Brain and Head Injury

This section focuses on the motorcycle helmet research related to the contribution of the helmet to the prevention or reduction of brain and head injury in the event of a crash.

A motorcycle helmet is the most common and best method to prevent skull fractures caused by direct head impact in the event of a crash.  The main purpose of a helmet is as protection against skull fractures, and modern helmets are usually efficient in this regard.

In contrast to skull fractures, brain injuries can result from direct impact to the head or indirectly by the motion of the head, even without impact. Injury to the brain can occur if any part of it is distorted, stretched, or compressed, or if it is torn away from the interior of the skull.  An impact to the head can cause the skull to deform and, even if it does not fracture, the underlying brain tissue can be injured as it distorts under the influence of the deforming skull.  Even if the skull does not bend significantly or fracture but the head as a whole is caused to move violently, distortion of the brain within the skull will occur.  This typically leads to generalized diffuse injury such as concussion, and in the extreme, coma.

Most modern helmets with a few exceptions (as of this writing) are not designed with brain injury prevention as a goal. This is because the evolutionary development of helmets does not parallel the development of the understanding of head and brain injury mechanisms, but follows the evolution of helmet standards. However, a sort of side benefit of wearing a helmet is, in fact, the prevention of brain injury. A helmet, by absorbing some of the impact energy reduces the amount of energy transferred to the head. It thereby can reduce the induced relative movement between parts of the head, and thus the probability and/or severity of a traumatic brain injury (TBI).

To estimate severity of brain injury after head trauma, various classification systems of head injury have been proposed and modified throughout the years. Most of them are based on the patients’ level of consciousness according to the Glasgow Coma Scale (GCS) which has been the most frequently used scoring system for assessment and classification of traumatic brain injury.

Brain & Head Injury Research Studies

2019 – “Unhelmeted Motorcycle Riders Have Increased Injury Burden: A Need to Revisit Universal Helmet Laws”

The aim of this study was to compare hospital outcomes for patients in a motorcycle collision with and without helmet use. Patients were divided into two groups: those wearing a helmet and those without. The authors conclude it is not well understood why many states are repealing or have repealed universal helmet laws. Lack of helmet use increases the severity of injury in traumatized patients leading to a substantial financial impact on health care costs. Our analysis suggests the need to revisit the issue regarding laws that require protective headwear while riding motorcycles because of the individual and societal impact.

2017 – “Biomechanical Evaluation of Motorcycle Helmets – Protection against Head and Brain Injuries”

This study was conducted to evaluate the effectiveness of current motorcycle helmets at reducing the risk of traumatic brain injuries. Results indicate that none of the standard helmet models tested provide adequate protection against concussion and severe traumatic brain injuries at moderate impact speeds. Only one of the standard motorcycle helmet models tested provided adequate protection against skull fracture. A new motorcycle helmet prototype, incorporating a liner constructed from a composite matrix of rate-dependent materials was tested, with comparison to standard motorcycle helmet designs, with very promising results. Knowledge learned from this study will facilitate the development of a new generation of advanced motorcycle helmets that offer improved protection against both head and brain injuries.

2016 – “The Preventive Effect of Head Injury by Helmet Type in Motorcycle Crashes: A Rural Korean Single-Center Observational Study”

The goal of this study was to determine the preventive effect on head injury by helmet type: full face helmet (FFH), open face helmet (OFH), and half-coverage helmet (HCH). The findings from this study suggest that FFHs and OFHs reduce the risk of head injury, and FFHs have a protective effect against minor and severe head injury.

2016 – “Motorcycle Helmet Effectiveness in Reducing Head, Face and Brain Injuries by State and Helmet Law”

Medical outcomes were compared between partial and universal helmet law settings. Medical charges and rates of head, facial, and brain injuries among motorcyclists were lower in universal law states.

2015 – “Motorcycle-Related Traumatic Brain Injuries: Helmet Use and Treatment Outcome”

The objectives were to determine the treatment outcome among traumatic brain injury patients from motorcycle crashes and the rate of helmet use among them. This study was in Nigeria and showed that the helmet use by motorcycle riders was close to zero despite the existing laws making use compulsory.

2015 – “Health and Cost Outcomes Resulting from Traumatic Brain Injury Caused by Not Wearing a Helmet, for Motorcycle Crashes in Wisconsin, 2013”

This is the third published evaluation by the author with the Center for Health Systems Research and Analysis University of Wisconsin (previous publication in 2007 and 2013) of the impact of a variety of motorcycle crash related factors on the likelihood of having a traumatic brain injury (TBI). Helmet use was found to have a strong protective effect on the likelihood of TBI across all other factors. The main protective effect provided by wearing a helmet was in reducing the number of crash victims who had traumatic brain injury.

