Time Delta Head Impact Frequency: An Analysis on Head Impact Exposure in the Lead Up to a Concussion: Findings from the NCAA-DOD Care Consortium

Abstract

Sport-related concussions can result from a single high magnitude impact that generates concussive symptoms, repeated subconcussive head impacts aggregating to generate concussive symptoms, or a combined effect from the two mechanisms. The array of symptoms produced by these mechanisms may be clinically interpreted as a sport-related concussion. It was hypothesized that head impact exposure resulting in concussion is influenced by severity, total number, and frequency of subconcussive head impacts. The influence of total number and magnitude of impacts was previously explored, but frequency was investigated to a lesser degree. In this analysis, head impact frequency was investigated over a new metric called ‘time delta’, the time difference from the first recorded head impact of the day until the concussive impact. Four exposure metrics were analyzed over the time delta to determine whether frequency of head impact exposure was greater for athletes on their concussion date relative to other dates of contact participation. Those metrics included head impact frequency, head impact accrual rate, risk weighted exposure (RWE), and RWE accrual rate. Athletes experienced an elevated median number of impacts, RWE, and RWE accrual rate over the time delta on their concussion date compared to non-injury sessions. This finding suggests elevated frequency of head impact exposure on the concussion date compared to other dates that may precipitate the onset of concussion.

Efficacy of Guardian Cap Soft-Shell Padding on Head Impact Kinematics in American Football: Pilot Findings

“…The decision to implement the mandate aligns with evidence suggesting that these position groups experience greater RHIE during practices and games relative to other position groups [9,10], and preliminary evidence suggesting that the preseason may also be a critical period of heightened vulnerability to concussion [11]. That is, greater RHIE in the preseason may increase the likelihood for sport-related concussion diagnosis during the preseason and throughout the remainder of the competitive season [11,12]. While many institutions are implementing policies and mandates relating to the use of soft-shell padding in the interest of preventing injury risk, the efficacy of these devices has not been extensively investigated in field-based settings.…”

Head Acceleration Events in Male Community Rugby Players: An Observational Cohort Study across Four Playing Grades, from Under-13 to Senior Men

“…In order to enhance player safety, it is essential to gain a comprehensive understanding of the contextual factors contributing to acute head injuries during contact phases [ 3 ]. On the other hand, recent insights have highlighted the potential influence of contact frequency on the brain injury threshold for contact sport athletes [ 7 ]. As a result, there is a growing emphasis on monitoring the severity of head impact events, especially those that do not immediately result in clinical outcomes, as a crucial aspect of player welfare strategies [ 8 – 11 ].…”