Medical Examiner

We’re Not Really Sure How to Assess the Concussions of Athletes With Learning Disabilities

The diagnostic tools we use to assess concussions don’t work as well on everyone.

Photo illustration: A football player lies on the ground with his helmet highlighted to suggest a possible concussion.
Photo illustration by Slate. Photo by Thinkstock.

Despite what many of last month’s headlines announcing the “concussion blood test” might have you believe, doctors still don’t have a good way to diagnose the brain injury. Concussions are finicky. They look different in different people. There still isn’t a clear biological signature we’re able to track. So instead, trainers and doctors lean on reported symptoms and neurocognitive tests, which measure things like memory, processing speed, and reaction time, to guide concussion diagnosis.

These tests, though, don’t serve all athletes equally: Disabilities, particularly learning disabilities like attention-deficit hyperactivity disorder and dyslexia, skew the results, making concussions more challenging to diagnose and treat in disabled athletes. Concussion management guidelines note that it’s a problem, but don’t give doctors and clinicians the tools to deal with it. What’s more, many studies on concussions exclude athletes who have disabilities, which means we know less about that group and what their injuries look like to begin with. Around 7 percent of the school-age population has ADHD, and about 1 in 5 students have a language-based learning disability like dyslexia. That’s thousands of kids, many of whom play sports—reason enough to push for robust data and standards for concussion management in these groups.

In an ideal situation, concussion testing is personalized. Every athlete takes the test and gets a score at the start of the season. If their coaches or trainers suspect a concussion, they can take the test again, see how it compares to their healthy baseline, and then continue using the test to track recovery back to their healthy score. But baselines for each athlete aren’t always available because not every school has the resources to individually test every student. It’s also possible that someone might get a concussion during preseason before their team goes in for baseline testing. In those situations, athletes’ scores after a suspected concussion and throughout recovery would be compared to the standardized range of healthy results for their gender and age.

But for athletes with learning disabilities, those standards can’t reliably guide diagnosis. At their healthy baseline, athletes with disabilities have lower overall scores than their peers on Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). ImPACT, one of the most commonly used concussion tests in high schools and colleges, is primarily comprised of cognitive tests, so it’s not surprising that a mild cognitive disability would make the test that much more challenging. Athletes with disabilities score lower on other neurocognitive tests, as well, like the Trail Making test and the Stroop Color and Word test. And while taking medications seems to keep athletes with ADHD consistent with the average in some of the ImPACT testing categories, according to a 2016 study, it doesn’t readjust all of them: ADHD medication seems to brings scores on visual motor speed and reaction time back to average, but not verbal and visual memory. Which points to another issue with the tests—because they’re multifaceted, and the ultimate assessments draw on a number of different measures, simply lowering the score as an adjustment doesn’t fix the problem.

If an athlete with ADHD who didn’t already have a baseline ImPACT score takes a hard hit, then, it’s much more challenging for a doctor or trainer to interpret their post-injury result using only standardized scores: If it’s significantly lower than the average, it’s hard to say how much of that was injury and how much was a result of the disability.

Athletes with ADHD also report more symptoms, like fatigue or difficulty concentrating, than their peers do during baseline screening on ImPACT and another common test, the Sport Concussion Assessment Tool, 3rd edition (SCAT-3). That complicates diagnosis and treatment as well. It also might be one reason why data currently suggests that athletes with ADHD and dyslexia are more likely to have a concussion, and to have multiple concussions. Concussion experts aren’t sure why this might be the case, but it’s worth considering that initial elevated symptoms might cause inflated rates of concussion diagnosis for this population—and make clinicians more likely to overestimate how hurt they are after a head injury or see one as more severe than it really is.

Researchers are trying to accumulate better data to use when they’re treating these athletes. In 2013, Scott Zuckerman, a researcher at the Vanderbilt Sports Concussion Center, developed the first standardized data on the ImPACT test for athletes with learning disabilities. Their study confirmed the difference between the groups and calculated preliminary baseline ImPACT scores for athletes with ADHD, dyslexia, and both ADHD and dyslexia.

Comprehensive data on the healthy baselines for athletes with disabilities isn’t all that useful, though, without also having a good understanding of how scores might change after a concussion, and how they’ll continue to change as an athlete heals. That’s particularly important for this group of athletes, who seem to also take longer to recover from injuries.

The 2016 study that included data on the influence of ADHD medication took what appears to be the first look at post-concussion ImPACT scores and recovery for athletes with the condition. The authors found that the gap between athletes with and without ADHD remained about the same between pre- and post-concussion testing—that is, athletes with ADHD had the same amount of a drop in scores from their baseline after an injury as the athletes without ADHD. But the authors also cautioned that their study was only a preliminary look at the trajectory of recovery for athletes with learning disabilities, and more work needs to be done.

So far, most of the focus on concussions and disabilities has primarily focused on learning disabilities. But the issues may extend further: A January study in the Clinical Journal of Sports Medicine found that deaf and blind soccer players, as well as those with cerebral palsy, scored off the normal average at baseline on SCAT-3 testing. The disabled athletes also reported different, and a greater number of, concussion symptoms when they were injured.

The existing research points out the scope of the problem and makes initial attempts to fill in the gaps, but wide holes remain. It’s hard to say how the doctors and trainers who are actually seeing athletes day-to-day should handle these complications. It could be that they have a sense of the problem that they’re facing and are making adjustments as they go—but they’re still doing it without strong evidence to back them up.

Disability doesn’t hold athletes back from participating at the highest levels of their sports. The Paralympics in PyeongChang demonstrate this well, but it’s also true of every level of sport, from professional to college to high school to recreational play. Athletes with disabilities should receive the same attention and tools as everyone else. Concussion research has dozens of questions to answer as it moves forward, and issues facing these groups are a key piece of the puzzle.