Evaluation of an Elastomeric Honeycomb Bicycle Helmet Design to Mitigate Head Kinematics in Oblique Impacts

Head impacts in bicycle accidents are typically oblique to the impact surface and transmit both normal and tangential forces to the head, causing linear and rotational head kinematics, respectively. Traditional expanded polystyrene (EPS) foam bicycle helmets are effective at preventing many head injuries, especially skull fractures and severe traumatic brain injuries (TBIs) (primarily from normal contact forces). However, the incidence of concussion from collisions (primarily from rotational head motion) remains high, indicating need for enhanced protection. An elastomeric honeycomb helmet design is proposed herein as an alternative to EPS foam to improve TBI protection and be potentially reusable for multiple impacts, and tested using a twin-wire drop tower. Small-scale normal and oblique impact tests showed honeycomb had lower oblique strength than EPS foam, beneficial for diffuse TBI protection by permitting greater shear deformation and had the potential to be reusable. Honeycomb helmets were developed based on the geometry of an existing EPS foam helmet, prototypes were three-dimensional-printed with thermoplastic polyurethane and full-scale flat and oblique drop tests were performed. In flat impacts, honeycomb helmets resulted in a 34% higher peak linear acceleration and 7% lower head injury criteria (HIC15) than EPS foam helmets. In oblique tests, honeycomb helmets resulted in a 30% lower HIC15 and 40% lower peak rotational acceleration compared to EPS foam helmets. This new helmet design has the potential to reduce the risk of TBI in a bicycle accident, and as such, reduce its social and economic burden. Also, the honeycomb design showed potential to be effective for repetitive impact events without the need for replacement, offering benefits to consumers.

An Air-Filled Bicycle Helmet for Mitigating Traumatic Brain Injury

We created a novel air-filled bicycle helmet. The aims of this study were (i) to assess the head injury mitigation performance of the proposed helmet and (ii) to compare those performance results against the performance results of an expanded polystyrene (EPS) traditional bicycle helmet. Two bicycle helmet types were subjected to impacts in guided vertical drop tests onto a flat anvil: EPS helmets and air-filled helmets (Bumpair). The maximum acceleration value recorded during the test on the Bumpair helmet was 86.76 ± 3.06 g, while the acceleration during the first shock on the traditional helmets reached 207.85 ± 5.55 g (p < 0.001). For the traditional helmets, the acceleration increased steadily over the number of shocks. There was a strong correlation between the number of impacts and the response of the traditional helmet (cor = 0.94; p < 0.001), while the Bumpair helmets showed a less significant dependence over time (cor = 0.36; p = 0.048), meaning previous impacts had a lower consequence. The air-filled helmet significantly reduced the maximal linear acceleration when compared to an EPS traditional helmet, showing improvements in impact energy mitigation, as well as in resistance to repeated impacts. This novel helmet concept could improve head injury mitigation in cyclists.

The Impact of Information Presentation and Cognitive Dissonance on Processing Systematic Review Summaries: A Randomized Controlled Trial on Bicycle Helmet Legislation

Background: Summaries of systematic reviews are a reference method for the dissemination of research evidence on the effectiveness of public health interventions beyond the scientific community. Motivated reasoning and cognitive dissonance may interfere with readers’ ability to process the information included in such summaries. Methods: We conducted a web experiment on a panel of university-educated North Americans (N = 259) using a systematic review of the effectiveness of bicycle helmet legislation as a test case. The outcome variables were the perceived tentativeness of review findings and attitude toward bicycle helmet legislation. We manipulated two types of uncertainty: (i) deficient uncertainty (inclusion vs. non-inclusion of information on limitations of the studies included in the review) and (ii) consensus uncertainty (consensual findings showing legislation effectiveness vs. no evidence of effectiveness). We also examined whether reported expertise in helmet legislation and the frequency of wearing a helmet while cycling interact with the experimental factors. Results: None of the experimental manipulations had a main effect on the perceived tentativeness. The presentation of consensual efficacy findings had a positive main effect on the attitude toward the legislation. Self-reported expertise had a significant main effect on the perceived tentativeness, and exposing participants with reported expertise to results showing a lack of evidence of efficacy increased their favorable attitude toward the legislation. Participants’ helmet use was positively associated with their attitude toward the legislation (but not with perceived tentativeness). Helmet use did not interact with the experimental manipulations. Conclusions: Motivated reasoning and cognitive dissonance influence a reader’s ability to process information contained in a systematic review summary.

