In this document, the biomechanical engineers at Robson Forensic provide an introduction to some of the foundational principles relevant to the science of traumatic brain injuries. The discussion includes how these incidents are investigated and the many expert solutions Robson Forensic can bring to bear.
Traumatic Brain Injury (TBI) Investigations
Evaluating injury causation in forensic casework involving Traumatic Brain Injuries (TBI) often requires the coordination of multiple experts to fully understand the extent of injuries, the forces experienced throughout the incident, and how those forces compare with the diagnosis.
Depending on the nature of the incident, whether it be a slip and fall, a vehicle crash, or of another variety, these analyses may require specialized expertise to address issues specific to vehicle safety systems, personal protective equipment, or other potentially esoteric topics.
This document provides an introduction to the technical foundations of TBI investigations. As a national leader in expert witness consulting, Robson Forensic is in a unique position to provide comprehensive forensic investigations into these complex and often contentious incidents.
Evaluating Causation in Traumatic Brain Injury Disputes
Using the diagnosis documented in the medical record, the biomechanical engineer applies physics, engineering, and the scientific method to determine if the forces/energy in the incident were sufficient and in the appropriate direction to have caused the diagnosed brain injuries. Having a sound diagnosis that is well documented in medical records is a crucial first step in conducting this type of analysis.
In many instances, the biomechanical engineer will incorporate information from other technical experts into their analysis. Using the example of a car crash, the biomechanical engineer may rely on the reconstruction of the collision conducted by either an accident reconstructionist or the police department. Then, following the scientific method and applying universally accepted principles in the fields of engineering and biomechanics, the motions of the occupant are determined throughout the crash sequence using the results of the reconstruction, physics, physical evidence, anatomy, and physiology.
Determining the magnitude of the forces the occupant was subjected to and energy absorbed by the individual’s head during the fall or impact can be calculated applying Newton’s Laws of Physics and the Conservation of Energy and Work Principles.
The calculated values are then compared to the injury threshold values from biomedical/biomechanical peer reviewed literature which are part of a large body of medical and scientific literature aimed at studying how and why traumatic brain injuries are caused and the forces required to cause these injuries.
TBI Injury Thresholds
The injury thresholds defined by this body of peer-reviewed research literature are routinely applied by scientists from both industry and academia to identify situations where individuals are susceptible to sustaining traumatic brain injuries and for developing protective measures to minimize the risk of injury.
The results of this research are used by government agencies for a broad range of applications, including the Consumer Product Safety Commission for determining the thickness of the impact attenuating material under playground equipment; the Department of Transportation for the approval of helmets for bicycles and motorcycles; the National Transportation Safety Administration for determining Federal Motor Vehicle Safety Standards; and the Centers for Disease Control in identifying fall precautions for the elderly and new guidelines for identification of and prevention for young athletes who are susceptible to traumatic brain injuries.
Brain Injuries: Diffuse vs. Focal
Clinically, brain injuries are classified as either diffuse or focal. Diffuse traumatic brain injuries are broader based and are the result of acceleration/deceleration due to sudden movement of the head. Because of the differences in the inertial properties of the individual components, or structures, of the brain, the individual structures accelerate and decelerate differently, resulting in intracranial pressure gradients and the shearing and/or stretching of the vascular and neurological connections or bridges between the different parts of the brain. Diffuse traumatic brain injuries often include swelling, subdural hematomas and diffuse axonal injury (DAI).
Focal injuries are those that are limited to a specific location and are the result of contact. Focal injuries include contusions, laceration, and intracranial hemorrhage. A concussion is a traumatic injury to the brain occurring from impact. Impact to the brain can occur when the head impacts a hard surface, rapidly decelerating the skull. The skull is stopped, but the brain, floating in cerebrospinal fluid (CSF), moves and is injured.
Age and its Effect on Brain Injury
Both age and physical condition can greatly impact the short and long term damages stemming from TBI. In an adult, traumatic injury to the brain can result in diminished or loss of cognitive and or executive functions. In a young child, research has shown that damage to the brain may not result in the reduction or loss of functions they currently have, but rather a loss of the ability to develop the part of the brain that is injured.
