Subconcussive brain vital signs changes predict head-impact exposure in ice hockey players

Abstract

The brain vital signs framework is a portable, objective, neurophysiological evaluation of brain function at point-of-care. We investigated brain vital signs at pre- and post-season for age 14 or under (Bantam) and age 16–20 (Junior-A) male ice hockey players to (i) further investigate previously published brain vital sign results showing subconcussive cognitive deficits and (ii) validate these findings through comparison with head-impact data obtained from instrumented accelerometers. With a longitudinal study design, 23 male ice hockey players in Bantam (n = 13; age 13.63 ± 0.62) and Tier II Junior-A (n = 10; age 18.62 ± 0.86) divisions were assessed at pre- and post-season. None were diagnosed with a concussion during the season. Cognitive evoked potential measures of Auditory sensation (N100), Basic attention (P300) and Cognitive processing (N400) were analysed as changes in peak amplitudes and latencies (six standard scores total). A regression analysis examined the relationship between brain vital signs and the number of head impacts received during the study season. Significant pre/post differences in brain vital signs were detected for both groups. Bantam and Junior-A players also differed in number of head impacts (Bantam: 32.92 ± 17.68; Junior-A: 195.00 ± 61.08; P < 0.001). Importantly, the regression model demonstrated a significant linear relationship between changes in brain vital signs and total head impacts received (R = 0.799, P = 0.007), with clear differences between the Bantam and Junior-A groups. In the absence of a clinically diagnosed concussion, the brain vital sign changes appear to have demonstrated the compounding effects of repetitive subconcussive impacts. The findings underscored the importance of an objective physiological measure of brain function along the spectrum of concussive impacts.

Brain Vital Signs in Elite Ice Hockey: Towards Characterizing Objective and Specific Neurophysiological Reference Values for Concussion Management

“…and the fact that participants were engaging in contact sport training between the scans. While short term effects have yet to be examined, longer term participation in contact sports has shown to significantly impact brain vital signs in proportion to the number of head impacts received over a specific period ( Fickling et al, 2021 ).…”

“…Given the relationship to higher-level cognitive processing, the N400 is an increasingly important brain vital sign response. Clinical ERP studies have repeatedly demonstrated the critical role of the N400 in acquired brain injury ( D’Arcy et al, 2003 ; Gawryluk et al, 2010 ) and recently shown the specific importance in understanding subconcussive/subclinical impairment ( Fickling et al, 2019b , 2021 ). The current N400 effects replicated prior empirical characterization of habituation effects.…”

“…Future comparisons will refine and stratify norms, such as closely matched norms for elite athletes in non-contact sports. This is a valuable next step given that, while no prior concussion was reported by any participant, existing subconcussive and/or undisclosed prior injuries may have affected the results ( Covassin et al, 2003 ; Haider et al, 2018 ; Fickling et al, 2019b , 2021 ); (2) The inverse problem with specific reference datasets is that they cannot be applied broadly. Indeed, a specific comparison to the general reference databases was selected, in part, to address this issue.…”

“…The NeuroCatch Platform (NeuroCatch ® Inc., Surrey, BC, Canada) is a Health Canada approved class 2 medical device that provides portable, rapid and automated acquisition, display, analysis, storage, reporting, and management of EEG/ERPs in brain vital sign monitoring ( Ghosh Hajra et al, 2016 ). Using this approach, recent brain vital signs research in ice-hockey concussion studies has demonstrated increased sensitivity to both concussive and sub-concussive impacts ( Fickling et al, 2019b , 2021 ).…”

“…The prior concussion studies used a within-subjects repeated measures model, where each player acts as their own control ( Fickling et al, 2019b , 2021 ). A baseline test was performed before the start of the season, when a player was theoretically “concussion-free.” However, the challenge with baseline testing is that the assessments must be performed prospectively and can therefore be impractical ( Schmidt et al, 2012 ).…”