Examining the Reliability and Validity of Coding Perceived Force Severity and Bracing in the NHL Concussion Spotter Program.

Abstract

Background: Data obtained from the National Hockey League (NHL) have shown that a risk prediction model, including both visible signs and mechanisms of injury, improves the identification of possible concussion. However, only about half of concussions diagnosed by club medical staff in the NHL exhibit visible signs. At present, the NHL concussion spotter protocol does not include central league spotters' subjective judgments of the severity of forces associated with a direct hit to the head (perceived force severity [PFS]) or whether players brace before a hit (bracing).

Purpose: To examine the interrater reliability, preliminary validity, and association with concussion diagnosis of central league spotter determinations of PFS and bracing.

Study design: Cross-sectional study.

Methods: Video footage of 1071 events after a direct or indirect blow to the head were observed from the 2020-2021 and 2021-2022 NHL seasons. These events were classified into 4 groups: concussion with visible signs; concussion without visible signs; no concussion with visible signs; and no concussion without visible signs. A total of 50 events were randomly selected from the total events in each group. Then, 2 raters (NHL central league spotters) coded PFS for each of the 200 video events as low, medium, or high. Bracing was coded as no bracing, insufficient bracing, or full bracing.

Results: Interrater reliability was fair to moderate for the categorical and continuous ratings of both PFS (κ = 0.36 and 0.45, respectively) and bracing (κ = 0.40 and 0.49, respectively). There was no significant association between concussion diagnosis and either PFS (Z = 0.00, P = .99) or bracing (Z = 0.77, P = .44). Exploratory, post hoc analyses suggested a possible relationship between bracing and reduced concussion risk among a select subsample of events with no visible signs (r = -0.29, P < .01).

Conclusion: The interrater reliability for PFS and for bracing was fair to moderate. Neither PFS nor bracing were significantly related to concussion diagnosis, but they were significantly associated with other visible signs and mechanisms of injury.