Quantifying head acceleration exposure via instrumented mouthguards (iMG): a validity and feasibility study protocol to inform iMG suitability for the TaCKLE project

Abstract

Instrumented mouthguards (iMGs) have the potential to quantify head acceleration exposures in sport. The Rugby Football League is looking to deploy iMGs to quantify head acceleration exposures as part of the Tackle and Contact Kinematics, Loads and Exposure (TaCKLE) project. iMGs and associated software platforms are novel, thus limited validation studies exist. The aim of this paper is to describe the methods that will determine the validity (ie, laboratory validation of kinematic measures and on-field validity) and feasibility (ie, player comfort and wearability and practitioner considerations) of available iMGs for quantifying head acceleration events in rugby league. Phase 1 will determine the reliability and validity of iMG kinematic measures (peak linear acceleration, peak rotational velocity, peak rotational acceleration), based on laboratory criterion standards. Players will have three-dimensional dental scans and be provided with available iMGs for phase 2 and phase 3. Phase 2 will determine the on-field validity of iMGs (ie, identifying true positive head acceleration events during a match). Phase 3 will evaluate player perceptions of fit (too loose, too tight, bulky, small/thin, held mouth open, held teeth apart, pain in jaw muscles, uneven bite), comfort (on lips, gum, tongue, teeth) and function (speech, swallowing, dry mouth). Phase 4 will evaluate the practical feasibility of iMGs, as determined by practitioners using the system usability scale (preparing iMG system and managing iMG data). The outcome will provide a systematic and robust assessment of a range of iMGs, which will help inform the suitability of each iMG system for the TaCKLE project.

Ready for Impact? A validity and feasibility study of instrumented mouthguards (iMGs)

“…The four-phase study evaluated four currently available iMG systems, consistent with the published protocol. [4] Phase 1 validated the kinematic measures of iMGs against laboratory criterion standards. [2,3] Phase 2 evaluated the on-field validity of iMG-triggered events by identifying true-positives, false-positives and false-negatives via video-verification from 80 rugby league player matches (20 ± 9 player matches per iMG company).…”

“…iMG companies were invited to provide 43 iMGs ( n = 3 Phase 1, n = 20 Phase 2, n = 20 Phase 3) and associated systems free of charge. The protocol[4] was shared, and companies were informed that the findings would help determine the appropriateness of iMGs for the TaCKLE (Tackle and Contact Kinematic, Load and Exposure) project. [8] Six iMG companies were initially approached, one declined, and one withdrew prior to data collection.…”

“…In-laboratory testing to evaluate the validity of iMG kinematic magnitudes was conducted at the Virginia Tech Helmet Lab (USA),[2] using a bareheaded dummy headform (Figure 1a)[9,10] impacted at various locations, impact magnitudes (target linear head accelerations 25, 50, 75, and 100 g ) and durations (rigid; nylon, 25 mm thickness, and padded; vinyl-nitrile foam, 40 mm thickness) using a pendulum impactor (127 mm diameter) (Figure 1b) as previously described. [4] Two tests were conducted at each configuration and three iMGs were tested for each iMG company (Figure 1c). Reference kinematics were measured at the headform centre of gravity with an instrumentation package consisting of three linear accelerometers (Endevco 7264b-2000; Meggitt Orange County, Irvine, CA) and a tri-axial angular rate sensor (DTS ARS3 Pro 18k; Diversified Technical Systems, Seal Beach, CA), recording at 20 kHz, and filtered using a CFC 1000 and CFC 155.…”

“…Valid iMG data can inform player welfare, safety, and medical initiatives, directly related to long-term brain health. [4].…”

“…This four-phase study[4] aimed to determine; Phase 1) the validity of iMG kinematic magnitude measures against laboratory criterion standards, Phase 2) the on-field validity of iMGs via video-verification, Phase 3) iMG feasibility evaluated via player perceptions of fit, function and comfort , and Phase 4) practical feasibility of iMG systems from a practitioner perspective.…”