The effect of the scalp on the effectiveness of bicycle helmets' anti-rotational acceleration technologies

OBJECTIVE

Medical data has lead to the common understanding that bicycle helmets need to be improved to better protect against brain injuries resulting from rotational acceleration. Although many different technologies exist for reducing rotational acceleration during impacts, the lack of an official testing standard means that their evaluation is based on customized set-ups that may differ and not represent real accident conditions. Previously, the authors have shown that scalp tissue plays an important role during helmet testing by absorbing energy and creating a low friction interface between head and helmet, thus reducing rotational accelerations and velocities. However, no published study has yet examined the effectiveness of anti-rotational helmet technologies in the presence of a biofidelic scalp layer. The objective of this study is to address this gap.

METHODS

Three different commercially available helmet models, each one equipped with a different technology, were tested in the presence of scalp tissue, in two different scenarios; with and without the technology present. The effectiveness of each of these technologies is already documented in other studies, but only in the absence of a biofidelic scalp layer. Tests were carried out using HIII headform with porcine scalp attached to the outmost layer. Motion tracking was used to compare the impact kinematics of each helmet model in both scenarios.

RESULTS

Results showed that when a biofidelic scalp layer is present, there is no statistical difference between helmet models with and without the anti-rotational technology in terms of rotational acceleration, velocity, relative rotation, impact duration and injury risk.

CONCLUSIONS

Results suggest that the presence of the scalp can obscure the functionality of anti-rotational acceleration technologies. This could indicate that the effectiveness of technologies tested in previous studies, which have not tested anti-rotational acceleration technologies in the presence of a realistic scalp layer, may exaggerate the contribution of such technologies if compared with a more biofidelic set-up. The study supports the fact that headforms should be better designed by incorporating artificial skin layers that can better imitate scalp's behavior and, in addition, provides insights for the design of technologies against rotational acceleration.

Trauma hazards in children: An update for the busy clinician

Trauma and injury continue to be common in children and remain an important cause of mortality and morbidity. Legislation mandating the use of helmets for all cyclists appears to have been effective in reducing the incidence and severity of head and facial injuries, with no clear evidence of a reduction in cycling usage or activity. Straddle injuries, whilst uncommon and generally minor, require careful clinical assessment as they may be associated with urethral trauma. Quad bikes remain highly dangerous with continuing reports of deaths in child riders due to their inherent lack of stability: a ban on their use by children would seem the most effective solution. The popularity of mobile devices and toys, coupled with the development of higher voltage, lithium button batteries have seen a surge in the number of cases and subsequent complications from ingestion. The problems seen in children following ingestion of high-powered, rare earth magnets in the late 1990s and 2000s has now receded due to legislation introduced in 2012. Inhaled, typically organic foreign bodies remain a diagnostic challenge with rigid bronchoscopy still the most effective diagnostic and therapeutic modality. Corrosive ingestion, now seen much less commonly, continues to be a potentially devastating injury when occurring as a result of caustic soda. Recent publicity concerning the problem of childhood drowning highlights the need for constant parental vigilance, the limitations of pool fencing and the importance of community cardiopulmonary resuscitation training, together with repeated education of the risk of rips when swimming in the sea.

Barriers to bicycle helmet use in young children in an urban elementary school

PURPOSE

Traumatic brain injury is a leading cause of death in bicycle crashes. The factors associated with bicycle helmet use in young children with diverse ethnic and socioeconomic backgrounds have not been studied. The purpose of this study was to identify barriers to helmet use in young children in an urban elementary school.

DESIGN

Qualitative content analysis with semistructured interviews, observational field notes, and artifacts.

SETTING

Urban elementary school.

PARTICIPANTS

Seventeen students whose age ranged from 5 to 7 years and whose ethnic background was identified as African American (14) or Caucasian (3).

