Widely used clinical concussion tests miss important changes to brain function in hockey players who have been cleared to return to play, a new multi-year study reveals. Researchers at Simon Fraser University and the Mayo Clinic have developed a more sensitive tool to measure the brain’s vital signs using complex brainwave data that can be deployed right at the rink. Their research — published this week in Brain: A Journal of Neurology — found that Junior A hockey players who pass concussion protocols often have persistent, undetected deficits in attention and processing. That means we are sending many players back on the ice too early, said SFU neuroscientist Ryan D’Arcy, the study’s senior author.
Brain Vital Signs is a portable system to analyze electroencephalography (EEG — or electrical activity in different parts of the brain) in real time at the rink, using a headpiece studded with sensors. The test takes 10 minutes to run and measures well-established brain functions, including sensory responses, attention and cognitive function and is intended to improve on and replace “subjective and error-prone” tests now in use. The researchers tested 47 players before the season started, so they were able to compare those results with scores taken after a concussion and after sub-concussive hits. But it turns out that the comparison was unnecessary. Concussions create a distinct “fingerprint” of brainwave patterns specific to concussion, said D’Arcy. When the players returned to play based on conventional tests, that fingerprint was still detectable. “What’s even more surprising … we also found that players who were not diagnosed with concussions showed decreased cognitive processing speed post season, thought to be the result of repetitive sub-concussive impacts,” said Shaun Fickling, the study’s lead author and a Ph.D student at SFU.