Methodological considerations of assessing meaningful/reliable change in computerized neurocognitive testing following sport-related concussion.

Objective: Traditional reliable change index (RCI) methods may be psychometrically limited due to their inability to account for particularly high or low baseline performance and regression to the mean following serial testing. The current study sought to examine differences between RCI and standardized regression-based (RBz) methods in a cohort of adolescent athletes engaged in sport-related concussion recovery.
Methods: Consultation records and results of computerized testing data via the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery were retrospectively reviewed among 240 adolescent athletes involved in return-to-play protocols following a sport-related concussion.
Results: High concordance rates were found between RCI and RBz metrics across ImPACT composites, consistent with previous literature. However, especially for those with lower baseline performance, RBz scores tended to suggest cognitive performance not meeting or exceeding baseline scores despite RCI metrics being appropriate across speed-based ImPACT composites. In contrast, results revealed high rates of RCI scores suggesting continued cognitive difficulties despite RBz metrics being within normal limits, especially for adolescents with higher baseline performance.
Conclusions: Results suggest value in interpreting RBz values in addition to RCI values as these allow for clinical interpretation more sensitive to statistical confounds, including baseline performance and regression to the mean.