, etc.

Here’s the catch:  everyone is going to score differently on a test like this.  You can’t compare Dale Jr. and another driver and tell anything about Dale Jr.’s concussion.  If you don’t have a baseline measurement – a measurement prior to any concussions – you don’t have a way to tell whether there was brain damage or whether the subject just happens to have a slow reaction time.   You can re-administer the test after the brain has had time to heal and look for improvement, but you can’t compare it to the pre-concussion condition without a baseline measurement.  Seems to me that every driver ought to have a routine test done at the start of every season.  You can read more about ImPACT at their website.  They do caution that their test is ONE component in making a diagnosis and determining treatment.  NOTE:  read Dustin Long’s story on baselines and their importance.