Background Early identification and evaluation of concussions is critical. We examined the utility of using visible signs (VS) of concussion in predicting subsequent diagnosis of concussion in NHL players.
Methods VS of concussion were identified through video review. Coders were trained to detect and record specific visual signs while viewing videos of NHL regular season games. 2460 games were reviewed by at least two independent coders across two seasons. The reliability, sensitivity and specificity of these VS were examined.
Results VS were reliably coded with inter-rater agreement rates ranging from 73% to 98.9%. 1215 VS were identified in 861 events that occurred in 735 games. 47% of diagnosed concussions were associated with a VS but 53% of diagnosed concussions had no VS. Of the VS, only loss of consciousness, motor incoordination, and blank/vacant look had positive likelihood ratios greater than 1, indicating a positive association with concussion diagnoses. Slow to get up and clutching of the head were observed frequently but had low positive predictive values. Sensitivity decreased and specificity increased when multiple VS occurred together.
Conclusions Non-medical personnel can be trained to reliably identify events in which VS occur and to reliably identify specific VS within each of those events. VS can be useful to detect concussion early but they are not enough since more than half of physician diagnosed concussions occurred without the presence of a visual sign. The results underscore the complexity of this injury and highlight the need for comprehensive approaches to injury detection.
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Contributors RJE And JMB took primary responsibility for the design and execution of this study and writing of the manuscript. JMB was involved in the design and execution of this study and in editing the manuscript. WM and MH were involved in the design of the study and contributed to the writing and editing of the manuscript. PC and MA contributed to the design of the study and editing the manuscript.
Competing interests RJE is Co-Chair of the NHL/NHLPA Concussion Subcommittee. He receives financial compensation for consulting services from the NHL, Major League Soccer, US Soccer Federation, NCAA, and Princeton University. JMB is an employee of the NHL. He provides unbranded talks for Novartis and is a member of the Novartis MS and Cognition Medical Advisory Board. He has worked as a consultant to Sporting KC and the Princeton University Department of Athletic Medicine. WM is an employee of the NHL and a member of the NHL/NHLPA Concussion Subcommittee and Co-Chair of the NHL/NHLPA Joint Health and Safety Committee. PC is the co-chair of the NHL/PA Concussion Subcommittee and a consultant to the NHLPA, for which he receives remuneration. MH is a member of the NHL/NHLPA Concussion Subcommittee and a consultant to the NHLPA, for which he receives remuneration.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data that form the basis for this study are propietary and not available for sharing.
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