Leveraging football accelerometer data to quantify associations between repetitive head impacts and chronic traumatic encephalopathy in males

Abstract

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy associated with repetitive head impacts (RHI), but the components of RHI exposure underlying this relationship are unclear. We create a position exposure matrix (PEM), composed of American football helmet sensor data, summarized from literature review by player position and level of play. Using this PEM, we estimate measures of lifetime RHI exposure for a separate cohort of 631 football playing brain donors. Separate models examine the relationship between CTE pathology and players' concussion count, athletic positions, years of football, and PEM-derived measures, including estimated cumulative head impacts, linear accelerations, and rotational accelerations. Only duration of play and PEM-derived measures are significantly associated with CTE pathology. Models incorporating cumulative linear or rotational acceleration have better model fit and are better predictors of CTE pathology than duration of play or cumulative head impacts alone. These findings implicate cumulative head impact intensity in CTE pathogenesis.

Fig. 1. Athlete CTE Status by Years of American Football Played.

Histograms (a) and percent distributions (b) for the study sample by duration of play. Of note: among the 69 athletes who played ≤5 years of football, 35 played another contact sport (13 of whom had CTE), 21 were in the military (7 of whom had CTE), and 9 were exposed to combat as part of military service (4 of whom had CTE). 47 of the 69 athletes had one or more of these exposures (16 of whom had CTE). Of the 69 athletes who played ≤5 years of football, 9 had CTE and none of these exposures. Please see Supplementary Fig. 1 for additional details. Source data are provided as a Source Data file. CTE chronic traumatic encephalopathy.

Fig. 2. Performance of Exposure Measures as Classifiers of CTE Pathology.

ROC Curves for Exposure Measures as Predictors of CTE Status (A) and CTE Severity (B). Source data are provided as a Source Data file. AUC area under the ROC curve, CHII cumulative head impact index representing estimated number of head impacts per donor, CHII-G cumulative head impact index representing estimated cumulative g-force experienced by each donor, CHII-R cumulative head impact index estimated cumulative rotational force experienced by each donor, CTE chronic traumatic encephalopathy, ROC receiver operating characteristics.

Fig. 3. Study inclusion and exclusion criteria for FHS and VA-BU-CLF study brain donors.

Source data are provided as a Source Data file. BU Boston University, CLF Concussion Legacy Foundation, FHS Framingham Heart Study, VA Veterans Affairs.