Effect of Repetitive, Subconcussive Impacts on Electrophysiological Measures of Attention.

Objectives In this preliminary study, the auditory P3b response, when measured during a visually distracting task, was investigated as an index of change in cognitive function resulting from exposure to subconcussive impacts (SCIs) in collision sports over time. Methods Both pre- and postseason P3b responses were examined in seven first-year collegiate-level American football players. Comparisons were made between a group of seven third- and fourth-year players and a control group of seven noncontact athletes. Results No difference in P3b amplitude was revealed in pre- versus postseason data of the first-year players. Furthermore, no P3b amplitude differences were found when comparing first-year players with controls. P3b amplitudes of third- and fourth-year players versus first-year players were smaller along the midline electrode sites. Conclusions Preliminary results suggest exposure to SCIs during the course of a season does not affect brain function negatively, as measured by the P3b response; however, differences between first-year players and the group of third- and fourth-year players suggest that exposure to hundreds of SCIs in multiple seasons leads to changes in brain activation patterns. Subtle effects such as difficulty with attentional resource allocation may develop. Longitudinal studies are necessary before definitive conclusions can be drawn.