Once the double vision, headache and dizziness caused by a cerebral concussion disappear, team physicians must evaluate an athlete's fitness to return to play, but according to a Penn State neuropsychologist, making that decision is not easy and should be individualized, not based on group data.
"If athletes return to play before the effects of a concussion are gone, they run the risk of incurring a more serious injury should they be hurt again," says Dr. Ruben J. Echemendia, director of Penn State's Psychological Clinic and associate professor of psychology. "On the other hand, if we prevent athletes from playing when they are well, it is detrimental to their careers and to the team's outcome."
In the past, physicians have judged readiness to play by standard clinical guidelines that a player can return to play a specified number of days after all symptoms disappear. Recently, a significant amount of attention has been focused on the use of neuropsychological tests for assisting in the return-to-play decision.
One method for assessing whether an athlete has improved enough to play is to use Reliable Change scores. Reliable Change Scores are calculated using data gathered from many individuals. They depend on a baseline, preseason test score for each athlete. The post-injury scores are then compared with the preseason scores and used to determine if the athlete is improving. The Reliable Change score creates a wide band of scores beyond which the athlete is thought to be either "reliably" better or worse.
For example, if a test has a Reliable Change score of 7 and a baseline score of 25 was obtained, a post-injury score of 32 (or 18) would be needed to be "reliably" different.
"The indiscriminate use of RC scores would lead to equal numbers of false positive and false negative decisions," Echemendia told attendees today (Aug. 20) at the annual meeting of the American Psychological Association in Boston. "Applying RC scores using a grand mean or a group mean just cannot be done. Decisions on athletes must be done individually."
Echemendia, who is chairing the conference session "Return to Play Following Mild Traumatic Brain Injury: Neuropsychology's Role," believes that RC scores can be used as a general guideline, but that there are some inherent problems in applying them routinely without evaluation. The tests measure cognition; attention and concentration; speed of information processing and memory, and learning. While anyone can administer the tests, it takes a competent neuropsychologist to interpret the test scores.
"Some tests have practice effects as well," says Echemendia. "Each time an athlete takes the test, they naturally become better at it, skewing any comparison to the baseline test."
One of the biggest problems is determining when post- injury scores have actually returned to the baseline. Determining the point beyond which scores are the same and not just appear to be the same through a chance variation is difficult. Determining the margin of error and the reliable significant difference is not trivial. Reliable Change scores also fall within a relatively wide band of what might be clinically significant rather than statistically significant.
"Because of the way statistics are, when using RC scores, there is an equal chance of putting someone in too early as too late," says Echemendia, a faculty member in the College of the Liberal Arts. "We don't want someone still at risk taking the chance on further injury or career- ending injury.
"People can be asymptomatic and still be cognitively deficient. They can still have problems with memory and processing of information."
Echemendia suggests that the athletes be looked at individually, evaluating the entire pattern including initial physical symptoms, how long symptoms lasted, the nature of the injury and the test data. Clinicians can not base their decisions on RC scores alone.
EDITORS: Dr. Echemendia is at (814) 865-2191 or at rje2@psu.edu by email.