METHOD

Children participated in a brain safety fair that included presentations and activities. Semistructured, pre- and postexperience interviews were completed. Observations of the students participating in the activities and reflective art projects from the students were collected.

RESULTS

The analysis found the following barriers to helmet use: (a) lack of access to a helmet, (b) poor fit of helmets due to hairstyles, and (c) lack of knowledge regarding helmet use.

CONCLUSION

The present study suggests that the issue of helmet design and comfort for younger children with variable hairstyles needs to be addressed in order to increase helmet use in this population.

Personal and trip characteristics associated with safety equipment use by injured adult bicyclists: a cross-sectional study

BACKGROUND

The aim of this study was to estimate use of helmets, lights, and visible clothing among cyclists and to examine trip and personal characteristics associated with their use.

METHODS

Using data from a study of transportation infrastructure and injuries to 690 adult cyclists in Toronto and Vancouver, Canada, we examined the proportion who used bike lights, conspicuous clothing on the torso, and helmets on their injury trip. Multiple logistic regression was used to examine associations between personal and trip characteristics and each type of safety equipment.

RESULTS

Bike lights were the least frequently used (20% of all trips) although they were used on 77% of trips at night. Conspicuous clothing (white, yellow, orange, red) was worn on 33% of trips. Helmets were used on 69% of trips, 76% in Vancouver where adult helmet use is required by law and 59% in Toronto where it is not. Factors positively associated with bike light use included night, dawn and dusk trips, poor weather conditions, weekday trips, male sex, and helmet use. Factors positively associated with conspicuous clothing use included good weather conditions, older age, and more frequent cycling. Factors positively associated with helmet use included bike light use, longer trip distances, hybrid bike type, not using alcohol in the 6 hours prior to the trip, female sex, older age, higher income, and higher education.

CONCLUSIONS

In two of Canada's largest cities, helmets were the most widely used safety equipment. Measures to increase use of visibility aids on both daytime and night-time cycling trips may help prevent crashes.

Bicycle helmet use and non-use - recently published research

Bicycle traumata are very common and especially neurologic complications lead to disability and death in all stages of the life. This review assembles the most recent findings concerning research in the field of bicycle traumata combined with the factor of bicycle helmet use. The area of bicycle trauma research is by nature multidisciplinary and relevant not only for physicians but also for experts with educational, engineering, judicial, rehabilitative or public health functions. Due to this plurality of global publications and special subjects, short time reviews help to detect recent research directions and provide also information from neighbour disciplines for researchers. It can be stated that to date, that although a huge amount of research has been conducted in this area more studies are needed to evaluate and improve special conditions and needs in different regions, ages, nationalities and to create successful prevention programs of severe head and face injuries while cycling.Focus was explicit the bicycle helmet use, wherefore sledding, ski and snowboard studies were excluded and only one study concerning electric bicycles remained due to similar motion structures within this review. The considered studies were all published between January 2010 and August 2011 and were identified via the online databases Medline PubMed and ISI Web of Science.

Bicycle helmet prevalence two years after the introduction of mandatory use legislation for under 18 year olds in Alberta, Canada

OBJECTIVE

To determine changes in helmet use in cyclists following the introduction of a bicycle helmet law for children under age 18.

METHODS

Cyclists were observed by two independent observers from July to August 2004 (post-legislation) in Edmonton, Alberta. The data were compared with a similar survey completed at the same locations and days in July to August 2000 (pre-legislation). Data were collected for 271 cyclists in 2004 and 699 cyclists in 2000.

RESULTS

The overall prevalence of helmet use increased from 43% (95% CI 39 to 47%) in 2000 to 53% (95% CI 47 to 59%) in 2004. Helmet use increased in those under 18, but did not change in those 18 and older. In the cluster adjusted multivariate Poisson regression model, the prevalence of helmet use significantly increased for those under age 18 (adjusted prevalence ratio (APR) 3.69, 95% CI 2.65 to 5.14), but not for those 18 years and older (APR 1.17, 95% CI 0.95 to 1.43).

CONCLUSION

Extension of legislation to all age groups should be considered.