Title:
Differences in change scores and the predictive validity of three commonly used measures following concussion in the middle school and high school aged population.

Abstract:
A battery of tests is commonly used to measure disability with and recovery from concussion. A number of different concussion-oriented assessment tests exist and each is considered useful. To the authors' knowledge, no study has compared the scores of these tests during recovery in the middle school and high school aged population to see how each change over time.
The purposes of this study were to analyze clinical data of concussed middle school and high school aged athletes to determine the concurrent and predictive validity for post-concussion syndrome (PCS) of the Post-Concussion Symptom Scale (PCSS), Balance Error Scoring System (BESS), and the five subscales of the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT).
The study was a retrospective chart review performed on middle school and high school aged individuals with a diagnosis of concussion from the years 2008-2010 within the Akron Children's Hospital Sports Medicine system. To be eligible for inclusion in the dataset, each subject required a baseline measurement for each of the three tests (and all five subscales of the ImPACT) and a post-test measure. The mean age of the population was 15.38 years (SD = 1.7) and ranged from 11 to 19 years. Pearson product correlation tests (correlation matrix) were used to analyze the concurrent validity of the test items during recovery following a concussion. Receiver operating characteristics (ROC) curves were used to determine the predictive validity of initial scores for developing PCS.
The correlation matrix captured five statistically significant findings; however, these suggested only weak to mild correlations. Five test items yielded an area under the curve (AUC) greater than 0.50 but only one was statistically significant. After qualitative evaluation, only one of the three tests (including the five subscales of the ImPACT) was useful in predicting post-concussion syndrome.
This study suggests that there is poor concurrent validity among three commonly used concussion tests and there is no baseline score that predicts whether post-concussion syndrome will occur.
2b.