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Are low-tech (and cheap) evaluations the future of on-field concussion testing?

  • Lisa Fratt
  • 9/3/2013 12:00:00 AM
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Plato may have been the first to cite necessity as the mother of invention, but the latest group to embrace the proverb may be coaches, athletic trainers and families worried about sports-related concussions in teen athletes. After an on-field blow to the head, neurocognitive assessment tools and high-tech helmets can measure symptoms of concussion, but their high cost and computer dependence limit use at one of the most common injury scenes—the sidelines of high school sport events.

As researchers at the University of Michigan in Ann Arbor pondered the problem, they struck it rich with a $5 gadget.

They hypothesized that a hockey puck attached to a dowel, or rod, marked in centimeters (dubbed a falling measuring stick) could be used to measure an athlete’s reaction time. Prolonged reaction time is one of the most common and sensitive indications of a concussion.

It works like this: to test reaction time, an athlete grasps the stick right above the puck. A trainer drops the stick, and the athlete grabs it as it falls, with the trainer noting reaction time in milliseconds. The researchers recorded their findings in a study recently published in the British Journal of Sports Medicine, which showed the low-tech tool was fairly accurate in measuring prolonged reaction time among concussed athletes. The findings suggest the jerry-rigged dowel provides a reasonable estimate of prolonged reaction time, which could help identify athletes who may have suffered a concussion.

Too good to be true?

“The results are very encouraging,” says Michael O'Brien, MD, associate director of the Sports Concussion Clinic at Boston Children's. “This type of approach (low cost, non-invasive and easily reproducible on the sidelines) is essential for screening athletes with potential injuries and preventing further complications,” he continues.

After assembling the nifty gadget, the researchers-turned-inventors sought to test its effectiveness. They recruited high school and college athletes and used the falling measuring stick to measure baseline reaction time at the beginning of three sports seasons—football, soccer and ice hockey. This step of gathering baseline normative data is essential, as each individual’s healthy reaction time differs, says O’Brien.

And then the researchers huddled on the sidelines, anticipating the inevitable blows to the head. During the sports seasons, 28 of the athletes who participated in the study sustained concussions. These athletes, along with 28 of their healthy teammates, re-took the dowel test within 48 hours of the injury. In these follow-up tests, the non-concussed athletes showed improved reaction times, likely due to a learning effect. In contrast, athletes who suffered concussions took significantly longer to grasp the falling stick.

Next, researchers noodled with the numbers to determine an optimum balance between sensitivity (correct identification of a concussed athlete) and specificity (incorrect identification of a non-concussed athlete).

They decided a cutoff score of zero milliseconds, or no change from baseline reaction time to follow-up testing, provided the best balance between sensitivity at 75 percent and specificity at 68 percent. Although the specificity, or false-positive rate, is fairly high, the tradeoff syncs with the current ‘when in doubt sit it out’ ethos in sports medicine, that instruct coaches to bench any player they may suspect of being concussed.

Beyond reaction time

The dowel-hockey puck approach may prove to be a good sideline screening test, according to O’Brien. However, after the sideline check of reaction time, it is important to assess additional measures other than reaction time. Athletes with abnormal results should proceed to further assessment of physical symptoms, balance and cognitive function, including immediate and delayed memory to determine a true injury. These same functions can be evaluated post-injury to assess recovery.

“The most important use of reaction time may be for sideline assessment, as reaction times may not be as helpful in decision making in the days and weeks following the concussion,” explains O’Brien. “Balance testing and reaction times may normalize as soon as three days after a concussion, but the athlete may still have symptoms and cognitive difficulties. Therefore, he or she wouldn’t be considered 'fully recovered' with normal balance or reaction times in the presence of other symptoms. On the other hand, continued abnormal results can be a sign that the athlete may not be ready for return to contact sports.”

Physical and cognitive rest (mental rest) are the mainstays of treatment for a concussion, he continues. Athletes diagnosed with a concussion will be removed from contact sports until fully recovered. They also may need temporary academic accommodations. Once an athlete’s symptoms are resolved and he or she can tolerate return to school with a full workload, he or she will be started on a graded exercise program before a return to full practices and games. This starts with low intensity non-contact exercise and progresses with higher intensity as prescribed by the physician and athletic trainer. Full recovery includes resolution of all concussion symptoms, academic tolerance and exercise tolerance. In addition, the athlete may take a test of cognitive function to confirm that memory, attention and reaction times have returned to normal before contact sports are attempted.

“Concussion affects millions of young athletes per year. The authors should be congratulated on their dedication to continued innovation,” O’Brien adds.

Visit this website to learn more about concussions and their affect on young athletes.

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