PHILADELPHIA—Head trauma among ice hockey players may produce abnormalities in brain function, as assessed by neuropsychologic testing, diffusion tensor imaging, quantitative EEG, and postmortem studies, according to research reported at the 66th Annual Meeting of the American Academy of Neurology (AAN).
“The relationship between these measures in the short term and midterm and postmortem findings of chronic traumatic encephalopathy (CTE) is still unclear,” stated Ozan Toy, a medical student at the Commonwealth Medical College in Scranton, Pennsylvania, and colleagues.
Head Impact Injuries in Hockey
The researchers conducted a literature review regarding the effect of concussions in male ice hockey players. In addition, a Google search was performed to obtain information regarding professional hockey players who have been diagnosed with CTE.
In one of the studies reviewed, Gaetz and colleagues reported that electrophysiologic evidence from a cohort of junior hockey players showed that multiple concussions can lead to long-term neurologic symptoms, including headache, decreased memory, and decreased thinking speed, which correlate with electrophysiologic deficits related to attention, working memory, and mental processing. The study authors concluded that multiple concussions in hockey players can lead to neurologic deficits that can linger for at least six months postconcussion.
In 2012, Koerte et al found that diffusion tensor imaging revealed changes in white matter diffusivity in 17 male ice hockey players (ages 20 to 26) throughout the course of one season. Also in 2012, Bazarian and colleagues found that two high school ice hockey players who had multiple subconcussive head blows had significant changes in a percentage of their white matter that was more than three times higher than in controls.
Furthermore, in 2013 McKee and colleagues found that in eight subjects who were examined postmortem for CTE and who had a history of playing amateur and professional ice hockey, five had a presence of CTE on examination. Of the five players who underwent neuropathologic analysis, four showed signs of CTE. Three of the former National Hockey League players had stage II CTE, and one had stage III CTE and Lewy body disease; one of the four was nonsymptomatic at the time of death.
CNS Injuries in Ice Hockey
In a related study presented at the AAN Meeting, Mr. Toy and colleagues found that concussion (0.2 to 6.6 per 1,000 player hours) and spinal cord injury (five per 1,000 player hours) were the most common CNS injuries among ice hockey players.
Other reported injuries were second impact syndrome, subarachnoid hemorrhage, subdural hematoma, epidural hematoma, spinal cord concussion, and vertebral hemorrhage.
“Although numerous measures have been taken to decrease the incidence of CNS injuries in ice hockey, it has been difficult to measure the impact of those changes,” stated Mr. Toy. “Nonetheless, knowledge of the potential for CNS injuries and the mechanisms of those injuries helps inform the athletes and trainers to make more informed decisions regarding play.”