Cumulative Head Impact Exposure Predicts Later-Life Depression, Apathy, Executive Dysfunction, and Cognitive Impairment in Former High School and College Football Players

• DOI: 10.1089/neu.2016.4413
• Publication Date: 2016-03-31T02:12:15Z
• Authors: Philip H. Montenigro; Michael L. Alosco; Brett M. Martin; Daniel H. Daneshvar; Jesse Mez; Christine E. Chai...; Christopher J. No...; Rhoda Au; Ann C. McKee; Robert C. Cantu; Michael D. McClean; Robert A. Stern; Yorghos Tripodis
• Keywords: Apathy; Depression; Executive dysfunction; Chronic traumatic encephalopathy

The term “repetitive head impacts” (RHI) refers to the cumulative exposure concussive and subconcussive events. Although RHI are believed increase risk for later-life neurological consequences (including chronic traumatic encephalopathy), quantitative analysis of this relationship has not yet been examined because lack validated tools quantify lifetime exposure. objectives study were: 1) develop a metric from football, which we “cumulative impact index” (CHII); 2) use CHII examine association between long-term clinical outcomes; 3) evaluate its predictive properties relative other metrics (i.e., duration play, age first exposure, concussion history). Participants included 93 former high school collegiate football players who completed objective cognitive self-reported behavioral/mood tests as part larger ongoing longitudinal study. Using established cutoff scores, transformed continuous outcomes into dichotomous variables (normal vs. impaired). was computed each participant derived combination athletic history number seasons, position[s], levels played), frequencies reported in helmet accelerometer studies. A bivariate probit, instrumental variable model revealed threshold dose-response impairment (p < 0.0001), executive dysfunction depression apathy = 0.0161), behavioral dysregulation 0.0001). Ultimately, demonstrated greater validity than individual metrics.