Development of Head Injury Assessment Reference Values Based on NASA Injury Modeling

Abstract

NASA is developing a new capsule-based, crewed vehicle that will land in the ocean, and the space agency desires to reduce the risk of injury from impact during these landings. Because landing impact occurs for each flight and the crew might need to perform egress tasks, current injury assessment reference values (IARV) were deemed insufficient. Because NASCAR occupant restraint systems are more effective than the systems used to determine the current IARVs and are similar to NASA's proposed restraint system, an analysis of NASCAR impacts was performed to develop new IARVs that may be more relevant to NASA's context of vehicle landing operations. Head IARVs associated with race car impacts were investigated by completing a detailed analysis of all of the 2002-2008 NASCAR impact data. Specific inclusion and exclusion criteria were used to select 4071 impacts from the 4015 recorder files provided (each file could contain multiple impact events). Of the 4071 accepted impacts, 274 were selected for numerical simulation using a custom NASCAR restraint system and Humanetics Hybrid-III 50 th percentile numerical dummy model in LS-DYNA. Injury had occurred in 32 of the 274 selected impacts, and 27 of those injuries involved the head. A majority of the head injuries were mild concussions with or without brief loss of consciousness. The 242 non-injury impacts were randomly selected and representative of the range of crash dynamics present in the total set of 4071 impacts. Head dynamics data (head translational acceleration, translational change in velocity, rotational acceleration, rotational velocity, HIC-15, HIC-36, and the Head 3ms clip) were filtered according to SAE J211 specifications and then transformed to a log scale. The probability of head injury was estimated using a separate logistic regression analysis for each log-transformed predictor candidate. Using the log transformation constrains the estimated probability of injury to become negligible as IARVs approach zero. For the parameters head translational acceleration, head translational velocity change, head rotational acceleration, HIC-15, and HIC-36, conservative values (in the lower 95% confidence interval) that gave rise to a 5% risk of any injury occurring were estimated as 40.0 G, 7.9 m/s, 2200 rad/s 2 , 98.4, and 77.4 respectively. Because NASA is interested in the consequence of any particular injury on the ability of the crew to perform egress tasks, the head injuries that occurred in the NASCAR dataset were classified according to a NASA-developed scale (Classes I -III) for operationally relevant injuries, which classifies injuries on the basis of their operational significance. Additional analysis of the data was performed to determine the probability of each injury class occurring, and this was estimated using an ordered probit model. For head translational acceleration, head translational velocity change, head rotational acceleration, head rotational velocity, HIC-36, and head 3ms clip, conservative values of IARVs that produced a 5% risk of Class...

Sports-Related Concussion in Helmeted vs. Unhelmeted Athletes: Who Fares Worse?

“…The most recent analyses reported the superiority of modern helmets compared to leather helmets after researchers performed 1 224 drop tests on 10 modern helmets and 1 leather helmet [52]. Outside the 4 major U.S. sports, helmet and headgear biomechanics have also been studied in a wide array of sporting activities, including soccer [46], lacrosse [9], speed skating [31], biking [27], cricket [51], car racing [59], skateboarding [35] and equestrian activities [20]. Despite extensive research on the biomechanics of athletic helmets, little is known about the neurocognitive and symptom sequelae of helmeted vs. unhelmeted athletes after SRC.…”

A revolution in preventing fatal craniovertebral junction injuries: lessons learned from the Head and Neck Support device in professional auto racing

“…29 An analysis of NASCAR data showed that increased head acceleration provided a good correlation with injury severity according to the Abbreviated Injury Scale (AIS), ranging from loss of consciousness to hemorrhage to fatal skull fracture. 24 These studies have not directly examined the benefits of the HANS device, but it may be interesting to investigate what effect the reduced loads on the head and neck of the driver would have on the overall AIS severity.…”

Concussion in motorsport: incidence, awareness and future directions

“…Motorsport is no exception, yet the published evidence on the incidence, severity and recovery from this condition remains scarce [ 1 ]. Motorsport is unique among extreme sports, since competitors are frequently subject to high velocity, high G forces with a large rotational component, even without impact [ 2 , 3 ]. The ongoing challenge for practitioners is threefold; making a diagnosis of concussion trackside, evaluating competitors in the medical center and approaching the return-to-race decision.…”