A group of Mayo Clinic researchers argued in a new review that sports concussions -- at least in ice hockey -- can be diagnosed more accurately with objective tests, such as encephalography and the King-Devick eye test, than with the neurocognitive exams favored by many leagues at all levels of play.
The researchers, including USA Hockey medical director Michael Stuart, MD, examined current and emerging methods of diagnosing concussions in ice hockey in the Clinical Journal of Sports Medicine.
If they are correct, they may have an answer to the underreporting problem long plaguing sports concussion diagnosis and treatment. "Most currently used diagnostic tests are imprecise, require athlete cooperation, and are vulnerable to player and evaluator bias," wrote the authors, led by Aynsely Smith, RN, PhD. "As objective diagnostic tools become available, the diagnosis will be less vulnerable to subjective overlay of overly aggressive athletes and assertive coaches" who often try to hide the athletes' concussion-like symptoms.
Those tools -- the King-Devick test, quantified electroencephalography and blood analysis -- are available to researchers and many find them promising. "The paper is theoretical but the data coming out is fabulous," Smith told MedPage Today. She said objective tests "are going to be giving us the information we need to know not only if there's a concussion, but the severity of it."
Smith and colleagues indicated that such tests are preferable to neurocognitive tests such as the Sport Concussion Assessment Tool (SCAT) and ImPACT test, which the National Hockey League advises team physicians to use as part of its concussion protocol. (The league last year announced it would also pilot the King-Devick with 12 of its 30 teams, according to a Chicago Tribune report). Besides the NHL, most other pro, college and high school teams also favor the established tests.
"A lot of them have put their careers on the line on these things," Smith said. "Is it going to be an uphill battle? Yes ... It won't be very popular with a lot of people right away."
In their paper, Smith and colleagues wrote, "The lack of objective measures for diagnosis of concussion and serial quantitative measures of recovery compromise the identification and assessment of prospective therapies."
Said Smith: "I think they've been all we had and people worked hard to make sure they're valid. The trouble is... they're still subjective.
"The ones we're using, you can't manipulate data," she added. "It's like in the emergency room: I can't fake a heart attack but I can tell you I'm not having any pain if my daughter is getting married in two hours."
While Smith's team and others continue their research, they advised clinicians to use diagnostic tests "with the greatest objectivity, availability, and affordability." That means eschewing the older tests whenever possible.
Clinicians working in hockey settings specifically should look for risk factors, including: history of previous concussions, head contact exposures along with the frequency to known accelerations at over 80% probability, and playing the forward position in ice hockey.
Other members of Smith's team include David Dodick, MD, who directs Mayo Clinic's concussion program, and William Roberts, MD, former president of the American College of Sports Medicine. Stuart's son Mark is an NHL defenseman.
The NHL did not immediately answer questions Friday afternoon.
The USA Hockey Foundation funded part of the study.
The authors did not report conflicts of interest.
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