Traumatic brain injuries

Traumatic brain injuries (TBIs) have been estimated to affect over 2.8 million Americans annually, and can have a profound impact on quality of life, potentially causing changes in mental status and capabilities. However, TBIs are often difficult to objectively prove and are therefore frequently disputed. While the presence of a broken bone, for example, can be proved clearly through common medical imaging techniques, physical evidence indicative of a TBI is generally less well characterized. The experience and knowledge of NBI’s accident reconstruction and biomechanics experts allow us to perform objective analysis to determine what happened during an accident, and its potential to cause a TBI.

TBIs can range from mild (including concussions) to severe, and occur due to an external force or acceleration applied to the head or body. In cases involving a direct head impact, a focused force acts on the skull and brain, often causing localized injury. Exposure to linear acceleration, as caused by sudden speed changes in a motor vehicle accident, may cause motion of the brain within the skull.  Rotational acceleration, often produced by motion of the body relative to that of the head, applies additional shear force to the brain, further increasing the risk of tissue damage. Additionally, in all loading types, there is a potential for the brain to collide with the same or opposite side of the skull as the applied force, producing coup and/or contrecoup injuries, respectively. These loading conditions are commonly experienced in a variety of accidents, particularly falls and motor vehicle collisions. Due to the complex biomechanics of injury production, analysis of TBIs requires the consideration of many accident parameters. NBI’s experts are experienced in a variety of approaches to TBI analysis, and are knowledgeable about the various factors contributing to the production of a TBI.

The fast and sudden nature of many accidents often prevents those involved from recalling exactly what occurred. For example, a person with a suspected TBI may not accurately recall if they impacted their head or how they moved over the course of an accident. To address this uncertainty, NBI’s experts analyze any evidence provided, as well as perform scene and vehicle inspections. With the known accident information and physical evidence, our experts are then able to determine potential accident scenarios and evaluate their likelihood. A reported forehead laceration following a motor vehicle accident, for example, would indicate a direct impact should be included in analysis. Additional analysis techniques, such as helmet testing, may be used to better determine accident conditions if applicable to a case. The varied backgrounds and expertise of our team enable us to provide a detailed analysis of accident conditions, which are then used to assess injury potential.

NBI’s experts use a variety of analysis methods to determine the potential for TBI depending on accident type. In cases where a direct head impact is known or suspected to have occurred, the force and associated accelerations at the head can be calculated based on accident parameters. Additionally, an algorithm developed by our experts, as well as analysis based on existing peer-reviewed work may be used to quantify the linear and rotational accelerations experienced at the head, for comparison to known injury tolerances. The head injury criterion (HIC), a commonly used measure of TBI likelihood due to linear acceleration, may also be calculated if applicable to a given accident. Validated simulation software may also be used to model complex human kinematics throughout an accident, allowing our experts to determine linear and rotational head accelerations through simulation results. Accidents are unique, and this wide range of analysis techniques allows NBI’s experts to approach the conditions of each case individually.

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