Common TBI Scenarios
The manner in which injuries occur can be complex, but the scientific data are available to reliably navigate these complexities. Two scenarios typical to traumatic brain injury investigations are outlined below, but there is virtually no limit to the variety and complexity of incidents.
Use versus Non-Use of Protective Equipment or Surfaces
In some venues, biomechanical engineers assist in determining if the use of a helmet, seatbelt, the required depth of playground mulch, or if other safety devices would or would not have made a difference in the injuries sustained during an incident. This sort of analysis is conducted in much the same way as earlier described. First, the analysis is conducted based on what occurred during the actual incident. A second analysis is subsequently conducted to determine if the use of a safety device would have changed the outcome. This is done by re-running the analysis with the inclusion of data regarding the energy dissipation provided by a helmet, the restrained motion expected from the use of a seatbelt, or the energy management provided by having the recommended depth of mulch on a playground.
Subconcussive and Secondary Blows
Recent research has shown a causal relationship between subconcussive blows and TBI. The research indicates the exacerbation of a brain injury resulting from secondary blows to the head following an injury causing blow. Using the example of an individual who is struck in the head and then falls down a set of stairs, available research now allows for the analysis of the initial strike, as well as further damage related to the subsequent impacts occurring during the stair fall. The subsequent impacts from the stair fall may be subconcussive impacts (below the energy threshold for concussion), while resulting in further “sloshing” of the brain back and forth within the skull, exacerbating the brain injury.
Standard of Care Experts to Address the Specifics of TBI Incidents
Robson Forensic is positioned to investigate injury causation in traumatic brain injury cases as well as the various technical aspects that may have affected liability. Below we have highlighted some of the disciplines most commonly associated with TBI cases. Contact us to determine which expert is most appropriate to investigate the technical aspects of your case.
Animal Scientist & Horse Expert
- J. Tim Potter Ph.D., PAS
- Dr. Potter’s academic and professional careers, and lifetime of involvement in horse breeding, training, and competition make him a uniquely qualified expert on issues ranging from nutrition, abuse, behavior, training, riding and facilities safety.
Playground Safety Expert
- Lisa A. Thorsen Ed.D., C.P.S.I.
- Dr. Thorsen has nearly 30 years of experience working in or administering care facilities and programs and is an expert in operations and compliance for the care and safety of children and adults.
Marine Operations Expert
- Hendrik J. Keijer
- Captain Henk operated cruise and cargo ships for nearly 25 years. Henk would later develop policy standards and conduct investigations into incidents and accidents for a major cruise line.
- Roland Hoover
- Roland was an R&D Engineering Manager at a motorcycle parts manufacturer, where he was responsible for root cause and finite element analysis investigations into product failures and complaints.
- Maria Bella AFOIT, CPOI
- Maria is one of seven Aquatic Facility Operator Instructor Trainers in the world. She has been active in the industry for over 40 years and participates in the development of industry standards & codes.
Vehicle Crashworthiness Expert
- Peter J. Leiss P.E., C.F.E.I., C.V.F.I.
- Pete is an automotive engineer with industry experience designing & testing production vehicles for safety. As the head of our automotive group, Pete directs expert placement in vehicle crash cases.
Robson Forensic employs a team of biomechanical engineers with individual specialties covering a diverse range of topics, including traumatic brain injuries, bone fractures, soft tissue injuries, and failed medical products/implants. Our experts remain active in their fields; many hold, or have held, teaching and/or research positions at highly esteemed universities and research institutions.
Contact the author of this article or submit an inquiry to determine which expert is most appropriate to investigate the technical aspects of your case.
Biomedical Engineer & Biomechanics Expert
Dr. Williams heads the biomechanical engineering practice at Robson Forensic. Her expertise is focused on traumatic brain injury and musculoskeletal biomechanics. Dr. Williams has been qualified to opine on the biomechanical causation of traumatic brain injury in state and federal courts. She has published in peer reviewed journals on topics related to TBI and injury biomechanics.