2013 – “Patterns of Head Injuries in Road Traffic Accidents Involving Two wheelers: An Autopsy Study”

This study was conducted to identify the patterns of head injuries in fatal accidents involving riders and passengers of two wheelers. A fracture of the skull with associated brain injury was found to be the most common cause of death in this study.

2013 – “Motorcycle Helmets – A State of the Art Review”

This is an extensively referenced must read report for anyone wanting to better understand the development of motorcycle helmets, helmet standards and the concepts related to head impact protection and energy absorption. The report includes a literature review of current and most commonly used helmet test standards, along with new tests and helmet concepts to assess the effects of rotational motion, with a special insight into brain injury, helmet design and standards.

2013 – “Impact of Helmet Use in Traumatic Brain Injuries Associated with Recreational Vehicles”

The objective of this study was to access the impact of helmet use on outcomes after recreational vehicle accidents including motorcycles. Lack of helmet use was significantly associated with having a more severe traumatic brain injury, greater likelihood being admitted to the hospital, significantly greater length of hospital stay.

2013 – “Health and Cost Outcomes Resulting from Traumatic Brain Injury Caused by Not Wearing a Helmet, for Motorcycle Crashes in Wisconsin, 2011”

This is the second in a series of evaluations by the author.  See description from the 2015 report. The main protective effect provided by wearing a helmet was in reducing the number of crash victims who had traumatic brain injury. Estimated costs were much higher for TBI crash victims than non-TBI victims. Altogether, not wearing a helmet was associated with 96 extra TBI cases, and an additional $97 million in “comprehensive” costs.

2013 – “Head Injury and Effective Motorcycle Helmets”

The crash characteristics and injuries to the head sustained by helmeted motorcyclists were examined by reference to data from motorcycle crash studies. The crash data regarding the head injury sustained in helmeted head impacts in motorcycle crashes suggests areas available to improve current motorcycle helmet effectiveness and motorcycle helmet standard test methodologies in reducing brain injury. This study defines some of these areas where motorcycle helmet effectiveness in preventing brain injury can be improved.

2011 – “Improving TBI Protection Measures and Standards for Combat Helmets”

How well do current combat helmets protect against Traumatic Brain Injury? According to the authors, to answer this question it is necessary to evaluate both the measures and standards of protection.  The authors define measure as a physical test that the helmet must be subject to and the standard as the quantitative threshold of performance in this test that the helmet must satisfy to be acceptable. The authors find that both the measures are inadequate and the standards are too low. While not a study of motorcycle helmets, this study contributes to the knowledge about helmets and TBI.

2011 – “Effectiveness of Different Types of Motorcycle Helmets and Effects of Their Improper Use on Head Injuries”

This case–control study was conducted to examine how different types and improper helmet use affected protection against head injuries helmet.  Analysis showed that compared with helmeted motorcyclists, non-helmeted motorcyclists were more than four times as likely to have head injuries and ten times as likely to have brain injuries. Compared with motorcyclists wearing full-face helmets, those wearing half coverage helmets were more than twice as likely to have head injuries and brain injuries.  Compared with motorcyclists with firmly fastened helmets, those with loosely fastened helmets increased their risk of head injury and were more than twice as likely to have brain injuries.

2010 – “Youth Motorcycle-Related Brain Injury by State Helmet Law Type: United States, 2005-2007”

This research is important not only for what it tell us about helmet use and TBI but also about the ineffectiveness of partial use helmet laws.  States with youth-specific laws had an increased risk of TBI that required hospitalization, serious and severe TBI, TBI-related disability, and in-hospital death among the youth they are supposed to protect. The only method known to keep motorcycle-helmet use high among youth is to adopt or maintain universal helmet laws.

2010 – “An Evidence-Based Review: Helmet Efficacy to Reduce Head Injury and Mortality in Motorcycle Crashes: EAST Practice Management Guidelines”

This is one of three high quality literature reviews highlighted in the Sept. /Oct 2014 Special Edition of Riding Smart. Literature reviews like this one are an excellent way to begin study of any research topic.  The authors concluded that the use of motorcycle helmets 1) decreases the overall death rate from motorcycle crashes when compared with non-helmeted riders. 2) decreases the incidence of lethal head injury in motorcycle crashes when compared with non-helmeted riders. 3) decreases the severity of on lethal head injury in motorcycle crashes when compared with non-helmeted riders. 4) increases in jurisdictions with mandatory universal helmet laws, and those areas have reduced rates of mortality and head injury compared with areas that do not.

