Gender Differences in Head Impact Acceleration in Collegiate Ice Hockey.

Principle Investigator: Richard M. Greenwald, Ph.D.

Institution:Simbex, Lebanon, NH

Title: Gender Differences in Head Impact Acceleration in Collegiate Ice Hockey

Abstract: The Center for Disease Control and Prevention estimates that the incidence of sports-related mild traumatic brain injury (MTBI) approaches 300,000 annually in the United States. Concussions in hockey affect 10% of the athletes and make up 12%-14% of all injuries. A critical piece in the puzzle for understanding MTBI is the link between the mechanical input (trauma) that causes injury and the clinical outcome. Unlike animal and cadaver models for TBI, there are no currently validated models for MTBI in humans. Therefore it is crucial to appreciate that if an understanding of the mechanics of MTBI and its prevention are to be studied, they must be studied in humans. To this end, sports offer a unique laboratory environment in which studies of MTBI can be performed. In order to rapidly advance human research related to Mild Traumatic Brain Injury (MTBI), we developed and validated Head Impact Telemetry System (HIT system) technology to allow data collection of head acceleration due to impacts on the playing field. Large-scale data collection of head impacts is required to study pathomechanics of concussion because of the relatively low incidence of MTBI per athlete exposure. In contact sports such as football, ice hockey and soccer, extensive public attention is focused on the possible effects of repeated concussive and sub-concussive events. Initial studies in football have resulted in over 250,000 recorded head impacts. The technology has recently been transferred to hockey and improved to allow for direct computation of rotational acceleration as well as linear acceleration. During the 2005-06 season, we completed a pilot study using HIT System technology in men’s ice hockey at Dartmouth College on 5 players and recorded 5,463 head impacts. Each of the instrumented players also underwent computerized cognitive testing. Preliminary results suggested that the magnitude of head impacts in hockey is lower than in football and there are notable differences between impact incidence and magnitude by player position. Cognitive scores showed differences from controls, but these differences were not statistically significant due to low statistical power. We propose to expand the pilot study to include both men and women from the Dartmouth and Brown hockey teams over two hockey seasons.

The Specific Aims of this project are to:

Specific Aim 1: Develop a database of impacts (linear and rotational acceleration, impact location, impact duration( for men and women’s collegiate hockey.

  • Specific Aim 1.1 test the hypothesis that head impact biomechanics do not differ between male and female hockey players.
  • Specific Aim 1.2 test the hypothesis that head impact biomechanics do not differ between male hockey players and male football players.

Specific Aim 2: Test the hypothesis that head impact biomechanics and clinical neuropsychology outcome measures in concussed (MTBI) female collegiate hockey players does not differ from collegiate male hockey players.

Our long-term goal is to validate a quantitative model of head impact acceleration that enables translational research and development of new clinical and therapeutic techniques to increase detection, reduce the incidence, and improve treatment of concussions or Mild traumatic Brain Injury (MTBI). The data collection in this study will permit us to explore the use of cumulative exposures to head impacts over time to better define predictive tolerance indices for concussion based on measurable quantities. These data can also be used to help establish better testing methodologies and impact requirements for new or improved NOCSAE standards that target MTBI as well as TBI.