Defining sports-related concussion (SRC) has been a topic of ongoing discussion within the medical and sports communities. Numerous definitions have been put forth, each with unique perspectives and limitations. To establish a more robust understanding, a comprehensive review was undertaken to analyze existing definitions and pinpoint the essential criteria for an effective operational definition of SRC, particularly in preparation for the 5th Concussion Consensus Conference in Berlin, Germany. This review also explored how biomechanical research contributes to shaping our understanding of SRC.
Current Definitions of Sports-Related Concussion: A Clinical Perspective
A systematic literature review meticulously examined a wide array of articles to identify prevailing definitions of SRC. This review, encompassing databases such as MEDLINE, Embase, and SPORT Discus, analyzed 36 studies out of an initial screening of 1601 articles. The focus was on studies that detailed clinical criteria for diagnosing SRC and those providing impact data related to concussions. The analysis revealed six distinct operational definitions for SRC, all primarily centered on clinical observations and the dynamic nature of these findings. These definitions underscore the reliance on identifying clinical signs and symptoms to diagnose SRC.
The Biomechanical Aspects Informing the Definition of Concussion
Beyond clinical symptoms, the review investigated the biomechanical forces involved in SRC. Data from biomechanical studies, predominantly from American football, were scrutinized. These studies linked angular and linear head accelerations to clinically diagnosed concussions. A key finding was the significant individual variability in head acceleration thresholds that resulted in concussion. This variability highlights the complexity of defining SRC based solely on biomechanical measurements and indicates that concussion is not solely determined by a specific level of head impact force.
Limitations and the Future of SRC Definition
The systematic review concluded that current approaches to defining SRC, while valuable, have limitations. The existing diagnostic criteria are heavily reliant on clinical assessments, which can be subjective. Critically, there is a lack of a definitive “gold standard” to rigorously evaluate the diagnostic accuracy of these criteria. Moving forward, the development of a more valid and objective definition of SRC is crucial. Such a definition would enhance the ability to accurately identify athletes with concussions, characterized by improved predictive positive and negative values in diagnostic testing. Furthermore, the current biomechanical understanding of SRC is largely derived from helmet-based systems used in a limited number of collision sports. To advance the field, there is a pressing need for innovative methodologies to discover and validate objective markers for SRC, moving beyond purely clinical evaluations and limited biomechanical data.