2009 – “Motorcycle Helmet Use and Head and Facial Injuries”

This report examines the relationship between motorcycle helmet use and motorcycle crash outcomes in terms of injury types, hospital charges, and other variables employing data from the Crash Outcome Data Evaluation System (CODES). Helmeted motorcyclists were less likely to experience facial and head injuries compared to unhelmeted motorcyclists. Helmeted motorcyclists were significantly less likely to experience a traumatic brain injury. TBIs are of particular concern in our study. TBI was associated with significantly higher hospital charges. Additionally, motorcyclists with TBI were much less likely to be discharged home and more likely to require rehabilitation or to be discharged to a long-term care facility following their hospitalization.

2008 – “Changes in Motorcycle-Related Head Injury Deaths, Hospitalizations, and Hospital Charges Following Repeal of Pennsylvania’s Mandatory Motorcycle Helmet Law”

This research provides information regarding the connection between helmet use and head injury as well as the impact of repealing all-rider helmet laws.  To evaluate the 2003 repeal of Pennsylvania’s motorcycle helmet law, the researchers assessed changes in helmet use and compared motorcycle related head injuries with nonhead injuries from 2001–2002 to 2004–2005. Helmet use decreased, head injury deaths increased, and head injury hospitalizations increased.

2007 – “Health and Cost Outcomes Resulting from Traumatic Brain Injury Caused by Not Wearing a Helmet, for Motorcycle Crashes in Wisconsin, 2003-2005”

This is the first in a series of evaluations by this researcher (see 2013 and 2015). Those not wearing a helmet were almost two and a half times as likely to suffer TBI as those wearing a helmet.

2002 – “Injury Patterns Associated with Mortality Following Motorcycle Crashes”

All patients involved in motorcycle crashes admitted to various hospitals in the Yorkshire region of UK between January 1993 and December 1999 were retrospectively reviewed to identify the factors that are likely to predict a reduced survival. There was a significant difference in the Glasgow coma scale (GCS) between patients wearing a helmet and those that did not wear any protective headgear.

2001 – “Head Injury Mechanisms in Helmet-Protected Motorcyclists: Prospective Multicenter Study”

The aim of this study was to analyze the current situation of a protection standard in helmet construction in Europe and to evaluate the mechanism of head and brain injuries in helmet-protected motorcyclists to create a basis for further development of helmets.  The results of this research expand on earlier reports showing that helmets provide protection for all types and locations of head injuries, and show that they are not associated with increased neck injury occurrence.  The motorcycle helmets currently available provide a high preventive effect, especially in sufficiently reducing the direct force effect to the head. Further improvements of the helmet shell can further minimize the direct force effects. The lesions caused by indirect force effect (e.g., acceleration and deceleration) remain a problem. In particular, rotation is an important and underestimated factor. The reduction of the kinetic consequences of the effecting forces should be a direction for future motorcycle helmet generations.

1999 – “Motorcyclists Head Injuries:  Mechanisms Identified from Accident Reconstruction and Helmet Damage Replication”

This is an earlier presentation of the research published in 2001, Head Injury Mechanisms in Helmet-Protected Motorcyclists: Prospective Multicenter Study. The researchers found notable correlation between helmet damage location and head injury region but also some possible exceptions. Both are important in understanding how head injuries occur, how helmet design may affect injuries and, in turn, how the design may be changed to improve protection.

1994 – “Head Injuries in Traffic Accidents with Emphasis on the Comparisons between Motorcycle Helmet Users and Non-Users”

The objective of this study was to analyze the characteristics of head injuries caused by motor vehicle accidents in terms of the injured person's demographic characteristics, time and types of crash, injury severity on the abbreviated injury scale (AIS), medical cost and benefits of helmet protection. The results showed that the most common cause of head injury in traffic accidents was a motorcycle incident. A significant difference was noted in the severity of injury of helmeted users of motorcycles, compared with those who wore no helmet. As expected, patients who did not wear a helmet had a greater AIS average and higher rate of fatality.

1988 – “Patterns of Injury in Helmeted and Non-Helmeted Motorcyclists”

In this study, the incidence of severe brain injury was 600 percent higher for patients riding without a helmet and the incidence of all brain injuries was nearly twice as high in the nonhelmeted riders.

1943 – “Head Injuries in Motor-Cyclists with Special Reference to Crash Helmets”

The early research by Hugh Cairns. His conclusion - the crash helmet is effective in diminishing local damage to the brain and its coverings at the site of impact, and it tends to lower the incidence of cases of prolonged amnesia.