Evaluating the "Threshold Theory": Can Head Impact Indicators Help?. Issue 2 (February 2017)

• Record Type: Journal Article
• Authors: MIHALIK, JASON P.; LYNALL, ROBERT C.; WASSERMAN, ERIN B.; GUSKIEWICZ, KEVIN M.; MARSHALL, STEPHEN W.
• Is Part Of: Medicine and science in sports and exercise. Volume 49:Issue 2(2017)
• Publication Date: 2017-02
• Subjects: BIOMECHANICS -- BRAIN INJURY -- CONCUSSION -- SPORT INJURY; Sports medicine -- Periodicals; Exercise -- Physiological aspects -- Periodicals; Exercise -- Health aspects -- Periodicals; 612.044
• DOI: 10.1249/MSS.0000000000001089
• Languages: English
• ISSNs: 0195-9131

Abstract

ABSTRACT: Purpose: This study aimed to determine the clinical utility of biomechanical head impact indicators by measuring the sensitivity, specificity, positive predictive value (PV+), and negative predictive value (PV−) of multiple thresholds. Methods: Head impact biomechanics ( n = 283, 348) from 185 football players in one Division I program were collected. A multidisciplinary clinical team independently made concussion diagnoses ( n = 24). We dichotomized each impact using diagnosis (yes = 24, no = 283, 324) and across a range of plausible impact indicator thresholds (10 g increments beginning with a resultant linear head acceleration of 50 g and ending with 120 g ). Results: Some thresholds had adequate sensitivity, specificity, and PV−. All thresholds had low PV+, with the best recorded PV+ less than 0.4% when accounting for all head impacts sustained by our sample. Even when conservatively adjusting the frequency of diagnosed concussions by a factor of 5 to account for unreported/undiagnosed injuries, the PV+ of head impact indicators at any threshold was no greater than 1.94%. Conclusions: Although specificity and PV− appear high, the low PV+ would generate many unnecessary evaluations if these indicators were the sole diagnostic criteria. The clinical diagnostic value of head impact indicators is considerably questioned by these data. Notwithstanding, valid sensor technologies continue to offer objective data that have been used to improve player safety and reduce injury risk.