Mild head injury (MHI) represents one of the most challenging neurological pathologies occurring during athletic participation. Athletic trainers and sports medicine personnel are often faced with decisions about the severity of head injury and the timing of an athlete's return to play following MHI. Returning an athlete to competition following MHI too early can be a catastrophic mistake. This case study involves a 20-year-old collegiate football player who sustained three mild head injuries during one season. The case study demonstrates how objective measures of balance and cognition can be used when making decisions about returning an athlete to play following MHI. These measures can be used to supplement the subjective guidelines proposed by many physicians.
Bryan L. Riemann and Kevin M. Guskiewicz
Klaus Schneider and Ronald F. Zernicke
With a validated mathematical model of the head-neck consisting of nine rigid bodies (skull, seven cervical vertebrae, and torso), we simulated head impacts to estimate the injury risk associated with soccer heading. Experimental data from head-linear accelerations during soccer heading were used to validate the nine-body head-neck model for short duration impact loading of the head. In the computer simulations, the mass ratios between head mass and impacting body mass, the velocity of the impacting body, and the impact elasticity were varied. Head-linear and angular accelerations were compared to standard head-injury tolerance levels, and the injury risk specifically related to soccer heading was estimated. Based on our choice of tolerance levels in general, our simulations showed that injury risk from angular head accelerations was greater than from linear head accelerations, and compared to frontal impacts, lateral impacts had greater angular and less linear head accelerations. During soccer heading, our simulations indicated an unacceptable injury risk caused by angular head accelerations for frontal and lateral impacts at relatively low impact velocities for children, and at medium range impact velocities for adults. For linear head accelerations, injury risk existed for frontal and lateral impacts at medium range to relatively larger impact velocities for children, while no injury risk was shown for adults throughout the entire velocity range. For injury prevention, we suggest that head-injury risk can be reduced most substantially by increasing the mass ratio between head and impacting body. In soccer with children, the mass of the impacting body has to be adjusted to the reduced head mass of a child, that is, it must be clearly communicated to parents, coaches, and youngsters to only use smaller soccer balls.
Jon Almquist, Donna Broshek, and David Erlanger
Susan L. Whitney and Jill L. Unico
Earl R. Cooper Jr., Michael S. Ferrara, Martin Mrazik, and Steven Casto
John A. Norwig
Brooklynn M. Knowles, Henry Yu, and Christopher R. Dennison
Wearable kinematic sensors can be used to study head injury biomechanics based on kinematics and, more recently, based on tissue strain metrics using kinematics-driven brain models. These sensors require in-situ calibration and there is currently no data conveying wearable ability to estimate tissue strain. We simulated head impact (n = 871) to a 50th percentile Hybrid III (H-III) head wearing a hockey helmet instrumented with wearable GForceTracker (GFT) sensors measuring linear acceleration and angular velocity. A GFT was also fixed within the H-III head to establish a lower boundary on systematic errors. We quantified GFT errors relative to H-III measures based on peak kinematics and cumulative strain damage measure (CSDM). The smallest mean errors were 12% (peak resultant linear acceleration) and 15% (peak resultant angular velocity) for the GFT within the H-III. Errors for GFTs on the helmet were on average 54% (peak resultant linear acceleration) and 21% (peak resultant angular velocity). On average, the GFT inside the helmet overestimated CSDM by 0.15.
Jaebin Shim, Deanna H. Smith, and Bonnie L. Van Lunen
Over the past decade, sport-related concussions have received increased attention due to their frequency and severity over a wide range of athletics. Clinicians have developed return-to-play protocols to better manage concussions in young athletes; however, a standardized process projecting the length of recovery time after concussion has remained an elusive piece of the puzzle. The recovery times associated with such an injury once diagnosed can last anywhere from 1 wk to several months. Risk factors that could lead to protracted recovery times include a history of 1 or multiple concussions and a greater number, severity, and duration of symptoms after the injury. Examining the possible relationship between on-field or sideline signs and symptoms and recovery times would give clinicians the confident ability to properly treat and manage an athlete’s recovery process in a more systematic manner. Furthermore, identifying factors after a head injury that may be predictive of protracted recovery times would be useful for athletes, parents, and coaches alike.
Focused Clinical Question:
Which on-field and sideline signs and symptoms affect length of recovery after concussion in high school and college athletes?
Takeaki Ando, Shannon Gehr, Melanie L. McGrath, and Adam B. Rosen
The purpose of this report is to present the case of a National Junior Collegiate Athletic Association football player diagnosed with Chiari malformation postconcussion. A Chiari malformation is characterized by the cerebellum presenting below the level of the foramen. The uniqueness of this case stems from the patient’s health history, length of symptoms, and diagnosis. The effectiveness of treatment options, and the primary means to reduce the risk of catastrophic head injury in those with Chiari malformations are debatable. Clinicians should be familiar with the potential for the presence of a Chiari malformation with persistent symptoms postconcussion.