JOURNAL OF NEUROTRAUMA

Kawata K, Rubin LH, Wesley L, Lee J, Sim T, Takahagi M, Bellamy A, Tierney R, Langford D
Journal of Neurotrauma
DOI: 10.1089/neu.2017.5376

Abstract:

Athletes in contact sports sustain repetitive subconcussive head impacts in a brief window, yet neurophysiological sequelae from repetitive subconcussion remain unclear. This prospective longitudinal study examined a relationship between changes in plasma Tau protein levels and subconcussive impact kinematic data in 23 Division-I collegiate football players during a series of pre-season practices. Plasma measures for Tau and S100β proteins, symptom scores, and near point of convergence were obtained at preseason baseline and pre-post practices. During each practice, impact frequency and linear and rotational head accelerations were recorded via an accelerometer-embedded mouth guard. There were significant elevations in plasma Tau levels at all post-practice time points compared to those of pre-practice and baseline levels. However, the highest degree of elevation in plasma Tau was observed after the first practice, for which players sustained the lowest number of hits and magnitudes for these hits. Subconcussive impact exposure during practice (e.g., head impact frequency and magnitude) did not predict increased plasma Tau levels. Concussion history and years of football experience were also unrelated to changes in plasma Tau levels. Increases in plasma Tau levels were associated with increases in S100β levels only after the first practice. There were no significant aassociations between changes in Tau levels, symptom scores, or near point of convergence. These data suggest that the changes in levels of circulating Tau protein were independent from subconcussive head impact exposure, pointing to the possibility that other factors may have played roles in changes in plasma Tau levels.