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Study Questions Reliability of Popular Concussion Measurement Tool

Results, says University of Texas researcher, emphasize need for multi-faceted concussion assessment

A computerized neuropsychological test commonly used to evaluate sports-related concussions misclassified up to 29 percent of healthy participants in a recent test by a University of Texas at Arlington kinesiology researcher.

The results from the study of the ImPACT computerized neuropsychological testing system emphasize the need for multiple types of assessments, said Jacob Resch, an assistant professor of kinesiology and director of the University's Brain Injury Laboratory. During the study, the system had "only poor to good reliability" in 45 healthy participants, he said.

The ImPACT test, which stands for Immediate Post-Concussion Assessment and Cognitive Testing, was developed in the early 1990s. It has five main outcome measures - composite and verbal memory, visual memory, visual motor speed, reaction time and impulse control. It is used for both baseline and post-concussion testing. 

Resch's findings were presented at the National Athletic Trainers' Association 2011 annual meeting and clinical symposia in New Orleans. 

Not only concussion measure

Concussion assessment and management has become a national concern in recent years as former National Football League players and their families have come forward with personal tales of the lasting impact of hard hits. Legislators, national sports organizations and parents of children seriously injured have called for a cultural change in how brain injuries are diagnosed and treated.

Starting in August 2011, public school athletes in Texas who sustain a concussion will not be allowed to return to play for at least 24 hours and must be cleared by a licensed healthcare professional. The University Interscholastic League strengthened the concussion management protocols after its medical advisory committee recommended the changes. Before, students with concussions could have been allowed to return to play if symptoms of a concussion cleared after 15 minutes.

The use of the ImPACT test, alongside other measures, is widely viewed as a useful tool in evaluating when a player may return to the field. Resch said the results of the study shouldn't be interpreted as an indictment of the test.

Multi-pronged approach urged

"What our results stress is that when developing a sport-related concussion management protocol, a multi-facet approach including self-reported symptomology, a balance assessment and computerized neuropsychological testing should be implemented," Resch said. "Ultimately, by incorporating this approach to concussion management we are significantly reducing the risk of returning an athlete back to the playing field too soon after a concussion which may lead to catastrophic consequences."

Rosemarie Scolaro Moser, Ph. D, sports neuropsychologist, head of the Sport Concussion Center of New Jersey, and a MomsTeam expert, agreed. She notes that "ImPACT is not advertised as the only, sole tool for return to play decisions  Balance testing is another component as well as others that may be developed and added.  The more tools, the better the diagnostic accuracy."   

Dr. Moser went on to say that the study was both "informative and not surprising. The important message, said Dr. Moser, "is that baseline testing is only a screening and not perfect. It should be interpreted by neurocognitive specialists [who] understand its limitations."  But parents, coaches, players, and clinicians also need to understand that it adds important information to the array of tools that concussion specialists use to help make more accurate return to play decisions. I, for one, am not ready to discard using neurocognitive testing as part of the concussion assessment process."

Study details

Resch, who is now using the ImPACT test in a lab study of North Texas high school athletes at risk for concussion, said researchers wanted to add to the limited scientific examination of the ImPACT test's reliability. This is especially important as state and local entities consider mandating baseline testing.

The healthy participants in Resch's study had an average age of about 22. They were tested once, then again about 45 days later and again about 50 days later. The time periods are similar to what would be used in a clinical setting. The researchers found that ImPACT misclassified 22.2 percent to 28.9 percent of the healthy study participants on one or more test variables at the 45 and 50 day marks. Those who were misclassified did either significantly better or significantly worse than their baselines, even though their health had not changed.

Resch began to study the test's reliability while at The University of Georgia. Co-authors on an abstract presented at the conference include University of Georgia faculty and researchers from the Shepherd Center in Atlanta and Georgia Neurological Surgery in Athens, Ga.

Improving test is goal

"Research like this reinforces the need to look critically at what we do and make it better," said Dr. Kimberly Walpert, coauthor of the study and a partner at Georgia Neurological Surgery. "I think this is particularly important in view of the growing evidence regarding how multiple, seemingly insignificant brain injuries may have long term consequences for athletes."

Resch hopes presenting the study data at the national conference will encourage ImPACT's parent company to improve test-retest reliability and motivate athletic officials to continue using additional methods - like balance assessment and interviews with the athlete.

"We are very excited about the work that Dr. Resch is doing," said Professor Lou Fincher, chairwoman of UT Arlington's kinesiology department. "This study, as well as his current and pending projects, will continue to help shape the standard of care for assessing and managing concussions."

Source: University of Texas at Arlington

Posted July 1, 2011; Revised July 11, 2011